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Posted: 7/19/2008 11:50:51 AM EDT
[Last Edit: 7/19/2008 11:53:07 AM EDT by dbshabo]
I noticed the AR10 has a twist rate of 1:11.25". Their website claims 1.5 to 2.0 MOA, not anything to write home about but decent for a NATO chambered rifle in my opinion. What's the heaviest bullet that can be used and still achieve the advertised accuracy?

I noticed the DPMS and RRA .308 rifles have a 1:10" twist rate like my Savage .308 bolt gun. I get great results out of the Savage with 168 gr SMK bullets. Thanks in advance for any and all help or advice.


Ooops I thought I was in the AR10 forum. Mods please move this if necessary. Sorry.
Link Posted: 7/19/2008 1:26:02 PM EDT
its actually more about length than about weight-- but longer bullets tend to be heavier. You should be fine up to 175. Every barrel has a preference, and its not always what its supposed to be. Like 1:10 is supposed to like 175 more than 168, and 1:11 should like 168 more than 175. The only way to know is to try it.

For example the Berger 210gr VLD has a commended twist of 1:11, and that is a LONG bullet.

One of the twist calculator I saw says the max bullet lenght for twists:

twist max bullet length
1:11 1.29"
1:10 1.42"

Twist rate/ Greenhill Formula

The thing is that this is all theoretical, and most agree Greenhill is a little conservative.
Link Posted: 7/19/2008 3:06:41 PM EDT
Heavy bullets are long. To get a long bullet to fit into the magazine you have to seat it deep into the case. By seating it deep, you lose powder volume within the case and velocity suffers.
Link Posted: 7/19/2008 3:57:15 PM EDT
I know a few guys over at the Hide that ran the 190s with good results.I run 178 AMAXs threw mine and have excellent results and these bullets are quite a bit longer than the 175 SMK but my is a 1/10. I have a buddy that runs them threw a 1/11.25 with no problems either...
Link Posted: 7/19/2008 4:01:46 PM EDT
I would says 190s if you want to use the mag, you could get heavier but it would be a single shot.

175 SMK work just fine for me,
Link Posted: 7/20/2008 11:47:57 AM EDT
AR10's have 1in11.25" ? Has anyone check that out to make sure because anything not a whole number means they single cut the riflings. Its not a pulled button style and barrels like that shoot better that 1 moa on a bad day.
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