Thoughts on TinStar powder compared to Trail Boss
Here's some info some may find interesting. Doing some checking with Quickload, two things become apparent.
First, the people who claim that TB is safe at 100% loading density in any cartridge are probably correct, except perhaps in the very weakest, junkiest firearms made originally for BP loads.
Doing a quick check of a .50 BMG round with an 800 grain bullet seated only .200" deep, 85 grains of TB is 100% load density, and gives 38,200 PSI and a muzzle velocity of 1520 FPS in a 26" barrel. Interestingly, raising the bullet weight to 2000 grains raises the pressure only a bit, to 39,500 PSI with M.V. of 978 FPS. Going for full-on crazy with a bullet of 7000 grains (one pound) gives 40,200 PSI and 525 FPS. This is all with the same 85 grain powder charge.
Second, according to Quickload, TinStar has almost exactly the same burning characteristics as TB on an identical weight basis. A charge of 85 grains of TinStar gives similar numbers as TB in these .50 BMG examples, and simulations on other cartridge/caliber combinations I have tried give similar results.
HOWEVER, and this is a very big deal, TinStar is much less bulky than TB. A charge weight that is 100% density with TB is only 67% density using TinStar. If we raise the charge with TS to 100% in our three .50 BMG examples, we get a charge weight of 126 grains and pressures of 66,000 to 68,000 PSI. This is not enough to bother either a Browning MG or a good bolt gun in this caliber, but it's an indication that TinStar carries some serious risks for the handloader with either a cavalier attitude or incomplete information. I'll explain:
Let's switch to the .45 Colt cartridge with 250 grain cast bullet. A charge of 8.9 grains of Trail Boss gives 100% loading density, 16,000 PSI, and 900 FPS out of a 5" barrel. This is 2,000 PSI above SAAMI Spec, but probably not enough to damage an original Colt.
Things get scary when we switch to TinStar. The same 8.9 grain charge gives only 67% loading density but a pressure of 17,400 PSI. Raising the load density to 100% gives us 13.5 grains of TinStar which gives a pressure of 38,000 PSI. Bye-bye original Colt...
TinStar is an interesting powder that can be used for reduced loads in modern guns by shooters who want more oomph than TrailBoss can deliver, but IMO in these cases there are always better choices.
As an example, a 100% density TinStar load in my beloved .500 S&W (24.5 gr.) with my 400 grain Alley Cleaner bullet gives 1200 FPS at 50,000 PSI. At an 80% loading density (19.6 gr.), we get 1060 FPS at 34,600 PSI. Neither of these loads will hurt the gun, but a powder like Ramshot Enforcer will give 1200 FPS at 23,000 PSI, the same velocity as the top TinStar load at less than half the pressure.
Even if TinStar were half the price of other powders, I don't think I'd ever use it. I think we're going to see some original Colt SAAs (and others) blown up with this powder by folks who mistakenly believe they can treat it like Trail Boss...
Here's some info some may find interesting. Doing some checking with Quickload, two things become apparent.
First, the people who claim that TB is safe at 100% loading density in any cartridge are probably correct, except perhaps in the very weakest, junkiest firearms made originally for BP loads.
Doing a quick check of a .50 BMG round with an 800 grain bullet seated only .200" deep, 85 grains of TB is 100% load density, and gives 38,200 PSI and a muzzle velocity of 1520 FPS in a 26" barrel. Interestingly, raising the bullet weight to 2000 grains raises the pressure only a bit, to 39,500 PSI with M.V. of 978 FPS. Going for full-on crazy with a bullet of 7000 grains (one pound) gives 40,200 PSI and 525 FPS. This is all with the same 85 grain powder charge.
Second, according to Quickload, TinStar has almost exactly the same burning characteristics as TB on an identical weight basis. A charge of 85 grains of TinStar gives similar numbers as TB in these .50 BMG examples, and simulations on other cartridge/caliber combinations I have tried give similar results.
HOWEVER, and this is a very big deal, TinStar is much less bulky than TB. A charge weight that is 100% density with TB is only 67% density using TinStar. If we raise the charge with TS to 100% in our three .50 BMG examples, we get a charge weight of 126 grains and pressures of 66,000 to 68,000 PSI. This is not enough to bother either a Browning MG or a good bolt gun in this caliber, but it's an indication that TinStar carries some serious risks for the handloader with either a cavalier attitude or incomplete information. I'll explain:
Let's switch to the .45 Colt cartridge with 250 grain cast bullet. A charge of 8.9 grains of Trail Boss gives 100% loading density, 16,000 PSI, and 900 FPS out of a 5" barrel. This is 2,000 PSI above SAAMI Spec, but probably not enough to damage an original Colt.
Things get scary when we switch to TinStar. The same 8.9 grain charge gives only 67% loading density but a pressure of 17,400 PSI. Raising the load density to 100% gives us 13.5 grains of TinStar which gives a pressure of 38,000 PSI. Bye-bye original Colt...
TinStar is an interesting powder that can be used for reduced loads in modern guns by shooters who want more oomph than TrailBoss can deliver, but IMO in these cases there are always better choices.
As an example, a 100% density TinStar load in my beloved .500 S&W (24.5 gr.) with my 400 grain Alley Cleaner bullet gives 1200 FPS at 50,000 PSI. At an 80% loading density (19.6 gr.), we get 1060 FPS at 34,600 PSI. Neither of these loads will hurt the gun, but a powder like Ramshot Enforcer will give 1200 FPS at 23,000 PSI, the same velocity as the top TinStar load at less than half the pressure.
Even if TinStar were half the price of other powders, I don't think I'd ever use it. I think we're going to see some original Colt SAAs (and others) blown up with this powder by folks who mistakenly believe they can treat it like Trail Boss...
