Barrel Length vs Veleocity

[Ganderite]

I have quite a few 9mm pistols. I have found that the DRG brand cast lead bullet of 135g Round Nose works well in all of them, and for most, better than the other weights. I load this bullet with TiteGroup because I have a lot of it on hand and because for accuracy, it seems to work well. I load this combo at 3.0, 3.3, 3.6 and 3.9gr, and then note on each pistol what the preference is. Most prefer 3.3 or 3.6.

Today I tested this powder and bullet for velocity in a 1911 (5”) and a M&P (4.3”). I also calculated the Power Factor.

The velocity difference was not as great as I expected.

M&P 9 (4.3”)
3.0gr 901fps & 121.6 PF
3.3gr 953fps & 128.6 PF
3.6gr 1027fps & 138.6 PF
3.9gr 1073fps & 145 PF

1911 (5.0”)
3.0gr 932fps & 125.8 PF
3.3gr 950fps & 128.2 PF
3.6gr 1060fps & 143 PF
3.9gr 1124fps & 151.7 PF

 

[StoneHorse]

You may find this site of some interest: http://www.ballisticsbytheinch.com/index.html

 

[Lead hammer]

That's a fair bit of difference I think. Could shoot less powder to reach the same power factor, and load more rounds.

 

[Juster]

Great to have actual data, thanks Ganderite. One wonders if a faster powder like Bullseye (I think you posted a powder speed list that I saved) would make slightly less difference.
It is easy to do this in QuickLoad, but it isn't real.

 

[Ganderite]

Great to have actual data, thanks Ganderite. One wonders if a faster powder like Bullseye (I think you posted a powder speed list that I saved) would make slightly less difference.
It is easy to do this in QuickLoad, but it isn't real.

I would not expect powder choice to make much difference. The longer barrel will always get higher velocity. If you go to the very slow part of the spectrum, the difference would be more pronounced, but the powder would not be a good choice, anyway.

Besides, I think your question is poorly posed. The issue is not the velocity difference between barrels, but the actual velocity achieved. I would expect the max charge of TG to produce a higher velocity than the max charge of Bullseye, so the actual velocity in the short barrel would be lower than the velocity achieved by TG.

But even TG is too fast for max velocity. For that you want a medium speed powder like Power Pistol.

I use TiteGroup because I get good accuracy, adequate power and because I happen to have 2 8 pound jugs of it. It was on sale for $98 a jug, so I bought some. (3 years ago).