.357 Mag start loads: help please

[Quoheleth]

I recently picked up Lyman's pistol and revolver handbook. For anyone looking for a second (or third) reloading manual for handguns, I highly recommend this one. I find it readable and full of good information - not to mention good load data, including each bullet had a particular load designated as potentially most accurate load (wonder how they determined that?)

Looking at the .357 Magnum data, I shoot 158gr LSWC out of my 6" GP100. Unfortunately, Lymann only lists data for a 155gr bullet and a 160gr bullet. I have AA#9 that I want to use to generate magnum velocity, working up to full-house loads. I want to see how far I can safely and cleanly push these lead bullets without creating a smoothbore.

But, in looking at data, just the starting data for AA#9 is a pretty wide spread.

Lymann 155gr LSWC: start, 13.0gr; max, 14.5gr.
Lymann 160gr LSWC: start, 12.3gr; max, 13.7gr
Accurate website: 158gr LSWC: start, 11.2gr; max, 12.4gr.

That's almost a 2 grain discrepency comparing the start datum!!!!!!

If I were "just" reloading .38 Specials for shooting out of my Magnum, I wouldn't worry as much about it. .38 Specials run at much lower pressures and the Ruger can handle it. These loads are in the 28,000+ CUP range - I really don't want to KB my gun or my hand.

So, the questions are: Is AA#9 sensitive to light loads? I know H110 is; I want to make sure I'm safe.

I'm leaning toward using the info on the Accurate website to start. Would you suggest sticking with their 12.4gr at max load, too?

I'm looking forward to wringing out the .357. I've not loaded higher-end stuff before - my max has been 5.0gr Titegroup behind this bullet.

Thanks,
Q

 

[Walkalong]

Accurate downloads much better than H-100/W-296, and doesn't have to have mag primers, but it still isn't a good choice for medium loads. It's best to stay at or over starting load data. That is still a pretty good range.

I have always used Speer # 13 for a guideline loading AA #9, while checking Accurate's data as well. I am not trying to max things out, so I have never pushed it to Accurate's max data in .357 or .44 Mag with AA #9.

 

[rcmodel]

O.K., look at the pictures of the two bullets Lyman lists.

The 155 SWC is a gas check design with several grease grooves.
The 160 LRN is not a gas check, and only has one grease groove.

If your LSWC bullets run true to form, it will be closer to the bearing surface of the 160 RN then the 155 gas check.

I would trust the Lyman pictures & data further then I would trust the Accurate website with data for an unknown SWC bullet design.

But in any event, neither set of data from Lyman or Accurate is going to blow you up, one way or another.

rc

 

[loadedround]

The discrepancy among the different manuals is because of their loading combinations...bullets, cases, primers and the powder lot number. Also take into consideration the temperature, any variance in seating depth and case crimp plus the differences in the firearm used; so you can see how the various manuals can be different. You may select the lowest starting load or just average out the three loads and start there, either way you would be safe. Welcome to the wonderful world of ballistics!

 

[Quoheleth]

Thanks. Biggest worry was not wanting a KB from not enough powder to start. Like my guns and hands. Hands more than the guns, but you know what I mean...

Rc, the bullet I'm using looks like Lymann's 160gr bullet - one lube groove plus crimping groove.

Q

 

[joneb]

I shoot 158gr LSWC out of my 6" GP100.

What are these bullets, swaged or cast ? if cast what is the BHN ?

 

[Steve C]

I stopped at 12.3grs of AA#9 behind a 158gr LSWC cast bullet. In miscellaneous cases lit by a CCI 550 primer this load chrono's at 1,268 average fps from my 4" S&W M66. Plenty fast from a 4" barrel and as noted the Accurate data stops around there anyway.

 

[ArchAngelCD]

As a rule when I can't find data for the exact weight bullet I'm using I look for one slightly heavier with the same profile. In reality there is no real difference between a 158gr and 160gr bullet. If one is a SWC and the other RN the OAL will differ slightly (maybe) but the charge weights should be fine.

 

[Quoheleth]

These are Missouri Bullet's .357 Action bullet, BHN is 18 per the website http://www.missouribullet.com/results.php?category=5&secondary=10

(I need to check my original box from my first order back in '07. I could have sworn it was BHN of 20).

Q

edit: I checked last night and I was right: the new .357 bullet is BHN 18. The first box was BHN 20.

 

[joneb]

These are Missouri Bullet's .357 Action bullet,/QUOTE]
I would load 12 @ 12.6, 12@ 13.0gr,12 @ 13.3gr,and 12@ 13.6gr with standard primers and a heavy crimp. The lesser charges may show pressure signs such as cratered primers and sticky cases but this will diminish as the charge increases, and then reappear somewhere past 14gr.
You have a strong gun there, I wear the proper protection and shoot alone when developing a new load