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Tight chamber Mauser
kabar
Member Posts: 1,247 ✭✭✭✭✭
I have a Polish short Mauser which is hard to chamber 8mm shells. Some will chamber but are tight and others I can't get the bolt to close and the shell sticks in the chamber. I noticed some scratches on the shells. Do I need the chamber reamed a little or can I do it with emery cloth?[?][?]
Comments
first I would take good bore cleaner,,brass brush that fits chamber tight,,pull bolt and run it in,,use a drill to spin brush in the chamber with the cleaner. that way you know you have no dried gunk in the chamber like dried cosmoline and it will not hurt the chamber.
+1. Then if it does not work proper, have the chamber cast and measured. Check headspace, etc. as well. Also, check ammo, or is this happening once out of a few rounds out of the same box?
As the Mauser is controlled feed the rim of the cartridge should raise up under the extractor as the bolt is pushed forward into battery. Make sure that this is happening correctly. The cartridge rim should slid under the rear face of the extractor without binding or causing any deformation to the extractor.
Are you pushing the rounds down into the magazine first than feeding them with the bolt, or are you dropping them into the chamber and than trying to close the bolt?
The Mauser feeds best out of the magazine. While it's possible to chamber the rounds directly, it requires some manual manipulation of the extractor to get the bolt to close on the round.
On the reloads that are "tight" from the mag, use a marker (Sharpie) to color the case and look for rub marks on it after cycling the round through the chamber.
I suspect that your not sizing the case enough / need to push the shouldres back slightly (or your bulging the shoulders during bullet seating and/or crimping).
The other thing to try would be to rotate the round 90^ at a time to see if you can find a spot where it chambers easily (possible the chamber isn't perfectly round).
BTW, finding a tight chamber in a military firearm would be a rarity
You will get some lengthwise "scratches" on the case during bolt closure, as the round rides down the feed rails and over the lead in chamfer at the front of the magazine.
On the reloads that are "tight" from the mag, use a marker (Sharpie) to color the case and look for rub marks on it after cycling the round through the chamber.
I suspect that your not sizing the case enough / need to push the shouldres back slightly (or your bulging the shoulders during bullet seating and/or crimping).
The other thing to try would be to rotate the round 90^ at a time to see if you can find a spot where it chambers easily (possible the chamber isn't perfectly round).
BTW, finding a tight chamber in a military firearm would be a rarity
These were reloads that were given to me. I haven't reloaded any 8mm yet. I guess its possible it might be the shells. I will buy a box of new shells and try again. Thanks for the help.
The round were reloads and the ones that jammed were fed separately. The ones that were fed by the magazine worked but were tight and had scratches on the cases after ejecting. The ones that jammed that I couldn't close the bolt were not in the extractor. I had to use a rod to push it out of the chamber. It does make sense that by hand feeding the shell, the extractor don't grip the shell. I will scrub the chamber real good and see if that helps.
In the statement above, you've just described the classic symptoms of rounds being pushed into the chamber ahead of the extractor.
Get the lip of the brass into the slot in the extractor prior to the round leaving the magazine! Best, Joe
As to the sticking ammo. The fellow who loaded them may have an oversize chamber or it may be reamed out of round. If the cases were only neck sized rather than full length sized they would stick/hang up in a good chamber.
If you are having trouble with new factory ammo your bolt may not be numbers matched and has insufficient headspace.