300MP in 357 Mag. Guidance

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kcofohio

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I'm looking to try out Hornady's 180 gr. SIL (silhouette) bullet using 300 MP in a rifle. 100 yd. target shooting.
Alliant's data only goes to 170 gr. for said powder. But they have data for 158 & 170 gr.
158 gr. GDHP with 18.6 gr. with OAL at 1.575".
170 gr. GDSP with 17.5 gr. with OAL at 1.590".
IIRC, and I will double check, but Hornady list the SIL and XTP OAL at 1.590".
So I'm thinking that if I stay within 16.3 gr. and the 10% below, with the 180 gr., it should be in the safe pressure zone.
Anyone see it differently?
These are left over bullets and I figure to try them before buying 180 gr. XTPs and MBC cast 180 gr. or possibly others.
TIA!
 
Thanks for the file! I'll have to look at the bullets closer. The author has the charge a little more than I expected.
I'll reread the file later when I'm home. :)


As always, I suggest you validate any info given there or here by another legitimate source.
 
As always, I suggest you validate any info given there or here by another legitimate source.
I agree. Sadly, there isn't much published data when it comes to 300MP. And not too many load for the 180 gr. variety of bullets to boot.
Once I figure out the work-up loads, I'm going to reach out to Alliant for a final approval or not, before actual range time.
Thank you!
 
I'm thinking that if I stay within 16.3 gr. and the 10% below, with the 180 gr., it should be in the safe pressure zone.
There is no way to know what pressure that load will generate. Rarely if ever do pressures increase linearly.

I suggest writing them and asking if they have data for that 180gr bullet.
 
There is no way to know what pressure that load will generate. Rarely if ever do pressures increase linearly.

I suggest writing them and asking if they have data for that 180gr bullet.
I was going to contact Alliant through their web site. When I read that if they haven't tested a certain bullet, which I have never seen a Hornady bullet in Alliant's data, to contact the bullet maker.
So on a whim, I did a web search. I found that THR member RealGun has a 2013 thread about 300MP with a 180 gr. Hornady bullet. He says Hornady's 9th edition listed 300MP.
https://www.thehighroad.org/index.php?threads/alliant-powerpro-300-mp-180-xtp-in-357.726972/

So I ordered the 10th edition and it should be here Monday.
20180922_233751.jpg
Here are a couple loaded up. 1.610" is the OAL. They are new old bullets. Pricing marked on the box is $11.39
 
So I ordered the 10th edition and it should be here Monday.
I hate to break this news to you but Hornady #10 does not list 300MP with their 180gr XTP bullet and I just went down to the basement and checked Hornady #9 and it's not their either. The data in both manuals is line for line, sorry.

Just because Alliant steered you towards Hornady doesn't mean they don't have data. What's the worst that could happen, they tell you they are sorry they don't have data?
 
I hate to break this news to you but Hornady #10 does not list 300MP with their 180gr XTP bullet and I just went down to the basement and checked Hornady #9 and it's not their either. The data in both manuals is line for line, sorry.

Just because Alliant steered you towards Hornady doesn't mean they don't have data. What's the worst that could happen, they tell you they are sorry they don't have data?
Okay, thank you for looking. Guess I got me another manual.
I'll contact Alliant then. You're right!
 
I submitted help request to both Alliant and Hornady. Neither have tested 180 gr. Hornady's and 300MP together, per their responses. Though both wrote that they would forward my info to the proper departments.
I'm going to shelve the 180s until either new data is developed, or try with a different powder.
I'm going to stick with 140 & 158 gr. for now.
Thanks Arch and Buck for your help!
 
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