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22 November 2014, 21:31
Most of the info I have found gives a 250-300 max range for a 14.5-16 inch barrel, which I'm OK with, but which ammo is better?
I have found a lot of discussions on this, but never anything conclusive. At longer ranges (max range for shorties) the 62 gr is better for penetration, but doesn't fragment, the 55 fragments better at longer ranges, but doesn't penetrate as well.
I have several thousand rounds of both, but while ammo is fairly cheap again,I want to stock up on a few thousand more, and I want to stay with one type.
I'm not concerned with brands, but I am staying with m193 or 855, in PPU, X-Tac or Wolf Gold depending on bullet gr.
So for best all around bullet weight, which do you guys think is best all around, 55 or 62 gr?

Stone
22 November 2014, 22:11
Bullet weight is in proportion to barrel twist not barrel length. 1:7 twists prefer the heavier bullets 62g-77g but will still shoot down to 55g and even the 50g TSX since it has a longer OAL since its all copper. All my barrels are 1:7's and as a standard I run 62g FMJ for training and 62-70g for self defense to minimize POI shift since my optics were zeroed with the 62g. A 1:8 twist is about the same info. If your barrel is 1:9-1:12 twist 55-62g will still run fine but its when you start going with heavier bullets, e.g. 70-77g in say a 1:12 twist is when you will start getting destabilization. There is no reason why you cant get out to 500-600 yards with a 14.5-16" barrel as long as you know what your holdovers are at those ranges. To be honest I would find out what your barrel likes the best and what is the most accurate from your rifle and then make your decision. If the ammo you mentioned is for training then M193 and the green tip are fine but you mentioned penetration and fragmenting which leads me to believe it may also be for SD and in that case there are much better rounds for that application.

jymbeux
22 November 2014, 22:13
What is the twist rate of the barrel? Unless it's a 1:12 or slower I'd go for 62gr. It depends on what you are doing as well (plinking, varmint hunting, etc.)

SINNER
22 November 2014, 22:58
I have found the M193 to be a more accurate round than the M855 in every gun I bothered to compare the two.

Icon
22 November 2014, 23:01
My twists are all 1 in 7. (5 in 14.5 and 2 in 16 in) This is for a general purpose round, nothing specific. I doubt if SHTF will happen any time soon, or even another ammo/gun scare, I just want to stock up on ammo that will be the best all around while it is cheap. I was just reading on another forum somewhere, and most prefered the 55 gr, but one guy who talked to actual military back from the Desert, said they did not have a problem with the 62 gr taking out bad guys, tho at what range wasn't mentioned.
I have a bit over 1K of home defense ammo if need be, but I am not one to use an AR for home defense.
I have always bought what was cheap or on sale, and have ended up with around 10 various brands and bullet weights. I need to narrow that down a bit.

GOST
23 November 2014, 05:57
Most suggest for a 1 in 7 14.5" to run M855. Every rifle is different though, so you need to find out which gives you the best most consistent results. So just go out to the range with your variety and find out what your rifle likes being fed. All the advice from others is not as good of data as range time.

voodoo_man
23 November 2014, 07:11
55gr will run fine.

62 is a sweet spot though.

Uffdaphil
23 November 2014, 07:23
Does it make any sense to designate ammo choice by optic? I was thinking to use the 55gr with red dots and irons, and the 62gr for magnified equipped guns. And my limited supply of 77gr for my most precise SS410 16" with glass to be determined. I like a 50yd zero for dots and 100yd for magnified. It just seems an easier way to keep trajectories straight in my head.

JHoward
23 November 2014, 12:23
Are you saying to run different zeros on each optic?

Uffdaphil
23 November 2014, 14:13
Just two. 50yd for short range. 100 for long. Figuring with the fifty I can place quick shots in a +/- 2.5" spread out to what? 200 yards? And with the 100 place more precisely at 100-300 as my Acog and 1-4 reticles are designed for that zero.

markm
24 November 2014, 05:17
Can you see yourself stepping up to the Magtech 77 gr? Those are pretty competitively priced right now... I think around $0.50 per round. That round is 10 times better than either M855 or M193

Uffdaphil
24 November 2014, 05:26
Ditto the Mag 77 gr. I just started stocking up for my best barrel.

markm
24 November 2014, 07:13
A buddy shot it in a recent Precision class in Illinois, I think... and said it slightly outperformed Black Hills ammo. (not hard to do in my opinion... but none the less)

WestTXarms
15 January 2015, 18:50
Are you just going to be punching paper with it? Either will work.

Optimizing bullet weight and twist rate for maximum accuracy is a moot point with M193 and M885 ammo. Neither is accurate enough to make it matter. If your rifle shoots one 2moa and the other 4moa, it is a sign of your individual rifle's preference. If you were to compare them in 10 different rifles with the same twist, some would prefer one and some would prefer the other. That's the nature of non-match grade barrels shooting non-match grade ammo.

For terminal performance, just plan on neither bullet fragmenting at any real distance. If you're only planning on using the ammo for self defense in an end of the world scenario that's fine. If you are planning on keeping loaded magazines full of it under normal conditions, pony up and at least buy some soft points.

rob_s
16 January 2015, 07:52
No amount of discussion on such topics will resolve anything. Buy a bit of both, go zero your gun with one, shoot at various ranges, re-zero with the other, shoot at various ranges, and make your pick.