Is overpressure 38 special ammo safe in a 1975 S&W model 10?

[UranusDestiny]

See thread title. The salesman said I could, and I'd think it would be ok, since its a steel frame revolver and everything, but I figure it'd best be safe and double check before attempting to do anything. If anyone could give any information it would be greatly appreciated.

 

[BlindJustice]

Any .38 special S&W revolver made since 1957 when they
put the 2 digit number deesignation on all their handguns can
handle +P .38 Special ammo.

SAAMI standards
Regular .38 Special is 17,000 PSI
the +P is 19,000 PSI

IF it is rated +P+ then all bets are off - there is no
standrd for that 'rrating"

R-

 

[UranusDestiny]

Excellent, thank you very much! I've heard that +P+ is closer to .357 pressures, and I really don't think it'd be a good idea to use it in my revolver

 

[Oro]

I've heard that +P+ is closer to .357 pressures

Most .38 +p+ I've seen actually tested was at the 23,000 level, well short of the 35,000 of .357. I have no idea if this is firm limit, just a convention, or what - BlindJustice may be right that there is no limit. But I haven't seen anything test over that level - but that doesn't me there aren't rounds that do.

AFAIK, there has been no real technological change to the steel quality and treatment of M&P revolvers since the heat treatment of cylinders started in the early 1920's. I would be willing to put the same ammunition in my 1930 M&P as in a current production model. If someone knows of some particular changes that were made somewhere, I'd like to know. Also, global .38 spcl. pressure levels are 20,000 psi (e.g., guns sold in Europe use a CIP standard pressure ammunition that is loaded up to this level). The US .38 spcl. "+p" level is actually lower than overseas standard pressure ammo.

 

[Old Fuff]

Believe it or not, the cylinder - or rather the seel it's made out of isn't the problem.

Nope, the problem, if there is one, is the yoke barrel. The "yoke" is the hinge part the cylinder swings out on, and the "yoke barrel" is the part of the yoke that the cylinder fits and revolves on.

If you look at the yoke barrel from the end you'll notice it's a hollow tube, with relatively thin walls. Inside the tube is where the extractor, extractor spring, extractor rod, center rod, center rod spring, and whatever else I can't think of at the moment goes.

If the yoke barrel is a little short the cylinder can bang against the end of the barrel with it's thin walls. Heavier loads will increase the cylinder's battering effect, and a condition called "end shake" can develop.

This doesn't always happen of course, but it does happen. I've fixed a fair number of police trade-in's that had developed end shake associated with the increased use of hotter .38 ammunition.

If you feel uneasy if your carry piece isn't loaded with +++++ P ammunition, by all means carry it. Never would I want you to not feel warm and fuzzy. But you can save money (at least during normal times) and wear & tear on the revolver if you shoot lighter loads for practice and play.

 

[UranusDestiny]

Most .38 +p+ I've seen actually tested was at the 23,000 level, well short of the 35,000 of .357.

I see. I think I came under the impression that they were ballistically similar when I heard some story somewhere about how the .357 magnum was at some point, considered a evil killer bullet with stigma attached to it, and that the +p+ .38 was a .357 equivalent that was an anti-lawyer tool designed to circumvent that idea in court. Or something like that, I don't remember exactly.

If you feel uneasy if your carry piece isn't loaded with +++++ P ammunition, by all means carry it. Never would I want you to not feel warm and fuzzy. But you can save money (at least during normal times) and wear & tear on the revolver if you shoot lighter loads for practice and play.

With the price of ammo right now, I won't be firing anything other than standard .38 Spl anyways, this revolver is primarily going to be a fun range gun
I do think however, that I'll probably get a box of +P hollowpoints just for carrying and home duty.

Thanks for all the advice guys, I really appreciate it. I'm not very familiar with pistols in general, this being my first one, so all the information is very helpful.

 

[Oro]

Ok Old Fluff, thanks. That makes things much clearer - the issue is end-shake developing, not kabloom. So this would be equal between any M&P, basically, as these dimensions never changed that I know of. Or not?

Personally my .38s don't see anything more than target loads; SD rounds go into my 357s. My K38s are for the sheer joy of shooting, of which I think no other gun does it so well as along action K38.

One anecdote that convinces me of that is what that Texas boy Adm. Chester Nimitz did to relieve stress during the dark days of 1942 in the Pacific War. He had a private shooting range behind headquarters where he took his M&P for target shooting to calm down. Now this was a man who had virtually unlimited budget and unlimited powers in a sense at the time. And his favorite form of relaxation was shooting his pre-war M&P.

 

[Old Fuff]

So this would be equal between any M&P, basically, as these dimensions never changed that I know of. Or not?

Smith & Wesson starting heat treating cylinders in 1919 at serial number 316,648 (.38 Special) and 81,287 (.32-20 Win.). Earlier ones are obviously somewhat weaker, but you seldom hear of an older gun going KA-BOOM!, and remember S&W made a million M&P .38 revolvers between 1899 and 1942, and that's not counting the .32-20's.

What continued use of overloads can do short of a blow-up is expand a chamber(s), which in effect ruins the cylinder. But the key term here is "continued use," unless it's someone's way overboard reloads.

Bottom line: I would be much more worried about excessive end-shake then KA-BOOMS!, expanded chambers, or streatched frames - all of which are easily prevented by using common sense.

 

[MCgunner]

Be careful of shooting high pressure rounds in a M10. Not that you'll blow the gun up with +P+ stuff, but I cracked a forcing cone on mine and had to rebarrel it. It's rather weak. I think lead build up from shooting so many wadcutters probably did it, never shoot any jacketed stuff in the thing, but still, I wouldn't stress it a lot with "over pressure" ammunition. If you want a .357, buy one. Don't try to make one out of a .38. JMHO.

 

[SaxonPig]

Sigh........

Maximum ALLOWABLE pressure for the 38 Special is 21,500. This means that ammo loaded to 21,500 PSI is safe to use in any quality made gun (like... oh, I don't know... maybe a Model 10 made in 1975) in good condition.

Current standard 38 Special ammo is loaded to an incredibly weak and wimpy 16,000-17,000 PSI. This produces and unbelievably pathetic 730 FPS with the 158 grain bullet.

Factory +P is loaded to 18,500 PSI. More than the weak and wimpy standard ammo made today but WELL BELOW maximum allowable for the caliber. Factory +P generally pushes a 125 JHP at a leisurely 925 FPS

The maximum pressure for the 357 Magnum is 35,000 which is nearly TWICE that of the +P load. Anyone who says the +P load compares with the 357 Magnum obviously knows absolutely NOTHING and should not offer counsel.

I have never in my life seen as much misinformation, mythology, and misunderstanding surrounding any subject as I have seen regarding +P ammo.

UD- 10,000 rounds of +P should break in your gun nicely.

 

[ArmedBear]

If you need +P+ rounds, just get a .357.

Why would you do this with a Model 10? What's the point?

Here's the problem. I was shooting a 686 yesterday with maxed-out handloads. I'd tested these loads thoroughly before without trouble, but because of the primer shortage, I used different primers. These were hotter.

This pushed the rounds over the pressure spec. The primers showed it, and the cases required a LOT of force to extract. I cut my hand on the ejector, forcing it, in fact.

The front latch for the ejector rod POPPED OUT of the gun with its spring, and the pin is still in there.

I was at the range, so it was just a matter of picking up the parts and switching to a different gun and caliber that I was also testing.
Now I'll have to fix the gun and hope that nothing worse happened to it. Obviously, I will be working up a new load with these different primers!

BUT... You DON'T want this sort of thing to happen when you use the gun for self-defense!

And if you're not using the gun defensivelly, there's no reason whatsoever to shoot anything more than standard .38s in an old Model 10.

Note also that even .357 K-frames crack their forcing cones with certain loads -- SAAMI spec loads!

Shooting rounds on purpose that are too hot for a gun is not just "not recommended by the manufacturer." It's stupid.