Ok, I have several Smith model 36 Chief Specials around the house loaded with + P ammo. Where can you find out if a gun is rated for +P. If you look at the internet you get dizzy, some say yay and some say nay
OK, back to basics. A +P 38 SP is dimensionally identical to a standard 38 SP. Thus, it will fit and shoot in any gun chambered for a 38SP. That being said, the pressure difference between the two is significant. A 158 gr HDY XTP 38 SP round maxes out at 16,600 CUP and that's hot for a 38SP. That same round in +P configuration maxes at 19,300 CUP. That will cause very accelerated wear on the frames of standard 38 SP guns and in some cases of older guns, destroy the frame or bulge the cylinder with just one shot. My go to load in 357 mag has always been a 150 grain lead Keith style bullet with mag primer and 12.5 grns of 2400. that load generates around 28,000 CUP. Fewer than 6,000 rounds of that in a M-19 caused some mild stretching of the frame. S&W advised I stick to 38SP loads for practice and use the hotter loads only infrequently. I asked about +P loads and they advised that even those loads in the M-19 (a light weight 357) will result in accelerated wear. So, can you shoot +P loads in your 38SP? Yes, but unless it specifically says +P rated you are going to cause problems. it's just a mater of time.
Here is a link to Smith and Wesson's customer service web site for downloading manuals. Click on the link modern revolvers. Lots of info on using the right ammo for you revolver. Just as stated by others, never use anything with higher pressures then what is stamped on the barrel.
In-fact, my model 66 is marked .357 magnum. But since its a K frame, Smith and Wesson recommends using .38 Special for target shooting, and .357 for carry. Wayne
Be very careful shooting +P ammo through a revolver not rated for it -- especially an S&W. There is a definite risk of ruining the weapon and possibly injuring yourself. I have a 15 year-old J-Frame (36 Chief's Special) which has shot a few boxes of +P without any apparent problems so far, but I stopped shooting +P after I saw a brand new 36 destroyed a few years ago during its first trip to the range. +P bulged the cylinder on the first box of ammo.
One issue with S&W is that the company has been through so many managerial changes in the past few decades that quality levels have been all over the place. My current Chief's Special has been one of the very best revolvers I've owned, but I bought another one with a cylinder that rubbed the frame right out of the box. If I showed you that brand new revolver, you would likely not believe it left the factory in this condition. Yet when I returned it to the dealer they didn't even seem surprised. Nor did they dispute that it was unfired and yet totally junk. So I asked if they'd seen such ridiculous quality problems on S&W products before and the guy looked at the owner, who said "no comment."
S&W has also been a little schizophrenic in maintaining an identity and the focus of their business model. One day it's dressed-up cheap Turkish shotguns, and the next it's "Military & Police" semi-auto pistols or black rifles. Ever owned a Sigma? Makes a $250 Hi-Point seem like a Sig 210.
Anyway, my point is that EE is exactly right -- shooting +P is a much bigger risk than many people realize. Drew's example regardng PDs using +P is off the mark. Few in law enforcement carry 38s anymore, and it doesn't matter anyway because walking around with +P ammo in your service revolver is a lot different than shooting it.