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I load mine down to 1.05. I had cz p10 f\’s and p10c that wanted lower seating depts for reliable use. I also tested them with chrono and found i get more consistent velocity at 1.05 seating depth vs. 1.08 out of a cz shadow 2
I’ve loaded my batches of the 124 gr MPR Nukes to 1.060”, with 3.5gr of Hi-Skor 700x. Looking back at my chrono data, I was averaging 1008 ft/sec out of my PSA Dagger. This worked well out of my Taurus 3GC and Ruger PCC as well, but I don’t have the chrono data for that range trip stored on my current phone.
rcgrube,
Relavent information when adjusting away from the suggested COL (which happens a lot on this forum).
My question is, the pressure increases but how does one tell by how much without a pressure gur setup?
Primer condiition is a notoriously inaccrate method for judging pressure in pistol rounds. A chronograph doen\’t show an increase in M.V. with a decrease in OAL?
At least not in my limited experimentation. No appreciable change in M.V. for 135gr MatchWinners loaded over Accurate #2 and Accurate #5 for cartridge lengths from 1.067\” to 1.100\” was recorded. There was maybe a small improvement in groups for the 1.070\” COL.
Knowing shorter rounds can produce higher pressures is academic unless a reloader can assess the affect using their loading components.
I think rather than straight increases or decreases in muzzle velocities related to seating depths picked up by chronograph or radar, it would be that you might see inconsistent readings. More so with reduced OAL rounds, and mainly with semi auto firearms. From my experience, if I went a little to far with a charge or short OAL, I\’ve seen fluctuations in velocities before flattened primers (and way before primer flow). I think another contributing factor has been case and primer brand but even more so is how many times that case has been reloaded as pockets may start to loosen. For clarity, these things I found were when working up 10mm loads in a pretty robust Springfield 1911, but the basic physics should still apply. I only mention it because with the 9mm work up, I\’m not really trying to \”Hot-Rod\” them so much as have reliable consistent performance. With the 10mm, I am looking to squeeze every last bit out of it but still run safe enough that I wouldn\’t hesitate letting my wife or kids handle it. (before anyone has a melt down, my \”kids\” are 28 and 32 years old)
Safe and happy shooting!I modified a case for Hornady OAL gauge and got 1.055\” to the lands. That\’s significantly less case capacity
I typically load for rifle, so I\’m not sure how far I need to set them back from that.
Any suggestions?Hodgdon has data for RMR JHP that says 1.120\” COAL.
Are they that much different than the Nukes?Thanks
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