You can't tell know it alls anything...they are always right

[dtknowles]

I never used Power Pro 300 but a quick search does show cast bullets listing for it.

https://loaddata.com/Cartridge/44-Re...ro-300-MP/5942

https://bayoushooter.com/threads/all...44-mag.129020/
Data below is what I got from Ben @ Alliant for cast bullets...

44 Rem Mag
250 gr Cast Lead
300MP powder start 23 grs max 24 grs

300 gr Cast Lead
300MP powder start 18.5 grs max 19.5 grs

357 mag
180 gr Cast Lead
300MP powder start 12 grs max 14 grs

A firm crimp on the bullet is recommend.

I've shot 23 grains of 300 MP with a 250 gr. Beartooth cast so far..pretty stout in my 10" Contender.
I have not run any through my chrony yet...but plan to using 300 MP, H110, and W296 to compare velocities...
Bulldog............

The lack of precision in those load recommendations caught my eye. That data is in at best half grain increments. I am more used to tenth of a grain increments. It would give me a more confidence if that 24 gr. was actually 24.0 gr. Why not three-digit precision. Why a one grain spread between the .44 mag start and max loads (about 4-5 %) but a two grain spread on the .357 loads (about 15%). Not thinking this is the best data.

Tim

[fredj338]

The lack of precision in those load recommendations caught my eye. That data is in at best half grain increments. I am more used to tenth of a grain increments. It would give me a more confidence if that 24 gr. was actually 24.0 gr. Why not three-digit precision. Why a one grain spread between the .44 mag start and max loads (about 4-5 %) but a two grain spread on the .357 loads (about 15%). Not thinking this is the best data.

Tim

Depends on the powder & cartridge. 1/10gr with slow powders in big cases isnt moving the needle much. With fast powders in small case, yes 1/10gr makes safety sense. While 1/2gr diff in magnums with slow powders might be a bit much, not ridiculous.

[JonB_in_Glencoe]

Have a good friend who started loading a number of years ago after he saw my set up. We've had good conversation, and shared ideas. He has always used jacketed bullets, and recently started using lead for practicing with an new SBH in 44 mag. He called me and said he had used PowerPro 300 using jacketed data for some equal weight lead slugs. I suggested he find another powder that could be used for lead and jacketed. He argued with me about it. It may be ok, but for some reason he is determined to use his powder. His current load is 24.2 gr of PowerPro 300 behind a 240gr lead slug. He thinks because he is under the max load for Alliant's data he'll be ok. Maybe, but I'll be standing down a few bays when he tests his load..

while I am with others here about working up a load. If the friend uses a GC boolit with a hard alloy, or heat treated, he could likely have an accurate load.

[JonB_in_Glencoe]

It's been my experience that a jacketed bullet load, and same weight
as cast bullet being considered would be safe load! Cast bullets have
much less resistance in the barrel than a jacketed one! Load & shoot
away!

Well, they do, until they don't.
As pressure increases, the boolit will try to obturate more (especially with a softer alloy), driving pressure up and increasing friction.

[TurnipEaterDown]

Used PP300MP w/ the LEE 310 GC quite a bit -- 310 Lee GC, seated long (1.70), 21.5 gr PP300MP, CCI300 primer. 1400 fps in a 14" Contender. Shot 2.75" full cylinder groups at 50 yd in my R SBH. One of my better for that bullet in that revolver.
Good powder in my opinion for Mag pistol.

BTW: Several years ago, article in Handloader mentioned that an industry rep stated that Accurate 11FS, Alliant PP300 MP, W296, H110 all have the same manufacturing specification -- in other words, given lot to lot differences in production: The can is different.
Must be popular if 4 different companies sell basically the same thing w/ a different label...

[rintinglen]

Used PP300MP w/ the LEE 310 GC quite a bit -- 310 Lee GC, seated long (1.70), 21.5 gr PP300MP, CCI300 primer. 1400 fps in a 14" Contender. Shot 2.75" full cylinder groups at 50 yd in my R SBH. One of my better for that bullet in that revolver.
Good powder in my opinion for Mag pistol.

BTW: Several years ago, article in Handloader mentioned that an industry rep stated that Accurate 11FS, Alliant PP300 MP, W296, H110 all have the same manufacturing specification -- in other words, given lot to lot differences in production: The can is different.
Must be popular if 4 different companies sell basically the same thing w/ a different label...

PP300Mp is made at the Saint Marks facility, but is much slower than 296/H110 (which are the exact same thing, wc296). Layne Simpson was wrong when he said those three were the "same." They have different burn rates despite being made from the same substances.

Accurate 11 FS is very slightly slower than PP300MP, due to the flash suppressant added (hence the "FS"). There was a flurry of debate about 8 or 9 years ago concerning this matter that erroneous info given by ATK made even worse but it was eventually sorted out. 296/H110 fastest of the three, 300MP about 10% slower, AA #11 FS slightly slower still. I will concede that there is substantial overlap between these, but do not presume that what is a safe load in one is safe in the others. It might be, but then again, it might not.

[oldblinddog]

Awhile back there was a discussion about using 300MP as a substitute for SR4759 in rifle cartridges. I tried it and it worked for me. Anyone else done so?

[dtknowles]

Depends on the powder & cartridge. 1/10gr with slow powders in big cases isnt moving the needle much. With fast powders in small case, yes 1/10gr makes safety sense. While 1/2gr diff in magnums with slow powders might be a bit much, not ridiculous.

Agreed but we all use scales that read to the nearest 1/10th gr. so why not report loads that are less than 100gr. to the nearest 1/10 gr. three digit precision. If over 100 gr. then reporting to the nearest gr. or nears 0.5 gr would seem adequate and would be three digit precision or better. I have always been a bit uncomfortable measuring very small charges in very small cases to only the nearest 0.1 gr. but I don't have a better scale and a better scale would need a special environment. 0.1 gr. is pretty small.

Tim

[poppy42]

Ya know I’ve been casting and reloading since about 1980. That’s quite a while. I can tell you in no uncertain term “ I learn something new every day”! I listen to every opinion, do a little research on the subject, apply common sense to the topic, and take it from there! Some of it turns it to be good information, some of it turns out to be useless or even dangerous. The point of all this is a simple fact. Anyone who think they have all the answers, is set fast in his acceptance of new information, and is not willing to acknowledge that he doesn’t know everything ( there’s a few more things but I think ya get the idea) is a FOOL! or god himself! I’ve meet an awful lot of fools but as of this time I’ve yet to, nor expect to anytime soon, meet God. You stated that your friend started reloading after he observed your setup. Yet he seems to think he has surpassed you and everyone else in knowledge. That is someone I would not stand next to at the range or when he’s reloading! Narrow minded attitude like his are eventually going to get him or someone else hurt! Good luck and watch your 6!

[jimb16]

In my gun club we have several hundred members. Most of us reload. Out of all of those guys, there are only 2 whose reloads I would trust and they are strictly BY THE BOOK reloaders who don't racecar any of their loads. They trust my reloads as well. I do some wildcatting, and I will not let either of them try any wild cat load until I've proven it safe. The both know I would never allow them to shoot any load of mine that might put them or their firearm at risk.

[TurnipEaterDown]

PP300Mp is made at the Saint Marks facility, but is much slower than 296/H110 (which are the exact same thing, wc296). Layne Simpson was wrong when he said those three were the "same." They have different burn rates despite being made from the same substances.

Accurate 11 FS is very slightly slower than PP300MP, due to the flash suppressant added (hence the "FS"). There was a flurry of debate about 8 or 9 years ago concerning this matter that erroneous info given by ATK made even worse but it was eventually sorted out. 296/H110 fastest of the three, 300MP about 10% slower, AA #11 FS slightly slower still. I will concede that there is substantial overlap between these, but do not presume that what is a safe load in one is safe in the others. It might be, but then again, it might not.

Good & Interesting info on the correction to my statement.
I will say that the lot of PP 300 MP I have is not slower than any of the W296 I have had, but as noted, lot to lot and all that.

[chutestrate]

I was wondering the same thing. Assuming other reloading procedures were followed correctly there’s basically a zero % anything bad is going to happen. The load 3% off max. Maybe not the ideal place to start but people do this all the time. It’s not very often I create a load with exact bullet, case, primer mentioned in manual.

I agree it probably won't harm his SBH, but my concern is the lack of data in any manual for lead loads using that powder. I go strictly by the loads in books. I may change primers or switch bullet manufacturers, but not bullet weights. I won't try to guess what a powder will do.

[Larry Gibson]

It's been my experience that a jacketed bullet load, and same weight
as cast bullet being considered would be safe load! Cast bullets have
much less resistance in the barrel than a jacketed one! Load & shoot
away!

Unfortunately, that is the common belief. However, I have been pressure testing many different cartridge load combinations for 15+ years now. I have not observed that is always the case. In fact several years back I set out to prove that theory using basically the same weight cast and jacketed bullets in both rifle and handgun cartridges using the same load for each cartridge. I could not verify the theory as sometimes the psi was higher with cast than jacketed and sometimes the jacketed bullets gave the higher psi. I also could not formulate any "rule" for such as it seemed to just "depend".

There is a very good reason most reloading manuals tell you to start low and work up, especially if not using the exact same components.

[dale2242]

What Larry said.
I have used jacketed data for cast bullets in handguns since I began reloading.
I do not have pressure testing equipment but have not had any issues.

[lightman]

I don't try to argue with these people. They will just drag you down to their level and beat you with experience!

[white eagle]

You can't tell know it alls anything...they are always right

JUST ASK EM'

[chutestrate]

Well, my buddy decided to disassemble his loads. He said that he thought he could do better with a different powder. I just agreed that other powders could possibly be more flexible.

[OS1880]

I was told once a little knowledge is a dangerous thing. Even more so with reloading

[castmiester]

while I am with others here about working up a load. If the friend uses a GC boolit with a hard alloy, or heat treated, he could likely have an accurate load.

Gas cutting happens when there isn't enough pressure to obturate the boolit

so much for obturation and fit.

boolit fit prevents cutting

Saywhat ?

[JonB_in_Glencoe]

you have taken my statements out of context.