S&W MP .38 with loose barrel

[country gent]

I would not peen the threads they are to fine and sift to get a reliable job done. I would polish the face on a small ball peen and then work around the shoulder on the outside edge lightly tapping the edge. This will lightly peen the shoulder out allowing it to tighten and time up. then the green loctite when assembled.

green loctite is wicking and is recommended for sleeve retention.

With a polished hammer dace very little of the repair will show. Light taps working around the face and checking often, when you get to around 1-2 hours on the front sight it should tighten nicely. Coat both the threads and shoulder with the loctite and assemble

[2152hq]

Peening the threads will tighten the barrel, but it will likely leave the sight out of alignment. A combination of peening the threads AND peening the shoulder should tighten the barrel while keeping the sight aligned. If only slightly loose the wicking loctite should work with the least effort(no disassembly required). Use brake cleaner on the joint a few times before applying the loctite.

Peening the threads (alone) will not leave the sight out of alignment.
Maybe you are not understanding what I mean by 'peening the threads'.
This is not simply flattening the threads, punching down the sharp tops of the V shape.
This is moving the V itself forward toward the muzzle by tapping the back side of the thread with a 'drift' very lightly.
You are only displacing the thread forward a couple .000. But that is enough to change thread take up and fit. That makes the thread fit tighter and the assembly come together at the end fit sooner. So the 'clocking up' is then tight,,very tight if done right.
Your sight(s) are just where you want them at 12 o'oclock and the bbl to frame joint is wrench fit tight.


It will tighten up the torque needed to screw the bbl back into the frame and will definitely require you to use a bbl vise and action wrench to draw to assembly to 12oclock .
That will place the sight straight up.

IF you get too heavy handed when peening the threads,,you WILL distort them and you WILL have a hard time with reassembly.
A very little does a lot.

Nothing will show on the outside of the assembly when finished. No hammer marks on the shoulder of the bbl.
No glue, no Loctite, just plain careful old fashioned gunsmithing skill.
A very small 'drift' that you can shape in a couple minutes from an already available punch that's most likely laying on the bench.
A lightweight hammer and some good lighting.

I just did the exact operation to a Pre-A Model 52 Winchester. The bbl had been disassembled from the recv'r for what ever reason. The rifle in parts.
The bbl hand assembled/screwed back on and went past 12o'clock nearly 1/4 turn.
Someone tried to take up the slack at some point by punching up multiple spurs in the face of the frame.
That didn't work well.

I did the thread peening operation on it's threaded shank. Reassembly went fine with bbl wrench and vise. Torqued up to 12o'clock with just the right resistance.

[ulav8r]

If the sights are currently aligned but the barrel is loose, then peening will not work. I have peened threads after making as punch to fit. Did not have sights to worry about and headspace was ok afterwards. Used my 4 oz ballpein hammer and light taps, working around the threads 3 or 4 times to gradually get a good fit.

[TD1886]

Thread peening will work, but is a much more tedious job then peening the shoulder. Believe me if you have a polished smooth hammer face and same with your support advil and tap lightly in small barrel rotation increment you will not leave any marks.

It's all moot as Dutch is going to use the wicking Loc-Tite and I'm happy that he is happy with that method.

[45DUDE]

Rubbing alcohol will work. Clean the threads with a buffing wheel. A hair drier will speed things up when it starts to set. Teflon tape should work also and take the slack out.

[Dutchman]

Tonight I de-greased using the WD-40 contact cleaner. It has a very powerful ~jet~ action and appeared to clean around the frame where the end of the barrel protrudes. Then I blew it out with 100 psi and cleaned it again using a bristle brush and more WD-40. After sitting for a short time I applied way too much (it got away from me!) and wiped it off. I was using a optivisor so's I could see clearly.

I hadn't handled this S&W for quite a while and it took some minor effort to turn the barrel back and forth against the frame pin. The amount of movement is actually quite small overall and I wouldn't have had a problem shooting this revolver as it was but deep down it bothered me so this is why I made even this minor effort to "fix" the problem.

Next will come a complete side-plate removal and deep clean and lubricate. Fortunately I feel comfortable opening up a S&W for this. As it is the double action is smooth and single action trigger pull typical S&W of this era. Pretty sure this revolver shot mostly lead bullets as the rifling is VG+ or better.

Pretty sure the suggestion to peen the barrel shoulder would've been the best ~official~ repair and I appreciate those who took the time to write out the instructions. They will be saved for future reference.

I put the Uncle Mike's Boot Grip on it but I think I'll put the Magna and Tyler Grip adaptor back on it to test fire it. Yes, I made sure to clock the front sight TDC.





Dutch

[schutzen-jager]

i have a very early M+P that had a loose barrel that could be turned by hand - the cyl. gap, end play, + sight alignment were correct - i removed the barrel pin, put in a few drops of crazy glue, + reinstalled pin - still tight years later - heat will break the bond if i ever have to remove barrel in the future -

[LAGS]

I have use JB weld to fix loose barrels on some pistols.
Mostly they were Cheap .22 revolvers that didn't have threaded barrels.
They were aluminum frames with the barrel just pinned in place like R&G revolvers.
The barrels came loose from people putting them in the tool box on their ATV.
Bouncing around made the barrel waller out the soft frame a bit.