Which Twist?

[yocan]

Originally Posted by Fdxpilot

I have a LMT 1:7 that fires UMC 45gr SP varmint rounds fine. Nice round .223 holes, with no sign of the round fragmenting. Obviously, a 1:9 barrel would be better for a dedicated varmint gun, but the 1:7 works for occasional use with the light rounds, as well as shooting 75gr TAP T2 for HD.

See what we should do is get data on different brands because I wonder if its luck of the draw or the different type of rifling by different brands (or possibly the amount of wear on the rifling)

and by the way unlike me, God loves you.

[Mercmar]

Originally Posted by yocan

1:7 is the best for combat/heavier loads. it will take a bullet under 55 grains and throw it out the barrel in four or five pieces. For the M4 thats what I'd go with.

That's pure, unadulterated horsehockey. You've never seen that happen, have you? You're just speculating, based on other horsehockey that you've read on forums like this. I've shot some 40 gr. varmint bullets, which have very thin jackets, out of my 1/7 M4 barrel. Not the greatest accuracy, but no breaking apart of the bullets, either.

[yocan]

Originally Posted by Mercmar

That's pure, unadulterated horsehockey. You've never seen that happen, have you? You're just speculating, based on other horsehockey that you've read on forums like this. I've shot some 40 gr. varmint bullets, which have very thin jackets, out of my 1/7 M4 barrel. Not the greatest accuracy, but no breaking apart of the bullets, either.

or maybe I've seen it happened three trigger pulls 11 holes. not all barrels do this, I understand that. However if your like me and can only buy once, play safe and follow what I said.

[HB of CJ]

Yep, you have covered about 95% of it. The 20" 1X12 rifle barrel will shoot just fine with 55 grain or lower ammo. Shooting the 62 grain SS109 ammo through your "retro" will ALSO work fine, only expect the POTENTIAL of keyholing at much past 100 yards. Inside that, you can still hit.

In my humble opinion (which is probably very suspect!) the 1X7 twist is the best for your 16" carbine barrel build. This will let you shoot accurately ANYTHING you can think of, except maybe Hornet bullets and the very heavy bullets now available. Your 16" barrel is just too short.

There seems to be a relationship between barrel length, twist rate and the accuracy one needs for a great gun. Generally speaking, the shorter the barrel, the tighter the twist must be. The longer the barrel, the longer the twist can be and still shoot well. Go figure. HB of CJ (old coot)

[Alaskapopo]

Originally Posted by Shay_Ellafrits

you could replace the barrel to 1/9. That would be better.

I must disagree. A 1/7 or a 1/8 is a better twist as it will stabalize the heavy bullets as well as bullets as light as 50 grains. The heavy bullets do the best and long range and also have the best terminal performance.
The 1/9 twist sometimes will and sometimes won't stabalize 75 and 77 grain bullets.
Pat