Trail Boss: 357 Magnum and 257 Roberts?

[sniper]

Hello, all;
Searched, not much luck.
I have followed the Hodgdon directions for determining charges, both for my 357 Magnum and the 257 Roberts, and have arrived at what I believe are some workable figures; but all on paper so far.

Just as a double check, has anyone actually used trail Boss in 357 magnum brass with cast 158-162gr. swc, or 125gr. plated boolits? Or the 257 Rob'ts with the Montana Bulletworks 100gr. GC boolit? It looks a lot like the discontinued RCBS 100 gr. offfering.

Has anyone used the .25 RCBS 120gr. GC with Trail Boss?

Any probems using TB in 38 Spl. brass?

What do you recommend for loads?

Thanx 8-)

[Hammerhead]

I've used TB in .357 with light lead bullets with good results. Search for cowboy data using Trail Boss, plenty of data out there. I also use it in 30-30 with lead bullets, but don't own a 257 Roberts.

[aspangler]

I use Trailboss in 38 spl a lot. Give me about 850 fps in a 4 inch barrel with a 158 gr swc.

[fouronesix]

Trailboss works fine in 357 Mag. But why insist on using it in 257 Roberts? Trailboss is simply an extremely low density powder with a burn rate around Bullseye or 700X. Unless you like using Bullseye or 700X in the 257 Roberts for some reason???

[BCRider]

IMO TB is best used in handgun ammo for lighter loads. If you look at the pressure vs muzzle velocity for rifle rounds and even bigger magnum loads where TB is one of the suggested powders you'll see that the pressure becomes very high for modest muzzle velocity values compared to the other powders. I suspect that this is also the reason why I only see Hodgdon suggesting TB for straight wall big bore rounds and not at all for bottleneck casings from my quick search of a few examples.

[sniper]

Just figuring what may be possible. I have worked up a couple of loads with 2400 and Unique that do very well in my Roberts, but the only TB data I have found to date that even comes close to the Roberts is for the 6mm Remington, which is the same case as the 257, which is the 7X57mm Mauser necked down.
I figure close enough... but why take a chance, seeing as how a little caution doesn't hurt?

[cbrick]

I've used TB in the 357 mag in a Marlin 94. Saeco #382 (150 gr, SWC, PB) and worked up to 5.0 gr TB, standard primer. No hunting load for sure, was about like a rimfire rifle @ 970 fps and a tack driver for a model 94 out to 100 yards. Was also a lot of fun spending an afternoon plinking away. The local ground squirrel population that was digging up our birms didn't agree with the fun part though.

Rick

[Nobade]

357 is no problem - max charge is powder to the base of the bullet with no compression. 257 Roberts is another matter. Trail Boss does work very well in cases like that, but at much lower loads than you would think. I would start at 50% of available capacity, and I doubt you'll see any accuracy above 70%. Pressures will be plenty safe, but more powder will start to lead the bore and not shoot well. I have gotten exceptional accuracy from many bottleneck cartridges with cast boolits and trail boss, but velocity is always very low (much slower than an equally accurate load of Red Dot or AA#2).

-Nobade