reloading tweaks for the CZ chambers

[brian45acp]

I run the sp-01 stock minus the sights because I actually like the gun as it is. Having said that the very stout sp-01 recoil spring I just realized is more forgiving of ammo issues. What I just discovered was that after buying my Rami the gun itself is less forgiving of any ammo discrepancies and my reloads need some tweaking. I already figured out very quickly CZ needs shorter OAL based on bullet profiles. What I now found was that some of my ammo is producing a bulge in the brass right at the base of the bullet when its seated. The bulge often times is worse on one side then the other.

The round would not feed in my Rami under normal firing conditions but on my SP-01 it would. However if I tried to slowly chamber it in the sp-01 it would hand up just the same. Pressing the rear of the slide would shove it in though. The really strange part is that I saved one of these rounds until I got home to inspect it. It will pass the barrel test dropping in and spinning and fall back out. However it wont feed from the mag into the chamber. I cant figure out why this is other then perhaps since the round is being fed at an angle the bulge may cause it to bind and not allow the slide to move all the way into battery. Also once the extractor has a hold of it its not going to enter the chamber perfectly straight like it would doing the barrel drop in test.

My only plan is to add a bit more bell and crimp. I have no perceivable bell on my brass before the seating station and I think because of that the bullet may get forced in at an angle and cause the brass to stretch creating that bulge.

These CZ chambers are picky for sure on reloads but factory ammo they seem to not be picky which is a relief for my self defense ammo.

Any advice? Thanks

[zzt]

I use a chamber checker on all the ammo I will use in competition. If it fails the test it gets put in the practice ammo pile. What you are experiencing is quite normal with range pickup or once-fired brass. Some chambers are relatively unsupported and cause the "Glock bulge". That weakens the brass on one side. Even if you fully resize it, it may show a bulge on one side of the case after the bullet is seated. There is no adjustment to you press that will eliminate this. Even if you use a two-step expander so the bullet goes straight in, you'll get the one sided bulge on some cases.

You will find that if the bullet fails to feed and causes a jam, it will feed fine once removed an put back in a mag in a different position. It all depends on the position of the bulge when feeding.

[MRevolutionIX]

After getting a backup gun (SP01 Shadow) to my AccuShadow. I quickly realized my handloads were too long to chamber my backup gun. A backup gun that cannot take my normal ammo is useless to me. I didnt want to change my current load because it works well with my primary gun so I opted to have the barrel in my backup gun opened up a bit (throat and reamed). My loads now "plunk" test fine and accuracy is still on par with the test target.

[brian45acp]

Thanks guys.

The bulge isnt near the base of the brass its directly at the base of the bullet which is about half way in the body of the case. I am buying once fired brass 9mm that has been cleaned and polished. I could opt for the de primed and roll sized brass for a bit more money.

zzt: You are right that cartridge if spun a different direction would feed.

All the rounds chamber check and pass the barrel test but under normal feeding from the mag the issue presents itself which is odd to me.

Edited May 25, 2015 by brian45acp