I don’t know why this powder keeps getting talked about for our rifles. It’s not accurate. Its only attribute is that you can fill a case full of it and get low recoil and low velocities with a relatively clean burn. It is not, nor was it designed to be a substitute for wood powders like King’s semi smokeless or Losmoke. It should not be compressed and very bad things happen when it is duplexed. It is simply not a useful powder for our sport.

40 Rod

You can see the stretch line in the case near the head when the loads are warm in the Stevens 44.  The other infallible indicator is that after a few boxes of ammo through either a 44 or a Ballard, the lever starts drooping, especially with no cartridge in the chamber.  On the 44, you can pull the breechblock back or push it down and see a sliver of daylight between the breech face and the end of the barrel.

Fired primers are not good indicators for these weak actions.

Graeme Wright in his Shooting The British Double Rifle reports locking up a double rifle using this powder.  Alot of people..myself included had thought this powder on account of it's low velocity to be of low pressure also.  This is not the case.  However, I have found over the years that blanket statements are rarely true.  While I have used TB in revolver ctgs. from .32 WCF thru .45 long-colt..and have gotten better accuracy with other powders..to say it is an inaccurate powder is not true.  While it may be my own dumb luck..I have worked up loads in an original Winchester-Lee straight-pull sporting rifle using this powder.  10grs. will group the Ideal 245495 100gr. g.c. into 3/4" at 50yds. and 1 1/4" at 100.  This load shoots to the open buckhorn rear/german silver blade front sights.  Interestingly, H4227 also was most accurate using 10.0grs..and also shot to sights...However, case necks were badly smoked and muzzle blast was evident.  With TrailBoss..even the low start loads left necks clean and bright with hardly any muzzle blast..could be the higher pressure/faster burn?

Trail Boss appears from Quickload database info to be as fast as Red Dot, but with much more bulk and lower specific energy.  

This issue comes up time after time on other forums, and I've run many trials thru Quickload, using small cartridges and big.  Bottom line is that a 100% load density always gives very sharp pressure rise to about 30,000 psi, which might not immediately damage a 44 in .25-20 Stevens, but would be pretty tough on one chambered .32-40, or even .32-20.      

I also have relegated it to plinking loads, just to use it up.  Accuracy in all my trials in .25-21 and .38 Special (for my Colt O.M. revolver) was poor.  It also smells unpleasant to me.

I'm more sanguine about the old 44 than many folks, but I'd suggest not exceeding 70% load density with TB in it.   Subsonic loads are TB's forte.  It is too fast a powder to load up to the 1450fps grail velocity for Schuetzen.  Indeed, it is so bulky that a 100% density load only calculates to 1300 or so. 

As far as pressure signs go,  I would not expect to see anything until you were way beyond safe pressures in the old 44.  Ballards I will not speak to.  I don't know. 

Yes, the stretch marks "1.4" above the head" is a sign of the action stretching under excess pressure OR a sign of excess head space. If the brass is sized to a crush fit in his chamber then it's a sign that the action is giving under pressure.
Jeff

Trail Boss has an extremely fast pressure curve. Pressure might be moderate but it spikes extremely fast. Not good in our guns or our sport.