AR-15 ammo 55 or 62 grain?

[radio2]

Which round do you prefer for a AR-15, The 55 or 62 in 5.56 FMJ?  just courious to see what people like.  Have shot both and like the 62 better.

[AtlLaw]

55.  All I've ever shot except in Hi-Pwr matches.

[jsoukup]

Right now it's a matter of supply and price. I get 55's because everything I see in 62 or 68 is $$$!

[Lloyd Smale]

i shoot a pile of 55s because i can buy bulk 55 grain bullets cheap. Even my 1in7 twisted gun shoots them well. But for the most part ive got a bit better accuacy out of all of them with 62 grain bullets.

[SharonAnne]

55s, they yaw and fragment better

[AtlLaw]

Very good Sharon!      I think that's the main reason for using the 55's!  Did you ever read that great terminal ballistics report that came out a few years ago?  I think it was on the 7.62, but maybe the 7.62 and the 5.56 both.  It dealt heavily with the yaw and fragment effect.  It certainly validated my observations from the 60's concerning the 5.56 and 7.62x39!   

[SharonAnne]

Thank you kind Sir!

[teddy12b]

I've never noticed much difference between the two bullet weights for target shooting.  I did notice better accuracy when I got into the 69gr bullets though.

[SharonAnne]

No I never did read the terminal ballistics report. Can you find a link to it?  I have used 69gr bthp to get some nice sub 1/2" groups at 100 yd.  Yes, they are more accurate than 55gr but I would use the 69 or 77gr btph MatchKings for use beyond 300yd. In the right barrel they can still maintain sub MOA at 600yd.

[AtlLaw]

Can you find a link to it?

I'll look for it when I get time... and remember... 
The subject was discussed ad nauseum over on AR15.com years ago.

[Terry C.]

I put back a bunch of 55 grain ammo when I had a Mini-14 with a 1:10 twist. It liked the 55 grain better.

Now that I've gotten rid of the Ruger in favor of a Bushmaster, it's a matter of using what I have (and hoping it doesn't run out before the supply stabilizes). I still have about 3K of the 55 grain .223 (Winchester and UMC).

The Bushy has a 1:9 twist, so it shouldn't have too much of a preference, but I won't know for sure until I put some of both down the barrel.

[gstewart44]

My Mini loves 62 gr.   It is accurate (for a stock mini - under 2"/100yds) with these bullets.  If I shoot 55 gr the groups are double in size.   

I did see the yaw effect once about 15 years ago.  I was on "search and destroy" outing with a friend whose fruit crops were being devastated by wild hogs.   He had a pair of AR's and let me use one.  Loaded with 55 gr ball.   

We happened upon a group of 14 pigs (3 sows and piglets).   I shot one sow quartering to me just inside the near shoulder crease.  That little round made mush out of the heart and then proceeded out the opposite site ribs exiting with a hole large enough to drop a golf ball in..

I never understood the effect until I saw in the first time.   Made a believer out of me.   Also could appreciate the 303 British MkVII round and how nasty those wounds were from the upset of the 174 gr ball. 

[Terry C.]

What series is your Mini-14? Mine was made in the '70s, I think the later ones switched to a faster twist.

[gstewart44]

I am away from home tonight - I will be back in the castle tomorrrow and will check the #.   All I know is it is stainless and I bought it in 1991 with a Redfield 3x9 scope with (5)  30 Rd mags that feed flawlessly  all for $375.

I'll post tomorrow on the serial, and twist. 

[Buckskin]

My Bushy and R-15 love the 55's.  Which is good because they are cheap.  I shoot Hornady SP's and just got 3,500 of the Montana Gold FMJ's.  Haven't done much on the bench with the Montana's, but hopefully they fly reasonable.  They were $238 to my door for the 3,500!  Can't hardly beat that...  Although I just checked their web site and the've gone up to $252 and are backordered now.  They also increased 1,000 count from $72 to $89. Man things change fast, I just got them last week!

[Lloyd Smale]

the problem with the yaw (or bullet not staying stable) about relys on hitting bone. Shoot something with a 55 grain ball bullet in soft tissure and it will just punch a small hole most of the time. If your looking for bullet upset soft points are the only way to insure it. Also rifle twist plays a big roll in bullet stablilization. A 55 grain bullet out of a 1-9 twist barrel will be more stable then a 60 grain bullet shot out of a 1-9. The military switched to 62s and now is switching to 70s because they tend to penetrate ammor better. But along with the change is faster 1-7 twist barrels to stablize them. the twist rate you chose will have alot more influence on how the bullet reacts in a target then 5 grains of weight change.