Alliant 300 MP for 357

A

AZ sharpshooter

New member
I have both a 357 revolver and a 357 rifle, the Ruger bolt action carbine. Alliant lists only a couple of loads for the 300 MP powder. I have used them in my revolver for both the 158 and 125 and that powder is amazing. I'm wondering if anyone has any data other than Alliant for 300 MP for 357 magnum, any bullet weight would be fine. Thank-you.
 
Alliant also has it for a 170 grain Gold Dot Soft Point. 15.8-17.5 grains.

One word of caution, though. All Alliant's data is for Speer Gold Dot bullets. In a conversation with a Speer tech, he told the Gold Dots have plated jackets and don't have the same jacket hardness as cup and core jacketed bullets do because the plated jacket doesn't get any work hardening as a normal jacket cup does during forming. As a result, he said the information is not necessarily interchangeable with jacketed bullets, and that he'd even seen some data where a Gold Dot starting load exceeded the maximum load for a conventional jacket.

Also note that Alliant's online data only includes maximum loads. They assume you will knock that published number down 10% and work up. Even though they call it a "recipe", it really is just a maximum load. Their manual in PDF form explains this, but the online data pages do not, unless I missed it.
 
To: Unclenick

Thanks for the info on the Speer Gold Dots. I am using the Speer 125's- the "plinkers" and have not had any issues, granted the max load is hot, but nothing strange has happened, no blown primers, etc. I am using the Hornady 158 XTP with a less than max charge out of a Ruger Blackhawk with no apparent issues. What did the Speer rep. suggest would happen if one used bullets other than Speer GDs?
Thanks.

AZ Sharpshooter
 
Maybe we might also mention that the velocity numbers that Alliant shows on their site with 300-MP in .357 Magnum are absurd.

This is my opinion. I will NOT prove my opinion. Anyone who reads my opinion may feel free to call my opinion absurd or better yet, prove me wrong.

But those reported velocities are silly. And ABSURD.
 
AZ Sharpshooter said:
What did the Speer rep. suggest would happen if one used bullets other than Speer GDs?
Click to expand...

What the tech is saying is that Gold Dot loads often use more powder than conventional jacketed bullets do, so the pressure would be too high with the conventional jacketed bullet.
 
Looking at my numbers for rounds I've loaded with both Hornady XTP and Speer GDHP, I see only small differences, like 0.1-0.2 grains to achieve the same velocity. GDHP tends to be the higher weight, but not always (.45 ACP is 0.1 less with the Speer).

Back to the OP, 300-MP is the only powder I've tried that matches 125 Hornady Custom commercial ammo in my 4" GP-100. With 158s, it's right there with H110 and AA#9, but no faster.

PS: The Hornady manual lists 300-MP loads.
 
In my experience, 300-MP gave the highest velocity with 158 gr jacketed bullets in my 6" GP-100, besting W-296 by about 50-75 fps and 2400 by 75 fps to 100 fps. It also took an extra 2-3 gr more powder to do so. I like it for jacketed bullets. For cast bullets, I have gone to Power Pistol. It gets within 100 fps of the jacketed loads using half the amount of powder and seems quite accurate, too.
 
ligonierbill said:
like 0.1-0.2 grains to achieve the same velocity.
Click to expand...

…Though, as a point of caution, that doesn't mean the peak pressures are the same. When velocities match, you can say the average pressures behind the bullets after friction is removed were the same. But high peak and low muzzle pressure can give you the same average pressure as a low peak and higher muzzle pressure do, so you can't accurately deduce peak pressure from velocity.

Nonetheless, given your charge differences were small it seems unlikely the peak pressure differences would be dramatic. Especially if you saw no pressure sign differences between them.

I don't know which data the technician I spoke with had in mind. There is a lot of data in the Speer manual that mixes the Gold Dot with their jacketed bullets all using the same data, though it's possible the data is below maximum for the GD in that case. No way to be sure without being privy to the pressure measurements. In any event, the technician's warning does not appear to apply universally. It strikes me as more of a caution to start at the very bottom of the range and work up, which applies to any load.

I have a .44 Mag barrel for my Encore. I may put a strain gauge on it sometime and see what the pressure curves look like. It wouldn't surprise me if some powders don't show a difference and others do.
 
Thanks everyone

Thanks for the info. on 300 MP. I really like the powder but need more data. I recall now that Hornady #9 lists charges for 125's and 158's. The 140 is my favorite bullet weight for my Ruger Blackhawk. I wish someone published some data for the 140 grain using 300 MP.

Thanks again.

AZ Sharpshooter

________________
NRA Life Member
 
Use 158gr data with your 140gr bullet and work up from there. (Carefully)

Also... e-mail both Alliant and Hornady and ask specifically, both sources have proven to be quite helpful and accommodating!
 
To: Sevens

Thanks for reminding me to e-mail them. One time, I actually called Hornady to ask about one of their bullets.
I'll try that work up for the 140.
Thank-you.
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NRA Life Member
 
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