paul788 Posted January 8, 2013 Share Posted January 8, 2013 How many feet per second of velocity can I expect going from a 4" to a 6" barrel? I'm thinking of switching to a 6" and wonder how much (or little) gain to expect. I seem to remember 40 fps per inch but haven't found a source that verifies it. Thanks Paul Link to comment Share on other sites More sharing options...
pskys2 Posted January 8, 2013 Share Posted January 8, 2013 Seems more like 35 f/s, BUT there are so many other issues you can't really say for sure. You must chrono each gun separately. About the only way you can be relatively sure of it is if you are actually cutting a barrel down. Revolvers are especially notorious for velocity differences between guns irregardless of barrel length. I have a NEW Barsto .45acp 5" barrel and it gets 30-40 f/s LESS than a 20 yr old, much shot .45acp Clark barrel. I took a buddies 5" 625 to the 2007 Nationals and it ran about 30 f/s more then my PC625 5". Link to comment Share on other sites More sharing options...
Toolguy Posted January 8, 2013 Share Posted January 8, 2013 About 50 feet per second per inch is a good rule of thumb. Each gun is an individual though. I have a 4" that has higher velocity than some of my 6" ones. I think half of the variation is the bore of the barrel, half is the cylinder gap, and half is other stuff. Link to comment Share on other sites More sharing options...
Blueridge Posted January 8, 2013 Share Posted January 8, 2013 I have found that with my revolver (a ruger alaskan [2 1/2"barrel]) that I lose approximately 40 fps compared to the reloading manual loads I have used. The barrel length of the barrel used for the reloading manual published loads I have is a 7.25 inch, so you can imagine that my loads have to be "hot" to make major in USPSA. The cylinder gap of the revolver added to the length of the barrel will effect the fps that you obtain, as was advised earlier. Link to comment Share on other sites More sharing options...
toothguy Posted January 8, 2013 Share Posted January 8, 2013 (edited) http://www.ballisticsbytheinch.com/ Very interesting website, you can look up many different guns, barrel lengths, cylinder gap ect. They have done a lot of testing with different loads. Edited January 8, 2013 by toothguy Link to comment Share on other sites More sharing options...
scarecrow Posted January 21, 2013 Share Posted January 21, 2013 30-40 fps second is about right but you really need to chrono the load. Too many variables to guess. Link to comment Share on other sites More sharing options...
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