55 grain vs. 62 grain
 

When it comes to all the variables to an AR its easy to start over thinking stuff. Lately I started wondering if 55 grain ammo had enough stopping power. The civilian market seems to be geared towards 55 grain ammo, at least in the carbine catagory and optics and such are tuned to 55 grain ballistics. The standard M-16a2 I shot in the Marines was 62 grain ball. I know theres differences in barrel length and rifle twists that have a lot to do with the best performance of ammo and etc, etc.
I was curious if anyone experimented with both ammo and found much difference at say 200 yards. I would assume there would be more bullet drop with the 62 grains naturally but enough to really matter? I'm really more concerned with a carbine rifle and if its a good option to consider. Or am I just thinking to much into this??

SemperFi brother. When I was in we shot 55gr M193. I havent tried them but from what I have read the 62 grain bullets are not quite as accurate but that is just from reading. I myself am wondering about 75 to 77 grain bullets

Stopping power how or rather for what? The steel core, 62 gr stuff will penetrate better but. the 55 should fragment more.

For short range, anti personnel use as in home defense hollow point is probably a better choice.

Ballistics Calculator says 0.2" drop diff. at 200yds with 100yd zero (0.6" with 50yd zero). BTW I have shot those green tip 62's at some steel targets. They penetrate 1/4" steel like a drill and make nasty divets in 1/2". Some scary stuff!

And that is why it is usually not allowed at ranges.:eek:

My M&P AR wont even stabilize a 62gr green tip bullet. I was shooting 8" high with a scattered pattern at 50 yards. 55gr xm193 shoots good tight groups. I am going to have to ditch this 1/9 twist barrel asap.

Semper Fi , I also was using the M193 in the Corps, the reason I have read that the steel core rounds are not as accurate is there is a void formed at the tip unlike the lead core which is solid and the void is not the same shape in each round throwing the round off a little.

If you are talking two legged varmints, there is a reason the military is beginning to use 77gr. OTM. I've never shot it so I'm not sure if it will stabilize in a 1-9 twist.

Winchester 64gr Power-Point is designed as a deer load. Any load using Barnes TSX would be a good choice. Over penetration is not an issue if you hit what you are shooting at. If you miss, it's a problem with any load.

Ain't that the truth at the range its called maggies drawers :cool:

What model M&P15 do you have with the 1-9 barrel. and the 62 grain xm855 is inherently not as stable as the 55 grain or basically any bullet that doesnt have the steel core. The steel core is not perfectly centered and therefore doesnt stabilize as well as the other weight bullets.

Well, I'll tell you. I get decent/satisfactory groups out of M855 with my Sport. I get somewhat less decent groups out of the 193 (55 grain). The 855s seem more consistent. That goes for my 20" SGW also, which is a 1:9 SS barrel. With the 193s, my groups opened up about an inch, and I'd get an occasional flyer at maybe 2".. so, I don't shoot much 193 anymore. But I don't shoot much 855 either, as I'm a handloader. That's what I found though.

What works the very best in both are my handloads, which are 60 grain Sierra Varminter hollowpoints (Sierra #1375). Very nice groups; tighter than either the 193s or the 855s.

I figure, shooting with an EoTech that has a "1MOA dot" and no magnification, a baseball-sized group at 100 yards is just fine. It will do the job that the rifle is made for. If I want to shoot bullseye or want to really reach and touch someone/something, I have other, more suitable armaments.... and I want to stress that I feel the Sport and it's barrel are very capable of doing that with the correct optics on board.

My OR stabilizes 855 , at least at 100 yds. I don't shoot much of it because it costs more than 193. Stabilization becomes more critical with longer distances but up close , even heavy HP defensive rounds will stabilize fine.

I thought the Marine Corps always used the M855 ball. I was in the early 90s where carbine length rifles was a BIG no no. In which I am glad to see that attitude has change since the Iraq war. Did you use the M193 with an M4?

Semper FI!

I was in from 1985-1989 and we had the M16 A2 and the A1 was still being used mostly for the MP's

oneyeopn just the standard M&P15 model. I could have got a bad box but alot of people have problems with 1/9 twist barrels and some have gotten lucky. I was one of the unlucky ones, it looked like I was shooting a shotgun.

This might not have anything to do with your problem, but the first time i sighted in the magpul gen II flip sights shooting 62grain it was 6" to 8" high.

Gentleman, I was in 75-79. We used the M193 with M16A1's. The Army may have had the A2's by then but we didnt. I disliked Mattels toy so much that as soon as I got to the position where I could, when I got to the fleet, I always humped an M60. That was firepower LMAO!!:D

imku, this was while using a scope that had been zeroed on xm193 ammo. I knew it was going to be off slightly but the scattering pattern is whats bothering me. It really does resemble shotgun peppering.

Different guns like different ammo, even guns made by the same manufacturer with the same twist rate. Find what it likes and shoot it.

"If I find 10,000 ways something won't work, I haven't failed. I am not discouraged, because every wrong attempt discarded is another step forward".
Thomas A. Edison

Weatherby rifles and cartridges are famous for their sizzling hot muzzle velocities. They do this with a longer throat or free bore than a standard rifle to allow the bullet to get a running start at the rifling and thus lower the chamber pressure. You also wont see any standard Weatherby rifles winning any bench rest competition with these long throated rifles because they are not as accurate.

I have a AR HBAR with a 1 in 9 twist and a bull barrel .223 bolt action with a 1 in 9 twist and they both like 55 grain bullets and are very accurate.

In my opinion the military didn't do anyone a favor by going to the M855 round with the M193 round being more accurate and having better stopping power. On the flip side of this the troops in Viet Nam complained that the M16 lacked penetration when firing through obstacles, barriers, etc compaired to the M14 or M60 which would go through them and hit the VC or NVA.

55gr seems to be the most common and best all around bullet for rifles in the 1-7 to 1-9 range. The other weight bullets have jobs in which they are very good at and better than the 55gr but for all around plinking or 100 yard or less target shooting the 55gr seems to set the standard. I will eventually load some 75 to 77 just because at longer distances they receive less deflection from wind and such but it is the length of the bullet and not the weight that does the work. Some Coyote hunting friends of mine in GA swear by the 52 or 53 grain bullet, they claim it is longer than the 55 and sails better, this too I will check out.

I'll swear by the 53's. Havn't shot the 52's cause I got the 53's first!

I zeroed my red dot with xm855 @ 50yrds, and have about 1k of xm193. I'll be shooting it next range trip i take. I'm interested to see if I'm going to have similar results... With that said, I have a 1:8 twist, so its probably going to work differently.

This is a little more expensive than "plinking" XM855, but it sure shot better groups.


Ammunition To Go : 20rds - 5.56 Winchester ZQ3314 Open Tip 62gr. FBI Training Ammo [ZQ3314] - $12.95

I talked to a guy at the range the other day and he was getting lousy groups with the green tipped rounds with the steel pin in them. I mean at 50 yds he was getting 6 to 8 inch groups. With his hand loads he was getting less than i" groups.

Each gun has its own preferances, generally The longer the bearing surface of the bullet the faster the rifling needs to be. The heavier the bullet and the length the bullet is at bore diameter will effect the accuracy. There are many variables including distance the bullet jump to the lead of the is. You have to load for each bullet in every gun,do you want minute of angle or minute of buck?

I'm not a very good shot, but my M&P likes the 55 gr FMJ better than the 62 gr Green tip @ 100 yards. Mine is a 1/9 twist and I'm not sure how it will stabilize heavier rounds.

1:9 twist should be good up to 70gr.

This is the accepted wisdom. All else being equal, at shorter distances, 1:9 bbl.s stabilize almost anything. This ability diminishes with range BUT at 50 yards you shouldn't notice variances not due to inherent characteristics of the ammo in any bbl.

I can tell you one thing, that is a certainty: XM855 and Wolf WPA ammo are equally as accurate, with XM193 being a bit more accurate and it does hold a bit better groups.

Federal Fusion hunting ammo in 62 gr. is really, really accurate stuff.

Also my experience, although I must admit, I don't shoot at 50yds. My 1:9 twist RRA will shoot 70gr bullets 1 MOA, while 80gr bullets are 3 MOA and keyholed at 300yds. As you get closer to point blank range the groups will tighten up but this is true with any barrel whether it is rifled or smoothbore.

Yes, the actual number that has been mentioned by ballistic folks on other sites has usually been deterioration begins about 200 yards. I mentioned fifty because many consider the home defense, anti personnel rounds used by Police departments as not good for their home defense with an AR. I am a proponent of the AR for home defense as opposed to a shotgun but that is a different thread.

At the distances contemplated for AR use in home defense or close quarter combat (which is the realm of unmagnified red dots and 1-4 power scopes many of us buy) the heavier, hollow point anti personnel rounds produced by Hornady, etc. will serve just fine and have the same advantages they offer in 1/7 bbls. Of course the 1/8 bbl. will also do fine with it, even at longer than the 200 yd. distances I had mentioned.

Very long military rounds, intended really as mid distance sniper rounds that can be used in ARs without going to larger calibers, may present problems due to their lengths and require as fast a twist as possible.

An interesting sidenote is that in the early years of military use of the AR, the tendency of the bullet to spin, end over end, was touted as a big advantage in close quarter combat and the twist rates were much higher (like 1/12) than in common use today.

M855 vs XM193
 

Finally got back out to the range and was looking for differences between the two for my rifle (1/8 twist). I am shooting off the bench with a rest, no magnification using a Aimpoint PRO (2MOA dot). The M855 is Federal and XM193 is American Eagle. 200 rounds each, 15 rounds per group. In my opinion, the XM193 was slightly more accurate holding groups of 3-6", the M855 was 4-8"...I almost always have a flyer. Here a pic of a 15 round group of XM193 and my best lookin 5 round group of M855. Targets are 1" squares

The best I could do with my Sport with M193 was 3 - 5 shot groups into a 3X4" box at 100 yards. I put a free float handguard on my Sport and 3 shot groups with M193 were cloverleafs at 100 yards, when I could hold still enough to get good groups. Here's the M193 at 100 yards 3 shot groups. The red bullseye is 1.5" in diameter.

My Sport really likes PMC 223 55 grain. Gets even smaller groups at 100 yards.

http://i36.photobucket.com/albums/e1...355gr100yd.jpg

I shot a 200 yard 100/100 3x at Saturdays highpower match, rapid sitting with 69gr Sierra matchkings. It was a group of just under 6" so I guess at 100 yards that would be about a 3" group. Not great as far as groups go but good enough. I am trying to shoot up all my 69gr ammo so I can switch over to 77's since that is the new cats meaw for 223/5.56

I load the pull down M855 projectiles for my wife to shoot, at her favorite distance of 50yards, I can't tell any difference between the M193 and M855, both of these rifles are 1/7 though.

http://blog.usni.org/wp-content/uploads/2010/05/m14.jpg

...168 grain works for me...

Green tip is less accurate than many loads out of most guns. Before you spend big $ to replace a barrel, try some other 62-69 grain projectiles.

*drools* :)

Might also try 52 grain BT hollow points using IMR 4895 powder. Very stable out past 250+ yards and plenty of knockdown for Coyote. Mini 14 with a wide angle 3-9x40 scope.

Nice seeing an old best friend that could and would reach out and touch at 800 yards. Reliable and one of the best.

...Patton said the Garand was "the greatest battle implement ever devised"...well...the M-14 is...SUPER GARAND!...

Plus one on the comment on Fusion 62 grn. Very accurate out to 200 yds. Out of my old Armalite.

If you're concerned with "stopping power" then I don't know if I'd use any of the military's experience with your decision. While the 5.56 has had it's detractors as a fight stopper...those were based off military FMJ ammo.

As a civilian you can use hollow-point, soft-point, etc, which will have much different terminal ballistics than military FMJ ammo.

Optimum bullet weight is determined by barrel ROT. A 1:9 barrel should be able to handle everything up to about 75GR.

I shoot 62gr in both my 1:9 and my 1:8 barrels.

Regarding stabilization - a study was conducted (Army or Marines, I don't remember) that found the vast majority of infantry engagements happened with 75 yards (or less) separating opposing forces. If your standard engagement ammo stabilizes properly out to 100 yards, you're gold. If you're interested in longer ranges, get a faster barrel (1:8 or 1:7) and use heavier ammo (70+).

FWIW, the steel core stuff is used specifically for its penetration capabilities at close ranges (out to 100 yards), such as going through glass windshields, thin walls, and even steel plate, and not being affected by incidental contact with obstructions in the line of sight.

For practice, I use Tula 62gr, but my "ready" mags are filled with 855 steel core, and I have no problems with accuracy with either one, regardless of the rifle I use it in.

My DPMS 1:8 will shoot under MOA with 77gr SMK and 75gr OTM/Hornday and PPV.

My VTAC M&P will nearly match it out to 100yrds with no problem. It works "best" with the 68gr Hornady OTM handloads I feed it.

Both work equally well with 55gr XM193.

I stopped buying/shooting 62gr SS109/M855 stuff a while back. None of the ranges I shoot at like to see folks with steel core ammo these days.

what is the heaviest bullet that can be hand loaded and will fit in the magazine ?

Rebs, I have read that 75 is about it although some people have been able to load 77's, all the 80's I have read about require hand insertion!

Just ordered 500 LAKE CITY .224 62 GRAIN SS109 STEEL CORE BULLETS. Going to load a few with Accurate 2460 for SHTF and some 100 yard plinking. Has anyone used any of these bullets in their hand loading?

My rifle is Frankin with a 1:7 twist with a 3 power Nikon P223.

Zombie thread.

When I handload, I use quality bullets capable of good accuracy on target. The SS109 ain't one of them with the accuracy requirement being about 4 MOA. However, most guns will shoot 2" groups at 100 yards.

Well, I got my Sporty a few months ago. I bought some Winny made M855, and some of that Winchester 64 gr. PowerPoint, and headed to the range to sight in. Started shooting the M855, and got it sighted in, at 100 yds., and then started shooting for group. I got some nice 1.25 inch groups with the M855, and then, I started with the 64 gr. PowerPoints. When I checked my spotting scope after the first four shot group, I was amazed to see a tiny 4 shot group inside the 1.25 inch group of the M855. For me, social work will be done with the Winchester .223 64 gr. PowerPoints. I believe that they would do the job, quite handily.......