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View Full Version : Issues with Jams in new CZ-75 barrel



KrakenFan69
09-25-2017, 08:46 PM
I had to replace my new CZ-75 SP-01 (non Shadow) barrel. The new barrel is having mad issues with projectiles not going to battery. It had been set with Go/no Go guages, then hogged out a bit more (twice) to give it a little more room. It still seems to catch the odd Magma Engineering 124gn BB NLG Hi-Tek coated projectile sized to .356 on the ogive which then is a bear to eject. I played with seating depth a bit more and I had to push it to 1.053" to get it to easily pass the barrel plunk test. That seems ridiculously short. I was wondering what the shortest people have ran in some of their guns. I also tried a Lee 125-356 2R and is passes at 1.063" Still very, very short. I have not fired any at those seating depths, just dummy rounds. If I grab a Magma 147gn FN BB NLG loaded out to 1.113" it passes fine. Also the Berry 125gn TMJ rounds loaded to 1.106 seem ok. It is more of a slanted ogive than the 1R/2R is and seems to fit fine. I am a bit confused as to whether or not I should ream out the chamber more or just switch over to the 147gn and be done. Thoughts? Damn, I really liked those 124gn BB NLG projectiles too.

Kraken Fan #69

tazman
09-25-2017, 10:17 PM
You need to have the barrel throated. The boolits are jamming into the rifling causing your failure to go into battery.
I would recommend Dougguy. He did a couple of barrels for me that had the same issue and did a wonderful job.

Bzcraig
09-25-2017, 10:18 PM
I would open the chamber or rather have DougGuy do it since I don't have the tooling or talent.

runfiverun
09-26-2017, 01:37 AM
I have a load that runs at .98 oal

if your jamming into the rifling you need the throat cut.

Virginia John
09-26-2017, 10:13 AM
I concur with the throating but you may just adjust the OAL for this specific barrel by "plunking". That is cheaper than all that machining.

KrakenFan69
09-26-2017, 12:55 PM
Thanks for the replies. The machinist that fit my new barrel will do it for me as part of the install. Just a little concerned about hoggin out too much and pooching the barrel.

Kraken Fan #69

tazman
09-26-2017, 04:43 PM
Thanks for the replies. The machinist that fit my new barrel will do it for me as part of the install. Just a little concerned about hoggin out too much and pooching the barrel.

Kraken Fan #69

At this point your gunsmith shouldn't be making the chamber longer. He should be tapering the rifling where it starts just in front of the barrel or giving it a little freebore. The actual chamber dimensions should not change.

blue32
09-26-2017, 04:48 PM
I had the same problem in my 75 Compact. Problem solved with the Lee 356-120-TC at 1.030. I think you'll find that if one bullet doesn't work in the 75 its best to keep trying others.