Model 15...+P or Not?

ColColt · Jan 25, 2011

I'm looking at a model 15 and noticed the new ones are rated on the barrel as +P but older versions(dash 2, 3, 4) don't have this designation. Are they still able to digest +P velocities or should this just be consigned to the newer models with the IL? It's a beautiful pistol and I thought it better to shoot Special or +P loads in a pistol designed for it over the 357 which can easily and quickly cause problems with carbon/lead build up from shorter cases.

In essence, I'd like to be able to use 38 Special cases and if desired, +P velocity from a revolver intended for that case. The Model 15 looks like a winner to me. The +P chamber pressure is around 20,000 whereas 38 Special pressure is somewhat less at about 17,000. I wouldn't want to work up a load with +P pressures and use it in an older revolver that's plainly stamped as "38 Special" rather than "38 Special +P"

Old cop · Jan 25, 2011

All I can tell you is that "back in the day" our issued revolver was the Model 15 4" and our dept. ammo was the 158 gr. +P. No problems ever with +P and this was back in the 80's.

murphydog · Jan 25, 2011

The factory states any model stamped steel K frame is fine for +P. I would think a model 15 would be fine for any sane .38 load, with the understanding that you can achieve .357 ballistics and pressure with the right (wrong?) load in a .38 case. It sounds as though you are aware of this already.

ColColt · Jan 25, 2011

My purpose and reasoning for this revolver, and others like it, was to give me something with a bit more power and versatility than just your standard 38 Special loads. I wanted something I could use in the 900-1100 fps area without any problems and a revolver rated at +P seemed quite feasible.

I know you can download the 357 to a middle of the road velocity but some powders, such as Unique that could easily give that velocity floor, is position sensitive and would not house very much powder space in a 357 case. Moreover, most likely the reason many find it dirty is not enough of it used to give a better "burn" due to lighter charges. So, with the Special case, you have a somewhat higher pressure and velocity potential and a better burn if for no other reason because more powder will occupy the space in a shorter case. I'd say most mid burn rate powders are like this but from experience and what I understand about powders, Unique is one of the great offenders.

Doug.38PR · Jan 25, 2011

S&W will tell you any K frame gun (like the M-15) made after 1956 is safe for +P. With the understanding that it will supposedly cause accelerated wear on the gun (now there are a lot of folks in here who will tell you even that's a bit of a stretch to say as the have put 1000s of +Ps through their pre-1956 K frames)

Provided the gun is in good condition, you're safe with +P.

ColColt · Jan 25, 2011

I've never seen a model 15-only photographs so, I can't get a feel for how big they are compared to an L-frame 686. I assume they're somewhere between there and a Ruger SP101. I haven't seen a K-frame in years so it's hard to draw on recollection.

That's good to hear that there's no problem with +P loads...reasonable loads. Nothing like the old Keith loads of around 13 gr of 2400.

girvin02 · Jan 25, 2011

For a size comparison, here's a model 15 (third one down) next to some other S&W's.

OKFC05 · Jan 26, 2011

It's a beautiful pistol and I thought it better to shoot Special or +P loads in a pistol designed for it over the 357 which can easily and quickly cause problems with carbon/lead build up from shorter cases.

If you're worried about shooting .38s in 66s or 686s, let me put that fear to rest.
I shot a 686 for many years in IDPA/SSR and am now shooting a 66.
That means I am shooting tens of thousands of .38 in a .357 mag chamber each year, with no problems in accuracy or clean up.
Sure, I have to clean the chamber after hundreds of rounds in a major match, but a quick swipe with a Brownells "Tornado" brush takes out any carbon/lead buildup easily. You need to do the same cleanup when shooting .357 also, because not all brands of .357 cases are the same length, and you can get into loading problems if you leave the residue.

Oh yes, I have model 14s and 15s too, and they will take commercial or reloads that follow +P SAAMI pressures. However, for a steady diet of +P, or those handloads that might be getting more like a "junior .357", I prefer the 686, which is built to shoot .357 all day. I have one 4" 686 that has shot about 75.000 rounds without breakage.

olskool · Jan 26, 2011

you can't go wrong with a model 15 i have had one for years and many handload +ps have went down the barrel. the gun is tight as a tick.

k22fan · Jan 26, 2011

OKFC05 said:
[...] I am shooting tens of thousands of .38 in a .357 mag chamber each year, with no problems in accuracy or clean up. [...]

I had the same experience back when I shot .38 spl. in quantity. The issue of .38s fouling .357 charge holes is mostly just another detail to chat about on the internet rather than an actual problem at the range.

ColColt,

While .38 spl. is a more efficient bowder burner than .357 mag. for what you want, picking cleaner burning powders to down load .357 cases creates loads that are not noticeably dirtier than similiar loads in .38 spl. cases and I see no reason not to fire all the .38 spl. you want in a .357 anyway.

For safety and longer gun life I think reloaders are better off selecting a gun that produces the power they want with loads that are well below its design limits rather than selecting a gun that they think is barely strong enough to do what they want. You did not write what weight of bullets you want to fire in the 900-1100 fps. range so I'm not sure if you want to push the upper limits of .38 spl. +P or not but since you are concerned I would just get a .357. Besides, you may enjoy having the option of full magnum power at a later date.

Best Regards,

Gil

Pigirondan · Jan 26, 2011

I was in a similar situation. My Model 15 is not marked as being +P rated. It was manufactured in the 1980's so I reasonably assumed that any and all +P ammunition is safe to use.

That said, I shoot very little +P ammunition through it. Same goes for my Model 10. The difference between my handloads and commercial +P loads is minimal, but, the pressure is lower.

ColColt · Jan 26, 2011

girvin02 said:
For a size comparison, here's a model 15 (third one down) next to some other S&W's.

It's for sure smaller than the N-frame one at the top. I figured it would be a noticeable difference. Thanks for posting those pics.

My fear initially was two fold...fear may be a too strong a word but; I wasn't sure about older guns being able to handle the somewhat increased pressure and secondly, I had "heard" that shooting 38's in a 357 cylinder would foul it so badly and build up with lead and carbon that you would spend 30 minutes just cleaning the cylinder to accept the longer 357 round.

I've had a couple 357's in years gone by (M28 and 19) but, back then I shot primarily jacket bullets and didn't experience the lead buildup I have read about so, there were no problems with that.

From what I've gleaned, it's all about matching chamber pressure with the BHN of the bullet and choice of powder to attain the velocity you're looking for as to how much lead and carbon you'll have to deal with. Of course, much has to do with the proper sizing of the bullet in conjunction with bore/chamber diameter as well but, for the sake of this discussion I think a BHN of 12 matched to the chamber pressure of 38 Special+P(about 20,000 psi) and a velocity of 900-1000 fps, I should be ok with powders like Unique, Power Pistol and HS-6. Matching chamber pressure for the +P divided by 1400 would give a BHN of 14 but, a number 12 hardness would be close. This is what I ordered from Missouri Bullet Co.

Unfortunately, the data in Speer and Hornady's manuals are for a BHN of about 10 for their 158 gr LSWC, from all I understand they use for their lead bullets so, what you see in their manual could be used at max for a given powder since I'll be using a 12 instead. A load using 6.0 gr of Power Pistol with this bullet or 5.2 gr of Unique should yield around 875-1000fps in a 3 inch barrel(since Speer used a 6" barrel and Hornady a 4") and get me about where I want to be and yet be under the max chamber pressure of 20,000. That's about the velocity Speer indicates at a max load with their bullet. Does this sound reasonable?

ColColt · Jan 27, 2011

k22fan said:
You did not write what weight of bullets you want to fire in the 900-1100 fps. range so I'm not sure if you want to push the upper limits of .38 spl. +P or not but since you are concerned I would just get a .357. Besides, you may enjoy having the option of full magnum power at a later date.

Best Regards,

Gil

I was thinking primarily the 158 gr LSWC. I have a 357 but just like the looks and classic lines of the model 15 which only shoots 38's. The 900-1100 fps floor I've arbitrarily chosen mostly because I'm not into too much full house 1400 fps or so from the 357 and figured cleaning would be an easier chore for me to use the shorter 38 cylinder of the model 15...could be it's not all that bad in a 357 but, I haven't shot enough lead through it to tell. I'm mostly regurgitating what I've read from others about lead build up in 357's.

Model 15...+P or Not?

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