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Barrel Length

Posted: Tue Jul 27, 2021 1:05 pm
by Glen Ring
What impact does barrel length have on the velocity of a Black Powder Cartridge? It seems that BPCR rifles commonly have 30 inch barrels ( or longer)
and I know about increased sight radius.

I know with smokeless powders, slower burning powder in a longer barrel usually gets more velocity.

I have not found any study/experiment on the topic of barrel length and Black powder velocity.

Re: Barrel Length

Posted: Tue Jul 27, 2021 2:27 pm
by George Babits
There were several studies done with that back in the 1970s, although they deal with muzzle loaders. One I can think of is the old Lyman "Black Powder Handbook" published in 1975. Mostly with round balls, but some data with conical bullets too. I think there might be some in the older Dixie catelogs as well.

George

Re: Barrel Length

Posted: Tue Jul 27, 2021 4:25 pm
by Glen Ring
I think I bought a couple of those old books a few weeks ago, but haven't read them yet....I'll find them tonight and dive in.

Re: Barrel Length

Posted: Wed Jul 28, 2021 8:32 am
by Kirk
We done it with 2 45-110's, my 26" hunting rifle and a buddies 34" express years ago, there was only around a 4-8 fps difference between the two.

Re: Barrel Length

Posted: Wed Jul 28, 2021 12:37 pm
by Glen Ring
Thank you sir...That answered that question. I have been looking at a 45-70 with a shorter barrel and now I know I won't be giving up much.

Re: Barrel Length

Posted: Thu Jul 29, 2021 2:41 pm
by axman
Kirk wrote: Wed Jul 28, 2021 8:32 am We done it with 2 45-110's, my 26" hunting rifle and a buddies 34" express years ago, there was only around a 4-8 fps difference between the two.
That 26” would be a lot nicer to carry than the 34”.

Re: Barrel Length

Posted: Thu Jul 29, 2021 4:41 pm
by mdeland
I suspected that Glen but did not know for a fact that with black powder it makes a lot less difference in barrel length than it would with smokeless.
I have a .58 Buffalo Hunter rifle that shoots a 620 grain Maxi bullet with 150 grains of 2F Goex out of a 26 inch barrel. The chronograph says 1400 fps and it appears that the whole charge is consumed in that short barrel. Course the recoil will knock you into next Tuesday but it is accurate and efficient for a muzzle loading rifle.
This is good news to me , this thread , because I still want to make a Gemmer in 50-70 from a long nose Trapdoor 68 action and a shorter barrel on the end of that rather long action would make the rifle much more manageable .

Re: Barrel Length

Posted: Thu Jul 29, 2021 4:59 pm
by Glen Ring
I Looked at a shorter 45-70 and wondered about it. This is good news to me also.