dstroyed Posted January 13, 2008 Share Posted January 13, 2008 I was doing some chrono work today and noticed something I need help from you all more experienced loaders. I don’t know much about the differences between double base vs single base powders. I was testing HS6, N350 and 3N38. Working up loads for 2 different guns both 9 Major shorties one with barrel ports other without also have different barrel manufacturers. New CED chrono today, last one quit after I put a bullet through the front of it. I didn’t really mind I hated that thing but I would have had more satisfaction if I had done it intentionally. Anyway that is another story for another time. I only ran 10 rounds of each load due to so many different guns and loads tested today proably should have ran at least 2 or 3 strings. 125 Zero JHP 7.8gr HS6 121 MG Int 7.8 N350 121 MG Int 9.2 3n38 Ported gun PF was HS6=158.7, N350=166.0, 3n38=168.2 Non ported PF was HS6=171.5, N350=168.4, 3N38=168.8 Finally my questions, do the double based powders like HS6 tend to have more spread with barrel or load differences? Possible I just had a couple of rounds in the group that threw the average? All the ES were under 60 with the exception of the non port HS6 171PF it was 117. Thanks-Mike Link to comment Share on other sites More sharing options...
Joe4d Posted January 13, 2008 Share Posted January 13, 2008 ES of 117 ?. that is about 100 more than it should be. Might want to revisit you press and check for something causing inconsitent powder charges or OAL's Link to comment Share on other sites More sharing options...
smokshwn Posted January 13, 2008 Share Posted January 13, 2008 Look back over the ten velocities you got for that string and I would bet there is one or two velocities that are way out of whack due to the chrono misreading them. Link to comment Share on other sites More sharing options...
Alan Meek Posted January 13, 2008 Share Posted January 13, 2008 Question on your brass, are you using same manufacturer or mixed? Link to comment Share on other sites More sharing options...
JThompson Posted January 13, 2008 Share Posted January 13, 2008 Question on your brass, are you using same manufacturer or mixed? Good point Alan... Link to comment Share on other sites More sharing options...
dstroyed Posted January 13, 2008 Author Share Posted January 13, 2008 Question on your brass, are you using same manufacturer or mixed? Yes all the same. Link to comment Share on other sites More sharing options...
dstroyed Posted January 13, 2008 Author Share Posted January 13, 2008 ES of 117 ?. that is about 100 more than it should be. Might want to revisit you press and check for something causing inconsitent powder charges or OAL's Not sure if i have the data being a new chrono still have to learn how it all works. What is a resaonable spread? Link to comment Share on other sites More sharing options...
HSMITH Posted January 13, 2008 Share Posted January 13, 2008 With sorted brass and N350 or 3n-37 I see single digit SD and most of the time ES too. HS-6 feels good, is accurate, but filthy nasty terrible stuff in the gun. Hate it, won't use it or recommend it. If you want a low cost powder try Silhouette, skip the HS-6 IMO. Link to comment Share on other sites More sharing options...
Alan Meek Posted January 13, 2008 Share Posted January 13, 2008 You want your standard Deviation as low as possible, most people want a single digit SD, but I prefer that all rounds make major. I test 20 all twenty should be major. Another trick, when you work up loads, calculate your PF using a bullet weight value of 1 less than the actual bullet weight. If you are using 124's then as you work up a load calculate you PF using 123 as your bullet weight. In my 9major data thread I do have SD's fro my HS-6 load Alan Link to comment Share on other sites More sharing options...
revchuck Posted January 13, 2008 Share Posted January 13, 2008 FWIW... You have a reasonable expectation of two of three rounds (65%) being within one SD of the average velocity, and 95 of 100 being within 2 SD. Let's say you need 800 fps to make the PF with your bullet weight. With an SD of 25, you'd need to load to an average of 825 to make sure that two of three rounds make the PF, or 850 to make sure almost all rounds make the PF. With an SD of 10, you'd need to average 810 for two of three, or 820 for a 95% confidence level. Having said that, I'm in the "all my ammo makes the PF+5" school of thought. Link to comment Share on other sites More sharing options...
AustinMike Posted January 13, 2008 Share Posted January 13, 2008 Something is up on that reading with 117 spread. Bad powder throws or maybe the chrono had some trouble due to shadows. My old Chrony will wig out with passing clouds. Best to do it on an over cast day where the light stays fairly even. FWIW, my ported shorty takes 8.4-8.6 of HS-6 to get 170PF (the lighter charge works in summer.) I don't think HS-6 is that filthy at major, but then again I clean my open gun after each use. I might have to try Silhouette. It's been recommended a lot lately. Link to comment Share on other sites More sharing options...
dstroyed Posted January 13, 2008 Author Share Posted January 13, 2008 Alan, Chuck, good info, thanks. Alan I went back to your 9mm thread and looked at some of the posts. I remember reading this thread about a year ago when I first had interest in 9 major. Lots of info in there, a lot of different results too. Your test gun seems to be very fast compared to mine. I agree I need to run some more strings with the current loads of HS6. Link to comment Share on other sites More sharing options...
dstroyed Posted January 13, 2008 Author Share Posted January 13, 2008 My Goal is to find out if I can find one load that will work for both guns. I have inventory of N350 and MGs that I prefer to use. Probably not going to happen. That explains why I’m using Zeros and MGs, to help keep things straight for each gun. I think we all agree the HS6 testing should be thrown out for now. To repeat or help clarify my thinking and question from my original post. It is possible the dbl base and/or faster powders create a larger PF spread compared to the slower and/or single base powders? Didn’t know if there was any correlation? It takes a lot of 3N38 to make major leading me to think that could be true just by volume of powder needed for fps change vs actual increase in fps (slow vs fast) I just realized my question is directed at a powder being able to lessen the velocity change between a ported and non ported barrel. The barrels are not going to change regardless, right? If the non ported barrel averages 25 fps faster wouldn’t that be true across the board with all powders? Wow this is getting way too complicated. Maybe is should get out the drill and dremel and fix the non port gun. Just kidding. Link to comment Share on other sites More sharing options...
revchuck Posted January 13, 2008 Share Posted January 13, 2008 I just realized my question is directed at a powder being able to lessen the velocity change between a ported and non ported barrel. The barrels are not going to change regardless, right? If the non ported barrel averages 25 fps faster wouldn’t that be true across the board with all powders? Speaking of two specific barrels, yes, there will probably be a consistent difference between them, but that applies only to those two barrels, and isn't necessarily related to whether they're ported or unported (but ported ones are usually slower). In general, the faster the powder, the smaller the difference in velocities. I'm mainly an IDPA revolver shooter. I have nine 4" .38/.357 revolvers, and there's about 80 fps difference among them with the same .38 Special load, and eight of them have the same barrel manufacturer (S&W - the odd one out is a Colt). The fastest one (M681, a .357 L frame) should be one of the slower ones since it has the longer .357 chamber. There just ain't a scientific answer to this one. Link to comment Share on other sites More sharing options...
dstroyed Posted January 13, 2008 Author Share Posted January 13, 2008 Sometimes it just takes writing it down or saying it out load to help you figure things out. I’m not sure what I was thinking but the more I typed the more I realized I was in the wrong forest. Thanks to everyone. Link to comment Share on other sites More sharing options...
Lexor40cal Posted January 13, 2008 Share Posted January 13, 2008 8.1 Gr of HS6 @ 1.150" AOL in Winchester brass, through a 5" no holes barrel with 3 hole comp, makes 171 PF with narrow SD, work comp great. HS6 is a little dirtier than other powders I have used, but cleaning is free? Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now