Home Forums Hunting & Shooting Gunsmithing 6.8 SPC bolt gun

Greetings everyone.

I have a hankering to put together a 6.8 spc bolt gun running on a CZ 527 (mini Mauser type) .223 and wonder if anyone has managed to do this with success?

My apologies if this has already been covered.

I did two of them when the cartridge was first introduced on the iterarms/daly/remington mini mauser action for a client when I was still in business. No issues, but my biggest concern was the modification of the extractor. Didnt want to mess it up as they were always tough to get replacements.

Thanks for the reply.

What size did you make the bolt face? I worked out around .427...
Re the extractor claw, was there much to come off this to pick up the new case?

Sorry I don't remember the exact size I opened up the bolt to. I do remember that there wasn't much to fitting the extractor as all my worry when I accepted the job was unjustified. The CZ 527 is different but I don't think it should cause much problem.

I have done them on CZ 527s and on 2 Howa 223s also. The Howa was super simple. Open the bolt face and rebarrel.

The CZ was also easy. Open the bolt face and extractor, rebarrel and then swap out the magazine and bottom metal for CZ parts made for the 7.62X39. A slight tweak on the feed lips and the guns worked perfectly.

Oh.......open the bolt face to .426"

Thanks for the reply.

Was there much to take off from the extractor on the CZ? I had figured using the 7.62x39 was the best option.

You only need to open the hook about .045"


And you can't use the 7.62X39 bolt because the recess is already too big. You have to start with the 222/223 bolt.

Thanks, it’s the 223 I have but the mag and bottom metal won’t run it so need the 7.62x39.

Looking forward to making this work. How have you found it in terms of use as a light hunt gun?

Bolt face needs to be slight larger then .422. I built mine on a savage and bought a bolt head from PTG. Shoots 3/4 inch groups if I do my part.
Any decent gunsmith can open up the bolt face on 223 bolt.

Note: .045" is what the diameter of the "bite" is going to be. The actual metal to remove from the hook itself is 1/2 of that. I do them by "feel" so the Mauser style extractor flexes about .005 when the shell head is in place, which keeps tension on the extractor and hold the shell from dropping off as you move the bolt rearward slowly.

The bolt heads and the hooks are not held to absolute specs as they come, so giving mathematical specs to cut is not the best way to do the work. It's best to cut the hook open about .020" and then go very slowly one stroke at a time, or in "zips" with a die grinder until your rifle feeds and functions perfectly. You want the extractor to hold the shell in places, but you don't want to have to use much force to slide the bolt forward.

It's a process of going back and forth a few times, but pretty easy to do. I set them so you can just barely feel the resistance of the shell head slipping under the hook as you feed from the magazine, but when pulling the shell out of the chamber shaking the rifle will not cause it to come loose from the bolt face before it hits the ejector.

On the Sako styles (M-16 types) and "T Head" extractors you simply open the hook and cam surfaces up about .023" and they are "self adjusting" because the hooks are either pivoting or sliding in their functions.

It's not hard to do. The explanation may seem to indicate it's difficult, but it's really not at all.