I recently received my Glock 40/10mm which will be a woods carry gun. I have started working up loads with an Oreo mold (deep HP's weigh in at 185gr and the shallow HP at 190gr) and a KKM barrel with longshot. I was curious what velocity you guys think would give decent brass life while not performing like a 40 S & W? I've looked in my manuals including the Hodgdon annual manual for 10mm data but most either don't cover longshot, my weight boolits or the loads they have are at 40 S & W velocities. I'm not looking to try turning a 10mm into a 41 mag but would like to achieve a good solid 10mm load. So far I'm content with the 190gr at 1200fps but I'm still working on the 185gr. Any of you guys have a load that has worked well for you?
As a general rule lead will run at a lower pressure than jacketed bullets with the same load. As a result, I personally would be comfortable with 185-190 grain cast bullets working up to near the 180 grain JHP data on Hodgdon's site. They list 9.5 grains of longshot as a max load with a 180 grain JHP, for nearly 1300 fps. I would probably start at 8.2 grains, and work up watching velocity and measuring the case head for excessive expansion. I probably wouldn't go over 9.2 grains until I had 50+ cases at that weight that were all showing no signs of excessive expansion.
A 40 S&W with those bullets would max out right around 950-1000 fps. I would expect even with 8.2 grains you will be 10% over that, and will probably be very safe up to 1250 fps with those bullet weights.
Stay safe, start low and work up.
Settled at 8.7gr with the 185 HP. Tried a few different loads but 8.7gr seemed to shoot the best groups at 25 yds. Even though this load is almost a full grain under max it still has plenty of velocity and doesn't seem to be stressing the brass or primers.
Do you have a chronograph so you have an idea of velocity? I am sure it is a solid load, but if you can report speed it adds a data point for reference. If not, no worries.
Five shots varied from 1303-1324fps for average of 1316fps. Plenty stout enough for what I need with no smileys or brass deformation. KKM 6" barrel seems to wring out every fps while keeping brass from getting trashed.
My standard load (in my Delta Elite) is a Penn lfn 180gr bullet with 8.8gr of Longshot. I have a chrono, but haven't had the opportunity to test them yet. Still below a max load, but they generate more recoil (I know recoil is subjective, but it's me comparing loads to me) than factory Hornady 180 XTP jhp's.
Sounds like a solid load.