When I first got into shooting these great guns I would get an alibi once in awhile with my reloads and even some factory target ammo from the big three.
Had a batch of factory Remington that just would not run, come to find out the ammo was loaded a tad too long to function smoothly in the M52 magazines(would have been fine in a revolver of coarse).Took what I had left and reseated them .020" deeper and all functioned flawlessly.
This got me to testing variables and come to what I do now for the M52.
Thought I would share my experiences and anyone else may have some points to share also.
First thing is I only use Remington brass, it is the thinnest so it will not swage the soft lead heads as much I believe.
Brass must be once fired because of what I do next.
Deprime, resize and then trim the cases to 1.130" (I know it is a bit, probably .025" for some cases).
After continuous reloading my cases have shrunk but stay in the 1.120"- 1.125" range.
I seat my heads so that I have .020" of shoulder sticking out past the case mouth.
I use the Lee factory crimp die set to crimp at .370"
My thinking is that once these are all loaded they are shorter than a standard load which will pretty much guarantee that they will feed out of the magazine without binding and also like the bit of lead exposed with the crimp to allow smoother feeding.
I use Bullseye powder and weigh each charge at 2.8 grains.
Scales are not perfect but if it says 2.7 or 2.9 or starts to shift between a tenth of a grain, it does not go into the case.
A tenth of a grain is 4% and I believe consistency is your best bet at the long line more so with such a light load.
Using Winchester small pistol and small pistol magnum primers.
Really saw no difference in performance but do think the Bullseye burns more complete using the magnum primers.
Have only been using Remington heads but have acquired some Speer and Hornady to work with in my spare time.
Just purchased a Lyman "M" die a few weeks ago and loaded some rounds for the short coarse match tomorrow.
The heads do go in straighter and a bit easier with no visible coke bottling and no speed bump feeling when going through the Lee FCD. With time will see how the "M" die stacks up. Seems like a good concept, makes sense for soft lead heads.
I may have left something out or you may have a question or something to share also.
Just wanted to strike up some discussion.
Since doing the above procedures have yet to have another alibi in well over a year. (I probably just jinxed myself on that statement).
As far as shooting the long line at 50 yrds, if you have a good follow through it is easy to shoot in the 90's.
At the 25 yrd short line there is no excuse not to clean it

My M52-1 is one awesome bullseye target pistol.
My personal best was an 872-26x
Good shooting everyone.
Clarence