Barrel replacement 4th change M&P 38 Special

[albroswift]

Hello, all
Came up with an M&P Serial # 810XXX putting it 1940-1945 according to my S&W book. Barrel had been cut off 2-1/2" - 3", star stamped on butt before serial number so I assume S&W cut the barrel but who knows. Also SV stamped. Book says these were stamped V. Barrel had a couple rounds stuck in to, noticeably bulged and front sight went into orbit according to the old boy who passed it on to me. So brings me to my question, are the threads on a pinned barrel the same as a non pinned barrel? I was told before that when they quit pinning barrels that they started to taper the threads a little bit so slightly different. Is this true or can I replace with any 38SP M&P barrel?
Thanks.
Edit: No lanyard loop FWIW

 

[Muley Gil]

Well, it ONLY took you 14 years to make your first post.

Please post pictures. Does your revolver still have the lug under the barrel for the front of the ejector rod to latch to?

Pinned barrels are easy to come by.

 

[series guy]

a friend gifted me a .38 M&P with a bulged barrel a few months ago. I bought a barrel on eBay and changed the barrel. I was very lucky that the replacement barrel fit with no modifications needed. It was a 20 minute job. Just make sure the replacement barrel has the same features as the original such as ejector rod cut out, front sight etc.

 

[JP@AK]

Came up with an M&P Serial # 810XXX putting it 1940-1945 according to my S&W book . . . Also SV stamped. Book says these were stamped V.
Edit: No lanyard loop FWIW

There were no units in the 810000 range that were marked with the simple V. Military production in the 810000 range before the actual V-marked Victory Models were part of the original serial sequence for the M&P with no letter prefix. By the time the numbers got that high in the V series, they were all marked SV because the new sliding hammer block had been implemented by that time. Hence, yours is correctly stamped SV810xxx.

Moreover, yours was not produced for the military during the war (1940-1945). Revolvers in the SV810000 range were shipping in March 1946, to various civilian locations. A large percentage of them in that serial range were going to the NYPD. Also, the butt would have the hole for the swivel, but most of them were plugged. If you look closely at the butt, you should be able to see telltale signs of the plugged hole.

 

[Shotguncoach]

Yes, the barrel threads are the same. Your biggest challenge will be matching the width of the front sight to the width of the rear sight. IIRC the front sight you want is a 1/10 inch half moon. Be patient in your search and one will turn up.

 

[glowe]

Starting with the first Model 1902 1st Change, the barrel remained the same some years past WWII. Any 38 Special pinned barrel above #33802 stamped on the underside will fit your frame. gunpartscorp.com has several for sale most of the time.

Pinned barrels require the right size punch and should be cupped tip and if I recall correctly they should be .057". Barrel pins require a light touch so as not to bend the punch, but those pins can be stubborn, so taking care not to bend the punch is key and the pin will come out. There are videos out there for removing gun barrels that can help if one intends to do it themselves. There is a real danger of bending the frame if not done properly.

 

[steelslaver]

Except for those previous to early 1905. K frames of all calibers use the same .540-36 threads, There is no difference in the pinned and non pinned threads except for a shallow groove for the pin across the shank of the pin barrels. Installation is also exactly the same. No matter how much anyone wants it to, the pin actually does nothing. You can install a pin barrel on a non pin frame of a non pin barrel on a pin frame if you simply file in the notch.

What did change was the barrels profile and the early guns with larger thread on ejector rod tips had a clearance cut for the nob. The front of the frames also varied as time passed.

 

[glowe]

Model 1902, 1st Change is when they changed the threads diameter to .540", not Model 1905. Only thing that changed before 1942 was the groove in the barrel to clear the ejector rod knob. A double groove was cut prior to 1927 and a single groove after. Either one will fit and work on any pre-WWII K frame.

 

[Retired W4]

Here is a 38 M&P, 1905 1st Change (I.A.W. letter), SN: 94608 that had the barrel changed. The barrel is from a 4th change (last patent date year 1914) cut for the barrel ejector rod knob, Vs the original mushroom knob. Don't know why the barrel was changed but when the 4th change barrel was installed they must have changed the rod to fit the barrel. I'm not sure what all this has to do with the original post but I thought I would run it up the flag pole to see if any one salutes. Oddly enough, the barrel flat is number to the gun but no S&W rework marks are to be found. A very professional job. Stocks are by Harry Jarvis

 

[albroswift]

Thanks for all the responses.
Barrel came out great, had to turn it in about 50-60 degrees, which was 8 or 9 thou. Didn't want to file the frame and setup in the mill would have been a pain so I elected to put the barrel in the lathe and push the shoulder back on that. Forcing cone gap came out about 1-1/2 to 2 thou so didn't need to re-cut that, bolt lock plunger was a little sticky and I managed to loose the little spring when I was smoothing that out, new one in the mail. If I was going to do another one, I would probably make a clamshell clamp out of HDPE or something similar.

 

[albroswift]

Does your revolver still have the lug under the barrel for the front of the ejector rod to latch to?

Crap, yes, got the old cutoff barrel with intact bolt lock, didn't need to order a new spring! (Unless I loose that one...)

 

[albroswift]

Well, it ONLY took you 14 years to make your first post.

Been busy.