Bench Posted September 16, 2019 Share Posted September 16, 2019 (edited) I'm working up a new load for 38/125's RN per load data that indicates for 125's a load of 3.9 HP-38 is low end/start load. The load data also indicates a start OAL of 1.060 but my barrel with this new bullet only allows a plunk test of 1.050". Is there a need to reduce the powder load also or is the start load still within safe bounds? I'm well aware of laddering within load data but haven't encountered laddering up from below "start data". Thanks all!! Edited September 16, 2019 by Bench Link to comment Share on other sites More sharing options...
GMP Posted September 16, 2019 Share Posted September 16, 2019 That's fine. Besides if you plunk at 1.050" your target OAL should be about 1.060" anyway. Link to comment Share on other sites More sharing options...
Helios Posted September 16, 2019 Share Posted September 16, 2019 9 hours ago, GMP said: That's fine. Besides if you plunk at 1.050" your target OAL should be about 1.060" anyway. Why would your target OAL be longer than the OAL at which you plunk? Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted September 16, 2019 Share Posted September 16, 2019 9 hours ago, GMP said: if you plunk at 1.050" your target OAL should be about 1.060". If I plunked at 1.05", I'd set my OAL for 1.02". That shouldn't affect the powder charge at all - Link to comment Share on other sites More sharing options...
GMP Posted September 16, 2019 Share Posted September 16, 2019 43 minutes ago, Helios said: Why would your target OAL be longer than the OAL at which you plunk? Because it was late after a full weekend and I had a brain fart! Absolutely right, but as jack said that much shorter should not matter. Link to comment Share on other sites More sharing options...
4n2t0 Posted September 18, 2019 Share Posted September 18, 2019 The OAL's listed in manuals/data is completely useless. Always find your own OAL and start at the minimum charge weight. Link to comment Share on other sites More sharing options...
George16 Posted September 18, 2019 Share Posted September 18, 2019 9 minutes ago, 4n2t0 said: The OAL's listed in manuals/data is completely useless. Always find your own OAL and start at the minimum charge weight. This. The OAL in the manuals were specific for the particular gun the testers used during testing. This is the main reason I always do the plunk test to determine the OAL for my loads and then I do my ladder test. Always use a chrono. It’s makes load development a lot safer. Link to comment Share on other sites More sharing options...
Bench Posted September 18, 2019 Author Share Posted September 18, 2019 19 minutes ago, 4n2t0 said: The OAL's listed in manuals/data is completely useless. Always find your own OAL and start at the minimum charge weight. Thanks, I was more concerned about increased pressures that a shorter OAL would produce even at the low charge rates, but herd knowledge has moved me on away from that concern. Link to comment Share on other sites More sharing options...
Bench Posted September 18, 2019 Author Share Posted September 18, 2019 10 minutes ago, George16 said: Always use a chrono. It’s makes load development a lot safer. LOL, I was doing fine with my chrono...up until I killed it Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted September 18, 2019 Share Posted September 18, 2019 9 minutes ago, Bench said: LOL, I was doing fine with my chrono...up until I killed it Join the rather large Club. Link to comment Share on other sites More sharing options...
George16 Posted September 18, 2019 Share Posted September 18, 2019 1 hour ago, Bench said: LOL, I was doing fine with my chrono...up until I killed it You’re not the only one . My first one died a horrible death on the very first day of use . Link to comment Share on other sites More sharing options...
Yondering Posted September 18, 2019 Share Posted September 18, 2019 6 hours ago, Bench said: Thanks, I was more concerned about increased pressures that a shorter OAL would produce even at the low charge rates, but herd knowledge has moved me on away from that concern. Shorter OAL does increase pressure, but you're starting with a mild load already so it's not a big concern. Keep in mind too that if you're using a coated, cast/lubed, or plated bullet the load may generate lower pressure than a jacketed bullet anyway. Also keep in mind that bullet shape makes a huge difference in OAL numbers, and one RN style may need a very different OAL than a RN from a different maker. Ultimately, you're doing it right. Link to comment Share on other sites More sharing options...
Bench Posted September 18, 2019 Author Share Posted September 18, 2019 29 minutes ago, Yondering said: Shorter OAL does increase pressure, but you're starting with a mild load already so it's not a big concern. Keep in mind too that if you're using a coated, cast/lubed, or plated bullet the load may generate lower pressure than a jacketed bullet anyway. Also keep in mind that bullet shape makes a huge difference in OAL numbers, and one RN style may need a very different OAL than a RN from a different maker. Ultimately, you're doing it right. This certainly has been a good lesson in OAL variance between RN coated bullet makers...from 1.145 from one maker down to 1.050 from another maker...and in the same gun. Thanks for the +1 on being on the right track. Link to comment Share on other sites More sharing options...
MemphisMechanic Posted September 18, 2019 Share Posted September 18, 2019 The manual states what length they used to load it. It does not say that you have to use *that* same length. Just know that if you load shorter you will increase the pressure, and if you’re not certain? Back down to minimum from wherever you were. Common sense and a combination of experience or caution will get you the rest of the way. Link to comment Share on other sites More sharing options...
Bench Posted September 18, 2019 Author Share Posted September 18, 2019 1 hour ago, MemphisMechanic said: Common sense and a combination of experience or caution will get you the rest of the way. The combination of common sense and caution has stood me well for these past 71 years Link to comment Share on other sites More sharing options...
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