If I can shoot the .45 S&W in my Leniad single shot derringer, great!

[Captain O]

If not, the market for an American Derringer chambered for the .45 S&W cartridge may not be a bad idea. If that's is a no-go, how about shooting it in an American Derringer chambered for the .45 Colt cartridge?

The reason I think that it's such a good idea is because the shorter case may be more efficient in the shorter barrel.

No? Yes?

Help!

[sqlbullet]

If not, the market for an American Derringer chambered for the .45 S&W cartridge may not be a bad idea. If that's is a no-go, how about shooting it in an American Derringer chambered for the .45 Colt cartridge?

The reason I think that it's such a good idea is because the shorter case may be more efficient in the shorter barrel.

No? Yes?

Help!

Yes, you can shoot 45 Schofield/S&W in a 45 Colt chamber.

I don't see any advantage to this though. Boyles law comes into play here. Velocity is the result of the average pressure exerted on the base of the bullet during it's travel down the bore. If we recognize the size of the pressure vessel at the moment the bullet base breaks from the muzzle is Vol₂, and that the size of the pressure vessel at the moment of powder ignition is Vol₁, and the Pressure_max is the same for both cartridges, then boyles law says that:

P_maxVol₁ = P₂Vol₂

Then we can see our highest value for P₂, and the corresponding highest P_avg will come from the cartridge with the largest Vol₁.  And the cartridge with the highest P_avg will have the best velocity.

So, bigger cartridges will always deliver better velocity.

There may be a volumetric efficiency here with the smaller cartridge (fps muzzle velocity per grain of powder burned) since you can hit P_max more easily with the smaller case, but for a derringer, I would be most concerned with wringing out the max velocity over any other consideration, including accuracy.  It is a belly gun.

[Captain O]

I guess I keep thinking about such early cartridges a the .44 S&W Russian and how efficiently a modern "smokeless" version would perfrom in a .44 S&W Special such as my "older" 1991 Charter Arms (Stratford Conn.) 3" barreled revolver. Too much "freebore"? 

[DM1906]

Sure. Why not .45Autorim? Or .45Superrim?

SQL is correct, but in my tests, barrel lengths of 3" or less produced negligible differences (within margins of error). I believe true to the formula, faster powders in a smaller volume are more efficient, and probably offset the brute force of slower powders that didn't have a minimum ideal dwell time (with often lower peak pressures). The .45 bore volume is large, comparable with .35x's at twice the length, but it just didn't show in the tests. Perhaps with lighter bullets, such as 185 gr, but we only tested 230's at standard pressures. A .45Superrim Derringer would be scary. "Hold my beer and watch this", scary. .460 Rowland? Not me!

[Captain O]

Just "noodling" while remebering the black powder loads of yesteryear developing their peak pressures (albeit low pressures) in longer barrels. I keep reading about .44 S&W Russian "smokeless" loads developing similar velocities to the .44 S&W Special loads (a smokeless load from it's inception). I'd be willing to bet that it's "improvement" has been "done to death" through experimentation since the 1930's. I presumen that this has been done since that time, due to the modern tempering of frames and cylinder.

BTW, The .45 AR isn't a bad idea for the Leniad.

I was simply "noodling" or "cogitating" if you will, that is all.