OM 45 Question

[steelheadnw]

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]

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]

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]

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]

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