38 Long Colt Pressures

[reno]

Been loading 38 Long Colt a long time and just now thought of a question. I have no way to check pressure, and I always try to stick to the manuals. I load a cast 38 RNSP 158gr. bullet not a 150gr. like the data shows, with 1.8gr. Trail Boss. The data only shows 1.8gr. for a 150gr. bullet. Starting load for the150gr. said 1.8gr, and Max. 2.0gr. with the extra 8grs. of lead I hope Iam not pushing it, as I shoot all 38 LC. in my Conversions. Do  you think Iam pushing the pressure up to much?
Thanks
Reno

[Abilene]

I am not a professional ballistician.  My opinion is that you are just fine. 

[reno]

Thanks Abiline, I thought I was okay, buy like to hear from people that have more knowledge , than myself.
Reno

[Professor Marvel]

Trailboss is a smokeless powder, designed to be "fluffly" so as to be  difficult to accidentally dump a double charge
in large cases. It is known to have a "faster" pressure curve than smokeless,  poops meant BP sorry.


so if one is using it in original
guns, I would advise against it.

If you are shooting it in modern conversions, if one wanted to consider the differences, by working the math we see
that one might reduce the starting charge by .093 grains... or less than 1/10 grains. Sooooo ....
not that much of a difference. But free advice is worth every penny. Just watch for pressure signs.

good luck and keep us posted
prof marvel

[reno]

Thanks, Professor, Iam shooting these loads in modern reproduction guns. I only use Black powder in my originals.
Thanks again for the inputs.
Reno

[Trailrider]

A 158 gr bullet is 5.3% heavier than the 150 gr. Multiplying 1.8 gr x 1.053 = 1.896 or appox. 1.9 gr, which is 0.1gr under the 2.0gr max for the 150 gr bullet. With the heavier bullet you could drop down to 1.7 gr. But it may not make that much difference depending on the guns you are shooting. Keep in mind, however, that other factors may obtain, such as bullet diameter, hardness, etc. One needs to be a little careful with minimum loads with Trailboss, especially in cold weather. I would try shooting at least 10 rounds with 1.7 gr and 1.8 gr with the 158 gr. bullet and see if you get changes in accuracy, Point of Impact, etc.

[reno]

Thanks Trail Rider, I am shooting these in 1860 reproduction Conversions, and they seem mild. I cast 20/1 with 9lb. wheel weights and 1lb 50/50 bar sodier.
Thanks for the info.
Reno

[Professor Marvel]

Thanks Trail Rider, I am shooting these in 1860 reproduction Conversions, and they seem mild. I cast 20/1 with 9lb. wheel weights and 1lb 50/50 bar sodier.
Thanks for the info.
Reno

that sounds positive.
watch your primersfor the usual: backing out, flattening, cratering, etc.
flattening and cratering you have to look for.
backing out hangs up the cycling.

oddly there was a huge batch of win white box .38 spcl hollowpoints that had primers backing out out hanging up every revolver
I tried them in....

good luck!
prof marvel

[Baltimore Ed]

Very light [target] loads will back out your primers but not have the oomph to drive the case rearward to reseat them back where they were. Then your revolver cylinder locks up. Hot loads cause cratering as the primer flows around the firing pin. Hot loads flatten the edges of primers too. That's why military primers are swaged in place.

[reno]

I have shot this load many times, with no problems, I was just wondering on the pressure with the 8gr. increase from 150gr. to the 158gr. I cast.
Thanks again,
Reno