Velocity for short barrels?

[TTv2]

I've got two short barrel guns that I'd like to get an idea of what velocity I can expect from them with certain powders, namely Triple 7 and Pyrodex P.

First gun is a chopped .36 caliber Uberti 1862 Police with a 2.5" barrel.

Second gun is not a black powder muzzleloader, but a .45/.410 derringer that I'm would like to try .45 Black Powder Magnum in. It's a 3 inch .410 chamber and the barrel length is probably 3.5 inches. With a 200 grain bullet over 60 grains of Triple 7, what velocity could I expect? Is 60 grains of Triple 7 too much for .45 Black Powder Magnum?

 

[rodwha]

I spoke with a fellow who chopped pistols and tested them. What I recall from him was that a standard .44 cal required about a 3.5” barrel for a full burn of the powder, that none would be found on a sheet before him. I wonder though if unburnt powder would still burn up prior to hitting the sheet. I’d think so.

You have a smaller chamber size on that .36, but I’d still imagine it not burning a full charge with a ball with that short barrel. To my thinking a heavier and longer projectile (bullet) might do better in that it will take just a bit more to get it moving allowing for a better burn of the powder, which would also be reduced as the bullet would take up some of that capacity.

I’ve seen Pyrodex velocities all over the chart. In many I’ve seen much slower velocities much like standard Goex and many other black powders. But I’ve also seen a few velocities where it performed very well much like T7 and Swiss.

I’d most certainly think a 60 grn charge of BP in a derringer would be a waste. I don’t see how it has enough barrel to burn that much powder. On the flip side I’d think the fireball would be impressive.

 

[tbob38]

I've got two short barrel guns that I'd like to get an idea of what velocity I can expect from them with certain powders, namely Triple 7 and Pyrodex P.

First gun is a chopped .36 caliber Uberti 1862 Police with a 2.5" barrel.

Second gun is not a black powder muzzleloader, but a .45/.410 derringer that I'm would like to try .45 Black Powder Magnum in. It's a 3 inch .410 chamber and the barrel length is probably 3.5 inches. With a 200 grain bullet over 60 grains of Triple 7, what velocity could I expect? Is 60 grains of Triple 7 too much for .45 Black Powder Magnum?

Where do you live? If close to SW Utah maybe we can get out the chronograph and see. I'm planning to to some tests on my Pietta 3" barrel belly gun.

 

[TTv2]

I’d most certainly think a 60 grn charge of BP in a derringer would be a waste. I don’t see how it has enough barrel to burn that much powder. On the flip side I’d think the fireball would be impressive.

The idea behind the .45 BPM in the derringer (and other .410 handguns) is to increase accuracy. Standard .45 Colt loads have enough velocity to be effective, but I can't shoot further than 5 yards with the derringer and the bullets are tumbling by that point. With the .45 BPM's length, I think it can help increase accuracy, but the velocity needs to be 600 fps minimum to be effective.

Where do you live? If close to SW Utah maybe we can get out the chronograph and see. I'm planning to to some tests on my Pietta 3" barrel belly gun.

Pretty far from Utah... New England.

 

[rodwha]

The idea behind the .45 BPM in the derringer (and other .410 handguns) is to increase accuracy. Standard .45 Colt loads have enough velocity to be effective, but I can't shoot further than 5 yards with the derringer and the bullets are tumbling by that point. With the .45 BPM's length, I think it can help increase accuracy, but the velocity needs to be 600 fps minimum to be effective.

Pretty far from Utah... New England.

Being a modern gun I’d be inclined to use Swiss 4F with filler and a long bullet with a wide meplat or a HP.

 

[paul harm]

It's a belly gun. They're meant to be shot a CLOSE distance. JMHO, but 5 yards would be a stretch for a belly gun. I think you might be trying to do what the gun wasn't intended to do. Maybe you just need to find another gun. This would be a good reason to buy a gun, and any reason is a good reason. Good luck in what ever you try.

 

[rodwha]

7 yds, to me, is a typical self protection distance. 15 yds is home protection distance. And 25 yds is hunting distance with a handgun. If it can’t do at least those numbers for those reasons it’s not worth using. And I see it as needing to be able to keep 4” groups or less at the range since they will most certainly open up further under stress.

 

[Eyrie G. Dogg]

… that a standard .44 cal required about a 3.5” barrel for a full burn of the powder ...

I doubt that. We would be doing well to get 'full burn' on an eight inch.

 

[tbob38]

[QUOTE="TTv2, post:
Pretty far from Utah... New England.[/QUOTE]

Yah, that's pretty far. Although I used to live in Kittery ME and the greater Boston area. Little help in this case though.

 

[rodwha]

I doubt that. We would be doing well to get 'full burn' on an eight inch.

I’m at a loss for what you are saying. Mind explaining that for me please?

 

[Snidely70431]

Black powder and black powder substitutes are propellants that burn. They do better in a longer barrel. Even rifles often do not get all the power out of the propellants, hence the muzzle flash when using two or three pellets. All that burning outside the barrel is just waste.

 

[arcticap]

Some powder may be wasted but the chronograph shows the increased velocities:


Published chronograph velocity data for a 5.5 inch Remington 1858 revolver.

Powder by Volume-------Bullet Weight ------ Average Velocity

28 grains 3F Pyrodex----138 grain 451 ball----593 ft/s

32 grains 3F Pyrodex----138 grain 451 ball----700 ft/s

32 grains 3F Pyrodex----140 grain.454 ball----850 ft/s

35 grains 3F Pyrodex----138 grain 451 ball----875 ft/s

35 grains 3F Pyrodex----140 grain 454 ball----945 ft/s

35 grains 3F Pyrodex----143 grain 457 ball----960 ft/s

37 grains 3F Pyrodex----138 grain 451 ball----950 ft/s

37 grains 3F Pyrodex----143 grain 457 ball----960 ft/s

42 grains 3F Pyrodex----143 grain 457 ball----1019 ft/s

46 grains 3F Pyrodex----143 grain 457 ball----1050 ft/s

37 grains 3F GOEX BP--140 grain 454 ball----898 ft/s

40 grains 3F GOEX BP--140 grain 454 ball----949 ft/s

42 grains 3F GOEX BP--140 grain 454 ball----964 ft/s

Source:


http://poconoshooting.com/blackpowderballistics.html

 

[jeepnik]

I've never chronoed my 3" 1860 Army. But, loaded with the same weight of the same powder, the flash is considerably greater. Since so darned much powder is burning in front of the muzzle instead of behind it I figure the velocity drop would be somewhat sizeable.

On the other hand, at close range you can set your target on fire. That would have to be a bit disconcerting for your enemy.

 

[Eyrie G. Dogg]

... at close range you can set your target on fire. That would have to be a bit disconcerting for your enemy.

One of the Swedish members at 58 Rem set an old suit coat to smoldering with a couple of 3-4 foot shots with an original 8” Remington just to see if he could. He could. Shot and a' fire would bring most any bad assailants to gesus and pacify them for the rest of the day.