Is this chart true? I see most barrels in 1/7, is this just

>>34450222
1 in 7 will stabalize 55 grain better than 1 in 9 will stabalize 62+ grain bullets.
That is the reason why 1 in 7 is so common. I prefer 1 in 8 though.

>>34450249
1:7 is common cause murrica fuckyeah muh milspec
every other country with a 5.56 uses 1:9

>>34450264
Muh tracers! Murrica!

>>34450222
1:12 is perfectly fine for 55 grain.

>>34450287
1 in 12 increases your stopping power cause the bullet is less stable and will tumble easier.

>>34450300
>increases your stopping power
Improves terminal ballistics against soft targets, yes.
Which is why I mentioned it in the first place.
The original AR was fitted with 1:14, but that was incapable of stabilizing tracers in Alaska testing and so was replaced by 1:12.

>>34450222
1:8 is the optimum for everything, but barrel makers aren't going to changer over just to appease an ideal. Everything is "muh 1:7 milspec" so no one gives a shit.

>>34450222
Being over spun is not nearly as detrimental to accuracy as being under spun. A 1:7 will do ok with 55 grain bullets. A 1:12 will make match grade boat tail hollow points in the 75 grain range print groups like a shotgun with extreme keyholing.

>>34450353
55 grain and 62 grain are the most common. Why would you want 1/7 or 1/12? Surely they're optimized for ammo fewer people use?

File: austria10k.jpg (61KB, 950x960px) Image search: [Google]

61KB, 950x960px

>>34450264
Every country that uses 1:9 uses 18-20" barrels and/or still uses M193/M196 because they aren't in NATO and the 55gr has better terminal effects on flesh. Once you get to like 16" with a 1:9 you lose your ability to use M856-type tracers. The AUG can

>>34450391
What about 16 inch 1/8? I see those in Midlength uppers. Seems like a good compromise.

>>34450391
The Austria AUG has a 1:9 twist because Austria doesn't NATO, but the Kangaroo and Kiwi versions have a 1:7 twist. The HK33, Galil, and FNC originally had 1:12 twists but were upgraded to 1:7. Tavors are 1:7.

>>34450428
>upgraded

>>34450376
1:7 will give you an ok group with lighter bullets and will give you amazing accuracy with hand loaded match bullets. They not cost the same to make, you don't LOSE anything going from 1:12 to 1:7, and they work well with a broader range of ammo. Its a no lose situation to take the higher spin.

>>34450400
You're not going to "overstabilize" an M193 with a 1:7 twist. 1:8 is the new tacticool thing that really does nothing that 1:7 wouldn't be (slightly) better at. 1:8 is just the minimum you need to shoot the 77gr Mk262 and and 75gr HPBTs. 1:9 and 1:8 barrels are cheaper to make than 1:7.

>>34450452
I don't get it.. How can 1/7 be better for 55 and 62? The chart says the opposite.

That's 99% of ammo.

>>34450546
Making the bullet spin faster does not decrease accuracy in 5.56 you don't see issues with over spin until much heavier bullet weights and longer projectiles.

>>34450559
I'm searching online and overspin does appear to be an issue? Probably small, but again, if someone never shoots anything other than 55 and 62 grain why would they opt for a sub optimal set up ?

>>34450623
Over spin would only be an issue if you're expecting better than 1 MOA accuracy from your AR, but here's the thing. If you want match accuracy, you want match bullets. Match bullets for 5.56 are what weight? You guessed it, right around 75 grains. The 55 grain bullets won't pull much better than 2 MOA no matter how optimal your barrel is, the bullet just isn't very aerodynamically stable. If accuracy is a concern then you get 1:7 twist and use heavy bullets.
If accuracy ISNT a concern you get a 1:7 anyways because an extra tenth of an inch on your group size isn't a concern and if you want accuracy later then you can have it.

Sure, you COULD optimize your build to 55 grain spam, but it still wouldn't be match accurate and all you could EVER shoot well out of it is 55 grain crap, so why bother?

>>34450653
I still don't get why you're suggesting using something suboptimal just because you need to handload to be the best.

If all someone is going to do is shoot common shelf ammo they're going to have less performance from the 1/7 barrel. It is simple as that.

Which happens to be what 99% of shooters do.