OM 45 Question

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steelheadnw

Bearcat
Joined
Feb 2, 2008
Messages
67
Location
montana
Well I finally slugged my OM .45 the other day, the cylinder is a nice .452, and the barrel is .4535. The question is what do I do with that? I've been shooting some cast 255s that are .452 and getting around 3 inches at 25 yards which really is not bad but it should do so much better.. do I have the cylinder reamed to .4545 and size bullets to .454? Or just be happy that I have an original Om and shoot it? Other Ideas?

James
 

Aggie01

Blackhawk
Joined
Oct 16, 2008
Messages
968
Location
Texas (DFW)
The first thing I would do if I came up with those numbers is check my gauges. That is not a discrepancy that is reported very often.

Can your .452 bullets drop thru the throats or do you have to force them through?
 

steelheadnw

Bearcat
Joined
Feb 2, 2008
Messages
67
Location
montana
I slugged the throats, they mic at .4525, which is what I had it reamed to by the cylinder guy (unfortunately I didn't slug the barrel at that time). The bullets I have, push through with a little finger pressure and they are sized at .452. Any one else have a barrel that measures this big? I don't have any reason to doubt my gauges accuracy, maybe my technique, but I slugged the barrel twice and I have measured the slugs many more times than that and the barrel measurement ranges I get are between .453 and .454.
james
 

Enigma

Hunter
Joined
Apr 17, 2002
Messages
2,146
Location
Houston metro area, TX
CAS doesn't list anything other than .4525" for .45 throats, so you might be out of luck there. You might try loading a softer bullet, and seeing if they will expand (obturate) to seal the bore. Other than that, not real sure what you can do.
 

J Miller

Blackhawk
Joined
Sep 30, 2000
Messages
977
Location
Not in IL anymore ... :)
steelheadnw,

My first year OM .45 has a grove diameter of .452". The chambers were grossly undersized and have been reamed to .4525".

If I had one with that oversize of a barrel, I'd be check the custom gunsmiths for a take off barrel that was of the correct grove diameter. Then have it swapped out.

Second choice would be to send the gun to Ruger for a new barrel.
Unfortunately you'd also get the warning and transfer bar conversion. And the barrel would not have the ejector rod bushing. Something I think is a necessity.
That's why it's the second choice.

The larger grove diameter that you are reporting is definitely not normal.

Joe
 

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