pressure concerns

[rlavinder]

I am loading for .357 magnum . 162grain swc with gas check. They weigh about 163 to 164 grains with the gas check. My progressive measure throws 6.8 to 7.0 grains of unique. On an average of 6 shots my chronograqh is registering 1186 ft per second. There is no sign of primer backing or leading of the barrel. The closest data I could find for my bullet is 158 grain fmj, 4 to 6 grains lighter. My late father always warned me to stay with published data only. I wish I could ask him, but he has moved on to that great loading room in the sky. In short, my concern is pressure. I have read that changing bullet shapes and even hollow points can cause pressure to vary greatly. I am using a bullet that is possibly up to 6 grains heavier then the one listed in the load manuel. As I said, there is no leading problem and my speed in fine, I just want know if I have varied to much and violated good safety. I don't want to be ridiclulously cautious , but don't want to be unsafe either. Any comments or advice would be greatly appreciated . Thanks, Richard

[tazman]

All the data I can find with one exception shows you are right at the safe maximum for that combination.
The one that is different is a Lyman 44th handbook. It says you could go up even higher but the data is old and things have changed a bit since then.
That manual says your powder charge is safe with a boolit that weighs 168 grains.

[rlavinder]

Thank you very much for the information. I have the mold that Dad used, gas checks, and many bullets already sized and lubed. I can now enjoy using the components and feel good about the load. Many thanks to you tazman and good casting and shooting. Richard

[Boolseye]

Welcome to the forum. You're smart to err on the side of caution. That said, you can afford to relax a little with this combo. I'm looking at data from an old Speer manual that lists 7.7 gr. Unique as a start charge for 158 gr. jacketed. Granted the old books sometimes went overpressure, but the .357 magnum is designed to be a hot round and you probably won't blow up a gun if you stay with published data. The thing to watch for is a squib followed by a double charge. That will leave you hurting.

[rlavinder]

Thank you very much for the information. This definitly makes me be able to relax and enjoy the loading and shooting. 10- 4 on the squib followed by a double charge. I just installed an led light on my progressive to shine through the flash hole if no primer is present, and have a micro camera that shows an image of the charged case on my laptop. I got this idea off youtube and it works like a charm. The double charge was my big concern when graduating to a progressive, and this seems to work well. I like the progressive for hand gun , but still stay with single stage for rifle. Thanks, Boolseye and happy loading. Richard

[reddog81]

2-3 grains in bullet weight difference is insignificant. 4-5 grains is starting to matter but can still basically use the same data assuming the bullets are the same shape. Personally I might back load down if shooting out of a lightweight snub nose revolver, but would be comfortable of shooting any medium sized or larger gun.

[Gtek]

Bless you for the critical thinking, seems to be a shortage of that these days. I had it hammered into me that when one ventures into a new configuration to always start at starting loads and work up, heavy inspection along the way. Individual dimensions and components are unique, putting them all together makes one unique stack. Boo-Boo's in this game can be life changing, sounds like you will be fine!

[rlavinder]

Thanks for your reply. The more folks that keep commenting the better I feel. I am using a heavy piece while shooting this load and I appreciate your comment in reguards to that. Thanks, Reddog 81, keep your powder dry! Richard

[rlavinder]

Thankyou for your comments and encouragement. 10-4 on the"Boo Boo's". My father always told me that there was zero room for errors in this game. I appreciate you Gtek, and keep those groups tight! Richard