Unique and Mag Primers

[Sunkist]

I know you guys have covered the topic from different angles. I just read all of the old posts in a search. The problem is that I didn't find a specific answer to my question.

Lyman's Cast Bullet Hdbk. uses CCI550 for all .357 Mag. loads listed regardless of powder or load. They just never got to my favorite of 6.0 Unique w/ 158 SWC (Oregon Trl. or Meister). I'm down to only CCI 550 now and I can afford bullets or primers but not both. The Recession has me hamstrung for now.

I'm hoping someone can save me the time of experimenting with limited resources. My 686's love this load and now I have to go w/ the magnum primer. What will the magnum primers do to the velocity? I doubt pressure will be an issue.

 

[Sunkist]

I know you guys have covered the topic from different angles. I just read all of the old posts in a search. The problem is that I didn't find a specific answer to my question.

Lyman's Cast Bullet Hdbk. uses CCI550 for all .357 Mag. loads listed regardless of powder or load. They just never got to my favorite of 6.0 Unique w/ 158 SWC (Oregon Trl. or Meister). I'm down to only CCI 550 now and I can afford bullets or primers but not both. The Recession has me hamstrung for now.

I'm hoping someone can save me the time of experimenting with limited resources. My 686's love this load and now I have to go w/ the magnum primer. What will the magnum primers do to the velocity? I doubt pressure will be an issue.

 

[thomashoward]

A magnum primer is not necessary for Unique, but if that is what you have start a a grain lower and work up as it may increase your pressures somewhat especially at the upper end of the load data listed.You may get a little bump on velocity, but also will be using proportionately less powder ,so I think it will be a case of ,6 of one...
buy primers and powder. You can always cast bullets.If you do not have primers it won't go bang.

 

[Steve C]

Mag primers may increase pressure somewhat and may increases or even decrease velocity. Takes a chrono to find out.

thomashoward is correct that you should reduce your load and work back up if you are at a maximum level, BUT 6.0grs of Unique is a relatively light load, slightly below start level and well below maximum with a hard cast 158gr LSWC. There's really no need to worry about over pressures with that load so just swap primers and see if your accuracy changes much. If its still acceptably accurate then you are good to go without any more experimenting.

 

[bogman]

I have been using 6grs. of unique & a 158gr. swc with mag. primers for 32 years & never a problem. I have always just bought magnum primers, that way I save money & can load unique or 2400 (the only powders I use) I get excellent groups & no pressure signs. I know unique does not need mag. primers, but it wont hurt to use them. 6.0 grs. of unique is not a max load. in my HB model #10 4" I use 5.5grs. of unique & a 158swc with a mag primer. again no pressure & great accuracy.

 

[Sunkist]

Thanks, Bogman. That's the reply I was hoping for. Someone who has used the load sucessfully is the best source. The other guys are right about working up and checking for pressure. I was hoping to hear from someone who already has. Years ago I read a piece by Bob Mileck about 6.0 Unique and I've used it ever since. I just hadn't used mag. primers.

Originally posted by bogman:
I have been using 6grs. of unique & a 158gr. swc with mag. primers for 32 years & never a problem. I have always just bought magnum primers, that way I save money & can load unique or 2400 (the only powders I use) I get excellent groups & no pressure signs. I know unique does not need mag. primers, but it wont hurt to use them. 6.0 grs. of unique is not a max load. in my HB model #10 4" I use 5.5grs. of unique & a 158swc with a mag primer. again no pressure & great accuracy.

 

[GC]

I have always just bought magnum primers, that way I save money & can load unique or 2400 (the only powders I use)

Many would say that a magnum primer isn't needed for either of those two powders. Magnum primers aren't recommended for #2400 by many load manuals and handloading authorities either.

 

[steveno]

a number of years ago I loaded up some 41 mag loads with Unique using magnum and standard primers. after chronographing 25 rounds of each the only thing I could seen was the extreme spread was a little lower than the standard primers. the average was just about the same. considering I don't have a ballistics lab the next time I try it the results could be different and I don't have plans to do it again. just start low and work back up. I only use magnum primers in the 41 mag so I don't have to sort them out by primer.