AR barrel twist question

[tittiger]

Hope I don't open a can of worms like asking "What is the best rifle"  :-)

But if one wants to shoot .223/5.56 lead anywhere from 55 grain to 72 grain
as far as possible is there a barrel twist that will accomplish this?

If not what are the compromises?

TIA
Joe

[jmdavis]

1 in 9 handles 55, 62, 68, 69 and for some people 75. My Bushmaster likes BlackHills 68gr and SS109 (62gr) alot. A friends Remington 700 likes 75gr Hornady's or loads that duplicate their velocity.

[wcmartin1]

1 in 8 would be very good for that range of bullet weights, 1in9 for all but possibly the longest profile to 72 gr

Agreed.

Get at least a 1 in 8.  It will easily stabilize bullets up to 80 grains and shoot the lighter ones just fine too. 

Although the 1 in 9 is the most popular twist rate sold (for other than competitive HP use), why limit yourself.

You may want to compete.

Git-R-Done! 

[Rocket Man]

1 in 8" is the choice.

Mine is 1 in 9" and I have no trouble with 75gr bullets, but it's not guaranteed to work -- some people with 1 in 9" have reported problems.

[tittiger]

Thanks all....
Is there a rough corelation between a bullets weight and how far it can remain stable?

[Old Dog]

A simple/quick answer is that the heavier/longer bullets are better for longer ranges.  Partly because they are more stable than the lighter/shorter bullets and partly because they maintain their velocity better (even though the start off slower) and are not as affected by the wind as the lighter/shorter bullets.

Some bullets are better than others.  Try different brands, styles/weights to find out what your rifle "likes".  I say "likes" because every rifle is somewhat different than the next one even if its the same type/caliber.

Many years ago, while I was younger and more picky about accuracy, I tried the brands available at the time.  I went through multiple powders, Sierra, bullets, Speer bullets and Hornady bullets.  The most accurate in my rifles (M1A in .308 and 03A4 in 30.06) were the Sierra 180 grain match bullets.  Hornady's were close but not as good as the Sierra's and the Speer bullets weren't close enough to keep buying.

In my Rem. M700 varmint rifle the best shooting bullets were Speer and Hornady (too close to say one was better than the other) while the Sierra bullets were a solid "third place".

If you really want accuracy at longer than normal distances (300 yds. or more) you'll want one of the hollow point boat tail match bullets in a heavy weight and you'll have to also try different brands of primers and powders to see what your rifle "likes".  In my AR's I've always shot the lighter bullets because they are for up close shooting.  When I wanted to shoot from one mountain top to another I got out the 03A4.

Good luck with it.  I find reloading to be a fun hobby.  Its not cheaper than buying ammo from the store because you end up just loading/shooting more so the total cost is similar although you do get to shoot more rounds for the same money.  You also get to fine tune loads that make your rifles shoot better than they will with store bought ammo.

[nemohunter]

8 twist will stabilize anything that will feed from a mag IE up to 77 gr. i shoot 9 twist and dont care. anything over 62 is expensive anyways. if the 62 wont carry up enough you need a bigger caliber not a heavier bullet. I know it's where you hit them not what you hit them with that matters but energy is energy plain and simple.

If your building an AR Build an A2 style Joe. Nice long sight radius and plenty of barrel to push those rounds to full speed. shop around and you can put one together for right at $600ish.

[AFTERMATH]

My Chromed 16.25in - 1 in 7 - Shoots 55's and 62's just fine, assumingly it should shoot 'em as heavy as they come.

I believe the 1 in 9 was really made so people could shoot 45's to 62's.

[Jungle George]

I think the A1 was 1 in 12 for the 55 grn bullet the 55 is good to about 300 yds before it starts to wobble it will shoot good in those faster twists out to that range.  So you are better off with a faster twist to shoot the longer ranges you will need the heavier bullets, of course you have to watch some as they won't load into the mags as they are too long.
   Stoner was not happy when the army slowed the rate of twist on his rifle and changed rifle powder.  Many paid with their lives because of it. 

JG

[fepowered]

Is there a rough corelation between a bullets weight and how far it can remain stable?

There is a general correlation because the heavier bullets can maintain velocity longer.  A heavier weight for the same caliber bullet will be longer which generally gives it a better ballistic coefficient.  In other words it cuts through the air better so it maintains its velocity longer.  This will allow it to beat the wind better and drop less for the same distance.
A 55gr bullet can still make solid hits to 600+ yards but the 62gr and heavier bullets will generally perform better at those ranges.

[fepowered]

But if one wants to shoot .223/5.56 lead anywhere from 55 grain to 72 grain
as far as possible is there a barrel twist that will accomplish this?

I have had the best luck with 1 in 9" twist.  I stay away from match chambers because they are more picky what you feed them.  The 1 in 8" twist barrels I have tried have not shot the 75 grain bullets any better and at times seemed to cause a greater point of impact change when changing factory loads.
My go-to rifle is a Bushmaster 20" stainless 1 in 9" rifle.  It is the standard profile and not a varmint or their DCM profile barrel.  I can shoot 55gr Wolf to 75gr Hornady Match ammo out past 500yds accurately.
This summer I plan to try it at 800-1000yds with the 75gr loads.

[nemohunter]

the biggest issue with ANY rifle is keeping it in food. If the ammo it prefers is too expensive for your budget then essentially you only buy when you have surplus $$$ rather than being able to purchase all the time.

i reload which everybody should do. my current batch off ammo that i'm loading is $3.92 per 20 on Fed or LC brass. I dont count brass cost because you might use it forever or you might loose it next time out. That cost could be a BUNCH cheaper since i use CCI primers Commercial powder and 62gr bullets. If you trimmed cost by using cheaper primers(i have) surplus powder (5/8 the cost) and say a 55 gr bullet it would much cheaper. say $2.76 a box

for that cost you get first rate high quality ammo NOT steel cased dirty import crap.