First post here. Roberts published data sure is interesting to read.
I own a G20 just for a little over a month now and have used N340 and N105. The N340 feels a bit weak and is IMO not the powder for a true 10mm.
So I've done most of my shooting with N105, the magnum powder, and according to the Vihta manual I should get some good velocities, but reading the data on this forum the velocities Vihta claims are quite a bit exaggerated (maybe they do their chrono testing on the moon?).
Now I use a 180 grain Berry double struck plated bullet with 9,3 grains of N105. Should give me about 1220 fps, but the real world data shows that I don't even get that kind of velocity with the max load of the old Vihta manual listed as 10,5 grains of N105.
Robert, if you're reading this (and you still got all your fingers to type
), do you know what the 9,3 grain N105 load will give in combination with a 180 grain bullet? I like this load as it is easy on my Starline cases and use my Glock in stock configuration. But obviously I also want some true 10mm velocities (no nuclear loads, just the real 10mm stuff) without ruining my cases after one or two loads. It seems that 10,5 grain of N105 may be the sollution for me: about 1200 fps in the real world and pressure should still be ok for a stock Glock, especially since N105 is a slow burning powder.