black powder barrel length vs velocity testing data?

[exarcher]

I've read test data concering barrel length and velocity in centerfire/rimfire rifles. I've never seen any data with black powder only.. it would be a good test because i don't think the "smokeless" data is relevant with black powder. Black powder is classified as an explosive, while the smokeless and bp alternatives are "propellants". I'm sure this data exists somewhere especially since black powder has been around so long. Does anyone have referance to black powder test data location/info?

 

[deermanok]

I saw a video online somewhere recently. He had a 28 inch barrel, I think?
Fired a shot through the crono. Then he cut a inch off the barrel, shot recorded the velocity. Kept going down to 24 inches, I think?
There was a drop in velocity but not huge. Man, I wish I could remember who it was on the video.

 

[Jasonb1911]

I've read test data concering barrel length and velocity in centerfire/rimfire rifles. I've never seen any data with black powder only.. it would be a good test because i don't think the "smokeless" data is relevant with black powder. Black powder is classified as an explosive, while the smokeless and bp alternatives are "propellants". I'm sure this data exists somewhere especially since black powder has been around so long. Does anyone have referance to black powder test data location/info?

Here is a ballistic calculator of sorts that might be helpful. It is set up for Swiss powder, but it will give you a good idea of what different barrel lengths can have on velocity, energy, etc. I have found it to be spot on in my experience.

https://www.p-max.uk/cgi-bin/black_powder.cgi

 

[exarcher]

Here is a ballistic calculator of sorts that might be helpful. It is set up for Swiss powder, but it will give you a good idea of what different barrel lengths can have on velocity, energy, etc. I have found it to be spot on in my experience.

https://www.p-max.uk/cgi-bin/black_powder.cgi

thanks much!! this will be fun to use!

 

[Hanshi]

I've chronographed most of mine and learned there are no absolutes. Velocity isn't necessarily linear and a very long barrel can slow the prb down before it exits. My .40 was an eye opener. The progression of velocities with each 5 grain powder increase was a reasonable double digit figure, until. Interestingly the 5 grain increase from 35 grns of 3F to 40 grns of 3F was a whopping 229 fps increase. That jump was not repeated for any other 5 grn increase. The rifle in question has a 38 inch barrel. Velocity at 40 grains of 3F was "close" to 1700 fps. At the same time a 60 grain charge came up with an average of 2140 fps. Forty grains was my favorite all around load for 1680 fps with an sd of 5. And with the 60 grn charge at 2140 fps had an sd of only 17. The 60 grn load really shined at 100 yards and the 40 grn load did as well and only hit the target 2" to 3" lower. At 50 yards both were super accurate.

 

[sonny from st. louis]

I liked your post. I have been doing chronograph testing for several years. These test can reveal very interesting data. Thank you for your post.

 

[Ka'imiloa]

I saw a video online somewhere recently. He had a 28 inch barrel, I think?
Fired a shot through the crono. Then he cut a inch off the barrel, shot recorded the velocity. Kept going down to 24 inches, I think?
There was a drop in velocity but not huge. Man, I wish I could remember who it was on the video.

Thompson/Center had a prominent ML writer ballistician/writer, Sam Fadala as I recall, test barrel length for optimum velocity. It was probably the more popular 50 cal. barrel. 28" was the optimum length, and at that time it was very likely with Black Powder as the propellant. So guess what the "compromise" 1:48 twist T/C barrel length is for their .50 and .54 ML rifles? Yes, 28"!
Aloha, Ka'imiloa

 

[Ka'imiloa]

thanks much!! this will be fun to use!

Your P-Max ballistic calculator was a true gem. I now know what the peak pressure and muzzle velocity was in the past for long range shooting using .45 cal. Pedersoli rifle with 545 gr. bullet and 107 gr. wt. of Swiss 1.5 F, and also the current load of 100 gr. wt. (95 gr. vol.) 1.5F Swiss and 500 gr. bullet in same rifle for current elk. Also the alternate load (different rifle, 54 cal. using saboted 330 gr. bullet) using 99.2 gr. wt. (93 gr. vol.) of 2F Swiss, as backup rifle for this elk hunt.
Priceless info, and much thanks to you for posting the link.
Notably, the two recent loads are very similar in velocity and energy, but the longer 500 gr. bullet is going to have less drop, it currently appears from 200 yd. trial shooting, than the 330 gr. bullet -- due to better ballistic coefficient. It will be interesting to see how the drop pans out at 225 and 250 yds.
Aloha, Ka'imiloa

 

[Jasonb1911]

Your P-Max ballistic calculator was a true gem. I now know what the peak pressure and muzzle velocity was in the past for long range shooting using .45 cal. Pedersoli rifle with 545 gr. bullet and 107 gr. wt. of Swiss 1.5 F, and also the current load of 100 gr. wt. (95 gr. vol.) 1.5F Swiss and 500 gr. bullet in same rifle for current elk. Also the alternate load (different rifle, 54 cal. using saboted 330 gr. bullet) using 99.2 gr. wt. (93 gr. vol.) of 2F Swiss, as backup rifle for this elk hunt.
Priceless info, and much thanks to you for posting the link.
Notably, the two recent loads are very similar in velocity and energy, but the longer 500 gr. bullet is going to have less drop, it currently appears from 200 yd. trial shooting, than the 330 gr. bullet -- due to better ballistic coefficient. It will be interesting to see how the drop pans out at 225 and 250 yds.
Aloha, Ka'imiloa

Glad to be of help.