Curious velocity differences between barrels

[mc89]

I was shooting two of my .45 revolvers at my brother's house a couple of weeks ago. My Ruger Blackhawk with 4 5/8" barrel, and my Ruger Bisley with 5 1/2" barrel. Both are stock revolvers. I was shooting some factory 45 Schofield ammo that somebody had given me, through both revolvers. My brother had recently bought a chronograph (one of the Doppler radar kind), and this is the first time I've shot with one.

Anyway, what surprised me was that the 5 1/2" barrel shot about 50-60 feet per second on average SLOWER than the 4 5/8" barrel. Now usually, I would think that a longer barrel produces more velocity, but with these two revolvers it was the opposite. The shorter barrel clearly shot faster.

Any ideas on what might cause this? Is this something that might be considered normal? Or might it indicate a cylinder or barrel problem such as tight throats or thread choke?

[dale53]

mc89;
The first thing I would do is measure the barrel cylinder gap. The tighter the gap the higher the velocity.

FWIW
Dale53

[Encore64]

A world of possibilities. Some barrels are just faster than others.

Throats, barrel gap, etc varies between guns.

Too many possibilities to list them all...

[mc89]

Yeah, I didn't figure there would be a quick easy answer. I do accept that certain barrels are faster than others. However, I haven't measured or touched the throats, and I'm definitely looking at renting a reamer to be able to make them all uniform. I shoot mostly cast bullets anyway. Don't think I've shot any jacketed bullets through either of them yet, but don't really plan to. I'll have to break out my feeler gauges to measure the barrel cylinder gap.

Thanks for the answers and opinions.

[cmillard]

You also have to look at what powder is being shot and with what bullet. Some fast burning powders don't net the higher velocity in a long barrel but will in a short barrel.

[mc89]

Jan 23, 2020 14:10:23 GMT -5 cmillard said:

You also have to look at what powder is being shot and with what bullet. Some fast burning powders don't net the higher velocity in a long barrel but will in a short barrel.

You are correct, however I was shooting the same ammo out of both of my revolvers in this instance.

[taffin]

Jan 21, 2020 17:26:31 GMT -5 mc89 said:

I was shooting two of my .45 revolvers at my brother's house a couple of weeks ago. My Ruger Blackhawk with 4 5/8" barrel, and my Ruger Bisley with 5 1/2" barrel. Both are stock revolvers. I was shooting some factory 45 Schofield ammo that somebody had given me, through both revolvers. My brother had recently bought a chronograph (one of the Doppler radar kind), and this is the first time I've shot with one.

Anyway, what surprised me was that the 5 1/2" barrel shot about 50-60 feet per second on average SLOWER than the 4 5/8" barrel. Now usually, I would think that a longer barrel produces more velocity, but with these two revolvers it was the opposite. The shorter barrel clearly shot faster.

Any ideas on what might cause this? Is this something that might be considered normal? Or might it indicate a cylinder or barrel problem such as tight throats or thread choke?

MANY VARIABLES. DAN WESSON 8" SIXGUNS WILL OFTEN SHOOT SLOWER THAN SMITH 6" SIXGUNS. i HAVE A 7-1/2" COLT NF .45 THAT SHOT SLOWER THAN MY 4-3/4" COLT .45 UNTIL I HAD HAMILTON SET THE BARREL BACK TO A TIGHTER GAP.

[cas]

Just the chamber dimension and the barrel can do it. I've shot the same load side by side in visually identical Contender barrels (different builder and barrel blank) and was shocked how far apart the velocities were.

[Yetiman]

As has been stated, guns vary.

I have a 2 3/4" Redhawk Kodiak Backpacker 44 mag that has a pretty tight gap for a factory revolver.

A couple years ago I was shooting it with my Magnetospeed, and another guy at the range wanted to look at the velocity from his 4" S&W. We were both quite shocked (him more than I) that the velocities were about 0-10 fps faster out of my Ruger.

This was true with two different loads of mine (240 xtp and 300 xtp) and with the Blazers he was shooting.

I have seen several reviews of the Kodiak and Alaskan 44 mag revolvers where they noted the impressive velocity from such short barrels.