I don't know how 300 MP will work but, a friend of mine uses 4227 in his 32 MS and does very well, he won the Mosesto ISSA regional with it.

Frank

I have had great success with the 300MP in my 32-40, 28-35 and 25-21. Since the day it first came out and was offered to the public I have gone through a tad over 64 pounds to date. If I can be of more assistance in regards to its use send me a PM and I would be more than happy to address any questions you might have. I have only used it for breach seating, if you intend to use it for fixed I can't be of any help to you.

JLouis

John, 
I didn't give the date but check back to 2014 and report the top 3. None of your guy's are shooting short cases and that's what the inquiry is about.

Frank

The original question was in regards to anyone familar with the use of 300MP Frank and not what might be a better choice for the gentlemans 32MS and 25 Hornet. If it were he would have asked that question.

JLouis

Frank I have used it in the 33RKS Schuetzen the 357 Max case left full length and straight tapered to 33 and the 28 Darr again the 357 Max left full length and straight tapered to 28. It was not on the market when I had the 32MS. It provides less pressure than the other favorite / more popular Schuetzen powders but I still could not get the loads to where they needed to be velocity wise for best accuracy without incuring undesirable pressure limits. The last match I shot with the 28 Darr before I re-chambered it to 28-35 required using 11 cases to shoot two 10 shot targets due to extraction being impossible. Both it and the 33 shared the same problem, they both needed just a tad more powder to really excel but I just could not get
there with any of the powders, the 300MP got me the closest to where I needed to be by far but it still was not quite enough. I also had the same problem with the 32MS pre
300MP it also shot like a house a fire on the ragged edge of to much pressure and on those days when I needed just a tenth or more I simply could not get there. All of them would shoot outstanding one day and not at all the next.
I hope that answers your question if not let me know what else I can provide.

JLouis

Your success is very interesting Frank and I am quite suprised the 300MP could not provide you with groups under 11/2" at 100yds.? Prior to setting the 5-5Shot 100yd. group average record I was consistently shooting averages of a 1/2" and under in my 32-40. Makes one wonder what would cause such a big seperation between your results and mine and it would be extremely interesting to actually know why?

JLouis

Frank actually I ended up getting the 33RKS shooting extremely well at 200yds. but I had to push it hard and the cases would swell at the web and I got tired of fighting hard case extraction. Last I heard the 4100 isn't due to hit the states until Oct. Eventualy I would like to try some in my 25-21, I have very fortunate in that the 300MP shoots extremely well in all my rifles. I just picked up another 8lbs. recently and was getting a little nervous as I was getting down on my last 8lb. Jug and it has been non existant in the past two years. I retired my 32-40, the 28-35 I just recently finished building is now my go to rifle and I just got it shooting pretty consistant. Barrel is a 12 Twist Douglas, Bullet is a bore riding truncated nose design that Barry made for me and it weighs in at 160.3grs. Powder charge is 13.5grs. of 300MP and CCI 200 primers. The 25-21 I just recently picked up has a Douglas 10 twist, bullet is the 120gr. Mos, powder charge is 9.5grs. of 300MP and Wolf SR primers. My youngest grand daughter is thinking about shooting our matches and the bark with no bit will be just right for her. Taking her out in the morning for her first practice outing and holefully she will like it.

JLouis