1/7 and 1/9 twists

[colt565]

I was reading the thread below of the 1/7 v 1/9 question. I have looked for different rifles sporting a barrel twist of 1/7 because theey handle the 55 gr bullets just fine and also will handle the 77 or 75 gr bullets well also.

Of the stock manufactures out there, most do not offer a 1/7 twist, except for colt. Why is that?

[HAMMERDROP]

barrels are also offered by BM, Sabre Defence, CMMG, just to name a few that instantly come to mind.
So maybe Colt, after all being a 'Tier 1' manufacturer, thought outside of the norm and since they're probably the company with the most accumilated data on 1x9 versus 1x7 determinded was the proper ROT for the 5.56 round ?

[John_Wayne777]

Of the stock manufactures out there, most do not offer a 1/7 twist, except for colt. Why is that?

...Last I knew you could buy rifles from numerous manufacturers that have 1/7 rifling, even from Bushmaster who is known for using 1/9....

Has something changed recently?

[colt565]

well, I checked websites of various manufactures and colt was the olny one that offered the 1/7 twist except for some special order bushmaster rifles. The stock rifles didn;t even list it as an option. 1/8 was offered by several in match barrels but no chrome lined 1/7.

It was a few months back but it seems like everyone is on this 1/9 kick for some reason.

[paulosantos]

Cmmg only makes 1:7" twist barrels in .223, although they are coming out with some 1:12". For my next build I will definitely be purchasing one of their 18 or 20" MedContour Barrels.

http://cmmginc.secure-mall.com/shop/?shop=1&cart=544600&cat=41&

[RAM Engineer]

All LMT chrome lined 5.56 barrels are 1/7. Or at least all of mine are.

1/7 makers
-------
Colt
LMT
BCM
Sabre Defense
CMMG
Bushmaster (limited runs)
Stag (limited run)


Am I missing someone?

What I want is a 16" Midlength Chrome-lined 6.8 barrel with a pinned on gas block and M4 feedramps. Anyone make THAT?

Jason

[Mike91A]

Gunsmoke Enterprise has 14.5 & 16 inch 5.56 barrels with chrome lining as an option. They are fluted before and aft of FSB.

[Mike91A]

Gunsmoke Enterprise has 14.5 & 16 inch 5.56 barrels with chrome lining as an option. They are fluted before and aft of FSB. I know nothing else about their barrels . Just saw the site.

[Robb Jensen]

barrels are also offered by BM, Sabre Defence, CMMG, just to name a few that instantly come to mind.
So maybe Colt, after all being a 'Tier 1' manufacturer, thought outside of the norm and since they're probably the company with the most accumilated data on 1x9 versus 1x7 determinded was the proper ROT for the 5.56 round ?

1x7 was used in the M249 and later in the M16A2/A3/A4/M4/M4A1 and MK18 because that what was required to stabilize the very long M856 tracer round, it's just a coincidence that it happens to stabilze the also very long Black Hills MK262 77gr Sierra bullets which weren't even around when the M16A2 was first adopted by the USMC in 1983 (which had 1x7 twist).

There is no 'proper' twist for the 5.56 round. The proper twist will depend on the end user who should use whatever twist will stabilize everything that he plans to shoot through his rifle. For some 1x9 will be perfect, for me 1x7 serves me best.

[Hawkeye]

What I want is a 16" Midlength Chrome-lined 6.8 barrel with a pinned on gas block and M4 feedramps. Anyone make THAT?

Jason
CMMG does both a govt profile and a medium contour 16" chrome lined 6.8 barrels. I am thinking real hard about the medium contour one.

[deadwood83]

many twist problems would be solved by the propper application of the 1/8 twist:D