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Warg
05-07-12, 10:31
Decided to treat myself to an 18" Kreiger barrel which is configured for rifle length gas. Given the shorter dwell time, I'm unsure whether I should use a rifle length RE, an A5 and which buffer and spring combo to start with. I plan on using a standard weight carrier and will be using .223 match and 5.56 ammunition. May also consider a lightweight JP carrier and low mass buffer if that would work better.

This rifle will be configured for precision work, FWIW.

Thanks.
AR15barrels
05-07-12, 11:02
Use a standard spring for the buffer tube length you go with.
The buffer choice will be determined by the gas port size and the ammo.
What size port are they drilling?
A Jp low mass buffer actually needs a slightly larger port on an 18" rifle gassed barrel than a standard rifle buffer does.
A Jp low mass buffer is the same weight as a standard carbine buffer, but the spring rate of a rifle length buffer tube and spring is lower than a carbine spring and buffer tube.
Warg
05-07-12, 11:17
Use a standard spring for the buffer tube length you go with.
The buffer choice will be determined by the gas port size and the ammo.
What size port are they drilling?
A Jp low mass buffer actually needs a slightly larger port on an 18" rifle gassed barrel than a standard rifle buffer does.
A Jp low mass buffer is the same weight as a standard carbine buffer, but the spring rate of a rifle length buffer tube and spring is lower than a carbine spring and buffer tube.

I believe it is 0.102
308sako
05-08-12, 15:26
http://i181.photobucket.com/albums/x160/308sako/DSCN0040-1.jpg


http://i181.photobucket.com/albums/x160/308sako/RockPebble.jpg

Mine is a Melonited or QPQ'd Rock Creek 1 in 8 twist 5R pattern barrel and the port size you mention should be perfect.

I run a standard buffer with a Tubb CS spring with a lightweight or 1/2 moon Colt SP 1 carrier. The gas block is a Noveske Switchblock, and the rifle runs 100%.
a0cake
05-08-12, 15:44
double.
a0cake
05-08-12, 15:45
308Sako, I bet that thing will shoot the wings off a fly. Nicely done. Whenever I shoot out my BCM SS410 I'm going to go the melonited chrome-moly barrel route. Any comments on the process, who did it, etc?
Warg
05-08-12, 15:49
http://i181.photobucket.com/albums/x160/308sako/DSCN0040-1.jpg


http://i181.photobucket.com/albums/x160/308sako/RockPebble.jpg

Mine is a Melonited or QPQ'd Rock Creek 1 in 8 twist 5R pattern barrel and the port size you mention should be perfect.

I run a standard buffer with a Tubb CS spring with a lightweight or 1/2 moon Colt SP 1 carrier. The gas block is a Noveske Switchblock, and the rifle runs 100%.

Thanks for the information. Nice rifle too.
Warg
05-08-12, 15:53
Make sure it's hand-lapped.

308sako, that was an inside joke.


308Sako, I bet that thing will shoot the wings off a fly. Nicely done. Whenever I shoot out my BCM SS410 I'm going to go the melonited chrome-moly barrel route. Any comments on the process, who did it, etc?
308sako
05-13-12, 18:23
Paul Tolvstad at Rock Creek Barrels handled the profiling and QPQ (Melonite) issues for me. I have found the rifle to be a very accurate shooter, but one would expect so considering the pedigree.
a0cake
05-13-12, 18:28
EDIT.
VegasKyle
05-13-12, 19:18
I have a Mk12 upper with an original SPR barrel and I've used it with a rifle RE, std spring and weight wit no problems. I've also used with a carbine RE and H buffer with no problems as well as a SR-15 lower (I cant remember where the SR-15 weight fits in) and had no problems. At least in my case it's proven to be a forgiving system.

All ammo was 5.56 pressure. Couldn't atest to how it would run on Wolf or anything else.
Warg
05-13-12, 19:22
Why, because I criticized the fact that the Nordic-Lilja barrels were not hand lapped in another thread? You don't think it's important in a match barrel?

Or am I missing something?

No, again (per the other thread) we're on the same page. My attempt at humor was supposed to reflect that, but apparently it failed.
a0cake
05-13-12, 19:23
No, again (per the other thread) we're on the same page. My attempt at humor was supposed to reflect that, but apparently it failed.

It's cool man I just didn't know what was going on. :lol:
Singlestack Wonder
05-14-12, 16:38
For their SPR 18" uppers with rifle length gas systems, Bravo Company recommends an H3 buffer.
munch520
05-14-12, 16:53
I have used the factory A5 system on my MK12 with 0 issues through the last 300 rounds (low I know, just got it a couple weeks ago). Federal 55gr all the way up to MK262.

http://i163.photobucket.com/albums/t294/myersma2/MK12/IMG_1715.jpg
http://i163.photobucket.com/albums/t294/myersma2/MK12/IMG_1676.jpg
Warg
05-16-12, 15:41
Thanks guys. That's exactly the information I needed.
TAZ
05-16-12, 16:42
I have a WOA 18" 1:7 barrel and I've used a standard rifle spring and buffer with an A2 and PRS and had no issues launching any ammo down range. I currently run a UBR with carbine buffer and spring. No issues with that set up either. Keep meaning to try an H2 and H3 for grins, but it's low priority for now.
mic2377
05-17-12, 13:44
I currently have a Nordic 18" rifle-gas barrel, 1/8 twist. It is a medium-weight barrel that I have a hunch was turned down from another manufacturer's blank.

I am currently running it with a carbine ext, carbine spring, H buffer, and Kies adjustable gas block. It runs 100% with .223 and 5.56 ammo. It seems like this barrel in particular comes with a fairly small gas port as the block is almost open all the way.

I will be trying an H2 and H3 this weekend and playing with the gas block some more.

Overall, the 18" rifle-gas seems to be a fairly tolerant system.
Alaska3006
04-14-14, 19:49
Decided to treat myself to an 18" Kreiger barrel which is configured for rifle length gas. Given the shorter dwell time, I'm unsure whether I should use a rifle length RE, an A5 and which buffer and spring combo to start with. I plan on using a standard weight carrier and will be using .223 match and 5.56 ammunition. May also consider a lightweight JP carrier and low mass buffer if that would work better.

This rifle will be configured for precision work, FWIW.

Thanks.

With my MK 12 Mod 0
I have 2 stocks

My B5 Enhanced Carbine
with Damaged Ind H6 ......5 OZ buffer
And Damaged Ind Enhanced CS carbine Spring.....

And my A2 Stock with Stock A2 Rifle Buffer.....and Damaged Ind CS Rifle Spring.

Most of my loads are the 77 gr MK.