[usmc_mwroseberry]

Ghillie installed a 1 in 7" twist barrel on my C93. Which is the heaviest grain weight round which will feed reliably in my rifle? I would like to run the 69grain weight bullet or heavier if possible because I'm going to be competing in an iron sight 580 yard match next month.

Thank you,
Merritt

 

[pb_removed]

You'll be fine with 69gr in 1:7".

77gr and lower for 1:7" carbines is the general rule for most.

 

[usmc_mwroseberry]

I know I won't have stability issues. I do alot of long range tactical shooting (7-08 bolt gun out to 1 mile shooting at 12"x12" plate). I'm more worried about reliable mag feed.

Thank you for the quick response though.

Thank you,
Merritt

 

[pb_removed]

My fault. I've always wanted to know if mk262 would work reliably in this system.

 

[JTinIN]

The Mk262 should feed out of the mag. I have used Wolf 75gr in the MM23eK and possible in the MM53, works great in the ARs for sure.

 

[Munch520]

Does 77 even fit in standard magazines?

 

[Uriah]

75gr fits and feeds fine. Don't know about 77 in particular, but I don't see any reason for it not to feed fine so long as there are not fit issues in the mags.

 

[pb_removed]

Is there any concern of set-back during feeding with some of these "match" bullets (as with the original mk262 with its lack of cannelure and feeding in the AR platform)?

 

[JTinIN]

High power shooters fire the rapid fire stages with out any crimp or cannelure, just make sure is a tight and consistent neck plus most of the long range loads are "full" of powder ;-).

 

[gunman40]

hornady 75g are meant to fit in a magazine when loaded.

 

[RyanW]

I've been shooting Black Hills 77gr with PMags and HK mags through my LWRC M6A3 with no feed issues. Everyone I've talked to says 80gr+ has to be manually fed.

 

[tmbrwulf]

Ive had no issues with everything up to 77 hpbt. The 80's do need to be feed manually but that is for the comp guys who have their bbl's throated for that round too. 55's work in a 1/7 but not cheap ones, they fly all over the place.

 

[Munch520]

I've been shooting Black Hills 77gr with PMags and HK mags through my LWRC M6A3 with no feed issues. Everyone I've talked to says 80gr+ has to be manually fed.

Thanks for that! I usually use xm193 and 855 for training. But I want a SPR upper and have been curious what I can run in it (mag fed)

 

[dbarnhart]

There is a chart somewhere on Brownell's website for barrel twist vs bullet weight. I've reproduced a portion of it here:


Barrel Twist vs Bullet Weight | ShootAndReload.com

 

[usmc_mwroseberry]

There is a chart somewhere on Brownell's website for barrel twist vs bullet weight. I've reproduced a portion of it here:


Barrel Twist vs Bullet Weight | ShootAndReload.com

That's a good rule of thumb but stability has more to do with speed and actual length of projectile than grain weight. And bullets of the same grain weight may have very different lengths. Thank you everyone for the input and it sounds like the 77gr rounds will be getting tested as soon as my rifle comes back from ghillie.

Thank you,
Merritt