How can I find the maximum proof pressure for an old gun? I have a 1930 Colt Police Positive Special. I know + P ammo is "not recommended" for this gun. I target practice with it using standard velocity 38 Special 158 grain RN ammo. The gun is very accurate with that ammo and is light enough and is already beat-up enough to be what I consider an ideal gun for knock-around, camping trip, fishing trip, and general floorboard -of -the-truck type use. (It's actually been most useful to me so far using shotshells to kill posionous snakes.) I've never fired +P ammo in it but when carrying it in the boonies I do usually keep several 158 grain LSWCHPs in it, just in case. I don't think it would present any danger to me to fire that +P ammo in it, but I am worried that it might loosen up and ruin the timing of the gun. Does anyone know what this old gun is actually proofed for - or know how I can find out?
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Proof pressures for old gun
- Thread starter DG45
- Start date
proof
There are probably others with more exact info. I don't know what Colt's proofing procedures were back when that gun was made. The .38 Spl is normally loaded to 17K psi (+P = 18.5K). The difference is about nine percent. From what I can gather, proofing loads can be anywhere from 17% to 30% higher than normal factory loads. In 1930.....?
Around that time, however, the precursor to the .357 Magnum - the 38/44HV - was available. That would have been fired in guns like yours.
Pete
There are probably others with more exact info. I don't know what Colt's proofing procedures were back when that gun was made. The .38 Spl is normally loaded to 17K psi (+P = 18.5K). The difference is about nine percent. From what I can gather, proofing loads can be anywhere from 17% to 30% higher than normal factory loads. In 1930.....?
Around that time, however, the precursor to the .357 Magnum - the 38/44HV - was available. That would have been fired in guns like yours.
Pete
I doubt a few rounds of +P or even higher pressure ammo would damage the old gun, but warnings are not based on a few rounds, but on the fact that after x rounds, the old guns will show damage. What is x? Ten rounds? 100 rounds? 10,000 rounds? The problem is that no one really knows. This is complicated by the fact that any gun will be damaged after y rounds of even standard ammo. What is y? 5000? 100,000? Again, no one knows. Even if someone shoots a gun to destruction and counts the rounds, that figure would be good only for that individual gun.
So gun companies, not knowing the exact load, and not wishing to set some arbitrary figure that could be seen as a challenge, simply say that the gun was made for standard loads and anything of higher pressure is not recommended. I hesitate to suggest that one disregard that advice.
Jim
So gun companies, not knowing the exact load, and not wishing to set some arbitrary figure that could be seen as a challenge, simply say that the gun was made for standard loads and anything of higher pressure is not recommended. I hesitate to suggest that one disregard that advice.
Jim
Sometimes, it's just when you post as to whether many people see it.Gosh, posted June 28 and so far only two responses, but they were helpful. Thank you Darkgael and Jim Keenan for your assistance.
Personally, I wouldn't load +P even for defense. There are "boutique" standard pressure loads that will get you the same velocities as most manufacturers' +p loads. Buffalo Bore has a couple of offerings that will do this. They are more expensive, but you're only talking about a box or two.
oneounceload
Moderator
Why risk damage to yourself or the gun? You said you were shooting the load the gun was designed and built for with good accuracy....Why mess with success???...At standard SD ranges, those will work just fine.......
Interesting to note, in the two old (1949-1950) Lyman reloading manuals in my collection, among the loads listed for the .38 S&W, several have a notation listed at the side "15,000 PSI". I have to assume that this indicates the use of caution in reloading as many of the guns chambered in that caliber were older models black powder proofed only.
Colt indicated that their service revolvers could handle the 38/44 loads, meaning the OPs while S&W cautioned against using them in their K frames. I doubt that the d frames would handle the 30,000 plus CUPs of the 38/44 loads for long, however judicious use of +Ps isn't something I would shy from. There are many scaredycat worrywart posters in here, on the other hand they problably have all their fingers and eyes.
I looked up the velocities of the factory loads for the .38/44 round and the .38 Hi=Speed as it was also referred to in those days. I used an old 1949 Gun Digest. Both rounds were within 15 fps of each other. The 158 gr bullet @ 1185 fps. The only Smiths rated to handle this load was, of course, the .357 Magnum and the .38/44 Outdoorsman and the other .38/44 without target sights. This Gun Digest didn't include ratings on the Colt unfortunately.
Select by bullet!!
In this case I would go with a 38 special with a quality jacketed hollow point.
Speer gold dot comes to mind. A fine older revolver deserves the added expense, and again bullet placement is everything.
Burn powder, practice, practice.
Good shooting will make up for poor gear, but superior gear will not make up for poor shooting. Jeff Cooper
In this case I would go with a 38 special with a quality jacketed hollow point.
Speer gold dot comes to mind. A fine older revolver deserves the added expense, and again bullet placement is everything.
Burn powder, practice, practice.
Good shooting will make up for poor gear, but superior gear will not make up for poor shooting. Jeff Cooper
If I'm understanding what I'm reading (which is always a question with me):
Jondar says that both the 38/44 and the 38 High Speed develop about the same pressure; i.e. 1185 fps. (Using 158 grain bullet?)
darkgael says 38 Special +P pressure is only about 9% greater than standard 38 Special. (Using 158 grain bullet?)
Standard velocity 38 Special 158 grain LRN fammo fired from a 4" barrel is usually reported at about 770-790 fps velocity, and I seem to remember reading that the same 158 grain weight bullet in 38 Special +P develops about 890-920 fps velocity.
This looks like the modern 38 Special +P develops nowhere near the pressure or velocity of the old 38/44 or 38 High Speed; consequently, I don't think it would cause a serious problem to either me or my gun to fire a few 38 Special +P rounds in it. (but I'm a paid professional* folks, so don't you try this at home.)
I'd definitely be scared of firing 38/44 ammo or 38 High Speed ammo in my old gun.
* I'm a paid professional credit manager.
Jondar says that both the 38/44 and the 38 High Speed develop about the same pressure; i.e. 1185 fps. (Using 158 grain bullet?)
darkgael says 38 Special +P pressure is only about 9% greater than standard 38 Special. (Using 158 grain bullet?)
Standard velocity 38 Special 158 grain LRN fammo fired from a 4" barrel is usually reported at about 770-790 fps velocity, and I seem to remember reading that the same 158 grain weight bullet in 38 Special +P develops about 890-920 fps velocity.
This looks like the modern 38 Special +P develops nowhere near the pressure or velocity of the old 38/44 or 38 High Speed; consequently, I don't think it would cause a serious problem to either me or my gun to fire a few 38 Special +P rounds in it. (but I'm a paid professional* folks, so don't you try this at home.)
I'd definitely be scared of firing 38/44 ammo or 38 High Speed ammo in my old gun.
* I'm a paid professional credit manager.
DG-45, I dug out an old Shooters Bible that did list the Colt revolvers. The Colt Official police model was listed as safe for using .38 Special both regular and Hi-Speed (same velocity as .38/44). Unfortunately, the Colt Police Positive revolver was listed for only .38 Special, mid range and regular. In my humble opinion I wouldn't feel threatened firing occasional (the key word here is occasional) Plus P rounds in my K model S&W made in 1941, and your Colt Police Positive is every bit as strong. I load for the .38 Special and usually keep them at mid range velocity as they are so much more pleasant to shoot, and keep the faster loadings for self defense rounds. Hope this helps.
Take the plunge, carefully!!!
fire one cylinder of modern +P ammo. See where it hits, and (important) how it extracts!. If the cases stick at all, its too hot for your gun, no matter what the rated pressure!
Any quality gun in good condition will handle a small number of over standard pressure loads with out damage. However, how many rounds this is depends on too many individual factors to be able to predict with any degree of accuracy. The only thing that can be said with certainty is that at some point damage will occur. And that damage, when it happens, could be as much as catastrophic failure. It likely won't be, but it could be.
I would not put 38/44 level loads in your Police Positive, unless if it was the only ammo available during a life threatening emergency!
Generally the first indication that the ammo is too hot for your gun is difficult extraction, not a blown cylinder. But when dealing with old guns, made in the days before our current understanding of metalurgy and pressure mesurement, its best to be cautious and careful.
fire one cylinder of modern +P ammo. See where it hits, and (important) how it extracts!. If the cases stick at all, its too hot for your gun, no matter what the rated pressure!
Any quality gun in good condition will handle a small number of over standard pressure loads with out damage. However, how many rounds this is depends on too many individual factors to be able to predict with any degree of accuracy. The only thing that can be said with certainty is that at some point damage will occur. And that damage, when it happens, could be as much as catastrophic failure. It likely won't be, but it could be.
I would not put 38/44 level loads in your Police Positive, unless if it was the only ammo available during a life threatening emergency!
Generally the first indication that the ammo is too hot for your gun is difficult extraction, not a blown cylinder. But when dealing with old guns, made in the days before our current understanding of metalurgy and pressure mesurement, its best to be cautious and careful.