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Post by fortyshooter on Jan 20, 2012 11:06:18 GMT -5
When I load up rounds,I always have a couple where the case head drags against the hammer area of the frame,like the cylinder counterbores could be a touch deeper. Winchester Super X,gives the least trouble,with Hornady being the worst. Trying out some Winchester Supreme Elite,and a couple of those lock the cylinder too. Yeah,I could send the cylinder back to MRI for a touch up on the CB cut,but I do have a Bridgeport mill handy,with my 35 years toolmaker expierence. Anyone else have this trouble??
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Post by AxeHandle on Jan 20, 2012 11:40:31 GMT -5
Don't have a 45-70 cylinder for my 450M BFR but I can tell you that I have not had any like issues with Hornady brass in my 450M. Haven't I read about variation in 45-70 brass by different manufaturers that becomes an issue when using 45-70 brass to make 475L brass? I have experienced a similar thing with slightly high primers in Freedom Arms revolvers. Not high enough above the case head to really catch your eye but anything above the case head sure jams up the gun
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Post by 5shooter on Jan 20, 2012 12:12:32 GMT -5
SAAMI specs for 45-70 are .070" to .077". You can get a pretty good idea of your headspace by measuring the gap between the recoil face of the frame and the cylinder with a feeler guage and measuring the depth of the recess in the cylinder. The sum of these measurements is the headspace. You could increase the headspace with an end mill in a mill but because of the body taper the chamber would become slightly smaller and you would loose clearance between the case mouth and chamber throat. This could be a good thing if you wanted to tighten it up.
The best way to increase headspace is with a proper reamer. It must have a larger than normal pilot for cylinder throats instead of barrel bores.
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Post by bigbores on Jan 20, 2012 13:14:12 GMT -5
When I load up rounds,I always have a couple where the case head drags against the hammer area of the frame,like the cylinder counterbores could be a touch deeper. Winchester Super X,gives the least trouble,with Hornady being the worst. Trying out some Winchester Supreme Elite,and a couple of those lock the cylinder too. Yeah,I could send the cylinder back to MRI for a touch up on the CB cut,but I do have a Bridgeport mill handy,with my 35 years toolmaker expierence. Anyone else have this trouble?? I have 2 of them, never had anything like that. I would bet MRI will fix the problem fast for you if you called them and send in the cylinder but it might be easier fixing it your self.
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Post by woodwright on Jan 20, 2012 13:57:33 GMT -5
Might be a stupid suggestion, but have you made sure your primers are seated all the way? Also, do they catch all the time, or just when you point it up? on mine, the gate wasn't quite flush with the hammer area and my cases would slide back and catch on the edge. MRI said they would fix it no problem, but I wanted to have it for hunting season so I had a local gunsmith smooth it down a little.
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Post by fortyshooter on Jan 20, 2012 14:24:59 GMT -5
Primers don't seem to be the problem,all being slightly below flush. Checked head thickness on several rounds and .065 is a spinner,but anything .070+ is a lock up. About going deeper on the counterbore...I thought about that issue of the tapered chamber,and having the case get tight in the bore,before bottomong out in the head pocket...that would not be good. May just send it to them and get it done,plus maybe get the gun fitted with the Marlin .450 cylinder too! ;D
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Post by fortyshooter on Jan 20, 2012 14:27:16 GMT -5
Oh,all this is with the gun pointing down.
Just measured headspace,which checked out at .070 result of .020 cylinder gap plus .050 counterbore depth. Also the case head thickness will vary couple thousandths from one side to the other.
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Post by subsonic on Jan 20, 2012 18:43:01 GMT -5
Make sure that it's not catching on the OD of the rim. My Hornady brass for my .475 is tight on the OD, but not thickness. A swipe with steel wool on the outside of the rim and making sure the counterbore is absolutely clean with a pocket screwdriver bit corner fixed it.
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Post by buckheart on Jan 20, 2012 21:05:18 GMT -5
I have the same issue with my BFR 45/70. I thought the primers on my reloads were standing proud at first but that wasn't it. I will have to check my chamber recess dimensions . I get light primer strikes every so often that result in miss fire too. Any one else have that issue?
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Post by fortyshooter on Jan 20, 2012 22:35:28 GMT -5
I have the same issue with my BFR 45/70. I thought the primers on my reloads were standing proud at first but that wasn't it. I will have to check my chamber recess dimensions . I get light primer strikes every so often that result in miss fire too. Any one else have that issue? No problems,so far,with light primer strikes. Gun shoots great,just get 1 or 2 rounds per 20,that will drag or lock the cylinder when loading. The case rim has .020 clearence around the head O.D. I will call MRI and see what the headspace and cylinder CB depth specs are supposed to be.
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Post by fortyshooter on Jan 21, 2012 9:15:34 GMT -5
SAAMI specs for 45-70 are .070" to .077". You can get a pretty good idea of your headspace by measuring the gap between the recoil face of the frame and the cylinder with a feeler guage and measuring the depth of the recess in the cylinder. The sum of these measurements is the headspace. You could increase the headspace with an end mill in a mill but because of the body taper the chamber would become slightly smaller and you would loose clearance between the case mouth and chamber throat. This could be a good thing if you wanted to tighten it up. The best way to increase headspace is with a proper reamer. It must have a larger than normal pilot for cylinder throats instead of barrel bores. Thanks for those specs,5shooter! I looked up the SAAMI specs too. Looks like my gun is right on the min. .070 backspace. The cartridge specs show .070 to -.010. So the problem is the result of cartridge production tolerances to the high side. Just as a thought,and this may be a wrong direction, could .002 be safely hand filed off the breechface? Only concern is getting any particles out of the firing pin area.
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Post by fortyshooter on Jan 21, 2012 9:19:07 GMT -5
Sorry...screwed up the above reply to 5shooter!
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Post by subsonic on Jan 21, 2012 10:57:07 GMT -5
I would file the offending case heads...or sort those out and only use the good ones. What happens if the brass dimensions swing the other way when you buy the next batch?
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Post by fortyshooter on Jan 21, 2012 11:22:07 GMT -5
Yeah,though about filing a couple,but the thought of holding that big round and filing around the primer area,makes me a bit nervous! Usually I find maybe 2 rounds out of box of 20,that will hit.
My Ruger Super Blackhawk Hunter,checks in at .062 headspace,with the rounds usually .056 to .059.
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Post by toroflow on Jan 23, 2012 0:21:30 GMT -5
I have the same issue with my BFR 45/70. I thought the primers on my reloads were standing proud at first but that wasn't it. I will have to check my chamber recess dimensions . I get light primer strikes every so often that result in miss fire too. Any one else have that issue? I get light primer strikes on my BFR 45-70 also. I am using CCI200 primers. Should I be using CCI300 (large pistol) instead? Thanks.
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