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Posted: 9/24/2004 6:52:56 PM EST
Just wondering about a future build. Most M4bbls seem to be a 1:7 or 1:9 twist. This is the preference for the 62gr+ bullet weights. In reality it seems the M855 is the wrong bullet for the short 14.5" bbl. With XM193 I believe accuracy suffers from the faster twist ? Anyhow for the practical user who shoots alot of XM193/Q3131A wouldnt a slower twist be desireable? I've read the ammo oracle and such but I'm looking towards a true 14.5/fixed phantom build as my next rifle and would only rarely shoot the heavier 75/77gr stuff and I have a 1:7 Hbar for that anyhow. Are there any slower twist M4 bbls (chromed) available or is the bushie 1:9 probably my best bet? Of course I'm not expecting MOA out of the M4 with milspec ammo but nothing over 2.5ish, after all it's not an AK.
Link Posted: 9/24/2004 7:24:56 PM EST

Originally Posted By Mr45auto:
With XM193 I believe accuracy suffers from the faster twist ?

Not in my experience.
Link Posted: 9/24/2004 9:12:07 PM EST
RRA makes chromelined M4 bbls.
Link Posted: 9/25/2004 5:44:53 AM EST
[Last Edit: 9/25/2004 5:46:33 AM EST by SBR7_11]

Originally Posted By Hoplophile:

Originally Posted By Mr45auto:
With XM193 I believe accuracy suffers from the faster twist ?

Not in my experience.



Back in 87-88 when I got my A2 barreled (1x7) Colt rifles, 55gr was all that was available in the stores, never had a problem hitting what I point the rifle at. Still shoot 55gr out my 1x7 and 1x9 barrels.

1x7 Colt 20" barrel

1x9 Bushmaster 11.5"

1x9 DPMS 7.5" and 12" stainless bull barrel
Link Posted: 9/25/2004 1:52:46 PM EST

Originally Posted By Hoplophile:

Originally Posted By Mr45auto:
With XM193 I believe accuracy suffers from the faster twist ?

Not in my experience.



+1000
Link Posted: 10/2/2004 10:13:45 AM EST
[Last Edit: 10/2/2004 10:35:52 AM EST by Bigger_Hammer]
Accuracy degradation is none to very minimully affected with 55 grain ball in 1-7 twist bbls.

Ammo Oracle also makes an interesting point that the faster twist bbls may also provide enhanced fragmentation with M193 due to the extra fast rotation of the bullet in the 1-7 bbls vs. 1-9 or 1-12.

As the 5.56 round is very effective when fragmenting and very uneffective when not fragmenting, I'd say anything that helps (especially with the loss of velocity from the shorter bbl) is something to keep!

Just my .02 worth

[b]"BIGGER_HAMMER"[/b]

h.gif
Link Posted: 10/2/2004 10:52:19 AM EST
Link Posted: 10/2/2004 12:18:00 PM EST
Link Posted: 10/2/2004 6:18:04 PM EST
I think he's got the 55 grainers mixed up with your statements about the lighter "varmint" bullets in the faster twist barrels, which as I know (because I reread the Ammo Oracle like 50 times) the lighter bullets will fall apart because their thin jackets can't take the inertial strain of spinning so fast....

-sc
Link Posted: 10/3/2004 1:03:17 AM EST
Link Posted: 10/4/2004 9:40:02 AM EST
Link Posted: 10/4/2004 11:01:23 AM EST

Originally Posted By Kisara:
www.boomspeed.com/kisara/KisaraRocksAgain.jpg


Holy shit.

I haven't seen one of those in a while.


Fortune for a quarter? I love quarters.
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