[Z71bill]

I just bought an M&P Sport II with a 1:9 - have not shot it yet - have been buying a few boxes of various ammo so I can see what works.

Wolf brass case 55 grain
Freedom Arms 55 grain
Tulammo 62 grain was on sale for $4.49 a box, so I threw a few boxes in the cart figured I would see if it can handle steel case (I assume it will)

I will be adding some soft point - most likely in a 6? grain

My assumption is anything between 55 and 68 grains will be acceptable. But then my vast and awesome shooting skills will make up for any variations in ammo. :animlol:

 

[APERS]

My 1-9 Stag likes 52gr BTHP Match or A-Max the best. 55Gr Nosler Ballisitic Tip is right there as well. 50 & 55Gr V-Max is also extremely accurate as well, but harder to find in our area. These are reloads I make for Coyote hunting, just adding these to consider. If you start loading .223 Rem. I've tried 65Gr Sierra Game King in the same rifle, point of impact was a bit higher @ 100yds. But accuracy was the same as the lighter bullets. IMI M193 55gr is a good choice for factory ammo, great brass too!

 

[ROGER4314]

Your 1:9 twist will love 55 grain bullets. If you're shooting at 100 yards, it doesn't matter much what you shoot. When you stretch out the distance, it matters a LOT!

I shot many NRA matches at 600 yards from my 1:9 barrels using 55 grain Winchester White Box (WWB) Q3131 or Q3131A. I won some cash prizes shooting that ammo from prone with iron sights at 600 yards.

Other 55 grain ammo may work as well, but I KNOW the WWB 55 grain ammo is a winner!

Flash

 

[Chesafreak]

I also have a 1:9 barrel. That twist stabilizes 55 to 62 grains the best. I buy Wolf Gold 55 gr .223 in thousand round cases for range and SHTF, and keep my magazines for home defense topped off with 5 Winchester Silvertips followed by 25 Wolf Gold. For the Range and SHTF, Wolf Gold is good, brass cased ammo that's clean, doesn't have any reliability problems, and is pretty inexpensive. I pay just over $300 per 1000 round case.

 

[TF2Addict]

The whole twist thing is overblown unless you want Moa bench rested groups.

Surely someone out there has quantified long distance effects of twist rates with actual shooting? I have yet to see such a thing. Perhaps we should start there.

 

[Kentak]

The whole twist thing is overblown unless you want Moa bench rested groups.

Surely someone out there has quantified long distance effects of twist rates with actual shooting? I have yet to see such a thing. Perhaps we should start there.

Use search terms like "twist rate test" and the like on YouTube. Not all results are strictly scientific, but will give some anecdotal results. Interesting to watch.

 

[Big Bird]

I believe we agree that the 62 grain bullet shoots accurately from a 1 in 9 barrel. However, the M855 cartridge was introduced at the same time as the M16A2 and the tighter twist creates more traumatic terminal performance. Have you ever seen a spinning top hit a wall and go careening off in another direction? The same thing happens with an over-stabilized bullet...once the spinning is stopped the kinetic energy has to go somewhere, causing fragmentation and directional changes.

The original M855 had a depleted uranium core. Later versions used tungsten or other hardened steel cores. When M855 first became my duty ammo, I was invited to participate in a Small Arms Tournament in Albuquerque. The first pepper-popper I shot with my A2 sent molten spalling all out the back of the steel target. Upon closer examination, the holes were tiny...only the hard core of the projectile passed through. Another thing is that any 5.56x45 cartridge loses a great deal of terminal performance if the velocity drops below 2500 fps. Therefore, the M4 or the CAR-15 won't match the longer range performance of an A2 with a 20" barrel.

There's no such thing as a over stabilized bullet and M855 like M195 is effective because it yaws, tumbles and fragments in flesh. The spin of the bullet is a very weak force that won't produce significant wound channels on its own.

M855 has never ever been issued with a DU core... I was in the Army when it was fielded alongside the M16A2 and its always had a steel core. The cost of DU or tungsten ammo would be so prohibitive that not even the DOD could afford it.

 

[Big Bird]

The original twist rate on the M16 was 1-12 when the 55 gain M193 was the official round.

Its changed to 1-7 when the Army went to the heavier 62 grain M855 in the early 80s. Contrary to internet opinion the 1-7 twist was not adopted to stabilize the M855 but to stabilize the much longer and slightly heavier L110/M856 tracer round.

Most High Power match shooters using 5.56 prefer a twist of 1-8 and they use this with bullets weighing up to 80 grains.

When it comes to accuracy certainly the twist rate comes into play. But the quality of the barrel/chamber are more important as is the quality of the projectile. Milspec ammo isn't exactly made to match specs and there is tremendous variation in projectile weight and uniformity.

 

[rds95991]

Is the barrel a 5.56 or a .223? If the first either will work but I've had better results with 5.56. If .223 then DO NOT USE 5.56 ammo (unless it's a Wylde chamber).

!/QUOTE]

It is not the barrel, it is the chamber.

 

[fnfalman]

Its changed to 1-7 when the Army went to the heavier 62 grain M855 in the early 80s. Contrary to internet opinion the 1-7 twist was not adopted to stabilize the M855 but to stabilize the much longer and slightly heavier L110/M856 tracer round.

Yep. The M855 is nothing more than the USGI version of the SS109, of which the Steyr AUG (aka STG-77) was chambered for several years before the advent of the M16A2. The AUG's rifling rate back then was 1:9.

 

[fnfalman]

When it comes to accuracy certainly the twist rate comes into play. But the quality of the barrel/chamber are more important as is the quality of the projectile. Milspec ammo isn't exactly made to match specs and there is tremendous variation in projectile weight and uniformity.

Dawg, my hand built ACME AR groups .005-MOA with Slovenian surplus GI ball ammo. Don't believe me? I got picture right here and youtube too.

And the ACME is bone stock too. No fancy match grade trigger, no free floating barrel, none of that fancy stuff.

 

[Z71bill]

I also have a 1:9 barrel. That twist stabilizes 55 to 62 grains the best. I buy Wolf Gold 55 gr .223 in thousand round cases for range and SHTF, and keep my magazines for home defense topped off with 5 Winchester Silvertips followed by 25 Wolf Gold. For the Range and SHTF, Wolf Gold is good, brass cased ammo that's clean, doesn't have any reliability problems, and is pretty inexpensive. I pay just over $300 per 1000 round case.

Glad to hear the Wolf Gold is good stuff - I found a sale - decent price - free shipping and bought a bunch.

 

[303hunter]

If you plan on hunting, Federal's 62 gr Fusion MSR is good stuff. It's very accurate, and has good terminal performance.

 

[303hunter]

Glad to hear the Wolf Gold is good stuff - I found a sale - decent price - free shipping and bought a bunch.

Wolf Gold is made by S&B in Serbia. It's quality ammo with excellent quality brass if you reload.

 

[Big Bird]

Dawg, my hand built ACME AR groups .005-MOA with Slovenian surplus GI ball ammo. Don't believe me? I got picture right here and youtube too.

And the ACME is bone stock too. No fancy match grade trigger, no free floating barrel, none of that fancy stuff.

Acme makes good stuff!

 

[FCastle88]

Wolf Gold is made by S&B in Serbia. It's quality ammo with excellent quality brass if you reload.

Unless things have changed in the last year or so Wolf Gold is made in Taiwan by a company that has supplied the US military with ammo. There are mixed chronograph results online but seems to be loaded to M193 specs, or close to it. Early on it was PPU ammo but has been made in Taiwan for at least 2-3 years now.

 

[Steel Head]

If you plan on hunting, Federal's 62 gr Fusion MSR is good stuff. It's very accurate, and has good terminal performance.

Good stuff.
I've whacked a few critters with it.
Its is accurate and what I have loaded for home defense.
My 1-9 carbine and my SPR both like it.

 

[WVSurveyor]

Any descent FMJ in 5.56 or .223 for range ammo. For self defense and hunting just a good brand of pointed soft point should work fine on man or beast. If you want to defend against an attack by folks in body armor then get some 5.56 green tip lap rounds.

 

[Z71bill]

Does barrel length also matter?

A 16" barrel with 1:7 twist - the bullet will make 2.286 revolutions before exiting the barrel.

A 20 barrel with a 1:8 - the bullet will make 2.5 revolutions - even a 1:9 twist would give 2.222 revolutions - which is almost the same as a 1:7 with a 16" barrel.

 

[Steel Head]

Does barrel length also matter?

A 16" barrel with 1:7 twist - the bullet will make 2.286 revolutions before exiting the barrel.

A 20 barrel with a 1:8 - the bullet will make 2.5 revolutions - even a 1:9 twist would give 2.222 revolutions - which is almost the same as a 1:7 with a 16" barrel.

The only reason barrel length would matter is because of its effect on speed
Extra speed will slightly make up for lack of twist rate.

Other factors include actual twist rate and bullet slip.

Button rifles barrels twist rate can vary.
I think that's why some shorter 1-9 barrels shoot 77's well
My Windham carbine loves them.
16" 1-9.


Almost for sure your barrel will like 69smk's
That bullet is more than enough target and small game bullet for 90% of ar shooters.