CMMG lightweight upper question.

[arthurcw]

Anyone had any experience with this upper?

CMMG 16" 1/7 Lightweight Mid-Length Upper w/625" FSB. Forth listing on this page: http://cmmginc.secure-mall.com/shop/?shop=1&cart=938524&cat=61&

I’d rather it be 1/9 twist. But my Google-fu and Ask-arate have failed me and this is the only midlength light weight upper I’ve found.

Thanks,
ACW.

 

[rbernie]

It's VERY nice; I have two (and one of their lightweight 20" models). Accuracy is good, build quality is excellent.

 

[arthurcw]

It's VERY nice; I have two (and one of their lightweight 20" models). Accuracy is good, build quality is excellent.

Do you think you give up too much perfomance on the cheaper 55gr bullets?

I'll be getting into realoading if I get it, so I can call my own tune. But it would be nice to know if I'm lossing too much with the cheaper plinking ammo.

 

[blackhawk2000]

1:7 works fine with 55g. Unless you want to shoot the really light varmint stuff, stick with the 1:7.

 

[rbernie]

The CMMG barrels shoot the 55gr fodder quite well - I've been using the Hornady, Winchester, and MidSouth generic bullets in my handloads with fine success.

 

[Soybomb]

I have the cmmg light barrel but haven't built it into an upper yet. I believe adco will turn down rra barrels to whatever profile you want for a somewhat reasonable fee. Maybe they'd have the 1/9 twist you want although for 55gr 1/7 will be fine.

 

[atek3]

I have the CMMG 16" medcon upper 1/7 on my rifle... i love it. tackdriver and reliable.

atek3

 

[Bartholomew Roberts]

Don't worry about loss of performance between 1:9 and 1:7 on 55gr ammo unless you can already appreciate 0.25MOA at 100yds difference.

If you want exact numbers, a poster named Molon at AR15.com took two same profile Colt barrels, one 1:7 and one 1:9 and shot 55gr out of them to establish just how much the different twist rate affects accuracy and dispersion. The answer is that the 1:9 DOES shoot better; but you have to be one hell of a shot to appreciate it (and you probably need to be benched, sandbagged and have a big ol' scope as well).

 

[Brian Williams]

They look nice, a little pricey, but nice.

 

[arthurcw]

Thanks guys.

I'm trying to design a middy that is just a tad bit lighter for the Mrs. I'm going to show her all of this and see what she says.

And no... I will not notice the difference in accuracy. But she might, she shoots better that I do. But I’m the cook, so she can’t lord it over me or she gets beans and rice.

Seriously, as long as the 1/7 will handle defensive ammo like 55gr Hornady TAP and the like, I'm good with giving up the light weight varmint rounds. If we ever want a Varminter, we'll get a different upper.

Thanks again.

 

[arthurcw]

gonna add this.

If anyone has any other suggestions in this category, please offer them.

Thanks.