Question American Reloading MP-75

[NapalmCheese]

I picked up some MP-75 from American Reloading not long ago. The container says it loads similar to IMR PB (which I have no experience with, but for which there is data). Looking at it, it seems to be a mixture of Red Dot, Green Dot, and maybe Clay Dot. I'm going to be using it for lower power Cowboy Action Shooting loads so I'm not worried about finding max charges, but I'm curious if anyone has loaded this for pistol cartridges yet?

I'm thinking 3.1 grain under a 125 RNFP in .38 spc, and 4.5 grain under a 205 RNFP in 45 Colt.

What are your experiences?

 

[doser]

I picked up some MP-75 from American Reloading not long ago. The container says it loads similar to IMR PB (which I have no experience with, but for which there is data). Looking at it, it seems to be a mixture of Red Dot, Green Dot, and maybe Clay Dot. I'm going to be using it for lower power Cowboy Action Shooting loads so I'm not worried about finding max charges, but I'm curious if anyone has loaded this for pistol cartridges yet?

I'm thinking 3.1 grain under a 125 RNFP in .38 spc, and 4.5 grain under a 205 RNFP in 45 Colt.

What are your experiences?

Never tried MP-75. Do you have load data for that? From what I saw its similar to titegroup. I have a recipe for titegroup. Do you have access to a chronograph? That's the typical way I try to establish a recipe trying to hit a particular power factor. As they say, start with the lowest recommended and work your way up.

Best I could find with IMR PB was this data sheet on page 55. I'd def use a chrono though.

http://pdf.textfiles.com/manuals/FIREARMS/imr_reloading.pdf

 

[NapalmCheese]

Yeah, I've got a chrono and will use it to work up. This is my first time dealing with 'surplus' style powder. In the past MP-75 was supposed to load like something else (i.e. not like IMR PB).

I do have a few old manuals that list IMR PB, so no problem finding data. I just think it's weird that it's some sort of mix of Red Dot, Green Dot, potentially Clays, and loads like IMR PB (which is slower than all of those IIRC). There's another forum where someone is loading it for trap loads.

 

[NapalmCheese]

For perpetuity, it does actually load like PB (for the most part).

Comparing it to Red Dot in .45 ACP

Red Dot: 5.00 grains under a 200 grain bullet is 870ish fps.
MP-75: 5.00 grains under a 200 grain bullet is 830ish fps.
MP-75: 5.5 grains under a 200 grain bullet is 900ish fps.

So it's in that same area and would probably work for an Harris style "the load" if you're plucky.