Possible Issue with CZ 527 7.62x39mm Carbine

[EchoM70]

Hey Guys,

I just got my CZ 7.62x39mm Carbine from my FFL and while I'm overall extremely excited to have the rifle. I've been working toward getting one for awhile. However there is something troubling me about it. I have both some PPU Brass cased and Hornady Zombie Max ammo that is extremely hard to close the bolt on. Like on some rounds I almost need to bring out a mallet to get the bolt handle down. However I also Have some cheap Tula steel cased ammo that the bolt closes on perfectly. I've heard that the chamber is to Russian specs and not SAAMI specs and some american made ammo can be troublesome. However I've seen videos and I have read reviews stating that the Z-max ammo and others have worked perfectly for them.

I wouldn't think it is the chamber or headspacing because of being able to chamber the steel case ammo... It almost has to be the ammo. what do you guys think?

Edit: Just wanted to add, I have not shot the rifle yet. Just chambered some rounds, something I have always done with a new firearm as a function test.

 

[HOOfan_1]

Close it on one of those rounds, then eject it without shooting it...see if there are any marks on the bullet. I wonder if is an OAL problem

 

[EchoM70]

I thought about that at first, COAL is actually shorter on the PPU ammo than the Tula. The Z-Max is within spec. I checked the bullets for marks but there was none.

 

[Inebriated]

I can't comment on why, but I had two boxes of PPU .243 Win that was also very difficult to close a bolt on. Two different rifles, both tight. Shot fine, no pressure signs or anything, but it was unusual.

 

[EchoM70]

I think I figured it out. It's the magazine. Upon closer inspection what seems to be happening is within the last two rounds the magazine cants the rounds preventing them from the claw to pick them up. However the claw is still able to push the rounds into the chamber and upon closing the extra force is from the claw having to snap over the rim when closing the bolt. Further proof of this is now all ammo types I own are doing exactly the same thing.

Now... Short of buying a new magazine, how do I fix this issue?

 

[eastbank]

call cz,they are very good at taking care of any problems with their products. eastbank.

 

[HOOfan_1]

I think I figured it out. It's the magazine. Upon closer inspection what seems to be happening is within the last two rounds the magazine cants the rounds preventing them from the claw to pick them up. However the claw is still able to push the rounds into the chamber and upon closing the extra force is from the claw having to snap over the rim when closing the bolt. Further proof of this is now all ammo types I own are doing exactly the same thing.

Now... Short of buying a new magazine, how do I fix this issue?

Same thing happens with my CZ 550, I've often had hang ups feeding the last round from the magazine depending on the bullet profile. The Claw doesn't engage most of the round straight from the magazine, they just kind of pop out of the magazine into the chamber and the extractor has to pop over them. I don't have to use much force to close the bolt though.

 

[chicharrones]

I had something like that happen on a Zastava bolt gun of mine. The last round wouldn't pop under the extractor correctly before chambering.

In my situation, I expanded the magazine spring to add more pressure for that last round. I also had to modify the mag follower a tad to let ride up a tiny bit higher in the mag. All in the name of getting the last round all the way up.

Still, my particular gun had a rough-ish bolt face and inside the extractor claw that I polished to allow the cartridges to slide up under the extractor more slickly.

Since I don't know that CZ magazine, does it have a follower with a front and rear leg on it or is it one piece? if it has legs, you can tweak them to change the angle of your ammo a bit. I'm sure the 7.62x39 doesn't exactly lay the same in a mag when loaded with 5 when compared to only 1.

 

[solvability]

When you can please publish your groups with different ammo - I am interested in the rifle and wonder how well it does for you.

 

[gazpacho]

Take it to a gun smith or get a set of GO NO-GO gauges to check head-spacing.

 

[MyRoad]

When I first read the OP I thought this was going somewhere else -- my CZ's bolt will jam if I use lacquered ammo. Specifically, when I try to pull the bolt back to eject the spent round, the bolt will jam partially open. It seems that the ejector (I hope I'm identifying the part correctly) doesn't fit properly over the slightly thicker rim of a lacquered case, and since its sitting wide -- not fully closed (not sure how else to describe that?) -- when the bolt is pulled back the ejector is slightly sticking out making the bolt too wide, and the bolt gets stuck before the spent case can be ejected.

No problems with polymer coated or brass cases of any manufacturer, just the lacquered stuff (was using older Brown Bear I had, surprisingly consistent ammo). I bought some VMax in bulk, that's all I use in it now.

 

[armoredman]

I've put more than a few rounds downrange with my 527M in 7.62x39mm, easily my favorite rifle. Never had that type of jam happen. That might be due to the fact that I use almost exclusively home loaded ammo, and very little factory or imported stuff. But, what I have used, which also includes Zombie Max, worked just fine. Zombie Max shown here for the heck of it.



But seriously, if this is a constant problem, dial 1-800-955-4486, press 2 for Parts and ask Adam for the gunsmith, or a new magazine. Do you have more than one magazine to try?

 

[fotheringill]

ECHO

It may not be the magazine.

My shooting pal just purchased a CZ 527 in 7.62x.39.

He had the exact same problem with the last two rounds with the next round stove piping against the spent shell on the last two in the magazine.

CZ's answer, and this is not an exact quote was ... use only premium brass ammunition. He did and the problem disappeared.

Now the other strange thing. I brought in some Serbian or Croatian ammo made about 12 years ago. The bolt would not close. Upon examination, the neck was a bit longer on the old ammo.