I made up some test rounds so I could find out what load would hit the target velocity. I made up 15 rounds each with 4.8, 5.0, and 5.2 grains of CFE pistol under the 124 grain bullets. I used Federal match magnum primers since that's what I have the most of. I wasn't sure what COL to use as I normally go 1.125 with FMJ's and these were considerable shorter bullets. I determined that they would plunk nicely at 1.065 so that's what I used.
Yesterday was the first one lately when the weather wasn't totally **** so I headed out to the range to run them through the chrono. Cliff notes version of the results were:
4.8 gr averaged 1047 fps, which is too slow, and I expected that. I was simply going by the start low and work up method. Strangely enough the very first round didn't cycle but the next 14 did.
5.0 gr averaged 1084 fps and cycled every round, but still not at the target velocity.
5.2 gr averaged 1134 fps so that seems to be well into the sweet spot while still below the maximum charge listed which is 5.3 on most of the tables I saw.
I know that changing bullets (from my usual 115 gr FMJ to the 124 gr MPR) can affect point of aim to point of impact so I'll need to do some testing on that but I don't think it's going to be a factor. I'm only shooting from about 5 yds away from the target when working with the chronograph but all 45 rounds I fired were in a pretty tight group of about 1 1/2". I'm planning on firing a couple mags of each bullet at separate targets and comparing the points of impact at 10 yds, then at 25 yds. That should tell me if there's any significant difference.
I guess most guys are shooting indoors right now as I didn't see any other footprints in the snow.
It was actually a decent day to shoot outdoors with the temp in the low 30's, bright sunshine and very little wind.