brytec Posted October 19, 2016 Share Posted October 19, 2016 Wanted to know what's the theory behind how over all length affect making power factor. For instance, I'm loading (shooting with infinity barrel with 5holes and 4port comp) 38SC with PD JHP 124g, WSPP, starline brass, WAC of 7.1gr, how would it affect PF if OAL is 1.119 vs 1.1235 vs 1.1245 vs 1.1255? I understand I can chrono but wanted to see what other people says. Thanks for all the info. Cheers!BryanSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted October 19, 2016 Share Posted October 19, 2016 The theory is that the longer your OAL, the less pressure, and frequently less velocity. Probably not a large amount of difference with WAC, since there's quite a bit of case capacity left over - I've loaded 9mm Major with everything the same except OAL was 1.145" and 1.170" and didn't see much difference in velocity. BUT, that might vary with different powders/bullets, etc BUT, even if velocity and pressure doesn't move too much, all of a sudden you could reach too short an OAL and get a spike in pressure. Or, the reverse, if you get too long an OAL, you could get a noticeable drop in velocity. If you get around to experimenting with this, I'd love to hear your chrono results. P.S. (I would imagine that you're actually loading your .38 SC longer than 1.12"?) Link to comment Share on other sites More sharing options...
js1130146 Posted October 19, 2016 Share Posted October 19, 2016 Jack, I'm assuming he means 1.19 1.235 etc. Otherwise that's crazy short for a super and major loads Link to comment Share on other sites More sharing options...
kimberacp Posted October 19, 2016 Share Posted October 19, 2016 Hi-Power Jack, said it right! Link to comment Share on other sites More sharing options...
ano Posted October 19, 2016 Share Posted October 19, 2016 Every 0,5mm in OAL increase at same powerfactor with say 3n38, drops pressure 1000PSI and ups gas pressure in comp. Link to comment Share on other sites More sharing options...
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