Which Twist? - XDTalk Forums

Superduty · 11-02-2009, 05:00 PM

I have a A1 Retro colt upper Pre-ban with a 1/12 twist 20".

I'm almost done with with my M4 build and ordered a Combat arms 1/7 twist 16" Chrome Lined.

Do I have the best of both worlds now?

Shane

reidic · 11-02-2009, 05:02 PM

I haven't done any research into the suitability of 1/12 twist, 1/7 is generally the best option to properly stabilize a heavier load bullet that you would associate with a combat ready patrol rifle, so I'd say you've got at least 1 half of that equation set. I would imagine, given what I know about 1/9 twist barrels, 1/12 would be well suited for lighter target rounds and varmint bullets.

Shay_Ellafrits · 11-02-2009, 05:11 PM

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

**yocan** · 11-02-2009, 05:16 PM

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. On impact its dramatically more likely to shed is jacket and acts like a hollow point splingtering whehn over 62 grains.

varmint lighter loads you want a 1:8 or 1:9 and a long barrel. for the 20" thats what I'd go with. Personally I love stainless 20" and 24" barrels.

Fdxpilot · 11-02-2009, 10:02 PM

Quote:

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. On impact its dramatically more likely to shed is jacket and acts like a hollow point splingtering whehn over 62 grains.

varmint lighter loads you want a 1:8 or 1:9 and a long barrel. for the 20" thats what I'd go with. Personally I love stainless 20" and 24" barrels.

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.

joshua79109 · 11-02-2009, 10:07 PM

Most folks are happiest with the 1/7 to be able to use rounds heavier than 69 grains. I have not heard of a 1/7 that doesn't do well with the 62 grain stuff. I did have one 1/7 barrel that did not perform well with 55 grain stuff, but I believe that is not normal. I shoot heavier stuff out of my 1/7s - I like the heavier stuff for protection.

1/9 is a fine choice and will usually do fine up to 69 grains - although every barrel is a little different and some 1/9 will do more than 69 grains - I have one that I shoot some 40 grain out of (accurately). I have not heard of a 1/9 that doesn't do well with the 55 and 62 grain stuff.

I don't know anything about the 1/12.

John A. · 11-02-2009, 10:09 PM

If it makes a difference, I have an MP5 that will occasionally throw some of the copper off of the bullet. I've found several little pieces of it in my suppressor while cleaning at the end of a long day.

No, it's not getting baffle strikes. Any copper coated ammo can seperate as it leaves the casing as it makes its' way through the bore.

RyanH · 11-02-2009, 10:59 PM

Barrel performance varies greatly IME.

I have a CMMG upper with a 1/7 twist barrel that I dropped a .22 lr conversion kit in after being told it couldn't be done. I can hit clay pigeons at 75 yards in a standing position with iron sights all day... and I'm far from an expert marksman.

I also have a 1/9 twist Bushmaster upper than stabilizes 77 grain bullets just fine. But my Stag 1/9 hated bullets heavier than 62 grain.

YMMV

.45StillAlive · 11-02-2009, 11:03 PM

ive always had 1/9 but really depends.

VR4 · 11-02-2009, 11:47 PM

Not this again.

11-02-2009, 05:00 PM	#1
Superduty XDTalk Member Join Date: May 2009 Location: Arlington, Texas Posts: 35	Which Twist? I have a A1 Retro colt upper Pre-ban with a 1/12 twist 20". I'm almost done with with my M4 build and ordered a Combat arms 1/7 twist 16" Chrome Lined. Do I have the best of both worlds now? Shane
	Share

11-02-2009, 05:02 PM	#2
reidic XDTalk 100 Member Join Date: Mar 2009 Location: Rochester, NY Posts: 371	I haven't done any research into the suitability of 1/12 twist, 1/7 is generally the best option to properly stabilize a heavier load bullet that you would associate with a combat ready patrol rifle, so I'd say you've got at least 1 half of that equation set. I would imagine, given what I know about 1/9 twist barrels, 1/12 would be well suited for lighter target rounds and varmint bullets.
	Share

11-02-2009, 05:11 PM	#3
Shay_Ellafrits XDTalk 500 Member Join Date: Feb 2009 Location: Gaylord, Michigan Posts: 922	you could replace the barrel to 1/9. That would be better. __________________ AR-15 (Building) Mossberg 500 Marlin 925 Mossberg 100 ATR The only easy day is yesterday.
	Share

11-02-2009, 05:16 PM	#4
yocan XDTalk 5K Member Join Date: Feb 2007 Location: Detroit Posts: 5,745	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. On impact its dramatically more likely to shed is jacket and acts like a hollow point splingtering whehn over 62 grains. varmint lighter loads you want a 1:8 or 1:9 and a long barrel. for the 20" thats what I'd go with. Personally I love stainless 20" and 24" barrels. __________________ The three requirements for a school shooting. 1 know the floorplan. 2 Know the threats inside the location and response time/entry time for the police 3. Royally screwed up intelligent analytic mind. We need more laws to protect these three rights. Ban guns in schools, it obviously works. Last edited by yocan; 11-02-2009 at 05:19 PM.
	Share

11-02-2009, 10:07 PM	#6
joshua79109 XDTalk 100 Member Join Date: Jul 2009 Location: Amarillo, TX Posts: 296	Most folks are happiest with the 1/7 to be able to use rounds heavier than 69 grains. I have not heard of a 1/7 that doesn't do well with the 62 grain stuff. I did have one 1/7 barrel that did not perform well with 55 grain stuff, but I believe that is not normal. I shoot heavier stuff out of my 1/7s - I like the heavier stuff for protection. 1/9 is a fine choice and will usually do fine up to 69 grains - although every barrel is a little different and some 1/9 will do more than 69 grains - I have one that I shoot some 40 grain out of (accurately). I have not heard of a 1/9 that doesn't do well with the 55 and 62 grain stuff. I don't know anything about the 1/12. __________________ USMC - SGT (Prior Service) NRA Endowment Member TSRA Member USCCA Member "The only thing necessary for the triumph of evil is for good men to do nothing" Edmund Burke
	Share

11-02-2009, 10:09 PM	#7
John A. XDTalk 1K Member Join Date: Jun 2006 Location: KY Posts: 1,063	If it makes a difference, I have an MP5 that will occasionally throw some of the copper off of the bullet. I've found several little pieces of it in my suppressor while cleaning at the end of a long day. No, it's not getting baffle strikes. Any copper coated ammo can seperate as it leaves the casing as it makes its' way through the bore. __________________ "The 2nd Amendment wasn't adopted into the Constitution because the authors liked guns or the destruction they could cause, but to give ordinary citizens the ability to protect themselves and their family and to take up arms against anyone in a governmental position who tried to deny those fundamental and God given rights." Ecclesiastes 3: 1-8
	Share

11-02-2009, 10:59 PM	#8
RyanH XDTalk 100 Member Join Date: Sep 2005 Location: DFW, Texas Posts: 455	Barrel performance varies greatly IME. I have a CMMG upper with a 1/7 twist barrel that I dropped a .22 lr conversion kit in after being told it couldn't be done. I can hit clay pigeons at 75 yards in a standing position with iron sights all day... and I'm far from an expert marksman. I also have a 1/9 twist Bushmaster upper than stabilizes 77 grain bullets just fine. But my Stag 1/9 hated bullets heavier than 62 grain. YMMV __________________ Just say no to cap and trade.
	Share

11-02-2009, 11:03 PM	#9
.45StillAlive XDTalk 100 Member Join Date: Apr 2009 Location: Iowa Posts: 118	ive always had 1/9 but really depends. __________________ "A strong body makes the mind strong. As to the species of exercises, I advise the *gun. While this gives moderate exercise to the body, it gives boldness, enterprise and independence* to the mind. Games played with the ball, and others of that nature, are too violent for the body and stamp no character on the mind. Let your *gun* therefore be the *constant* companion of your walk." -- Thomas Jefferson, Foley, ed., Encyclopedia of Thomas Jefferson, p. 318.
	Share

11-02-2009, 11:47 PM	#10
VR4 XDTalk 1K Member Join Date: Oct 2008 Location: WA Posts: 1,289	Not this again. __________________ XDm 40. XDm 9 OD/ DGR / #16 / PRP Trigger/ Dawson FO's/PistolGear Magwell SA TRP 1911 w/Trijicon NS SA GI 1911 A1 Stag-AR-15 2T/ Aimpoint M2/ FAB Grip/POD / Geissele Hi Speed Trigger /CAA UPG 16 Grip / FSC556 Daniel Defense M4 / Aimpoint M3 / FDE Magpul Moe stock / FDE Magpul Moe pistol grip / FSC556 / Geissele SSA / MS2 sling WAHTF Mega AR build
	Share

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

LinkBacks (?) LinkBack to this Thread: http://www.xdtalk.com/forums/ar-talk/134780-twist.html
Posted By	For	Type	Date
XDTalk Forums - Your XD/XD(m) Information Source!	This thread	Refback	11-02-2009 10:06 PM