1-7" twist with 50 &55 gr bullets?
I know the 1-7" twist 223s are designed for the 77,80,90 grain bullets, but I'm wondering how useful the 50 and 55 grain factory loaded cartridges would be fired in an AR. Would the excess spin cause significant degradation of accuracy? Since it would be for an AR we are limited regarding reducing velocity in order to cycle the action.
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They don't shoot too bad in my Colt Sporter. 62gr shoot better [;)] 0 -
Some of the best groups I've seen out of a couple of our AR rifles are using 50 grain "tipped" varmint type bullets at factory load velocity. 0 -
Ray B
A lot of it depends on how tight the concentricity tolerances are within the bullet itself.
Todays standards of concentricity are far better than bullets even as recent as the mid-90's.
With the older 50, 52 and 53 gr. varmint and match bullets, concentricity is going to still be pretty good. Not up to todays standards but still very good.
Where I think you will run into issues is when you get hold of the 55 gr. FMJ's. They were not usually made to the same tolerances and you will find groups spreading out.
My suggestion is if you got hold of a bunch of milsurp 55's then slow your velocities down a bit and see how that works. That is if at full velocity, the 55's aren't giving you the accuracy you desire. This is not a cure-all and doesn't always work. Sometimes tolerances just don't meet our expectations. I had some Hornady seconds once that no matter the velocity, did not shoot straight. Seconds are usually blems. These were incorrectly made bullets somewhere. They were cheap and served to blow off in an AR15.0 -
The US military's maximum allowable dispersion from an M4 with it's issue 62 gr. M855 round is very far from tack driving accuracy.
Keeping that standard in mind consider they restrict M4/55 gr. M193 use to emergency situations only.0 -
If you are searching for sub- moa accuracy from your AR, use match grade bullets, loads, etc. If you are searching for adequate accuracy for a fun shoot or plinking session, you will be just fine loading your cases with 50 to 55 gr bulk bullets in your AR.
Unless you are finding incredible velocity with your loads, the quicker twist should not affect your bullets in flight or your resulting accuracy all that much.
Now a too- slow twist with long or heavier bullets will definitely cause bullets to be unstable and tumble towards the target.
Have fun finding a load that works for you! [8D]0 -
I am not sure about the 50, and 55 grain bullets, but I do know that a Hornady Superformance 40 grain V-Max, did not really like the 1 in 7 twist in an M-4. You could barely keep it on an 12"x 12" target at 100 yards. Switched to the Remington 62 grain match HP, and you could cut the groups with a dime.
YMMV
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