What is the of +P ammunition on guns not rated for its use?

[John in WYO]

Hi, Bill,

Great post on explaining +P effects on non +P firearms.

Auto-correct may have got to your statement.

“Turned out that brazed head had stretched out, and the breach wasn't locking up.”

Respectfully, it is the “breech” when referring to the end of a firearm wherein a cartridge is inserted into the chamber. I’m sure you already know that.

For our younger readers who missed English class and spelling or are stronger in math and science:

“Breach is a noun referring to (1) an opening or gap or (2) a violation or disruption, and a verb meaning (3) t o make a hole or gap in or to break through . Breech is only a noun. It refers to to (1) the lower rear portion of the human trunk, or (2) the part of a firearm behind the barrel.”

John

[Outpost75]

Thank You Mr. Outpost75! (insert loud explosion noise here) Detailed description with dimensions and it just doesn't get any better than that, copy made and placed in S&W library.

The 0.028-0.032 driven protrusion is for a frame-mounted firing pin. With firing pin mounted on hammer nose striker tip protrudes at an angle so driven protrusion will be greater. Vector quantity and increased friction also reduces energy, so copper indent measurement is what determines acceptance.

[Handloader109]

If I'm not mistaken, Taurus says that all their .38 Special firearms are +P rated except the magnesium frame versions.

ABSOLUTELY NOT. I've a polymer metal mix Taurus in 38 special and it states no +p ammo. Unless they are clearly marked +p, then they are not made for that ammo. Direct from the website and manual.

Sent from my SM-G892A using Tapatalk

[Gtek]

0.028"-0.032", revision updated. Thanks again!

[Scrounge]

Hi, Bill,

Great post on explaining +P effects on non +P firearms.

Auto-correct may have got to your statement.

“Turned out that brazed head had stretched out, and the breach wasn't locking up.”

Respectfully, it is the “breech” when referring to the end of a firearm wherein a cartridge is inserted into the chamber. I’m sure you already know that.

For our younger readers who missed English class and spelling or are stronger in math and science:

“Breach is a noun referring to (1) an opening or gap or (2) a violation or disruption, and a verb meaning (3) t o make a hole or gap in or to break through . Breech is only a noun. It refers to to (1) the lower rear portion of the human trunk, or (2) the part of a firearm behind the barrel.”

John

Breach is also the presentation of a baby feet first, instead of head first. They are complicated, and often result in death of both mother and child. And the plural of breech is a pair of pants. The number of meanings of a word in English is one of the reasons why it's one of the hardest to learn of all the non-tonal languages. And I get in a hurry and don't always proofread, which I should certainly know better by now. Let BedBugBilly know you caught me, it'll give him a chuckle!

Where ever possible I do not use Spellck because it meses things up.

Bill

[Walks]

I heard that Steel frame S&W revolvers are ok with +P loads if they are Numbered, i.e. Model 10, Model 15. rather then older revolvers that are named, i.e. Military & Police, Combat masterpiece.

[Stacts]

Thank you for the replies.

The comment about the barrel being pushed out raises the next question: What is done to a revolver barrel to enable it to handle more pressure (such .357 mag. or even just a +P loading) without moving? Is it a material difference, a manufacture difference (as in tighter tolerances), or a design difference? (or any combination?)

What about the top strap? Do they simply thicken the metal or is some other strategy used?

What about firearms made before the employ of "+P" as a term? Is there a strategy to determine if such a revolver would be safe for +P ammunition?

Concerning cylinder stretch: Do the chambers in the cylinder widen or is the stretch length-wise?

Is there any way to detect the onset of these issues early?

Right now I'm just brimming with questions, so forgive me for their number.

[Scrounge]

Thank you for the replies.

The comment about the barrel being pushed out raises the next question: What is done to a revolver barrel to enable it to handle more pressure (such .357 mag. or even just a +P loading) without moving? Is it a material difference, a manufacture difference (as in tighter tolerances), or a design difference? (or any combination?)

What about the top strap? Do they simply thicken the metal or is some other strategy used?

What about firearms made before the employ of "+P" as a term? Is there a strategy to determine if such a revolver would be safe for +P ammunition?

Concerning cylinder stretch: Do the chambers in the cylinder widen or is the stretch length-wise?

Is there any way to detect the onset of these issues early?

Right now I'm just brimming with questions, so forgive me for their number.

Some of the original revolvers didn't have a backstrap. They couldn't be as strong as the ones with a backstrap just because the material of the day wasn't all that strong. As technology advances, you get alloys that are stronger because they figured out how to add them to the mix. There are also treatment for the metals that can make them tougher, harder, etc. Heat treatment is the blanket name. Used to be the books on metal working talked about hardening and tempering. Still do, but it's gotten a lot more complicated.

There are certain temperatures where the grain of the metal gets smaller, which is desirable, larger, which often isn't, and all of that depends on the particular mix of alloying elements in the particular alloy. Pick one alloy for certain properties, and another for different properties, use various heat-treatment techniques, and get the results you can. Use thicker, wider, heavier parts to make a gun tougher. They also do cryo treatments, now. Liquified gases, and that sort of thing.

Check out the Chiappa Rhino, for an example of bigger, thicker, heavier. But, while bigger, heavier guns can be easier to steady for a shot, they're more work to carry for a long time.

I would not use +P ammo in a gun that isn't rated for it unless you don't care if the gun lasts. If you're going to anyway, and you want to test it, you need high resolution measuring equipment. Even cheap imports are not really cheap, so you're going to be spending significant money buying the stuff to test the guns. Micrometers of several kinds, inside, outside, and depth, gauge blocks, a surface plate, surface gauge, optical comparators, etc. You'd also need to study metrology, so you learn what kinds of measuring and testing you'd need to do, and learn how to do it. Really, it's cheaper, easier, and faster, to just match the ammo to the gun. I've bought a bunch of the measuring equipment because I've been learning to become a machinist. Ain't there yet, but I've passed the class, got my certificate of completion this past weekend. For what I've spent on tooling, and I have not gotten all I want, I could probably have one nice higher end handgun. Not really high end, either.

Bill

[Stacts]

There are certain temperatures where the grain of the metal gets smaller, which is desirable, larger, which often isn't, and all of that depends on the particular mix of alloying elements in the particular alloy. Pick one alloy for certain properties, and another for different properties, use various heat-treatment techniques, and get the results you can. Use thicker, wider, heavier parts to make a gun tougher. They also do cryo treatments, now. Liquified gases, and that sort of thing.

Check out the Chiappa Rhino, for an example of bigger, thicker, heavier. But, while bigger, heavier guns can be easier to steady for a shot, they're more work to carry for a long time.

I would not use +P ammo in a gun that isn't rated for it unless you don't care if the gun lasts. If you're going to anyway, and you want to test it, you need high resolution measuring equipment. Even cheap imports are not really cheap, so you're going to be spending significant money buying the stuff to test the guns. Micrometers of several kinds, inside, outside, and depth, gauge blocks, a surface plate, surface gauge, optical comparators, etc. You'd also need to study metrology, so you learn what kinds of measuring and testing you'd need to do, and learn how to do it. Really, it's cheaper, easier, and faster, to just match the ammo to the gun. I've bought a bunch of the measuring equipment because I've been learning to become a machinist. Ain't there yet, but I've passed the class, got my certificate of completion this past weekend. For what I've spent on tooling, and I have not gotten all I want, I could probably have one nice higher end handgun. Not really high end, either.

Bill

So... the major difference is of material, and the second difference would be amount of material? Not necessarily a difference of design then?

[Outpost75]

The various engineering changes on S&W are the dashed numbers after the model number stamped in the yoke cut. After the Model 10-5 heat treatment was changed and other changes made to enhance durability with +P. Older S&W revolvers are no longer serviced by the factory, because parts are no longer available.

[Stacts]

... and other changes made to enhance durability...

Such as?

I'm really trying to learn more of the details.

[Groo]

Groo here
Much depends on the gun.
S&W says that all model marked STEEL guns are ok for +p...[ m-10 etc]
Note this may be because the STEEL guns [including steel J frames] were proofed for 38-44 high speed ammo.[between 38 and 357] and modern +p is of equal or lesser pressure.

[Outpost75]

Groo here
Much depends on the gun.
S&W says that all model marked STEEL guns are ok for +p...[ m-10 etc]
Note this may be because the STEEL guns [including steel J frames] were proofed for 38-44 high speed ammo.[between 38 and 357] and modern +p is of equal or lesser pressure.

If you believe that I have a good deal for you on a bridge in Brooklyn. S&W corporate honesty is on a parity with VW.

The pre-1980 J and K frames are plain carbon steel similar to 1050 quenched and tempered and most will not even register on the Rockwell C scale. About 80-90 Rb is common. The Model 19, 10-6 and later and Model 13 are typically Rc 20-24 in the frame and Rc 30 in the cylinder, as were the .38-44 Heavy Duty and the other N-frames. A Model 19 .357 requires factory rebuild after about 1000-1500 rounds of .357 and a later Model 10-8, model 64 or 66 will not pass a 5000 round endurance test with .38 Special 110-grain Treasury loads. Later L frames did better and passed, but had the primer cup flow and cylinder lockup problem. Test reports of S&W 65 and Rugers from Customs and Border Patrol are public domain and readily obtained. If you would PM me with an email address which will accept 15MB in .pdf files I can send copies you.

Also read Mike Wood's articles in Police One and on the Revolver Guy blog about barrel cracking issues in .357.
Here are some pics of S&W Scandium, Ti and MIM part failures for you:

[Stacts]

I'm interested in any information you can share.

Their .357s can't last more than 1500 rounds without work? I don't think I've ever heard that anywhere else and it's really interesting.

[Outpost75]

I'm interested in any information you can share.

Their .357s can't last more than 1500 rounds without work? I don't think I've ever heard that anywhere else and it's really interesting.

15MB of .pdf files on the way to you.

[Scrounge]

So... the major difference is of material, and the second difference would be amount of material? Not necessarily a difference of design then?

You're missing that the treatment of the metal, and quantity of metal, is part of the design. A kind of steel designated 4130 is frequently used in firearm's, among many other things. It's a chrome-molybdenum alloy, with those materials and probably some others as well, in addition to the iron and carbon that make steel. It can be relatively soft, or it can be quite hard and tough, depending on heat treatment. It's considerably harder and tougher even in its "soft" state than mild steel, which is essentially what most of the older guns were made of. If you want, you can make a part lighter, or smaller, or thinner or whatever, by choosing the right alloy and heat treatment. Or you can make it a lot stronger by using more of the material. All that is determined in the design phase. You can get by with mild steel. Lots of guns have been made with it. You take into account that it isn't as strong as some other materials, and perhaps use more of it. You can get strength in aluminum alloys, too, by adding a metal called scandium. It's expensive, but makes a very light alloy that is still very strong. Smith & Wesson makes guns using that alloy. Again, it's part of the design phase. Glocks are partially plastic. Part of the design includes determining how much plastic it takes, and where it needs to be, to make a strong and durable firearm. Not my thing, but some folks love them some plastic fantastic!

Design is a process. Lots of folks approach it a bit differently, but a poorly designed firearm will be dangerous to user, uncomfortable to handle, unreliable, too bulky, or any or all of those factors, and probably many others. You can just slap some pieces of metal and wood (or plastic and metal) together. It might even work. And it might blow up in your hand. Better to design it for the use you want it to serve. Stress calculations, ergonomics, forces involved, lots of other factors need to be considered.

HTH!

Bill

[El Bibliotecario]

I'm interested in any information you can share.

Their .357s can't last more than 1500 rounds without work?...

After two decades the only required repair for my S&W Model 19 was replacing the cylinder axis pin. Apparently I was doing something wrong.

[Stacts]

15MB of .pdf files on the way to you.

Thanks