I was wondering if anyone had any experience with Alliant's two new spherical powders, 2000-MR and 4000-MR?

Dave, I did an extensive reloading project for my 35 Whelen Ackley improved 40° with 2000-MR. I used 200 Hornady SP, 225 Nosler PT, 225 Accubond, 250 Hornady SP, 250 Nosler PT and 275 Hawk RT bullets. This powder is just a tick slower than Reloader 15 but quicker than Reloader 17 or the 4350s. Case fill is superb with the fine ball powder.

PP 2000-MR proved to be too slow for the lighter bullets. Varget and A2520 have given better results for me with the 200-225 grainers. But the 2000-MR comes into it's own with the 250+ grain bullets. My barrel is 24 inches, and gave the following max velocities:

250 Hornady SP @ 3.34" - 62.5 gr = 2645 fps
250 Nosler PT @ 3.34" - 61.5 gr = 2600 fps
275 Hawk RT @ 3.30" - 58.5 gr = 2455 fps

These were average of 3 shots for each load over chrony at 15' from the muzzle, so add 12-15 fps for corrected muzzle velocities.

Not having any data on 2000-MR for the Whelen Improved, I started low and worked up in 1 grain, and then .5 grain increments as I neared max. The above max loads were on the 10th reload of the brass, and primer pockets were still tight. Case head expansion was from .0015 to .0019 of an inch, just in front of the extractor slot.

Naturally, I cannot guarantee the safety of these loads in any other firearm than the one used to develop them. The case capacity of my fired brass is 74 grains of water, average.

Someone on another forum had equally good results in a 9.3x62 Mauser, with 286 and 300 grain bullets. Case capacity of the Mauser is about 77-78 grains, not sure about his specific rifle, though.

If the 2000 is a bit faster burning than the 4350s it would be interesting to see what it would do in the 22-250 or Swift. roger

Thanks guys...