Ok What twist rate should I go with on a 14.5 barrel? Yes it will have a perm atached hider!!
Gun will be used for shooting cans and paper dont see it needing to shoot beyond 200yrds! It will also be eating cheap ammo!
I have found 1/7 and 1/9 if I could find a 1/8 I would be set

Please Help

1:8 would certainly give you a wide range of bullet weights. Unfortunately, getting one from a quality source can be tough. Paul Howe of CSAT runs 1:9s for everything on the simple premise that 90% of what you're going to find out there at a reasonable price is going to be 55 or 62gr ammo.

I'll go farther than that. The 1:7 was developed for the military for shooting 62 grain ammunition better specifically in the 14.5" barrel.

I think you will find most companies that offer an M4 configuration offer a 1:7.

Tj

TJ, the 1:7 twist rate was spec'd out prior to the M4, in response to the length of the M856 tracer round being used in the M16A2. The issue was that the M856 was originally developed for the M249 SAW and had stability problems in 1:12 barrels. Where the 1:7 really shines is with mK 262 77gr ammo in M4. But generally speaking, if you can fit it in your mag (excepting some long OAL benchrest ammo), a 1:7 will stabilize it.

This post has been edited by KellyTTE: November 17th 2009 10:04 PM

1/9" Twist is the way to go in your situation.

Geez man, people were shooting 14.5" barrels long before the SAW and the M856 bullet weight is 63.5 grains nominal compared to 62 grains nominal M855 ball which can easily hit 63.5 grains in manufacturing tolerance.

When the military adopts something has very little to do with when something is developed. It actually has not much more to do with when they are put in the field, only when they standardize.

The M16 carbine goes back to Vietnam days and the M855 predates the mK 262. I couldn't tell you when the military finally realized something is a good idea and standardized without looking at Wikipedia. They don't do development on rifles much.

Tj

Twist rate is one of those nice problems where it's pretty hard to go wrong most of the time. There's adequate overlap so that from 55-69gr either 1:9 or 1:7 works well. If you're going to be at the light end of that range or lower, then go with 1:9. Or if you'll be at the upper range or higher, 1:7. Also a 22LR conversion unit is more accurate in a 1:9 barrel (which makes sense since it's a very light and short bullet).


There, how can you disagree with Thomas Jefferson anyway! Unless you're John Adams...

This post has been edited by Quentin: November 18th 2009 12:05 AM

Will be getting a 22lr kit. I figured that with the shorter barrel the faster twist would help but I just dont know! Thanks for the help so far

Then you want a slower twist. If you over stabilize a 22lr projectile, it can disintegrate on leaving the barrel. Generally, .22lr is used in 1:14 or slower barrels. Just to clarify: Twist rate has more to do with bullet LENGTH, than WEIGHT. Heavier bullets happen to weigh more generally, tracers being the exception of long AND light.

The stabilization issues with the M856 bullet were because it was 1.15" inches long, compared to the M855 (.906 @ 62gr) or the M193 (.760 @ 55gr). Regardless, you still need a slower twist rate if your intention is to run a .22 conversion a lot.


This post has been edited by KellyTTE: November 18th 2009 12:45 AM

Now don't get me laughing.

My Bushy is a 1:7 but really I'd probably be happier with a 1:9 myself. Its not like I'm going for the distance record with a 14.5" barrel. I like lobbing bullets as much as the next guy but that short of a barrel is really lobbing.

The real intent of my original post was the 1:7 is extremely common manufacturing wise in the 14.5" barrel length. Until this recent 1:9 trend in manufacturing the 1:7 was about the most common barrel twist on the market for a 14.5" length.

A lot of guys like the 1:7 for defensive round use in the smaller rifle profile due to its handling of the heavier weight and to make Kelly happy LONGER bullets. I actually find it a tad difficult to load for using what I call "Stinger" bullets which are basically a high velocity light weight varmint round. I have to slow it down so much, it takes the "Sting" out of "Stinger".

To parody all you other guys, most of what I shoot anyway are 55s which do very well in almost all AR barrel lengths and twists out there for the magic 0-300 range.

I don't shoot .22lr in any my ARs. Quite frankly the AR makes a lousy .22lr gun unless it has a .22lr barrel which is more than just twist but the bore diameter is just a tad wider than the .22 lr. Besides, .22lr rifles are pretty inexpensive typically way less than an AR conversion kit.

I've been reading and the guys have done some posts on Colt is or has released the old Air Force training rifle now to the civilians for buying, which is basically an AR looking dedicated .22 lr if someone just has to shoot a .22 lr that looks like a M16. Other than playing with the old ones here at the fort I live by, I don't have any experience with them and wasn't too impressed with the ones I do.

Tj