Light-Mid .357 loads

Contrast Man · January 11, 2013, 10:26 AM

I just bought a S&W 686 and I have a few questions for loading for it. The load I plan on starting with from Lyman's 49th is 125gr Berry's plated with Bullseye powder. As far as charge weight, would I be able to use data from 38 spl in a .357 case? The range for the 38 spl loads goes from 3.2gr to 4.4gr, but the .357 range is 6.5gr to 8.6gr.

I'm fully aware of the limitations of plated bullets and have no intention of loading them even close to the high end.

If using lighter loads, would a magnum primer still be required or would it be sufficient to use a standard small pistol primer?

Thanks for your input!

Ifishsum · January 11, 2013, 10:37 AM

You can load a .38 special recipe into a .357 case - and pretty much anywhere in between .38 and .357 data if you like. Because of the larger case size, the same load in the larger case will be a bit lower pressure, so at least a small bump might be needed to achieve the same result.

Primer choice is dictated by the powder used - not the cartridge. Most load books will indicate when a magnum primer is recommended, most often that's with spherical powder like H110. Bullseye does not need a magnum primer in any case.

Jim Watson · January 11, 2013, 10:39 AM

There would never be a need for a magnum primer with Bullseye.

Using .38 Special data in .357 brass would give somewhat lower velocity because of the greater volume... unless you seated the bullets .135" deeper, which would not likely be an option with 125s.

Do be careful, the only gun ever demolished on our range was a .357 loaded with Bullseye at the high end. A double charge will fit and will blow it up.

Contrast Man · January 11, 2013, 11:02 AM

Thanks for the quick responses!

It's good to know I won't have to buy a new type of primers and can just use what I have in stock right now.

Also good to know that there will be a slightly lower velocity due to the extra space from .38 to .357. I like to think I'm good at keeping an eye on charge throws, but I also use an RCBS Lockout die which, while not absolutely fullproof, does help.

L_Killkenny · January 11, 2013, 11:07 AM

You should be fine with Bullseye but I don't like it with some other powders, even Unique. As I stated on another post today some powders don't like to be loaded light but Bullseye is traditionally used for light and target loads.

Like stated above you'll probably have a little less velocity using the .38sp loads in .357 cases. It was recommended to me that if I want to recover some of that loss add .5gr to the load OR use a mag primer. No, you don't need a mag primer for bullseye but it seems to bring the pressure up to compensate for the added case volume.

GP100man · January 11, 2013, 10:51 PM

With fast powders I always inspect the powder twice before seating .

I`ve found with fast powders ya don`t need mag primers .

& with fast powders in the 357mag when ya reach `bout 1k fps they get a little spiky in pressures, & keepin the plated bullets under or near 1k is a good idea.

joneb · January 11, 2013, 11:54 PM

I have loaded 140gr Raineer FP plated with 8.2gr of Accurate #5 and standard primers with excellent accuracy from a 4 and 2.75" 357 mag.

January 11, 2013, 10:26 AM	#1
Contrast Man Senior Member Join Date: November 2, 2011 Location: Illinois Posts: 178	Light-Mid .357 loads I just bought a S&W 686 and I have a few questions for loading for it. The load I plan on starting with from Lyman's 49th is 125gr Berry's plated with Bullseye powder. As far as charge weight, would I be able to use data from 38 spl in a .357 case? The range for the 38 spl loads goes from 3.2gr to 4.4gr, but the .357 range is 6.5gr to 8.6gr. I'm fully aware of the limitations of plated bullets and have no intention of loading them even close to the high end. If using lighter loads, would a magnum primer still be required or would it be sufficient to use a standard small pistol primer? Thanks for your input!

January 11, 2013, 10:51 PM	#6
GP100man Senior Member Join Date: August 1, 2007 Location: Tabor City , NC. Posts: 1,969	With fast powders I always inspect the powder twice before seating . I`ve found with fast powders ya don`t need mag primers . & with fast powders in the 357mag when ya reach `bout 1k fps they get a little spiky in pressures, & keepin the plated bullets under or near 1k is a good idea. __________________ GP100man

January 11, 2013, 10:37 AM	#2
Ifishsum Senior Member Join Date: September 15, 2005 Location: Oregon Posts: 1,033	You can load a .38 special recipe into a .357 case - and pretty much anywhere in between .38 and .357 data if you like. Because of the larger case size, the same load in the larger case will be a bit lower pressure, so at least a small bump might be needed to achieve the same result. Primer choice is dictated by the powder used - not the cartridge. Most load books will indicate when a magnum primer is recommended, most often that's with spherical powder like H110. Bullseye does not need a magnum primer in any case.

January 11, 2013, 10:39 AM	#3
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	There would never be a need for a magnum primer with Bullseye. Using .38 Special data in .357 brass would give somewhat lower velocity because of the greater volume... unless you seated the bullets .135" deeper, which would not likely be an option with 125s. Do be careful, the only gun ever demolished on our range was a .357 loaded with Bullseye at the high end. A double charge will fit and will blow it up.

January 11, 2013, 11:02 AM	#4
Contrast Man Senior Member Join Date: November 2, 2011 Location: Illinois Posts: 178	Thanks for the quick responses! It's good to know I won't have to buy a new type of primers and can just use what I have in stock right now. Also good to know that there will be a slightly lower velocity due to the extra space from .38 to .357. I like to think I'm good at keeping an eye on charge throws, but I also use an RCBS Lockout die which, while not absolutely fullproof, does help.

January 11, 2013, 11:07 AM	#5
L_Killkenny Senior Member Join Date: February 2, 2007 Location: Iowa Posts: 2,676	You should be fine with Bullseye but I don't like it with some other powders, even Unique. As I stated on another post today some powders don't like to be loaded light but Bullseye is traditionally used for light and target loads. Like stated above you'll probably have a little less velocity using the .38sp loads in .357 cases. It was recommended to me that if I want to recover some of that loss add .5gr to the load OR use a mag primer. No, you don't need a mag primer for bullseye but it seems to bring the pressure up to compensate for the added case volume.

January 11, 2013, 11:54 PM	#7
joneb Senior Member Join Date: December 10, 2005 Location: Central , OR Posts: 1,888	I have loaded 140gr Raineer FP plated with 8.2gr of Accurate #5 and standard primers with excellent accuracy from a 4 and 2.75" 357 mag.