Hello! I have the opportunity to pick up a cz 527 in 7.62x39, I'd like to convert it to 6 arc, what would that process look like? I know the bolt face is slightly different and I'd need a new barrel, how would I fix the bolt face issue? I've never converted a rifle to a new caliber before.

Thanks,
Love your forum.

I ran across this forum doing a Google search and after checking it out, joined. I have been a big fan of the 6mm cartridges and acquired a 6.5 Grendel with the intention of converting it to 6ARC.  

Anyhow, nice to meet you all.

Im looking into swapping out the 300 blackout barrel on my mk18 mod1 to an 11 inch 6 arc barrel. The couple sites im looking at allow you to choose the gas tube length for the barrel. Options are pistol, carbine and midlength. 

my concern comes from way more experience with 556 than 6 arc. I know i need to account for dwell time. My goal is to keep my mk18 clone but upgrade to a better round. It will be suppressed with a sandman k. 

can someone with way more arc experience school me on tube length for 6 arc barrels? Id love to go mid length, but i know mid on 556 requires tuning. I want to avoid adjustable gas blocks, lighter springs or buffers, etc. 

current set up for consideration. 
geissele braided H1 buffer and braided spring, SSA-E trigger, PSA grendal BCG, geissele CH, deadair brake, sandman k. 
running either 108 ELD-Ms or 77 grain cutting edge bullets. 

all advice is appreciated.

Having a small collection of commonly used 105gr bullets I decided to take some measurements and make notes for my folder. This is in no way conclusive or extensive but I thought it would give a fair indication of bullet consistency. Measurements are taken with no special tools are should be representative of what most people will have on their benches. Just an inexpensive digital caliper, digital scale and a Hornady bullet comparator.

Unfortunately at this time I do not have any Berger bullets to include but when I get some I will edit this and add to it.

List will be OAL" - BTO" - Weight, gr

Hornady BTHP Match 105gr

1.2290 - .7410 - 105.16
1.2260 - .7400 - 105.10
1.2260 - .7420 - 105.08
1.2285 - .7415 - 105.00
1.2260 - .7420 - 105.28

Lapua Scenar 105gr

1.2525 - .7305 - 104.86
1.2585 - .7380 - 104.74
1.2580 - .7360 - 104.82
1.2625 - .7285 - 104.84
1.2555 - .7305 - 104.90

Barnes Match Burner 105gr

1.2000 - .6535 - 104.96
1.2095 - .6535 - 105.16
1.1900 - .6500 - 105.12
1.2060 - .6535 - 105.06
1.2040 - .6535 - 105.14

When I put my build together, I bought 2x 10 Round MDT AICS pattern magazines in 6ARC/6.5 Grendal, they work, but the issue is that I am using the American Rifle Company Coup De Grace action which is AW cut, so I had to trim a bit of the mag catch on the back of the magazines in order to get them to seat in the chassis.  They feed fine, however, I am also working towards the AW pattern mags, and knowing that was a less common item, didn't expect to see any in 6 ARC specifically, so settled on 308, partially because 300 Win Mag, 338 Lapua, and 50 BMG are the only other ones out there right now, all 'a little too big'.

I was able to get lucky on ammoseek and Optics Planet had some 308 available, and have received a pair of them yesterday.  They seat well into the build, and as you are likely expecting at this point, the rounds don't exactly like the extra room in the mags.  I can seat them forward in the mag, but I don't think there is much/enough tension holding them in against the lips, and am curious if any one has ideas other than just being gentle with it.

One of the big advantages with these is they are double stack, so I wouldn't have to be killing fingertips when loading rounds into them.

Mostly looking for cross compatibility thoughts, and workarounds people have used.

Pros and Cons for this

Thanks

Im fairly new to reloading and would like to understand the different approaches reloaders used to develop their loads. Please share your load development process?

Still learning this cartridge and it's idiosyncrasies so today I did a little investigating and an inconclusive test with these two brands of brass..

Took one piece each and plugged the primer pockets with an upside down primer and then used my new Hodgdon LeveRevolution powder as the media to try and measure case volume.

After five drops and leveling off full cases the Hornady averaged 148.5gr and the Starline avg. was 147.4gr The cases themselves weighed; Hornady 110.7gr., Starline 109.3gr..

So with this short test it looks like the deviation between the two brands is not that great. Being only 0.3gr difference. With the Starline have a slightly larger capacity.

I got this from another site and was interesting

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Finally got a picture together of my rig, it shoots, it kills gophers, it makes me smile, mission accomplished.  Side mission is to now get it to shoot it better, or at least me be able to shoot what it is capable of, once I find a recipe it likes.

MDT Timbr chassis
American Rifle Complany Coup de Grace Action
Preferred Barrel Blanks prefit barrel, 26" 1:7 twist, M24 contour
Triggertech Diamond Single Stage trigger, very light, very crisp, my oh my
Vortex Viper 6-24x50 HS-T, SFP, simple reticle, I like a clean scope