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1851 RM Conversion Question


Rube Burrows

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I recently bought a brand new 1851 RM Conversion and finally got to put a little over 100 rounds through it yesterday. Gun shoots good but I kept running into a problem. 

 

The gun is in .38spl which I am not nearly as familiar with because I normally shoot .45s. When I load the cartridges in the cylinders they slide back and fourth. When the barrel is tipped up they will back out of the cylinder and cause the gun to not want to rotate. It binds up the hammer and wont let the gun cock. Also when I tip the gun up to use the ejector some of the empty brass moves enough to cause this problem again. Its quite frustrating and while the gun shoots well enough I could not see using this in any sore of timed fashion because of this problem. 

 

When loaded I can shake the gun front to back and the shells move about in the cylinders a good bit. 

 

Any idea why this is? 

How do I fix it? 

 

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53 minutes ago, Rafe Conager SASS #56958 said:

Just going out on a limb check the depth of your wedge! You might not have it in far enough and it is allowing to much gap between the cylinder and the barrel.

Rafe

The gap is in the back though. I’ll post some photos after while. The gap though is between the rear of the cylinder and the back from where the hammer is. 

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Hi Rube, take off the cylinder and check where the loading gate rotates, see if there is a misalignment of parts to make a ridge that the rim catches on.  Otherwise, put a singe case in the cylinder and turn to find out where it is catching.

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Piddling with the Wedge on Uberti built Open Top design guns is a waste of effort.  The guns, Open Top, Conversions and Cap Guns suffer a decades old manufacturing flaw.  The Barrel to Arbor fit is abysmal.  The solution is to shim the Arbor so the Barrel seats to the correct clearance EVERY time.  When the Wedge is seated, the barrel SHOULD NOT move at all.  The Richards/Mason Conversions and the Open Top have a "Gas Ring" integral with the cylinder that establishes end shake and maintains Head Space.  Until the Barrel to Arbor fit is fix'd, other measures are a waste.

 

Anyone who shoots Uberti Open Top, R/M Conversions and Cap Guns needs to avail themselves of Larsen E. Pettifoggers tutorial for setting up these guns.  Until the Barrel/Arbor fit is correct, every time the guns are taken apart for cleaning, you get a different gun when you put it back together. 

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4 hours ago, Abilene, SASS # 27489 said:

Hi Rube, take off the cylinder and check where the loading gate rotates, see if there is a misalignment of parts to make a ridge that the rim catches on.  Otherwise, put a singe case in the cylinder and turn to find out where it is catching.

I actually did just this. I wish I would have seen your comment sooner. Could have saved me a couple min. 

 

 

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Hi Rube.  I'm very glad you posted that video.  When I saw that ridge on your recoil shield, I went "huh?"  Pulled out my older R-M's (15-20 years old) and they do not have that ridge.  However, my lastest (Type II .38, which has the same ring) from a couple years ago does have it.  Never noticed it before.  I can feel it with my finger, but I have never noticed it before and it certainly hasn't caught any rims.  Maybe the edge is just worse on yours, differences in machining or wear of tools, but I also wonder if it only sticks with a particular brand of brass for you?  Possibly a brand with sharper edges?  If that ridge is indeed where it is catching (one shell at a time will verify) then I'd probably try to stone it down.  Give it a little bevel or ramp.

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1 hour ago, Abilene, SASS # 27489 said:

Hi Rube.  I'm very glad you posted that video.  When I saw that ridge on your recoil shield, I went "huh?"  Pulled out my older R-M's (15-20 years old) and they do not have that ridge.  However, my lastest (Type II .38, which has the same ring) from a couple years ago does have it.  Never noticed it before.  I can feel it with my finger, but I have never noticed it before and it certainly hasn't caught any rims.  Maybe the edge is just worse on yours, differences in machining or wear of tools, but I also wonder if it only sticks with a particular brand of brass for you?  Possibly a brand with sharper edges?  If that ridge is indeed where it is catching (one shell at a time will verify) then I'd probably try to stone it down.  Give it a little bevel or ramp.

Yes. I put one shell in to be able to see where it is catching and it is def stopping at the place where it would be to catch that rim. Its a very small rim but I do believe that is the culprit. 

Was using Winchester brass. 

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26 minutes ago, Sedalia Dave said:

Wonder of there is a way to stone the edge into a ramp so that the rims will no longer catch.

I plan on trying to knock it down some. 

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I don't usually reply on the wire anymore but I feel your pain on this one.  I just tuned up a pair of these.  Corrected the arbor fit, action job, etc.  The area around the firing pin is what sets the headspace.  All revolvers relieve the rest of the frame or the rounds would drag when the cylinder is turned.  As the round approaches the firing pin a ramp raises the round.  It is to bad Uberti is doing such a poor job on these ramps.  What exacerbates the problem is that some brass has very little taper on the back edge of the rim that contacts the ramp.  In the photo is a quick shot I just made of a Ruger showing a proper ramp.  I grabbed a macro lens so the back of the photo is out of focus but you can see the ramp.  I would take a Cratex wheel (or some other soft mildly abrasive wheel) and hit the sharp edges and round them off a bit.  Do NOT use a grinding wheel.  You don't want big scratches in the recoil shield.  Don't worry about getting bright spots on the frame where you are polishing.  They can be left as is (no one can see them) or touch them up with some cold blue.  Most cold blues will blend nicely with the colors on the frame.

DSC_0005.jpeg

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Thanks for the photo and info Larsen. That ramp looks much better. Gives me an idea of what I'm shooting for as I try to correct this one. 

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