Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 10/5/2004 6:56:35 PM EST
Anybody know where I can buy a 1in14 or 1in12 16" m4 barrel?
Link Posted: 10/5/2004 6:58:42 PM EST
It will be a custom job. Why do you want it?
Link Posted: 10/5/2004 7:07:38 PM EST
WHY would you want a twist that will NOT even handle 55gr!

Seriously, 1:9 is the SLOWEST twist you should EVER use with .223, PERIOD.

1:12 was a MISTAKE, which is why it was changed...

Link Posted: 10/6/2004 2:12:58 AM EST
Link Posted: 10/6/2004 9:49:01 AM EST
Ive read that the original ar15 used a 1 in 14 twist rate. The slow twist rate with lite bullets made for a very unstable flight, which resulted in maximun damage once the round hit tissue. Im not an expert on this, but its what Ive read from numerous places. This would not be for my primary AR, im just building a new M4 for fun and Im curious how it will shoot a 40-45 grain bullet through a 1 in 14 or 1 in 12. However, I cant seem to find anything slower than a 1 in 10 for a 16 inch barrel.
Link Posted: 10/6/2004 10:02:55 AM EST

Originally Posted By UMD_Jesse:
Ive read that the original ar15 used a 1 in 14 twist rate. The slow twist rate with lite bullets made for a very unstable flight, which resulted in maximun damage once the round hit tissue. Im not an expert on this, but its what Ive read from numerous places. This would not be for my primary AR, im just building a new M4 for fun and Im curious how it will shoot a 40-45 grain bullet through a 1 in 14 or 1 in 12. However, I cant seem to find anything slower than a 1 in 10 for a 16 inch barrel.



read this Jesse.

www.ammo-oracle.com/
Link Posted: 10/6/2004 10:10:12 AM EST
If you want an effective rifle, get 1/7 and NATO spec 77gr Noslers. I hope you never plan to fire 55gr in a 1/14 at low temperture, the bullets won't be stable enough in the air.
Link Posted: 10/6/2004 10:15:49 AM EST

Originally Posted By UMD_Jesse:
Ive read that the original ar15 used a 1 in 14 twist rate. The slow twist rate with lite bullets made for a very unstable flight, which resulted in maximun damage once the round hit tissue. Im not an expert on this, but its what Ive read from numerous places. This would not be for my primary AR, im just building a new M4 for fun and Im curious how it will shoot a 40-45 grain bullet through a 1 in 14 or 1 in 12. However, I cant seem to find anything slower than a 1 in 10 for a 16 inch barrel.



What you have read is wrong.

Scott
Link Posted: 10/6/2004 10:11:13 PM EST
Link Posted: 10/7/2004 7:42:36 AM EST
If you can keep your muzzle velocity up around 3200 fps or above, a 1/14 twist will do a good job of stabilizing the 55gr M193 bullet. The US Army ran into a problem with 1/14 when testing early M16/AR-15 rifles with 1/14 in Alaska under "extreme" cold. With lowered MV, bullets were not spun up enough to stabilize them. That problem led to the 1/12.

The 1/12 twist is ideal for the 55gr M193. Many millions of M16A1s can't be wrong.

Personally, except for formal competition, I think it was a mistake moving to a 1/7 twist with heavier bullet. Reduced velocity (less wounding) and dramatically increased bore wear are a result.

But maybe that's just me.

Actually, it is probably just me since everyone else seems to love the M855 and 1/7 twist.

Link Posted: 10/7/2004 7:56:43 AM EST
[Last Edit: 10/7/2004 8:05:09 AM EST by Dave_A]

Originally Posted By Tweak:
Did you mean 1X14 instead of 1X12 Dave?



Both, Tweak...

1:12 less so than 1:14, but both were still too slow... And he wants a 16" barrel, which will make it even worse...

.222 Remmington bolt-actions had these twist rates, and with no experience in making a shorter barreled (20" hunting rifle??? Most are 24 or 26" bbl) weapon in a slightly larger caliber, they just copied the twist rate...

Finally, twist rate has nothing to do with wounding, this is a myth...

All twist rate has to do with is weather or not you can hit the broad side of a barn... Too little twist with too heavy a bullet -> keyholing and horrible groups...

Proper twist -> accurate group size, and the bullet fragments (does NOT tumble) in flesh or similar mediums....

And as for fast twist rates, 1:7 is perfect for the new, heavy/long .223 rounds such as the Mk262 (77 gr Sierra)... Given the poor performance of M855 (M193 would be worse if it were still in use) out of the 'chosen' 14.5" barrels, the fast twist is a GOOD thing...
Link Posted: 10/7/2004 8:13:52 AM EST
[Last Edit: 10/7/2004 8:14:39 AM EST by mr_wilson]
Fulton Armory sells these 1/12 uppers, buy one and whack it off:



Or just buy a barrel and build your own......

Mike
Link Posted: 10/7/2004 12:37:20 PM EST
It's true that twist rate, by itself, has little to do with wounding ability ...

However, a faster twist is almost always associated with a heavier bullet, which means reduced velocity.

And, reduced velocity certainly does have something to do with reduced wounding capability...

Link Posted: 10/7/2004 2:43:19 PM EST

Originally Posted By ftierson:
It's true that twist rate, by itself, has little to do with wounding ability ...

However, a faster twist is almost always associated with a heavier bullet, which means reduced velocity.

And, reduced velocity certainly does have something to do with reduced wounding capability...




Bullet construction is a factor. The 77gr Mk262 is the slowest of the NATO pressure rounds, but without doubt the most effective.
Link Posted: 10/7/2004 4:19:29 PM EST

Originally Posted By mr_wilson:
Fulton Armory sells these 1/12 uppers, buy one and whack it off:

www.fulton-armory.com/LegacyUpper-450_50.jpg

Or just buy a barrel and build your own......

Mike



Buy one and "whack" it off? I dont think its that simple. If you cut the barrel to 16" with that upper, I dont think the bullet is in the barrel long enough past the gas port to cycle the action. You would need to have it redrilled back at the carbine length and install a gas block under the guards, like a dissy.... no?

Besides, dont pay Fulton for their overpriced crap.... find a deal in the EE on a good used Colt M16 upper.
Link Posted: 10/7/2004 4:23:35 PM EST
FALARAK, you can open the gas port on a 16 inch with a rifle gas system and it will run OK.
Top Top