I have never reloaded with

Trail Boss. So I have no experience on which to base my question. I believe Trail Boss is similar, volumetrically, to black powder. The old buffalo hunters used to fill the case and seat a bullet on top. Modern BP loaders use a drop tube in some instances to consistently get more powder into a case, AKA compressed. BP revolvers get the cylinder filled and a ball seated resulting in a compressed load.

I don't know if BP was meant to be compressed, but for more than a 100 yrs it was routinely, safely done.

Now, I know Trail Boss says not to compress the powder in any load. So, TB is more energetic than BP. Has there ever been any trials or xperiments performed on the safety edge with reduced volume compressed TB loads?

I AM NOT ADVOCATING THIS AT ALL! I DON'T WANT ANYONE TO TRY IT! Only, human nature being what it is, there are those that push the limits. I'm just curious if anyone has ventured into this area and with what results.

Hogden says to fill the case to the base of the bullet, weigh that load, reduce by 70% as a start load then work up to the max weight you established, WITHOUT COMPRESSING THE LOAD.

Given that TB is more energetic than BP. Suppose you took 1/4 of the max weight you established, used an over powder card, with a filler over the card and seated a bullet such that it compressed the filler and powder (reduced volume of TB is now compressed).

I say this only to explain what I meant by "reduced volume compressed TB"

This is only an acedemic thought exercise. I know there are better way to get from here to there, but what if......

Skgreen said:

FWIW,,, An opinion found online:

It has been long understood that Hodgdon's Trail Boss powder should not be compressed and forum attempts some months ago were unsuccessful in trying to find out why that was the case, a warning or just a lesser but unexplained admonishment. The likely assumption was that it was a warning. But finally an explanation appearing in the June 2016 issue of Handloader magazine appears to provide the answer. In the article, Hodgdon's Ron Reiber is credited with the following: "Reiber cautions that Trail Boss does not respond well to compression and becomes erratic in its performance--not dangerous, just erratic." The article identifies a starting load of TB as 70% of the powder weight to the base of the bullet (which is the usual definition of a starting load) and then working up from there to max at the base of the bullet. However it is pointed out that pressure levels could become dangerous with TB and the .50 BMG if the powder formula is not followed, which I guess means do not compress when using with the .50 although there is no additional explanation.

Another opinion:

I've explained my own "oddities" with Trail Boss in several previous threads - particularly how erratic it was with normal/"Hodgdon-method" loads in .327 Federal.

My experience with (minor) compression was what Ron Reiber mentioned, but including the danger: Extremely erratic behavior.
Sometimes it was close to normal.
Sometimes it was way over pressure. (Small rifle primers in a revolver cartridge, randomly appearing like they got hit with 68k psi. View attachment 1111556)
Sometimes it just varied so much that accuracy was a fantasy, rather than an attainable goal.
Overall... completely unpredictable.

Erratic, wonky, unpredictable,,, Just doesn't sound like the thing to do.

Click to expand...

Thank you. I was unaware of the Handloader article. I should have done a better search before asking. I just wondered if anyone found if unpredictable could actually be predicted. Thanks for all the answers.