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Old January 27, 2019, 07:48 PM   #1
Join Date: June 30, 2013
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Cylinder bore seems big for the round.

I have a 5 shot Iver Johnson cadet revolver so yes, it's an extremely inexpensive revolver from the 1960's, but I like it and it goes well with my retro suit.

It seems to have a bit of a clearance issue in the cylinder.
The 38 S&W brass diameter measures .374, but the cylinder chamber diameter measures .390 and I can see what looks like the forcing cone in the cylinder.
That's .016 larger and gives it a clearance of .008 all around the brass.
As you load a round, it rattles around until the rim seats, and the brass after firing is obviously wallowed out.

The shop I got it at is long gone and it was so inexpensive, I'm not pissed if it's buggered, and it does shoot accurately.

Is it normal for 38 S&W to be loose like that or might someone have bored it out to clean it up to pass it off and decent?
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Old January 27, 2019, 08:13 PM   #2
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You may have the 38 S&W, which is not the S&W SPECIAL.

I don't have the dimensions but this link give the various points on it.
Science and Facts are True whether you believe it or not
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Old January 27, 2019, 09:12 PM   #3
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When I first saw it I hoped it was the 38 Special as the tag listed but then I tried some of the 38 Special ammo I had leftover from years gone by and the cylinder on this gun is way too short to fit it.

The dimensions listed on the Wikipedia page you linked to seem to fit the dimensions I'm getting off the gun cylinder I have, so I wonder if the ammo could be wrong.
I got one 50 count box of S&W 38 ammo from the place I got the gun from and one more from on line and they were both the same.
.38 S&W
Funny that Buffalo Bore and Mag Tech offer defense ammo as if this pea shooter could handle much more than it already has stock!

This is all the information I can find on the gun on line.

I.J. CADET MODEL 55SA----------------------------------1961-1978
The difference between this A series and the earlier series is the addition of a loading gate to the right side of the frame. All specifications are the same except a small weight gain because of the loading gate. Also two new calibers offered 32 S&W Long and 38 S&W.
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Old January 27, 2019, 09:20 PM   #4
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Also two new calibers offered 32 S&W Long and 38 S&W.
As was mentioned, 38 S&W and 38 S&W Special are two totally different cartridges.
Which one are you using in your gun?

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Old January 27, 2019, 09:54 PM   #5
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.38 S&W cartridges should measure .3855 at the neck and .3865 at the base. The forcing cone you are seeing is the chamber throat.
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Old January 27, 2019, 10:43 PM   #6
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"Hawg's" stated cartridge dimensions are correct. It looks like your ammunition is undersized. If your cylinder is not counter bored, or recessed, for the rim, the chamber diameter at the breech end of the cylinder (not the barrel end) should measure .3900 according to SAAMI (Sporting Arms and Ammunitiion Manufacturers' Institute) specifications. So probably your revolver is okay.

My Webley revolver (which was likely not made to SAAMI spec's) still does conform and the chambers measure .3900 at the breech end of the cylinder. I have some old Remington-peters, .38 S&W ammunition, and it measures .381 just below the rim, which is still undersized by SAAMI standards. (The .381, coincidentally corresponds to the saami base diameter for .38 special. It makes you wonder if, in the interest of manufacturing economy, .38 S&W is being made using the .38 special dies and draws.)

I doubt if your revolver's chambers have been bored out. There would be no reason to do that. First, your cylinder is too short for the .38 special. Second, some Smith and Wesson M&P revolvers were chambered for .38 S&W and sent to Britain during WWII (the victory model, I think). Since the cylinder was long enough, some importers of the surplus revolvers reamed the chambers LONGER to accommodate the .38 special. They didn't need to bore the original chamber larger, because the .38 special is smaller than the .38 S&W. The chamber was already too big.

Last edited by hammie; January 27, 2019 at 11:08 PM.
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Old January 28, 2019, 03:01 PM   #7
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.38 S&W should be around .386 and .38 Special should be around .379. Both are larger than .374... If the chamber measures .390 I'm guessing it's a .38 S&W revolver and whatever ammo you have is not.
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Old January 28, 2019, 03:26 PM   #8
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Do remember that ALL factory ammo is "undersized", compared to the published specs for the cartridge. Usually the dimensions given for a case are the maximum dimensions.

Factory ammo ALWAYS mic's a little bit less than max specs. This is intentional, so that the ammo will chamber in about everything despite the slightly different tolerances of different makers, and individual unit QC.

Sometimes, one finds ammo made significantly smaller than the chambers you are firing it in. As far as the ammo makers care, that's fine. The (undersize) ammo has to chamber (and it does) and it only has to fire ONCE, in order to do what the makers expects it to do.
All else being equal (and it almost never is) bigger bullets tend to work better.
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Old January 28, 2019, 06:38 PM   #9
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reddog81: It is 38 S&W, and some I have spoken to have referred to it as 38 S&W short.
I know it's not the 38 Special, also that caliber was not offered in that model.
The left side of the frame has 38 CAL stamped into it and the opposite side has the SN.

44 AMP: It's just that it almost looks like when someone shoots a slightly smaller caliber round, and the case comes out distorted, but the rounds I purchased is in the 38 S&W box from 2 different makers.

I guess it's a case of smaller dim ammo in a large SAAMI chamber.
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Old January 28, 2019, 08:37 PM   #10
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Where did you get the ammo from? It kind of sounds like reloads someone made using .38 Special dies.
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Old January 29, 2019, 12:31 AM   #11
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One was from the gun shop where I purchased the gun, it was a brand name and appeared new, the other was on line, brand name also appeared new in box.
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Old January 29, 2019, 09:27 AM   #12
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The last factory .38 S&W round I dissected was a WW...

I do not remember the factory loaded neck diameter, but IIRC the bullet was 146gr dead soft round nose that mic'ed .354", and had a hollow skirt that would bump up to whatever diameter groove barrel is was fired in...

This was 20 something years ago, so I do not know if this is still the case...

The fired cases did indeed look a tad 'pregnant', but reloaded fine...And I am still loading them...
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Old January 29, 2019, 11:21 AM   #13
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Short trip to a reliable gunsmith should answer your questions about which cartridge to use. Don't use any guesswork.
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