Working with Alliant Powder's Power Pro 300-MP Magnum Pistol Powder in my 480R.

BY Bob Roach

My research looking for 480 Ruger loading data using 300-MP did not come up with much that was useable. Alliant did have a little data for 3 jacketed bullets, the Speer 275, 325, and 400 grain. Nothing for cast. The Lyman Pistol & Revolver Handbook did not have 300-MP powder listed and not much lead bullet data for the 480. They did show a single Cast Performance 370 grain Load using H110 in the Handloading Big Bore Revolver Section. From my reading it looked like it would take around .75 grains more of 300-MP than H110 to reach the same velocity. One can find H110 loading data for the 480 Ruger.

My bullets are cast from a Custom 2-Cavity Mountain Mold. My design was for a 375 Grain bullet with a 70% Meplat, and the base was for a Straight Shank Hornady Gas Check. The bullet has one large grease groove and a crimp groove. I am currently using Hornady Gas Checks, and my bullet lubrication is with White Label (Carnauba Red Bullet Lube)
http://www.mountainmolds.com/
http://lsstuff.com/store/index.php?main_page=index&cPath=3
My as cast, lubricated and gas checked bullet weight using wheel weights sweetened with a little extra Tin was 370 Grains. I am reloading on a Dillon 550B using an RCBS die set with an extra seater die to crimp in station 4. My 480 Ruger handgun is an older Six Shooter 9.5 Inch Super RedHawk with Hogue Tamer Grips. I have a 30mm UltraDot optical sight mounted on a Weigand Combat 480/454 scope base.
My Brass is a mix of Hornady,and Speer.

From my research I figured any loading data for a 400 grain jacketed bullet would probably be safe under a 375 Grain Cast bullet. However Safe and tolerable may be two different things. I decided to work up slowly and see what happened.

NOTE: The loading information listed appeared to be safe in my handgun. As with any reloading experiments do not start with upper end loads. Work up slowly and carefully from well below maximum listed loads. Stop at any signs of high pressure.

My first loading was using 20.0 grains of 300-MP under the 375 grain WFN-GC bullet ignited with Winchester Large Pistol Primers.

Brass: Speer/Hornady Mix
Primers: WW Large Pistol
Powder: 300-MP
Bullets: 370 Cast

20.0 grains of 300-MP
Velocity Readings at 15 feet:
1066 fps
1028 fps
1002 fps
1082 fps
1017 fps
Average Velocity: 1039 fps Extreme Spread: 80 fps

Load #2
21.0 grains of 300-MP
1026 fps
1070 fps
1084 fps
1050 fps
1070 fps
Average Velocity: 1060 Extreme Spread: 58 fps

Load #3
22.0 grains of 300-MP
1182 fps
1128 fps
1137 fps
1202 fps
1165 fps
Average Velocity: 1163 fps Extreme Spread: 74

Load #4
23.0 grains of 300-MP
1235 fps
1201 fps
1220 fps
1159 fps
1185 fps
Average Velocity: 1200 fps Extreme Spread: 76

At this point I adjusted the Crimp Die down a little more.

Load #5
24.0 grains of 300-MP
1285 fps
1287 fps
1259 fps
1264 fps
1280 fps
Average Velocity: 1275 fps Extreme Spread: 29 fps

Load #6
24.5 grains of 300-MP
1317 fps
1319 fps
1319 fps
1303 fps
1272 fps
Average Velocity: 1306 Extreme Spread: 47

Load #7
25.0 grains of 300-MP
1322 fps
1299 fps
1326 fps
1290 fps
1304 fps
Average Velocity: 1308 fps Extreme Spread: 36

I was getting quite a bit of Extreme Spread up until my 24.0 grain loading. I also put a little more crimp on the bullets when I started loading the 24.0 grain loads. This makes me wonder if the lighter grain loadings might have tightened up with a little more crimp also.

I believe 24.5 grains of 300-MP with an average velocity of 1306 feet per second is my maximum load with my 370 grain cast bullet. I will probably save this loading until the Missouri Department of Conservation gets the T Rex population up to a hunt able level here in the Missouri Ozarks. I think I will probably go with 22.0 - 23.0 grains of 300-MP with an average velocity of 1163 fps - 1200 fps for my Missouri Whitetail Deer load with this powder. I have in the past loaded the 480R using 296/H110, Lil-Gun, AA#9, and Unique. My observation is that 300-MP seems to be a little softer shooting at the top end. This may be due to it being the slowest powder of the bunch. I plan to do a fair amount of practicing in the next 70 days till deer season here in Missouri. I will probably give H110 and Lil-Gun some trigger time with the chronograph and see how they compare to 300-MP. My local dealer had several cans of 300-MP on the shelf when powder got short. No one was buying it, so over a couple month period I hauled it all off at $19.95 a pound. It is now looking like that was a very good investment.
I am not sure that 300-MP is any improvement over 296/H110, Lil-Gun, or AA#9 just yet. I am sure that it is a very good powder for the 480 Ruger.

Thanks for the informative post Bob. I was thinking of picking up some 300-mp. Sounds like a good fit

Always wondered how 300 MP would work as I hardly see any reload data for it. Well Bob... you have answered my question. Now if I can find some. Thanks, James

Works great in my 44 and 454. I've had better luck with the 300MP than with H110. It seems to take a little more to get the right load, but it has been more consistent for me. Puts out a heck of a flame from the 454. While working up loads for both, when you got to the sweet spot you could tell from the sound of it and the feel. If I can ever find more I am going to try it in 357 and 475. Trying to save what I have for hunting this year with the 454. Got a elk and deer tag to fill.

Looks to me to be a little slower burning 2400 that is a little less position and charge sensitive than 110,296

Keep in mind I load everything from 38 spl to 454-480 with 2400.

There is no surprise when you work up a load.

2400 rocks

You will never get that extra 100 fps but you will also never get that squib load that blows your gun up.

There is a little bit of load data on loaddata.com , but of course there is a lot more data for H110.

If, or I should say when, I manage to get a Super Blackhawk in 480, this is one of the molds I am considering,( http://noebulletmolds.com/NV/product_inf...6vjlmgcbv270hj0 ) will likely start with the Lee due to cost, as that will give me time to do my research and find "the mold", I really want it to be a one and done gun.

That bullet will work just fine. It has around a 77% Meplat which will hit hard. I personally would go with the gas checked version.

NOE can be a pain to get exactly what you want unless you are patient, and can wait for them to get what you want back in stock. I am not real patient when I am ready to order.
With that said NOE has some very good prices, as well as some good mold designs. I lucked out and found a 360-180 WFN-GC 5 cavity aluminum in stock when I was ready to order for a 357 Maximum build. I believe it was $109 shipped. That is pretty hard to beat for a 5 cavity bullet mold.

Another option is, you can go to the Mountain Mold web site and design your bullet. They do not have a catalog of bullets. You have a spread sheet. Pick your bullet diameter. Select a weight. Select the base design. I normally pick Hornady Gas Checks myself. I normally like ONE Healthy Grease Groove. You can adjust the nose length, etc. So far I have designed a 480/375 WFN-GC and a 429/310 WFN-GC. Both for Super RedHawks. Both molds have worked out very well.

Good Luck

Bob R

I looked at this again, as I picked up a pound of this powder to try in the SBH 480, with a 400gr Speer GDSP they list 24.2 as the maximum load, with a 355gr Oregon Trail WFNGC bullet they list 29.0 grains as a maximum load. The Oregon Trail load was shot in a 6" FA Model 757, they don't list a firearm or barrel for the Speer bullet.

AKBman You mention way back when about trying LILGUN Longshot is better for the 480 than LIL GUN.
Glad to know about the 300MP

Depends on what you want to get out of it.