The Original CZ Forum
CZ PISTOL CLUBS => CZ Polymer Pistols: P10, P-07, P-09 => Topic started by: Earl Keese on November 30, 2018, 09:56:56 AM
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My P10C is milled for an RMR and I use the OEM recoil spring. After mounting the RMR, I tried running a lighter recoil spring but had some failures to return to battery. Occasionally I get these jams, but only with coated bullets. Anybody else have this issue?(https://uploads.tapatalk-cdn.com/20181130/1f722330157bf164e175ab68fa30e163.jpg)
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I have used some Minuteman Munitions Poly 125 gr. ammo and did not have issues. Sorry I can't be of any help. What type of ammo is pictured?
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My reloads, ACME 124's.
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Did it have the same issue with the factory recoil spring assembly? The slide speed is a fine line of extracting/ejecting the spent round and the timing of the live rounds moving up the magazine in time and feeding into the chamber. David
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Did you try it with stock spring with RMR? Seems your assumption was that RMR adding weight and so changed to the lighter spring. Have a Before and After comparison should be more telling.
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Did it have the same issue with the factory recoil spring assembly? The slide speed is a fine line of extracting/ejecting the spent round and the timing of the live rounds moving up the magazine in time and feeding into the chamber. David
I happens with the OEM recoil spring. The gun wouldn't cycle reliably with lighter springs and a CGW P-07 rod.
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Did you try it with stock spring with RMR? Seems your assumption was that RMR adding weight and so changed to the lighter spring. Have a Before and After comparison should be more telling.
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RMR adds zero weight as it weighs basically the exact amount as the material removed from milling.
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It looks like the slide is not completely stripping a round from the magazine and the bottom of the breach face is catching the bullet itself. Any photos of the failure when it happens? I'm trying to figure out what might cause that and the main thing I've got is that the slide is short stroking and not stripping a new round correctly. Normally, that would be resolved by a lighter recoil spring, but you've tried that with no luck. How fresh are the mag springs? It's hard to imagine any P10C having tired mag springs with as new as they are, but if you are using modifed P07 mags, the springs might be tired.
How light of a load are you running? It could be that with a light target load and the possible deviation between rounds, that you are getting an occasional subpar round that's just not cycling the slide far enough. Could be the COL might be causing the bullet nose to drag in the mag interfering with the feeding.
Lots of ideas there. Sorry for shotgunning the diagnosis, but with only a couple of photos to go by, there are plenty of possibilities.
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Here is what I would do if it was my gun. I have an early P10C with a milled in RMR. Put the pistol back stock. Just like from the factory except for the RMR. Use factory ammo. WW white box or Federal bulk or even NATO 124 FMJ. If the factory stuff won?t function then it?s your reloads. I shoot PC bullets in mine with zero issues tho.
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First few hundred rounds after I had my slide milled for RMR and black nitride finished by Jagerwerks I had the same problem. Was previously using a 15 lb recoil spring. Had to revert back to an 18 lb. Now that i?ve been shooting it for a while I can go back to a 15 lb spring. My guess is I had to break the pistol back in after refinishing.
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Is that coating and lead shaved off the bullet?
If so, is it shaving it off the top of the bullet or the bottom? Is the bullet still in the magazine, but pushed forward a bit? Or it hung up on the feed ramp of the barrel?
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Is that coating and lead shaved off the bullet?
If so, is it shaving it off the top of the bullet or the bottom? Is the bullet still in the magazine, but pushed forward a bit? Or it hung up on the feed ramp of the barrel?
Feed ramp. More of a huge dent on top than shaving. [emoji16]
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It looks like the slide is not completely stripping a round from the magazine and the bottom of the breach face is catching the bullet itself. Any photos of the failure when it happens? I'm trying to figure out what might cause that and the main thing I've got is that the slide is short stroking and not stripping a new round correctly. Normally, that would be resolved by a lighter recoil spring, but you've tried that with no luck. How fresh are the mag springs? It's hard to imagine any P10C having tired mag springs with as new as they are, but if you are using modifed P07 mags, the springs might be tired.
How light of a load are you running? It could be that with a light target load and the possible deviation between rounds, that you are getting an occasional subpar round that's just not cycling the slide far enough. Could be the COL might be causing the bullet nose to drag in the mag interfering with the feeding.
Lots of ideas there. Sorry for shotgunning the diagnosis, but with only a couple of photos to go by, there are plenty of possibilities.
Looking at the dent in the bullets, this makes sense(breech face contact). Load has been chronoed a few times at 1085fps, so 134.5pf. My S.D's are typically fairly low, but a weak charge can't be ruled out. I will say, they didn't sound or feel different from other rounds. OAL is 1.11.
These 3 failures were on the tail end of a training class(800rds), so the gun was pretty dirty and the jambs were cleared quickly. I'm going to retry the lighter springs soon. I may need to turn the guide rod down a little. I have a Primary Machine barrel on the way, so I'm not going to change much until that goes in. After that, I'll try adjusting oal and re-chrono.
FWIW, the gun never ran 100% with the FLGR and lighter springs, so I wasn't implying a change after mounting the RMR.
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I use coated cast lead bullets all the time and no issues - my COAL is 1.095, works best in all of my CZ pistols. Have you tried a different bullet profile, like a truncated cone?
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I use coated cast lead bullets all the time and no issues - my COAL is 1.095, works best in all of my CZ pistols. Have you tried a different bullet profile, like a truncated cone?
Tried some Acme 147 flat points, no issues but only a couple dozen rounds. I'm just finishing up the last of my new profile ACME 124's. From an accuracy standpoint, none of my pistols like them...at all. Come to think of it, the gun has never failed to eat anything but these. At this point I'd feel pretty good blaming the bullets. [emoji41]
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Yeah, that's what I would say. Some guns just don't like some rounds/bullets/powders/mouth held wrong. Mine love the Lee 124 gr cast slug sized to .356 and powder coated, but absolutely hate the 125 grain single lube groove bullet from the same outfit. That mold just sits around gathering dust.