My M40A1-ish Attempt

[Mexican Kerry]

Just getting started, its not going to be an accurate clone down to the last detail. Starting with a Rem .308 Varmint, and mounted the USO on a Leupold base. Heavy bugger, but I knew it wouldn't be a lightweight.

Trying to source out a McMillan stock for it to round things out, but going to see what I can do with it in the meantime.

Hoping its a fun way to get myself into shooting a little further out than I'm used to.

 

[SPEEDGUNNER]

Is that a real Unertl? CMP purchase?

 

[Mexican Kerry]

No, its a newer US Optics. Found it on consignment at an outdoor store, but like new condition near as I can tell.

 

[Ivan the Butcher]

Looks like fun! The 168 grain Match ammo's groups start falling apart around 700 yards. 175 SMK's are pretty good to 1200 yards or so.

155 grain Sierra Palma bullets over 47 grains of Varget powder should do 2900 out of a 24" barrel. It is suppose to be good for a mile, but I've only been to 1100 yards (1000 meters) with that load (from Hodgdon's yearly loading magazines!). At that distance you should get 1/2 MOA groups (5.5") or even a little better!

Ivan

 

[WR Moore]

I settled on the 155 Palmas (old style) a long time ago. Less recoil, nearly the same wind drift as the 175's and a whole lot less drop. I was getting 2850 f/s, it would drop sub sonic somewhere past 1000 yards. I gotta doubt the mile with accuracy.

Hope you got the manual for that scope and the tool to set parallax.

 

[Mexican Kerry]

I didn't get the manual, but it did come with the tool. I've been scouring the internet for info on setup/use of the scope, and collecting everything I find. I'm going to stick with 175 SMK (2600 +/-) for now, as the majority of what I've read states the scope is basically setup for this cartridge alone. I know there's a significant cost, but at this time I'm going stick with store-bought ammunition, simply because I have enough on the go without diving into load development etc. Down the road I may entertain loading myself, but I can't do it right now. Trying to learn too many things at once tends to push some of my old retained knowledge out!

I'm going to try out the factory barrel and see what kind of results I can get before I worry about an aftermarket replacement. If I end up going down that road I'll likely look at an option that gives me a more "correct" barrel. This is simply a 26" Remington varmint, upgrading is always a possibility later on.

I would only be fooling myself thinking that I can take this rifle out and perfect 800-1000 yd shooting in a couple afternoons.

The majority of my rifle shooting has been under 400 yds, I need to take it slow and improve THAT before I worry about beyond. But that is my end goal.

Figuring out the scope come-ups, the characteristics of this cartridge at various distances, wind (when I eventually do push my targets further out), etc are all new to me, but I'm looking forward to the challenge.

A fellow on another forum sent me the charts for the Unertl 10x, which should give me two things, a template for documenting my progress, and a rough baseline for how this optic should work. I realize the USO is slightly different than the Unertl but I'm hoping the principle is transferable.

 

[Wise_A]

Sweet thread, going to enjoy following along, have all my likes. I'll be throwing a whole bunch of stuff at my own 700 Varmint (in .223) later this month. Out of the box--plastic stock, Chinesium scope, and me having maybe 50 rounds of rifle experience--it's already produced a couple nice sub-1" groups, so I'm already quite pleased.

 

[WR Moore]

My Remy factory barrel does 1/2 MOA. YMMV. For factory ammo, Black Hills rocks.

SFAIK, the scope design predated the 175 gr SMK. There was, however, a 173 gr bullet loaded by the arsenals in a match load (originally in the .30-06, carried over to the 7.62x51 mm round) and frequently used for sniping. It was nothing like the SMK, having a prominent flat meplat at the tip. The 175 gr SMK was developed due to the shortcomings of the 168 gr SMK, which was designed as a 300 yard bullet. It didn't stay supersonic beyond about 850-900 meters and lost accuracy during sub-sonic transition.

The scope has 1 MOA (1.047 in at 100 yards and yes, that 0.047 adds up way out yonder) increments, stopping half way gives you about 1/2 MOA. Users were expected to learn the drop/range figures for the ammo in use, so the scope really isn't "set up" for anything. Users kept a data book recording the actual corrections for that rifle/scope for various ammunition/range/conditions. The mil-dots are one mil apart, center to center and, if oblong, are 1/4 mil long. A mil is about 3.6 in/3.4 moa at 100 yards, 7.2 in/6.8 moa at 200, etc. You use them for range estimation and hold offs.

If rusty memory is correct, the parallax was expected to be set at 300 meters for all around use. Depending upon need, it could be set otherwise. Given the purpose of the scope, minor errors in parallax that would drive an across the course competitor mad were't all that important. I believe, but don't know, the tool operates something at the objective end of the scope. (Moves objective lens assembly in/out?) Again, if rusty memory serves, windage adjustments don't amount to much. [ Make sure your reticule is centered before mounting and bore sight as close to dead on as possible.] Once the rifle was zero'd the rifleman was expected to use hold off to compensate for wind.

There are any number of books out there about competition shooting that might benefit you way out yonder. I'd suggest starting with the 3 book set by Jim Owens-one of which is titled "Sight Alignment, Trigger Control and The Big Lie". Another deals with reading the wind-shooting to 600 or so yards is a science. Beyond that, due to wind and atmospheric issues, it's a craft. If you search his name, the books show up on Amazon. There are several places that specialize in stuff for long range shooting, unfortunately, I can't recall them at this time.

For specific information, you might search for the following USMC publications:
Operation and Maintenance, Rifle, Sniper, M40A1 and Related Optical Equipment, TM 0539-13&P/1 and M40A1 Sniper Rifle 7.62 mm, FMFRP 0-11A.

There is a 4 volume history of the program by Norman Chandler of Iron Brigade Armory, who also may be a direct source of information.

 

[Ivan the Butcher]

Since you plan on using 175 SMK's, I checked my stash of M-118 173 gr. Match. The speed is 2550fps. If you find some, don't worry about the Meplat being flat. I shot about 2000 rounds out of my Remington 700 PSP and they were fantastic (I still have 500 of the same lot from 1968) Yes, the 175 SMK is a little higher BC, but until you get past 350-400 yards (depends on the individual rifle) you probably won't be much difference for your scope's dope between the two!

Don't worry about shooting any 7.62x51 LC Match in your rifle. Non of it was ever corrosive primed. All US military ammo is intended to be good for 75 years. I've shot 100 year old 30-06 and 125 year old 45-70 and never had a misfire! (but I had to scrub with the stinky bore cleaner!)

There is another ammo you might be interested in for practice. There is a 168 grain Special Ball (also M-118 or also XM-118) for sniper use in the 70's. My cans of it had a FMJ 168 gr "Ball" and were at 2650fps. The projectiles were better than machine gun ammo but not really match quality. Many men on Army NG rifle teams were issued this ammo in the late 80's and some serious shooters would pull the bullet and load a 168 SMK over the same powder/primer. There was a derogatory name for it but it got the better than average shooters higher scores (until they could get REAL handloaded Match ammo!) It was engineered for M-14 platforms, but worked fine in bolt guns. (My HK-91 thought highly of it too!).

Ivan

 

[Mexican Kerry]

I sure appreciate the insight, everything I "know" about this scope is simply what I've read . I'm definitely open to suggestions/corrections from those who have more experience.

I understand that results will vary and I expect my particular setup will be no different. I need this cold weather to break so I can get out and get started.

 

[WR Moore]

If you run across it, XM-118LR is loaded with the 175 gr SMK. My data books are down stairs but it does better than 2650 f/s out of my rifle, IIRC. Good stuff. The particular batch I got didn't meet velocity consistency standards, resulting in >1MOA vertical spread at 1000 yards. [Which is why it's XM marked.] Since I had/have issues holding 1 MOA @ 1K, I don't worry about it. Also, my scope runs out of elevation before I get to 1K with that ammo. Out to 600 yards, works great.

 

[Wyo]

This one was built some years ago by GA Precision as per USMC procedures. I used the 168 SMK’s for a long time, then went to the 175 SMK. That took the rifle from an 800 yd rifle to an 1100+ yd rifle. It will shoot 1/4” at 100 yds consistently if I do my part.

 

[WR Moore]

Just to bring information in two different posts together, there are 3 versions of M118 ammunition.

As noted by Ivan, the original M118/XM118 was loaded with the 173 gr LC match bullet with a flat meplat.

M118SB/XM118SB (SB=special ball) was loaded with 168 gr bullets. This allegedly included lots with the 168 gr SMK bullet with the hollow point swaged closed. Obviously, this didn't do anything to improve ballistics. As noted, it dropped subsonic before reaching 1000 yards.

M118LR/XM118LR uses the 175 gr SMK to improve the long range performance of the round, that's why the LR suffix.

The "X" indicates surplus to government contract and may indicate some slight specification deficiency from contract standards.

If "PD" is included in the marking, it indicates the ammunition was pulled down to components due to not meeting some specification and reloaded using the same components. Powder would be pooled, mixed, load data calculated and reloaded using all components.

 

[Mexican Kerry]

Well I got out to try it last weekend, still need to fine tune my zero. I was adjusting it using a bag by myself, so it took a few tries. Frozen fingers and a crisp wind kept me from going any further. Windage still needs some tweaking, I'll do that when its a bit nicer out.

I did put about 80 rds down range, but admit most were at 25 yds going back and forth with adjustments haha. I was using Fed 168 gr smk's, despite my previous post about planning on 175's. I was using what I found on the shelf locally, but I would like to play around with a few different things to see what works best.

When I stretched it out to 100 yds, this was the result.

A 3 shot group (the single to the left and down was unrelated):

By this time I was honestly too cold to continue for much longer, so with a couple more 3 shot groups that resulted like this, I decided to pack it in. I had dialed a slight windage correction for these two just to play with the scope a bit.

I blame my teeth chattering on these results! I'm fairly confident the rifle can do better, and I hope I can too.

For a last hurrah I took three shots at a 250 yd plate, holding center. Missed with the first, fairly strong breeze from the left. Held one dot to the right on the gong and second and third hit. Not sure how centered my hits were, too cold to go for a trudge at that point. But happy to hear the rings.....

Very pleased with the rifle so far, as I said I need to do some fine tuning with the MST-100.

One thing I'd like to change after one range session is the trigger. The factory one could use some improvement.

 

[Ivan the Butcher]

When I had my PSP Remington the M-118 173 gr, would do 3 shot groups about a dime size at 200 yards. The 175 Gold Medal match with Sierra SMK's would group a 1/4" or smaller at 200. I had been wanting a metal chassis 308 for some time when Savage brought out the 10-BAS and 10-BAQ, I bought the BAS, it has a collapsible M-4 rear stock. The gun outshot my PSP so much I never fired the Remington again. I stripped the Nightforce off it and sold it to a guy that just had to have it! The Savage is out of production now in favor of a far more affordable version. They may or my not shoot as well but they absolutely cannot shoot any better: 1/4 MOA (1.25") at 500 is the normal with a better group once and awhile. At 1000 1/2 MOA or just a bit larger (5 to 6 inches) is the norm and 1/4 MOA (2.5") about 25% of the time. I assume that's all my fault!

But this brings me to the point I wanted to make. Cleaning your rifle is more than getting the powder fouling out! The copper build up will make a difference in the small group accuracy! I have loads I love!, and won't both with the new powders that fight copper build up, but to find out how good they can be, you'll need to start from a absolutely clean barrel, and then go for a number of fouling shots.
The build-up in the barrel is in layers like tree rings. The solvents for "Powder Varnish" and for "Copper Fouling" don't work on each other, in fact they neutralize each other! So in the cleaning process you need to alternate between the two types of cleaners, I was taught to use a mop of rubbing alcohol between them to speed the process up. Lastly, the use of Bronze bore brushes is the best for powder fouling, and the worst for copper removal (black bristle is the best compromise, but you have to Alcohol rinse between solvents) I use two rods, one for varnish and one for copper to speed things up! (and a third for the Alcohol mop.)
I do 3 or 4 rotations, and then let the copper cleaner sit for over an hour. Clean it out do a varnish clean and repeat the copper removal over night. In the morning, remove and oil.

The brand of bullets affects the amount of copper build up. Berger Bullets use J-4 pure copper jackets, Sierra uses their own alloy. So far the same copper solvent works well on both!

I have used just about every brand of solvent, and ended up using Hoppe's No,9 or Shooters Choice for varnish and Shooters Choice for The Copper removal. (Everyone swore by "7.62" solvent from Australia, but the alloy of copper I had wasn't affected by it at all!) If the brand of solvent you're using isn't coming out green or blue, it is not working, because the copper is there.

Keep us posted on your progress!

Ivan

By the way, my wife says, "It isn't the cost of a new rifle, it's all the accessories that break the bank!" My BA 110 in 338 Lapua cost $1700 OTD (great bargain!) but the scope, mounts, dies, brass, bullets and so on cost an additional $5400 before I fired a shot! Family Tranquility is best not discussed in the gun room!

 

[rhm0351]

Looks like a good project. I was a PIG in STA Plt. when we had the A1s and then transitioned to the A3s. As much as I preferred the A1s, the 1:12" twist and the Unertl optic were limiting over today's rifle trends. I'd still take an M40A1 over any of the later models, though the XM-3 was a pretty good "best of what was available at the time" option.

 

[Mexican Kerry]

Its been a while since I worked on this project, here goes with an update.

I'm waiting for a McMillan A1 stock but really wanted to keep shooting so I installed the 700 in this A5 McMillan stock for the interim. Its bedded now and I took it to the range yesterday to play. Re-zeroed with a different mount to improve eye relief a bit.

I really need to get more trigger time, these were the best results I got for the day.

100 yds, 10 shot group. Approx 1.25" isn't very impressive. Just for the heck of it, I would like to shoot it from a sled just once to remove as much human error to find out how well the rifle will actually do.

I know that's not an accurate way to gauge real shooting but it would show me how much I could improve.

 

[forrestinmathews]

Bag the rear of the rifle and get a target that allows a precise repeatable aim point. Something with a cross.

 

[Mexican Kerry]

I agree with that, was just using what I had with me. My boys were shooting too and the other bags were busy with the rimfires.

 

[Ivan the Butcher]

Rear Bags: One old USMC trick is a sock 1/2 to 2/3 full of sand. Place it under the grip and squeeze with the left hand. My second son was in the Marines from 99-03 and used that trick for long range targets, and reports the trick still works.

A second type of bag I use is an emptied 25 pound shot bag. Filled about 3/4 full of old tumbling media. Sewn shut and a carry strap installed. Also placed under the grip and squeezed to bring the crosshair up to the point of aim.

Targets: Just a suggestion, use a black 1" or 2" dot in the center of you red 8" circle. The old saying "Aim small, miss small!"

Group size and shape: The overall group is very encouraging! I notice small clusters. If those are from controlled consecutive shots great! If they are from a large pattern of shots that repeatedly land every 4th shot on top of each other, they indicate a problem or two. MY PSP would do the later and was corrected with pillar bedding and measured torque on the Action Screws. There may also be some trigger weight or control issues.
One of my friends was a Marine Sniper in 67 & 68. He prefers a ultra light trigger 3 or 4 ounces! Another friend was an US Army sniper trained by the West Germans in 1957 and prefers a good repeatable 2 pound (32 ounces) trigger. My preferred weight of trigger is 19 ounces (1 1/4 LB.) That is actually what my 308 Savage 10BAS came from the factory with, and the 338 110-BA came with 12 ounces (Even though Savage swears they set them for 3 to 3.5 pounds!)
I say this just to say there are all manor of weight preferences, but everybody agrees that their triggers need to be crisp and repeating!

One other thing I notice. Your photo shows a Harris Bi-pod or a clone. There is often a bounce when shot prone and from a concrete pad! (or concrete bench) A shooting mat or even a piece of carpet between the concrete and the Bi-pod helps a great deal. (Wooden benches don't seem to have this happen)

Keep up the good work and let us know how you are shooting.

Ivan