I am not an expert with the CZ rifles, so take the following with a grain of salt:
I bought one of these a while ago and, like most folks, started off by shooting a bunch of the cheap, Russian, steel-cased ammo. Functioned flawlessly.
I then bought some factory brass cased ammo (PMC) for the brass and, also like a lot of folks, found that nearly half the rounds suffered light primer strikes. The issue has to do with minor, but apparently significant, chamber dimension differencess between the CZ's CIP chamber and ammo based on the SAAMI chamber.
My solution was to insert a 0.030" spacer on top of the shell holder when I installed the RCBS (SAAMI) sizer die. Effectively, this leaves the rounds fire formed in the CIP chamber except for that portion of the neck that is more than about 30 thou forward of the shoulder. I'm pleased to report that every single round functioned flawlessly this morning.
Load data follows:
I bought one of these a while ago and, like most folks, started off by shooting a bunch of the cheap, Russian, steel-cased ammo. Functioned flawlessly.
I then bought some factory brass cased ammo (PMC) for the brass and, also like a lot of folks, found that nearly half the rounds suffered light primer strikes. The issue has to do with minor, but apparently significant, chamber dimension differencess between the CZ's CIP chamber and ammo based on the SAAMI chamber.
My solution was to insert a 0.030" spacer on top of the shell holder when I installed the RCBS (SAAMI) sizer die. Effectively, this leaves the rounds fire formed in the CIP chamber except for that portion of the neck that is more than about 30 thou forward of the shoulder. I'm pleased to report that every single round functioned flawlessly this morning.
Load data follows:
Code:
7.62 x 39 Chrono Data
Date: 8/28//2017 - 70F - HSC Date: 8/28//2017 - 70F - HSC
Gun: CZ 527 18-1/2" 1:9 Carbine Gun: CZ 527 18-1/2" 1:9 Carbine
Round: 7.62 x 39 mm Russian Round: 7.62 x 39 mm Russian
Load: 123 gr. Hornady PSP COAL: 2.192" Load: 123 gr. Hornady PSP COAL: 2.192"
25.5 gr. A-1680 26.0 gr. A-1680
1 2201 Mean: 2248 1 2336 Mean: 2314
2 2226 Max: 2311 2 2336 Max: 2338
3 2227 Min: 2201 3 2307 Min: 2251
4 2274 ED: 110 4 2338 ED: 87
5 2311 SD: 44.10 5 2251 SD: 37.29
6 CoVar: 1.96% 6 CoVar: 1.61%
7 7
Date: 8/28//2017 - 70F - HSC Date: 8/28//2017 - 70F - HSC
Gun: CZ 527 18-1/2" 1:9 Carbine Gun: CZ 527 18-1/2" 1:9 Carbine
Round: 7.62 x 39 mm Russian Round: 7.62 x 39 mm Russian
Load: 123 gr. Hornady PSP COAL: 2.192" Load: 123 gr. Hornady PSP COAL: 2.192"
26.5 gr. A-1680 27.0 gr. A-1680
1 2353 Mean: 2378 1 2408 Mean: 2400
2 2363 Max: 2415 2 2399 Max: 2421
3 2382 Min: 2353 3 2421 Min: 2377
4 2415 ED: 62 4 2377 ED: 44
5 SD: 27.29 5 2397 SD: 16.15
6 CoVar: 1.15% 6 CoVar: 0.67%
7 7
Note: PMC Brass, sized 0.030" shy of shell holder, to avoid light primer strikes with factory SAAMI ammo. Worked:
function was 100%.