Evenin' everyone, OM cyl question

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scooterpsp

Bearcat
Joined
Nov 8, 2009
Messages
8
I see a 9mm BH cyl for sale on Gun Broker but the seller is unsure if its OM or NM. Is there anything I can ask him that may help me know such as s/n or other? I have an OM 357, will a NM cyl work OK if it happens to be one?

Really love this forum, pretty new and just readin and enjoyin learnin and listenin. You are a great group of folks and I look fwd to hangin w/ya'll for a good long time.

Havin a lil trouble with getting registered but I'm workin on solving that but that's another story for another time. May be askin for some advice from the experts.

Scotty
 

scooterpsp

Bearcat
Joined
Nov 8, 2009
Messages
8
seller just told me "There is an S on the back of the cylinder, on the front (put on with an engraver), an R O 8 O between chanbers, there is no turn ring , it could be unfired but I dont know, the only residue in the chambers is red lint from the bag".

What do you think?
 
Joined
Oct 24, 2007
Messages
11,162
If the overall length of the cylinder in question matches the original cylinder in overall length . . . to three decimal places . . . it will likely fit, and probably work. There is no absolute guarantee, however.

The "S" is the factory proofmark, and the R080 refers to the "fitter" and the last three digits of the original gun's serial number.

JMHO YMMV
 

DGW1949

Hunter
Joined
Apr 10, 2005
Messages
3,638
A NM cylinder is considerably fatter than an OM cylinder, and will not work in your gun....so get both an AOL and an OD measurement from the seller and compare them to your's.

Hope this helps.

DGW
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
20,993
I think the best way to determine an OM vs a NM, is the length of the cylinder boss. (That little ring of metal where the base pin goes into.) A short one, vs a longer one. Now we are talking about a difference of around .100 if my faded memory is correct. I'd hav to dig into my stuff & measure a few. If I weren't going to a shooting match today, and had time to dig, i'd measure a couple for you. Maybe someone else can give you the dimensions.
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Ja, the OM 9mm cylinder is designed to fit the "mid sized" .357 cylinder frame whereas a New Model 9mm cylinder is designed to fit the "large sized" cylinder frame common on ALL Blackhawks and Super Blackhawks from late '73 to date, excluding the '05 and newer mid sized .357's and .44 Specials.

So, a quick cylinder diameter and length comparison will "tell the tale."

JMHO,

flatgate
 

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