Ok, so first time out with mine and a cheap 3x9 mounted and using cheap Monarch steel 145 gr to cycle it in, the gun ran good and killed my shoulder.

Couple of weeks later and here I am with a Magpul stock with PAD and a Tacticool brake installed, using same cheap ammo to sight in new scope.

Gun will not run two rounds without jamming. New round stuck at an angle to chamber , but when it does cycle fully there is no round in the chamber.

I am not sure if it is short or quick cycling? It does pick up a new round mostly, but jams at an angle about half stroke.

It spits the steel out at 90-100 deg at about 8-ft or possibly more, which seems a lot to me, but I am not sure what is normal.

And the only thing dynamically changed is the Brake?

It is lubed up, and I ran a cleaner and boresnake through it after the first 40 rds, using PMAGs 10's, and tried a different one just in case. Same as before.

My thoughts are that the restricted exit orface on the brake may increase gas pressures somehow to cause quick cycling, as it will not pick up the new round at times, possibly wrong?

All works fine charging by hand, which is allways!!!! Either to feed or un lodge angled round.

Thoughts appreciated!

I was going to say magazines, but you've tried more than one. I'm having a hard time believing a brake could cause these malfunctions, but as that's the only thing you've changed I'd recommend taking the brake off and head back to the range with the bare muzzle to see if the problems go away.

The only other thing I can think to try would be a different weight buffer, maybe a heavier one to slow the action down? That's assuming it is cycling too fast. But the brass ejecting at roughly 90 degrees seems to indicate it's not cycling too fast, doesn't it?

__________________
- Fourth Horseman -

You said that you changed the stock to a magpul stock. Did you pull the recoil buffer tube off? Maybe you didn't put it back on properly. It has to be screwed in to the proper length and not too far in. If you did not take the tube off then maybe you need a heavier weight buffer. Also it might help to lube it.

__________________
Tom
NRA Pistol Inst

You'd have to cycle that bolt pretty fast to outrun a good mag. First thing you need to do is get good factory 308 ammo between 150 and 168 grs and see how the rifle runs with that. It sounds like the ammo is underpowered and causing short stroking

Take a look at the casings and see if there are any aggressive extraction marks or unusual side abrasions compared to casings when your rifle was cycling properly .. the aggressive marks could be a sign of fast cycling [bolt carrier set in motion too early while the casing is still at full expansion in the chamber]. If this seems to be the case, add buffer weight.

Also, inspect your bolt & gas components to make sure you do not have any gas leaks or impingements ... in another thread, someone experiencing similar symptoms discovered that their rifle had worn gas rings which were allowing gas to blow by. In that circumstance, replacing the worn rings cured the problem.

No changes to the tube, just a slide on.

[/QUOTE]You'd have to cycle that bolt pretty fast to outrun a good mag. First thing you need to do is get good factory 308 ammo between 150 and 168 grs and see how the rifle runs with that. It sounds like the ammo is underpowered and causing short stroking [QUOTE]

That is what I thought as well and explains no pick-up at times, but how the others are getting lodged at an angle under the bolt is ? Unless it is simply recoil letting them rise and bolt not catching the rear of the case.

Now that I think back, I cannot swear the first 40 rds that ran well were identicle to the last Monarch 145gr. Similar little box, but it is possible they were 150gr Tul or something.

Even with the stock setup and cheap scope and pain flinch, it seemed I was getting better groups first time out at about an inch at 50 yds, better scope, less recoil and I am throwing scattered 1.5 groups without consistency, and I do not think it is me, prolly **** ammo.

None of those signs that I seen, only dings on the cases were from lodging at angle on the ramps. And it is new and has been disassembled , inspected and lubed. I run grease on the carrier, and oil on the bolt to stay wet.

From your description, you're experiencing what is called a "Bolt Over Base" or simply a "bolt over". This happens either when the magazine sits too low, or from short stroking. Since you're using cheap ammo, your problem is most likely short stroking resulting in a bolt over. When the carrier short strokes, the bolt does not come back far enough to catch the rim of the case. However, the body of the case sits high enough to get caught by the bolt and push it partially out of the mag, jamming everything up.

Your problem is from undergassing from underpowered ammo or there is a gas leak and/or a blockage in the gas system. Switch to quality made standard velocity 308 ammo with a bullet weight of 150-168 grains and see if the problem persists. Troubleshoot one thing at a time and start with the simplest solution

@CopeMech, I had a very similar problem with my MP 10 when I first bought it. It caused me all kinds of headaches and I finally sent it back to the factory for repairs. All they would tell me is that they replaced the mag and repaired the barrel.
When I had the problem of not ejecting, the rounds would get jammed half way between the chamber and the mag. The rounds would also get long scratches on the brass and dents in the shoulders from the bolt carrier group.
My suspicion is that it's the steel mags that I was using too along with needing the feed ramp smoothed. However, I'm not a gunsmith and I'm new to ARs. I bought a S&W MP 15/22 and any time I use the factory mag with it, the gun jams because of the mag. If I use after market mags, the gun works fine. I have only used factory ammo from Federal in the MP 10 and I was using Remmington factory ammo for the MP 15/22.
The link to a previous thread that I talked about on is:New m&p10 cycling issue

QUOTE: 'You'd have to cycle that bolt pretty fast to outrun a good mag. First thing you need to do is get good factory 308 ammo between 150 and 168 grs and see how the rifle runs with that. It sounds like the ammo is underpowered and causing short stroking' Let's not forget for one second that many, MANY brand new M&P 10's have had a slew of feed issues. They are a particularly picky rifle in many cases.
After working over a good 15 of these for guys now, my recommendation is that if the rifle worked fine with the stock muzzle flash hider, reinstall it and try the rifle.

If it works fine, then try it with a minimum of 3 manufacturers' ammo. If it will run them all without issue, then the rifle is well set up with that combination.
At that point, if you wish to run the muzzle break, you will likely need to look to altering the buffer weight to absorb more of the increased back pressure. OR, install an adjustable gas block so you can get the rifle to deliver acceptable gas amounts.

If the rifle does not like multiple types of ammo, then you are best off to plan on tuning the rifle until it does accept different ammo types. You can do this in conjunction with the brake, work on buffer weight or an adjustable gas block.

Your AMMO is not the culprit here: You have stated that the rifle is ejecting some-odd 8feet away. There is PLENTY of force to stroke the bolt back fully with that much ejection force. Your bolt is moving too fast with the current setup, plain and simple.

90-100 degrees is ideal, and an ejection of 8ft. or more indicates a LOT of pressure being delivered to the bolt for cycling the next round.
You are correct on both fronts.

Now; FWIW, my rifle will run a magazine with 4-5 different types of ammo in it all mixed up, and it does not flinch when it comes to cycling that ammo. When set up properly, this ammo speculation becomes a pure myth. In most cases where a rifle has issues not cycling the bolt fully, the rifle is under-gassed via a small gas port opening, or a restriction via the gas block not being placed properly over the gas port.
Also; if the magazines were functioning perfectly well on day 1, there is pretty much ZERO chance they are now suddenly not seating properly into the rifle. A magazine issue tends to manifest itself immediately if the seating height is the problem. Most magazine issues come from wear and tear, and it is usually a grimy/ worn follower that is the problem, regardless of whether it's a rifle or pistol.

I appreciate your and all elses comments and suggestions. As you have read into this the potential for my confusion, as I seemed to get good ejection, however through the course of this, several items got brought up here and by a friend who is an AR nut.

Obviously cheap ammo, but these were indeed 145gr, and with a potentially pickey gun to begin with, well?

Then the potential of the bolt literally dragging the case halfway in on a short stroke, as the edges are sharp enough to catch and drag, and the bolt was not but halfway up the case on a jamb.

Another point made was if the bolt locked back on last round, answer, not that I recall, yet possibly half the time with the first batch, yet I did not think too much of it at the time.

Although I totally dislike overly pickey guns, I do totally understand the necessity for an auto action to run within some standards of pressures and such. As stated, I shall try to establish a new baseline here, as Wally World had some ammo today at a somewhat reasonable cost of $18 per box from some ferign company called Reminton or something like that, came in a green box that said a bunch of stuff, but basically 150gr soft points. I figure that would be about as close to a standard charge as you would find without going to heavier weight. Gas pressures should be ok as a baseline. And if nothing else I can keep the brass!

At the price of $30-40 a box, some of that stuff is just nuts!

I did not expect perfection, just want to run -in the gun, so I am still ok, we shall see how it does next time out.

ps- the old rcbs press may have to come out of the closet, as I do have methods to make the machine cycle if need be!

To the sections in bold: The bolt drags when going FORWARD at ultra high speed, and it leaves no mark on the back 1/4 of the round in general because the bolt rebounds so quickly that it starts to pass the bullet rim before the magazine spring has pushed the round into position.
IF a rifle FTE (Fails to Eject) it is oft due to low powered ammunition. And, the drag mark is VERY DIFFERENT: The drag mark goes from front to back, not back to front. The spent brass is usually on the ground right next to you, or hung up inside, cockeyed and oft stuck in the ejection port sideways.
(Look for a metal curl or a stop edge on the scratch in the brass. It's usually there to tell you which way the bolt is actually dragging. You will likely need a magnifying glass)
A bolt which hits the new bullet going really fast where the bullet has not fully risen into position will drive the round cockeyed because the bullet is still feeding UP as it is snagged from behind by the bolt and driven at a slightly off angle feed. With the 223/ 556, the round is smaller, and it seems to affect that caliber much less overall. (The feed ramps are larger by percentage, and angle of feed seems to be a bit better at really high feed speeds.) With 308, and especially with soft tipped ammo, it is more of a potential issue.

I hope I have explained a bit better for you the how and why of the rifles' feed issues. Definitely NOT an issue only visited by S&W's 308 platform.

As to pressure standards, this weekend I shot Wolf/ WPA. German 7.62 surplus....circa 1953, US surplus 7.62, circa 1958, Federal soft points, some reloads from the gun show, and some CBC M80 ball, specifically because there were several guys HERE who were upset with the ammo in their rifle. 250ish rounds later, and not one issue. The closest to a **** was the gun show reloads. One would have the powder of a 308. The next had the powder of maybe a blackpowder rifle, or a 223..... and then the next round would have a 30-06 powder charge in it (seemed like it) Even with that junk, the rifle chugged along without complaints.

What I am saying is; the rifles are already mildly over-gassed to cope with lower power ammo. The muzzle break probably enhanced that situation.

The FTE is a result of too little backpressure. One of four things: Weak ammo. The gas port is too small or blocked. The rifle is so filthy that the gas tube is clogged. The gas tube is kinked or pinched.
My guess is #2. Gas port was drilled a little on the small side, or the gas port was blocked by a slightly off set gas block. Fixed rather quickly when the rifle was inspected and torn down.

Your post helps to highlight the differences in issues with the gas cycle problems

I forgot to mention that the mags supplied by S&W are not worth keeping. I retired the 10 rounder that came with mine as soon as I could get PMag replacements. Most experienced shooters do. The factory 10 rounder was rough, hard to load and has sticky feed.

There is underpowered 308 ammo out there. I got a lot of CAVIM that would not cycle the action. Had to manually cycle the rifle after each shot even from the PMags. Switch to commercial ammo fixed that.

The last thing I'd reccommend with the M&P-10 is opening up the gas port. Once you do, there's no going back. The recoil of mine is sharp enough to tell me that opening the gas port would likely be a mistake. First, I'm going to see how it shoots with the BABC, then experiment with the buffer weight & action spring. Not because I'm having trouble with short stroking but because recoil is a bit sharp.

It's popular to blame bolt overs on high carrier speeds and attempt to fix the problem with heavier buffers & springs. But, in tracking posts about bolt overs, every one has been fixed by solving short stroking, not slowing down the carrier. The exception has been when the problem was traced to a bad magazine

Since the M&P10 has come out, I have now fixed feed issues on 13 of them. A few went back to the factory. All the ones we tuned will take about any ammo and work with any magazine that fits the DPMS profile magazine/ LR308 magazines.

90% of the rifles have the same issue. The bolt simply moves very fast, and the bolt is ABSOLUTELY recoiling completely and ejecting ammo rather well. (Average ejection is 6-8ft! and at the shooters' 4-5o'clock) The issue is to slow down the recoil, and more importantly, to increase dwell time. Regardless of the bolt weight combination, if there is not sufficient dwell time for the round to rise? The bolt will ride over the round consistently.

If you decide to use the search feature here in this sub forum..... you will see that for over a year now, I have been helping people get these rifles sorted out.
And you'll find that after we posted our findings HERE.....S&W came out with some materials to correct these feed issues with their rifles. (Yes- they read the forum. ) You can guess at what they have found and how they have been modifying the rifles to get them to feed better......

If you feel that the felt recoil of the rifle tells you there is plenty enough pressure that there is no need to open the gas port, then it would be IMPOSSIBLE to say the rifle is short stroking.
My suggestion is directly aimed at the possibility of having a rifle that has 3 likely possible issues-1. Gas block not seated correctly and blocking port partially. 2. Filthy rifle. And lastly, 3. Gas port was drilled too small. If you are wondering how this can happen? Drill bits break in a machine shop..... and it does happen. 1 of the 13 rifles I have torn down and had to rework had this issue. Sized the port up and it was remedied. It IS the last resort, I agree with you on that.

I'll stand on the dozen or so posts already made on this subject in here, and the consistent fixes to the rifle that are pretty much universally the same.

Yes, I think that is kinda where I am at with this so far, as the mags were p-mag 10's for the sake of shortness at the range I think they should be fine.

And your exact comments are what still concerns me, and as this one was bought new in December, I would think it may have production mods performed as a later build.

As I am not sure of things, all I can tell is on the second outing it was much more tolerable to shoot(no bruises) with the butt pad and the brake installed, yet it would still hop off target sitting on the bi-pod, so must re-acquire sight picture. Still slinging out the steel case for quite a distance!

I am not sure if fast action can/ will also over ride the stop on last round, yet same principles apply.

Gas block seating? I am not exactly sure how to test it. I had read something about using compressed air to flow ck, yet I have no ref on this.

Not dirty, it is new! I looked at it after first 40 with a buddy that knows about this stuff, bolt was clean, add comments about cheap being dirty, wiped things, sprayed cleaner in the bore and chamber, let sit a sec, then pushed some CLP in the bore and ran snake through twice, reassembled. Bolt still well greased and oiled.

I guess I could allways knock off the gas block just to look at things if I had measures, but I would need educated on proper alignment upon reassembly.

Will set baseline with the Rem ammo, should not take 40 to find out!

I would find other suggestions of buffer/ springs of interest if need be.

Okay, I can give hints and helps!
1. The rifle will ALWAYS jump off the sight picture, unless you weigh it down a metric ton or so. The AR recoils in BOTH directions, every shot. A kick back, followed by a slam forward. Much more noticeable on the 308 than the 223, especially with a carbine style rifle weighing in under 9lb.
We have a 24" barreled rifle (Tims', not mine) and it weighs in at a svelte 14.5lb. Barrel is 1" diameter, fore grip is extra heavy, the A2 stock has weight in it, and the bipod is very heavy for what it is. This one hardly moves when you shoot it. The gas block is adjustable, and the recoil spring was chosen for the softest one that would function the rifle. His wife likes to shoot it because it does not get 'upset' as she put it.

When the rifle is operating- it moves about 4 times as fast as you can humanly pull the trigger a second time. If the 308AR were a full auto rifle, it would easily cycle in the 400-500 rounds/ minute range without breaking a sweat. No human outruns the bullet, on either side of the bullet!!

Yes indeed, when the bolt is moving that fast, it can easily blow right past the magazine follower and not stop on the last round hold open. That is in fact a good indicator that the bolt is moving very fast, and more importantly, there is not enough DWELL TIME. Dwell time is where the bolt is basically stopped for a nanosecond at the peak of the recoil before it starts pushing forward.
Your gas block is set correctly..... the rifle was functioning well. That tells you the story. An easy way to see if the block is offset is to take an air nozzle and a cotton ball.
Open the rifle up.
Lightly oil the cotton ball and stuff it into the chamber.
Air nozzle goes onto the gas tube. Lightly blow air into the tube, no need to blast it. 5-10psi is plenty. Feel the air at the front of the barrel. If you have very, very little air? The gas block might be offset, or the gas port might have a blockage. If so...... crank the air up to 60 and see what you get. You will not hurt the rifle.
An easy way to tell if the gas block is leaking and letting out excessive pressure (venting) is to spray soapy water on the gas block while doing the air nozzle job with relatively low pressure. Should not see much in the way of bubbles, at 60psi. If the leakage is really bad, you will see powder dust all over the gas block and the port where the gas tube enters the gas block.
It should be noted that a little gas venting is not bad. The rifle will expand and seal things as the barrel gets heated up and the gas tube will seal with the pressures created from firing. 60psi is nothing compared to the pressure developed by the powder being burned in the chamber.

Rifle is clean, I believe you. Saying 'Filthy rifle' is only a reference point. People seem to like to shoot 10K rounds thru their rifle without cleaning..... just to prove it can get dirty. Some relish in dusting them out, or dropping them in mud, etc.

If the rifle performs well with the brake removed still, then the easy and cheap modification is to start by adding weight into the buffer tube and try the rifle with the brake installed. The buffer has weights inside it. Add some more weight, and keep track of what you have added, so you can always go right back to stock as a reference point.

rojodiablo, thanks for defining what you mean by "dwell time". Your definition doesn't match what is generally meant on other sites. (Of course, I realize that dwell time can apply to many situations.)

I'm coming at this from the perspective of the small AR so please bear with me. I've heard many times about bolts out running mags but have seen no hard data to support the claims. In the past, with the little ARs, the bolt overs have been solved by eliminating short stroking. Not saying this to disccredit your experience, far from it. Making this statement to let you know what my experience has been and that it's not been much with the Big Smith. I figured being the same basic system, the same basic troubleshooting was a good place to start. In fact, this is the first place I've heard of the M&P-10s having problems.

I'm not surprised to learn gas port diameters are varying. I know from first hand experience that hole diameters can vary with something as simple as a change in drill pressure. Sometimes the flutes will collapse with too much feed & speed, especially with reamers and the holes come out smaller. We also found out that reamers will open up their holes too big when they heat up due to stresses in the metal from cutting the flutes. When trying to eliminate hole quality problems at McDonnell-Douglas/Boeing, we made a few discoveries about bits and hole quality.

I'll search your posts and read them

MistWolf; the rifles are... the same.

Or- in THEORY, they are the same!! But in reality, the 308 platform is not just a larger brother. It's a bit different.
Weak ammo can affect the 15 platform because their is a lot of interchangeability with buffers, springs, gas lengths. A rifle of mixed parts very well might run fine with strong ammo, yet malfunction on weaker ammo ruthlessly. Usually it's tied to a mismatch of parts; a mid length buffer on a rifle spring, or a carbine with a lighter BCG, and it is then sensitive to ammo. So many people, sub-contracted out parts supplied to manufacturers that things get mixed up easily. Weird thing is, many times, they will still work.

On the 308 platform, no 2 manufacturers are alike. Too many proprietary platforms, and it makes customizing more of a challenge in some ways. The problem is, with proprietary stuff, the spring, muzzle break, gas block that works perfectly well on brand A makes brand B act up and it suddenly will not function as well as brand A, or as it did before it was modified.

AR15's are much better in this respect. Spikes barrel on a Colt rifle with a DPMS trigger works just fine if that it how it gets set up.

You will be the first guy I call when I have the itch to make a titanium barrel........ (Never. EVER going to happen. Not by me. And I'll let you explain to the folks why a Ti barrel would not be an easy thing to create!!)

There must be a good reason or it would be done by now!

I did speak with S&W tech rep today just to ask if there was anything new as far as updates or changes with these issues, he said no, but if it will not run after further testing with standard factory ammo and reinstall of flash hider, send it in!

Reviewing the muzz brake install in my head, I cannot quite get my head around a major change in dynamics here, as X pressures and Y lengths would be unchanged.

I did review some buffer options today, they all make great claims, and the weights seem all over the board to me, then you get into springs!

All this is fun and all that, but I shall not be spending tons on experimental combinations to find a working solution to cover a broad range of ammo. All within reason, cause cheap **** is still get what you pay for to a given extent. It may work fine in a bolt gun.

Not to step on the toes of the Red Devil, but I suggest returning everything back to stock and seeing how the rifle works with factory ammo. It doesn't have to be anything special, just ammo loaded to normal pressure. I'm pretty sure Winchester white box would be good to start. If you still have short stroking, then you know it's not ammo. You have to establish a baseline of performance to troubleshoot your problem.

The truth about any self loading rifle is that you have a narrower range of ammo that it will function with reliably than with a manually operated repeater.

Rojo, deep boring drilling is beyond me. We were just trying to figure out how to drill holes clean & round in the aluminum and aluminum & titanium stack up of the structure of the then new MD-11. One type of fastener required an interference fit and had to be driven in with a rivit gun. Hole tolerence was .185"-.187" and had to be drilled with a pneumatic hand drill

Range update. So I took it out today with the factory Rem 150, Monarch 150, and Tul 150, later two being steel.

Gun ran ok, ran 3-4 rd groups, had last round lockback issues with both steel(cheap)rounds while Rem worked well, and a soft point it was. Made no difference switching between brake and stock flash hider.

Still pitches cases a long way, and I did notice a couple things today, as the brass ammo did have a couple sharp edge scratches on the neck from the ramps, but also a nick or sharp edge mark in the bottom apparently from the ejector hitting.
Not sure if this is any indication? As I think it is still a bit "on the edge" and perhaps the heavier buffer is the key?

Brakdown after revealed a 2.96oz buffer weight(say 3 oz). It rattles a bit so I decided to take it down to see what is in there or if weight could be added. Well, I had a time getting the plug out, found three steel weights with pads with no room to add more it seems. Possibly remove steel for lead it it were the correct size, or just fill with shot or something? Totally unsure here.

Did see brass mark on the ejection port hump today, yet no case dings, once again, not sure about indications here.

So as things go, gun is working, and now down for trigger work as well. That creep just creeps me out! We shall see if we can go from a long 5 to a short 3.0 or so!

Rojodiablo,

I have found and read a few of your comments on similar threads, and we kinda think alike it seems.

I have still seen no specific recommendations for the M&P from you.

So based upon what I have read, this 3.0 oz buffer would be like standard AR carbine issue, and an H or H2 buffer at 3.8 or 4.6 oz may be called for.

Having read some reports on the standard 223 gun, even them guys often say the H2 is the way to go, and as I have no tungsten nuggets in my pocket, I will likely have to buy something as I am totally out of depleted uranium at the moment.

Suggestions?

Trade the steel ball out for a round lead fishing weight of the same diameter. It's a little bit heavier, and often the difference can be less than a half ounce when the rifle is close to ideal. If they rattle, you can add cotton ball material to fill the voids. If you want a bit more weight, #8 or 9 shot from a shotgun shell and that makes a great buffer material that adds weight. I have found in general that adding around 1/4-3/8oz. tends to be the little bit that takes the speed down just enough.

On the brass dragging; A good little trick to see just where the brass is getting scratched is to do THIS:

Insert a round into the chamber with the bolt open, and directly on the side facing you right where the extractor will grab the brass, take a sharpie pen and put a mark on the brass.
This will tell you exactly how the brass sits, and by simply looking at the brass after firing, you will know what is scratching your brass, as well as see what if any mark is made by the extractor.
or, load a magazine with the rounds, and on each round put a mark which will be on top. The bullets do not rotate much at all when being fed into battery, and you can wail away on a mag and then investigate and compare brass.
This can be really helpful when you find one mfg. has an ammo which gives you a different looking scratch, or feeds a little different, etc.

If you feel the ammo is scratching from the feed, it's pretty easy to figure out: Load a mag, with the top round marked as described. Pull the charging handle back all the way, and let it fly closed.
Now, do not fire the gun, just extract it ssllowwly. This will keep you from scratching on the extraction.
If the brass comes out clean, then you might be scraping on the extraction and not the feed. Remember, the feed speed IS the same when you drop the charging handle if you are full back and you truly just let it go as when a round is fired.

Extraction...... there is no way we can extract a round quick enough to emulate the rifle functioning a firing cycle. So this is how you can find that particular difference.

If the round IS indeed scraping the brass on the feed ramp, then it's kind of a witch doctor thing to start playing with it. Anything you take off..... can not be put back on.
Polishing the feed ramps was a very common thing years ago before M4 feed ramps were the norm. I am impartial to rubberized wheels which polish and take very minimal material off. Second choice is cotton buff wheels and rubbing compound or black beauty polishing compound. Last choice ever is files and sand paper. On the old rifles, we used to use silica wheels and would real carefully polish the transition from aluminum to steel, and widen the bottoms of the feed ramps. (I'd get all anal-retentive and make them tapered and BS.... but the factory version we have today is just as good, if not even better.)
Feed ramps will smooth out and self polish..... after lots of cycles of ammo thru them.
A dremel and small cotton wheels and polishing compound/ automotive rubbing compound can make a ramp edge slick in a few seconds time. TREAD CAREFULLY. A little can be a LOT. A pinky finger feeling for a hanging edge should be enough to feel the difference. A TINY improvement in felt smoothness will translate into a MUCH better feed, similar to how a little elbow grease and love can transform a trigger in a matter of 5 seconds on each contact face.

But yeah, it can make a magazine which feeds so-so become a Lancer plated in gold, if that was a problem for the rifle.

You indeed hit the nail on the head. A machinist friend of mine makes a lot of car parts from Ti. I asked him if he could actually make a barrel out of Ti. He laughed at me, and told me to hand drill a chunk with a 1/4" bit a distance of 2". Welllll........ I hung that bit 4 out of 4 tries. In a drill press, I hung 2 out of 4 tries. The only Ti I had ever drilled previous was maybe 1/8" -1/4" thick. I had no idea how bad it grabbed on drill bits. He said a 20" barrel run would be one VERY complicated task, and the sheer cost of the experiment of getting it right would run several thousand in mistakes. (Maybe he tried it and was just letting me know how bad it was...??!!)

He then told me "If you want a really nice barrel, just buy one."

I would suppose your .02 tolerance was enough to make one or two of your crew VERY particular and VERY GOOD hole drillers!!

Copemech, I have a spare 4.5ish oz carbine buffer I will mail to you to see if it works as a solution. If interested, shoot me a shipping address through private messenging.

Thanks for the offer, however in the past week or so and the absence of further comments from others here, I did order an H2 buffer which should be 4.5 ish to try. And if for some reason too much I can now swap out tungsten for steel to take it down to an H 3.8 or so.

In other AR threads I have read that the H2 does help with felt recoil(which I have a lot), so we shall see.

Rojo, thanks for the long reply. At least I am now fairly sure the gun will run as of the last tests using even the steel case 150. Last round lockback with it not withstanding.

I can live with the two scratches from sharp feed ramp edges on the necks, minnow and I would not condemn the cases as unusable because of it, however I hope they wear in.

It still kicks like a mule and spits brass like watermelon seeds, so all good. I did pick up another box of the cheap 145 Monarch just for testing again with heavy buffer.

In the eventuality of things I may need to settle things with some 168gr decent ammo, but that does not mean I do not want it to feed whatever I put into it within limits.

Thus far I have not impressed myself with accuracy, and even though I have not taken it beyond 50yds, the combo of cheap ammo and me flinching has been an issue. 1.5 - 2.0 or so groups, not great at that range. My 10/22 will beat that, but it is easier to shoot!

Trigger on its way, so hope to re-test soon!

Thanks all!

Good luck sir. There are a good number of folks on the board watching and rooting for your solution.


AP


License to kill gophers by the government of the United Nations. Man, free to kill gophers at will. To kill, you must know your enemy, and in this case my enemy is a varmint. And a varmint will never quit - ever. They're like the Viet Cong - Varmint Cong. So you have to fall back on superior intelligence and superior ... M&P 10 ... firepower. And that's all she wrote. -- Carl Spackler

Copemech, I am curious about your feeling that the 308AR has a lot of recoil. A couple questions:

Do you have/ shoot any other equal or heavier calibers; ie 30-06 or 7mm mag, etc?

Do you feel the rifle's recoil is bringing on a flinch due to a trigger issue- like say it's grabby, or feels sloppy, or it feels like you need to hit it with a truck to get the trigger to move?

And, does the recoil bother you due to the kick, or is it the rifle bucking back and forth from the bolt movement?

I ask because the 308 is a fairly mild round to shoot. And in a semi, the recoil is usually buffered a bit and lessened. The one difference I see is the bolt assembly and action; a shooter with even an ultralight SOCOM 308 will not feel the bolt's action upsets the shooting, while many feel the 308AR jolts around a lot. A lot more forward reaction from the bolt assembly.
You'd not be the first with that complaint; it's one of the things guys sometimes ask me to help eliminate. (About doubling the rifles' weight tends to do the job..... but kiss goodbye any thoughts of mobility once it starts weighing in at 12-14lb......) The new trigger might make you happier with the rifle and help tighten up your groups.

Rojo,
It has been many years since I have shot .308 and -06 in bolt guns. I originally figured the 10 would be a bit more than my old 15, and dampened a bit by the action, but combo of the larger round and factory hard plastic stock took its toll! Better now with the padded stock, break, and a couple pounds worth of scope and bipod mounted! No bruise!

Friend at work just scoped his big DPMS and took it out last weekend. Said he found himself closing his eyes in anticipation of pain when pulling the long creepy trigger! I just laughed! And he is a big boy!

I bought the Smith because of its light weight and I am no pack mule! Everything is a tradeoff, seems I just need to figure out what it will do, and I still like to keep range ammo on the cheap side, but in the end if I can pound out 6" groups with this thing at around 300 yds, I will be happy and call that a dead hog!

I am spoiled with short sweet triggers so that will help. My test with/without the Tacticool break installed revealed little difference in recoil, I think it may be more a compensator by design, and am still looking at other recoil reduction options like the JP.

AR recoil is definitely different than bolt rifle recoil.

I'm pretty used to heavy hitters, so I don't even notice the 308AR, other than it will always bug me that the rifle wants to kick forward as well as backwards............

I have had my M&P-10 a couple of months and I did not really like the recoil either.
I bought the THE MAKO GROUP - AR15/M16 RECOIL REDUCING STOCK from Brownells and love it. it was a little stiff at first but has softened up nicely and I can shoot all day with no issue.
I also added the JP silent spring buffer. Be sure to get the one for .308 as the AR-15 one says it works for some AR-10 but it does not. You will need to add a piece of the included spacer material but it is easy to cut with a tubing cutter.
Another thing I did was swap the stock compensator (which worked pretty well in my opinion) for a Battlecomp which is amazingly effective at reducing muzzle rise. I don't think it did anything for the recoil but I couldn't swear to it.
I changed the hand guard for the 9" magpul. This requires the tool for compressing the delta ring (you cannot do it without it) but it went on with no filing, cutting or alteration. I did need to use a plastic hammer to encourage it initially but have since taken it off and put it back on and it went much easier. (Tip; put the rail sections on before you install the hand guard.. DOH).
I have run mil-surp, LAX reloads, GGG, and berdan primed 7.62 through the gun and it loves it all.
I really like this gun.

Lief,

Congrats, followed your path as well to reduce recoil, follow-up shots were terrible in stock, but after the Battelcomp (it even reduced sound at least to the shooter), heavier handguard, and yet to test the JP captured spring and Magpul UBR.. the Beast is tamed. I had the MAKO stock but frankly did not notice any reduction in recoil and the thing rattled so I was not really impressed, please post pics.

When I put the PRS stock on my M&P10, I also picked up a Zel Custom Tactilite buttstock pad adapter which uses a Pachmayr Premium Large Field Pad. Although the adapter and pad set is very heavy (which isn't a bad thing unless you're toting the rifle several miles on a sling), it adds a surprising level of ergonomics and comfort in shooting the rifle. I have bad arthritis in my shoulders, and after 200 consecutive shots through the rifle within an hour, my shoulder felt like I had been shooting a BB gun the whole hour.

Pics as requested, Sonny Gunny.

I forgot about the MOE grip and the 2-7 Redfield in my description. I had that M-223 mount from a previous rifle and it is working very well for me here.

I hadn't really noticed that the Mako rattled and in fact mine rattles less than the stock adjustable. Mine does work as advertised though.

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Lief,

Nice one, I see you live in Commiefornia‎... bullet button bull

As an update, no trigger group yet, things running behind and I cannot eve strip out my old AR15 group because of pin size so have to sit and wait, and such is life!

Range update as of today was a bit mixed! After setting trigger back from Bill Springfield, it works better, but the gun was still iffy with the H2 buffer.

Took 4 types of ammo and intentionally picked up a pack of the original offender Monarch 145gr(steel) which would not cycle. Ran 20rds.

It actually worked pretty well with occasional failure to lock back last round.

I bought TULA steel 150, it SUCKED! Out of 20 rds, 4 dead primers, two bolt overrides, 2 failures to feed(no pick-up). Found cases next to me. at times. That is the **** because I have another 4 boxes of this stuff at ten bucks each!

Monarch 150 Brass soft point ran well, no issues using two at a time, only used ten within the group test. Saved the rest for later.

Remington 150 core lock works as well as before, with no issues.

Grouping still an issue, seems some of it shoots high and some low, with the Rem being most consistent thus far, yet I cannot dial it in because of a 2" spread at 50 yds. I have not bothered going to 100. The Rem seems to perform within 1" or so at this range, so a 2" at 100 may be workable with it, time will tell.

But for now, and given results, I am wondering if I should try the H3 buffer, or just try and stick with brass, which seems to work.

Btw, casings seemed to fall in a 6-8 ft range today, with exception of the suspect shortstrokes and FTF which were nearby. I consider this more normal but input from others appreciated.

My guess is your buffer is too heavy. I tried German milsurp in mine and needed to run a carbine buffer. Even the H buffer gave me short stroking. I haven't had the chance to try commercial ammo yet

The Enidine buffer I am using weighs 6oz. I had to increase the gas port diameter slightly to eliminate the short cycling.

Im sorry your having trouble. That sucks no doubt, I've been there too. I shot some .308 Tula this month and was blow away by the accuracy at 200 yards, but I'm shooting another brand of ar-10 platform. Hope you get it figured out, if not, sell it and get something else. I became so frustrated I did. My only regret is not doing it sooner. The .308 i ended up with will cycle any .308 or 7.62x51 i put in it. Even the CBC NATO stuff my M&P hated.

Well you see there within lies the issue. People want to run whatever they want through these high strung guns! And you admit you have not even tried any standard US made ammo!

I get back to what the fellow a S&W told me, if you send it in and we run it fine on standard US ammo, we are sending it back!

OK, fair enough, no hiccups as yet with standard brass, US or otherwise. I have to run race gas in my bike too! Just a given.

Yes , I am still cheap! But not that cheap.

Time will tell what the racehorse will feed upon and what it will not. Biggest issue with the Tula was the primers, sorry but they sucked!

So, funny you are still here in this thread, what magic combo is in your gun?

You are fighting one end against the other it sounds to me!

Where is Rojo when you need him!

Well, knock on wood, the rifle is in check and has run great for just over 1200 rounds since the last gas system mods in early December.

Factory spring rate, bcg weight, and port diameter are never perfect. Instead they are averaged not matched. You should only attempt to mess with one variable at a time to fix these issues. the spring is the easiest to change/modify without serious cost or serious consequences to the gun.

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