blaster113 Posted November 10, 2012 Share Posted November 10, 2012 I normally use a 6" custom STI build for Limited. So after reading the post about spare parts I realized in my spare parts kit I have just about all the parts to build a new gun except for the major components such as the slide/frame/barrel. If I build a 5" back up gun, how much velocity loss should I expect with my 6" loads? Was thinking about building a 5" as I wanted to build a 10mm blaster/.40 Limited dual purpose gun. I normally load my 165 gr. match loads to 170-172 pf. tried searching, my search fu is weak. Link to comment Share on other sites More sharing options...
al503 Posted November 10, 2012 Share Posted November 10, 2012 I think much would depend on the burn rate of the powder(s) you use. If you're using clays, you might gain velocity with the shorter bbl. If you're using a slower powder that burns completely in a 6 but not a 5, then you'll lose some velocity. Link to comment Share on other sites More sharing options...
Carmine Posted November 10, 2012 Share Posted November 10, 2012 Hmmmmm.... I've allways found that going from my 6" .45 to my 5" .45 with the same load is a drop of 45-60 fps. Now mind you, I'm powerfactoring "old school" at 180+....so a few fps isnt going to drop me into minor.....just say,n Link to comment Share on other sites More sharing options...
RIIID Posted November 10, 2012 Share Posted November 10, 2012 The barrel is the variable that can't be checked until you fire rounds through it. Velocity will vary from barrel to barrel with the same loads. Running the same load for two different guns may require a hotter load to make PF in one gun. Rich Link to comment Share on other sites More sharing options...
Carmine Posted November 10, 2012 Share Posted November 10, 2012 RIIID speaks the truth. Get 2 of the same guns with the same loads.....you"ll get 2 different chrono readings. Link to comment Share on other sites More sharing options...
blaster113 Posted November 10, 2012 Author Share Posted November 10, 2012 If the velocity drop from a 6" to a 5" is 45-60 fps then my little project is a no go as I would have to load to about 174-5 pf, too snappy with my light 6". My powder of choice for Limited is fast burning N320. 5.3/5.4 grains gives me 170-172 pf. Link to comment Share on other sites More sharing options...
EkuJustice Posted November 10, 2012 Share Posted November 10, 2012 There is no way to say unless you check it. Some barrels have more of a spread than others Link to comment Share on other sites More sharing options...
Carmine Posted November 10, 2012 Share Posted November 10, 2012 Can you run with a stronger recoil spring and bump your load up?? I mean, your power factoring at the minimum for major in IPSC......Just say'n. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted November 10, 2012 Share Posted November 10, 2012 Hello: Rich is telling the truth on barrels. I have a load I use in my 6" with 165 grain bullets and it is 174.1PF and a friend of mine tried them in his 5" factory Edge and they were 174.6PF. He either has a fast barrel or mine is slow. I also have shot the same load in my 5" single stack and it makes 169.4PF but it is a little too snappy for me. I like heavier bullets in the 5" pistols. I use Tite Group which meters about the same as N320. Thanks, Eric Link to comment Share on other sites More sharing options...
blaster113 Posted November 10, 2012 Author Share Posted November 10, 2012 (edited) For major in USPSA pf is only 165. I shot loads in the 175 pf range in my light gun and they were unpleasant. 5.4 grains of N320 gives me a pf of 172, so loads in this range should be OK. Even a pf drop of 5 points would still get me major in the backup gun. good points about the individual barrels and the variances in velocity. Are there any brands that run faster than others? this future build will be on the budget side. I'm thinking STI, KKM or Schuemann for barrels in that order just due to pricing. After having a disaster at Area 2 last year that could have been construed as a gun problem at the time, I'm thinking more and more about a backup gun. Had I had a backup gun available and had to shoot another stage I would have brought it out. The goal is to build a cheap backup Limited gun that I can blast some hot 10mm through (with a barrel and recoil spring change of course) when the mood strikes haha Edited November 10, 2012 by blaster113 Link to comment Share on other sites More sharing options...
steviesterno Posted November 10, 2012 Share Posted November 10, 2012 well why dont you just built the 5" 10mm/40 and not worry about it? If you have to break out the backup gun, your day has probably already gone to hell, so who cares if you're going minor? Unless you're a top of the pack guy (not sayin you aren't, but I'm sure not) it wouldn't matter, gets you shooting, and keeps you from driving home cranky Link to comment Share on other sites More sharing options...
blaster113 Posted November 10, 2012 Author Share Posted November 10, 2012 Good point. Not in danger of winning anything haha, if I went minor on the chrono then at least I finished. Already had a disaster on the last stage of a major. It was a very long 6 hr flight home. Link to comment Share on other sites More sharing options...
blaster113 Posted November 10, 2012 Author Share Posted November 10, 2012 (edited) Oops, double post. Stoopid iPhone. Suppose I could build a dedicated 6" .40 upper for this project later on and have a short 5" 10mm upper..... Edited November 10, 2012 by blaster113 Link to comment Share on other sites More sharing options...
jrbet83 Posted November 10, 2012 Share Posted November 10, 2012 I've heard barstos are a quick barrel. May look at getting one, to help equal out the velocities Link to comment Share on other sites More sharing options...
superdude Posted November 10, 2012 Share Posted November 10, 2012 I've heard barstos are a quick barrel. May look at getting one, to help equal out the velocities My Bar-Sto is slower than my other barrels (Colt, Kart, Nowlin). And it's a half-inch longer! Really. Link to comment Share on other sites More sharing options...
blaster113 Posted November 11, 2012 Author Share Posted November 11, 2012 looking at STI bull barrels for my project since I can get them for a good price from Brownells Link to comment Share on other sites More sharing options...
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