357 mag with 148gr wc using Trail Boss

[joshuamalezi]

I got a sample pack of 148 grain hardcast wad cutter bullets (.358 dia)  from a local bullet maker. Just purchased some Trail Boss for the first time, too.  Having trouble finding data for my bullet/ powder combo, though. I've never loaded wad cutters before, so I'm not sure about taking data from a similar weight bullet that's not a wad cutter given differences in seating depth. Any help or advice is appreciated.

[The_Shadow]

I take these are a full wadcutter profile bullet...Full wadcutters probably would be seated to about  flush at 1.290" for the 357Mag.
You might want try to work around 4.0 grains - 4.2 grains of Trail Boss with a standard SP primer.

Good luck!

[joshuamalezi]

They are full wad cutters. There is load data in the Lee manual listing o.a.l. at 1.330 for most loads. I was going to try 3.3 grains of Unique, as per the Lee, too.

[my_old_glock]

Trial Boss can be used in any metallic cartridge. The case can be filled anywhere between 70% and 100%. Not over, and not under.

1) Measure the length of the bullet.

2) Measure the COAL (cartridge overall length).

3) Subtract the bullet length from the COAL.

4) Subtract the number you got in #3 from the empty case length.

5) The number you get in #4 is the distance between the powder and the top of the brass case.

6) Fill the brass case to this height.

7) Weigh the powder you have in #6

The weight you got in #7 is the maximum powder you can load (Trial Boss does not like to be compressed).

9) Multiply the weight you got in #7 by 0.7 (That would give you 70%).

10) The weight you got in #9 is the minimum powder you can load.


Trail Boss is a fun powder to shoot. It is impossible to find. You are lucky to have some.

You can use the above method to load ANY metallic cartridge, but it will not cycle a semi-auto.

Note: "8 )" above turns into a smilie.

.

[my_old_glock]

As for how high/deep to seat a wad cutter:

If the wad-cutter has a crimp groove; seat to the crimp groove.

If the wad cutter does NOT have a crimp groove; seat to the top of the bullet, or to where the radius/taper at the end of the bullet starts.

If one end is flat and the other end has a nipple, it will most likely have a crimp groove. The nipple improves accuracy at higher (357) velocities. The nipple end faces out towards the target.

.

[joshuamalezi]

The one shop I go to always has Trail Boss in stock. I finally decided to try some out.

[gandog56]

Trail boss not meter good. I just fire Red Dot in a .38 special case.