Does anyone know what ammo that these 1950-ish pre-model 10 38 special military and police revolvers were designed to used for these fixed sights?

158 grain lead round nose would have been the standard ammo of the day. 158 grain LSWCs will hit to the same point as the LRNs. Either will do about 800 fps from a 4-5 inch M&P. You can still find plenty of it today from sporting goods stores or big box retailers, often in the plain vanilla product lines from the big three ammo makers as well as other brands.

How fast can you push the 158 LSWC's in these older guns safely?

Yes, it is designed for 158 std velocity .

Maybe it's a regional thing , but it has pretty much disappeared from the shelves in my area . It has been replaced by the various generic 130 fmj . Of course it's still listed from the major mfgs, and the usual smaller and regional mfgs , you'll just have to order from the internet .

If it's a true pre-10 made in the 50's you should be good to go with modern day +P which is not real hot.

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Yes. The factory qualified these K frames to shoot the pre-war designed .38-44 High Speed rounds, which is almost identical to modern +P.

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Chris
SWCA #2243 SWHF #292

I thought their stock answer was that only model numbered guns are safe to shoot +P in?

I have a reloading manual from the '70s that says that .38/44 is good for 1090 ft/s, FWIW.

That is the standard answer but some "experts" say any post war (WWII) all steel revolvers are safe because of the heat treating.

I am not telling anyone to do anything the think is not safe, I'm only relating the information I have found. I have 1948 M&P and I have shot several cylinders of the FBI load through it but just to be on the safe side will not do it again.

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SWCA #3437

A 158 gr Lead bullet. Probably best to shoot 158 gr LRN, LSWC or even LSWCHP +P for defense if you want. 148 gr Wadcutters would be good too.

I believe the original Hi-Speed .38-44, at least some variations, was closer to modern Buffalo Bore .38 Spl+P than other factory +P. Buffalo Bore +P out of a 4 inch is about 1180 ft per second.

Other sources like Bill Jordan's No Second Place winners put the .38-44 Hi-Speed at 1059 ft per second out of a 6 inch barrel.

I have a 1944 Colt Official Police that I shoot +P ammunition in on occasion. Old advertisements show the gun rated for .38-44 Hi Speed. Jack First as well as Cylinder and Slide have both told me +P is okay in the gun just to not give it a steady diet.

For +P, it's really not a question of if it is safe you or safe for the gun, but rather if a steady diet is healthy for the gun. Shoot enough +p in any gun (even modern made guns) and it will accelerate the wear to some degree or another more than standard ammo would. Normal factory +P is safe for a K frame, even a prewar K frame, just use it in moderation. Buffalo Bore, on the other hand, is something entirely different. While it is +P, it's velocity is quite a bit higher and will accelerate the wear that much more, so I would not shoot much of that in any old gun if at all unless my life depended on it.

Just my opinion for what it's worth.

Day in/day out, if you load a .38 with a hard cast 158 grain SWC, it will probably shoot to POA, and perform well on 2 legged attackers, without being harsh to shoot or hard on the gun. My recollection is that .38-44 ammo is noticeably hotter than +P, especially modern +P; there have been strings on the issue in the last few years that included testing.

The 158 RNL will shoot ok, but is a horrid round for personal defense, and the only thing worse is the 130 grain ball; even less effective and often not hitting POA. One should use those loads only for making empty brass. I would carry a decent 148 grain wadcutter in preference to those.

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NHI, 10-8.

There have been several threads here over the years about .38-44 ammo .

The oversimplified recap is that ".38-44 " actually has three meanings :

1. Original 1930's factory ammo
2. 1950's era factory ammo
3. Various handloads to maximize performance using .38spl cases in strong revolver .

Modern compaisons would be :

1. .38 +P+
2. .38 +P ( or just slightly morel
3. Up to full .357 prssures .