I see that Hodgdon lists a 470 load with Trail Boss. 500 grain Woodleigh, 45.5 grains. A light load without a filler, so I can see some definite use for it. Does seem to compress the powder a bit. So......

Anybody tried this?

I loaded 35.0 gr in my 450/400 NE with a 400 gr cast bullet for a mv of about 1600 fps. The powder was well below the bullet. I understand TrailBoss should not be compressed.

No less than 70% filling and no more than 100%, nasty pressure spikes if you do.

Lots of information on Tail Boss here from past posts go to find and enter Trail Boss.

True, lots of posts on the general topic.

However my question that I can't find addressed is shooting the Hodgdon load of 45.5 grains with the Woodleigh bullet. Lots of cautionary notes on "don't compress" TB, and that's the reason I'm asking. To the bottom of the bullet, I measure about 37 grains. So if that's the max, I'm nervous about the 45.5 load Hodgdon has published.

Think I will just call them tomorrow. See if they even publish a starting load.

Is Trail Boss the approximate of the 75% rule many of use?
Cal

NO, I use a 405 grain bullet in a 458 Win Mag. 16 to 19 grains of trail boss.

Cal,
It probably is of use. Trick is that Trail Boss is so fluffy that measuring before and after a little tapping the case yields different levels in the case. I wonder if that's where their load came from....

I look forward to talking with Hodgdon and getting more information.

I talked to Hodgdon today. Mike. Very helpful. He recited that measuring to the base of the seated bullet was 100% and knock 30% off that for a starting load. Same thing others have posted as a general rule for Trail Boss. So, that's where I'll go.

I did ask him why it was that their max was 45.5 grains but even after several measurements, I kept coming up with between 37 and 38 grains as the max, based on the 500 grain Woodleigh. He said the guys in ballistics came up with that 45.5 load, tested it for pressure, and found it would work. I said my understanding was to not compress Trail Boss or you get erratic pressures. He just related what they had found.

So max for me will be 37 grains. And I better hear a little rattle when I shake the case.

Shot some loads on Sunday, getting those in before it gets so dang hot here in Phoenix.

Worked up from 26 grains to 35 grains of Trail Boss, Woodleigh 500 soft point and seated to the cannelure. Not crimped. Fed 215 magnum primer. Bell brass. The powder filled the case nicely and it's good to not have any overpowder wads to fool with.

For my Chapuis 470 double, and not trying to say this would apply to any other rifle, here's what happened. 26-35 grains shot well and comfortably. Low at 50 yards but coming up as the loads increased. At 35 grains was pretty close to an inch or so low.

Had some minor primer extrusion at 34 and 35 grains. Not much, but I could feel it with my thumbnail. So...will stay at 33 grains or below. And instead of the factory 50 meter/yard rear sight will use the 100 yard sight leaf to enjoy being closer to the center of the black.

Pleasant to shoot. Didn't chronograph it yet, but don't really care. Mostly just wanted to have a light load that is easy to load and easy on the shooter and rifle.

As for the 45.5 grain load shown in the Hodgdon manual, I will not load anywhere near that.

Thought I should share !

I have always wondered about some of their loads. They publish reloading guidelines and then don't follow them. Oh well.