Magnum Primer with Unique in 357?

[gaston_r]

I bought some Gold Dot 125 gr hp and loaded them with 9.2 gr of unique for use in my SS 4" Ruger GP-100 .357. This is from Speer's load data (max load 9.6 gr). I used magnum primers because that's all I had on hand. Speer's load data shows magnum primers with 296, h110, hs-7, & hs-6, but not with Unique. I found a load from Sierra for same bullet weight that did use magnum primers. Sierra's max load is 9.3 gr of Unique. Is this a safe load with magnum primers?

[versifier]

Yes, it's safe. It is a pretty hot load, but I wouldn't worry about it a bit. That is a really strong design. My S&W handles the max loads with no problem, though they are not the most accurate - 9.0 is the load I use. Max used to be 10.0 until they started to measure pressure data in PSI instead of CUP, Sierra now lists it at 9.3 for their bullets. Just for future reference, pressure signs in a revolver include flattened primers and difficult extraction, but if there is too much oil/protectant in the chambers it may get sticky, too, without being overpressure. I use mag primers in all my .357 loads for better ignition, it was the first case I ever loaded for (with Unique & CCI SPM primers) 35 years ago. Worked great then, still works great, though now I shoot nothing but cast out of them. As long as you work up to max loads one step at a time and watch the primers like you would with a rifle, you will have no problems. Caution is good.

[gaston_r]

Thanks Versifier, I was waiting for some responses before I head to the range. I would have liked a slightly lower charge, but my Lee auto-disk pro seems to have picked this one for me. It's difficult to get Unique to flow well in my set up. I'm considering trying 296 because I've heard it flows better in the Lee auto-disk.

[runfiverun]

296 is a ball type powder it will drop a more consistent "load"
drop after drop.
but you use a different disc to get the velocities you are now

[versifier]

Yes, those are the drawbacks of the Lee measure. They lack charge versatility and have "attitudes" with certain flake and extruded powders. Ball powders do work a little better in them, but again you have to go with whatever volumes of those it allows you. Before you go out and get some 296, there are smaller PPM cavities that will give a lighter charges that still falls within the working range of Unique (7.6-9.3gr). There should be a set of charge tables that came with it, but I have a copy in my Lee manual. The .88 or .95 cavities should do it.
Cavity/Charge Weight of Unique
.82...............7.5
.88...............8.1
.95...............8.7
1.02.............9.3
Ironically, the cheaper Perfect Powder Measure is completely adjustable, but I much prefer conventional models by Lyman, RCBS, Redding, Dillon, etc. They're a lot more rugged and will stand up well through many years of frequent use, and I use a lot of Alliant and IMR powders. For now, you have what you have. Later, you may decide to upgrade. A set of Lee dippers cost less than $10 and might be an option, too.

[dale clawson]

The Lee adjustable disc will solve your problem easily. I like it in my loadmaster press as I change boolit weights regularly, and the recorded settings repeat easily and dependably. Dale

[kg42]

I finally listened to the advice given by some on the internet about American flake powders:
1: I removed my home made baffle,
2: I fill the (pro) hoppers of my Auto Disks at least 50%.

I haven't taken the time to weight the resultant regularity, but I am now very happy with 4.4gr of 700X in 45ACP.
I had to postpone the 9 Luger test (3.4gr) as the range's floor was littered with 9mm brass, but I certainly didn't catch half loads like usual.

kg

[gaston_r]

Just an update. I went the range Saturday and the 9.2 gr of Unique did fine with the mag primers. FELT like the Remington sjhp UMC loads that I use to pay $40/box for before I began reloading. Thanks for the advice guys.