55 grain vs. 62 grain

[Mots0311]

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??

 

[oneyeopn]

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

 

[MPDC]

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.

 

[storeyteller]

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!

 

[KeithR]

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.

 

[isaidme1]

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.

 

[GMC man]

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

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.

 

[MichiganScott]

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.

 

[GMC man]

. 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

 

[oneyeopn]

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.

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.

 

[RainDodger]

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.

 

[MPDC]

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.

 

[Mots0311]

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

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!

 

[GMC man]

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

 

[isaidme1]

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.

 

[imku]

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.

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.

 

[oneyeopn]

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!

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!!

 

[isaidme1]

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.

 

[storeyteller]

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

 

[bigedp51]

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.