Trailboss question

[mdevlin53]

I am kind of confused about load data for Trailboss. I read a PDF that said fill the case to the line where boolit will be seated and that is your maximum charge. Pour that out and weigh it. then multiply by .7 and that is the starting load.

So for the 32-20 with a 90g PB RN Lee. I fill the case to the bottom of the boolit and weigh it and it comes out 4.7 grains x 70% = 3.29 so my load should be 3.9 to 4.7.

Now here is the rub, if you go to the IMR load data they give is 2.5 to 2.8 Why are they so much lower than the calculated weights?

Thanks for your help.
PS this load will be for a bolt action rifle.

[detox]

Liabilty reasons. Case thickness/capacity and boollit seating depth can vary .

[Whiterabbit]

IME trailboss accuracy nodes are WELL below casefill. In my case (7x57 and 460 S&W) casefull was around 16 grains, best accuracy was around 12 grains. Roughly. full case didnt get me anything near what I wanted.

your mileage may vary.

[44Vaquero]

Mdevlin53, I inclined to think that IMR is erring on the side of caution, due to the fact that the 32-20 is not a modern cartridge so to speak. Not knowing the condition of the rifle/pistol the load will be used in, they are deliberately being cautious. You may also note that the suggested load for the .32 Mag is 2.4 to 2.8 and it does fill the case!

I never gave the fill the case concept much credit anyway. I suggest you follow the load data as presented in the IMR data base and see what type of performance you get.

It has been my experience that Trailboss is good for 650 fps to about 850 fps regardless of caliber or bullet weight. I use it for .32 Mag, .38/357, 44 Spc/Mag and .45 ACP, 750 to 800 fps is my usual goal. If I need more power I move to another propellant.

[mdevlin53]

I am one for using published data for loading so I loaded some from 2.5 to 2.8 and I will let the rifle let me know what's best. I have loaded the 32-20 with a 115gr boolit and found that the trailboss had an accuracy edge over Unique and Titegroup so I thought I would start with the trailboss for the lighter projectile. If the rain holds off I will see tomorrow at the range.

[jsheyn]

From what I read trailboss was designed to be a "Safe" powder making a double charge imposible.

I load 215 SWC on top of 6gn of TB in my 41 mag. Not nearly a full case.

I would stick with published data and work up from there until you see demising returns or attain a desired level

[Guesser]

I cast Ideal 3118 and load it over 2.9 grains of TB for use in 4 Colt revolvers. It has proven to be a very accurate and serviceable load. I'm sure another couple 10ths would be OK but this works for me.

[303Guy]

Trail Boss is a fast shotgun class powder so too much of it spikes in pressure very early it seems. This causes boolit base upset which could destroy accuracy (being irregular). On the other hand, at the 'right' amount it may obturate the boolit to give good accuracy. You can see where the 'accuracy node' comes in and why it works best at very subsonic velocities. Although, in a larger case it might produce somewhat higher velocity because of the larger case capacity.

Very fast powders can do funny things in a bottle neck cartridge although I'd think the 32-20 is too small for the effect I've found, that being the neck expanding into rust pits in the chamber while the primer shows little flattening while a slower powder does not expand the neck while showing considerable primer flattening. I would not have noticed this high neck pressure effect if the chamber had been good.

[nekshot]

yup, trailboss is meant to go slow (real slow) any thing other than that from my experience is simply wasting powder and raising pressure. But I do prefer trailboss for going real slow.
nekshot

[.22-10-45]

Hello, 303Guy..I think you are spot on about low velocity/higher chamber pressure with TrailBoss. In a .236 (6mm Lee-Navy) Winchester-Lee straight-pull sporting rifle..using the Ideal 245498 100gr. g.c., with a start load of 10.0gr. H4227 up to max. load where groups turned into patterns..all case necks were powder blackened...yet muzzle blast was quite noticable. 10grs. TrailBoss gave best accuracy..left case necks clean & no noticable muzzle blast. There have been reports of big British double rifles being locked shut with low velocity TrailBoss loads.

[prs]

The published data for TrailBoss is relative to its Cowboy Action theme. Mouse phart loads for those that to avoid recoil. I have used the rule of thumb max loads (the max amount of powder adequate to just barely avoid compression) in several different rounds and no signs of over pressure (30-30, 32 SPL, 45 Colt, and even 40 S&W). Its kinda boring compared to Unique or real black powder; but makes a really nice plinking round in the 40 S&W. ALWAYS work your loads up to your goal or until signs of trouble or inaccuracy are noted.

prs

[quilbilly]

In my own testing of TB in various cartridges, I found that even if the charge slightly touched the bottom of the boolit, velocities on my chronography were all over the place (often 250 fps variance). At a 95% fill, velocities only varied as little as 30 fps. At a 95% fill, the velocities of the cast boolit were universally about 60% of a factory load of the same size jacketed bullet.

[Whiterabbit]

In my own testing of TB in various cartridges, I found that even if the charge slightly touched the bottom of the boolit, velocities on my chronography were all over the place (often 250 fps variance).

Probably explains my accuracy troubles at max fill.

[303Guy]

I've just measured my Brit case capacity of Trail Boss and it's 16gr. A load of 14.5gr under a 168gr boolit produced mild pressure signs on the primer. 5gr of AS30N (Clays) hardly showed signs of powder being present.

Here's the comparison
70045

Although a lot more primer flattening occurs with slow powder full power loads, I would consider my load max and depending on how it shoots, might reduce it some. These are with pretty hard alloy so boolit deformation is not a consideration.

70047
Here one can see the base is not distorted from over-pressure.

[mdevlin53]

Well the range results show that this rifle has no taste for 2.5-2.9. I shot 50 today and been better off putting the little 93 grain boolits in a shotgun hull. Trailboss was the accuracy winner with the 115 grain boolit but I think I went to 3.5 with that. I am going to load another spread from 3 to 3.5 and give that a try. Then its time to decide which one thing to change. Perhaps the powder or the seating depth. I will play with it until the gun says it likes it.

[Harry O]

I experimented with Trail Boss and the 32-20 when the powder first came out. It works great for light loads that duplicate present day factory loads. I use the 2.8gr load in my lightweight Colt PPS. That gun cannot handle anything stiffer than factory loads or handloads that duplicate the factory loads (it was bent once -- but has been fixed).

I also have a rechambered S&W NewModel 16 that I tried stiffer loads in. It is a much stronger gun than the Colt. I worked it up to 4.5gr. I did not chrono it, but it felt pretty much like my moderately stiff loads using SR4756. I did not go higher because that was full to the base of the bullet without compression. I did not stay with it because the 4756 load was more accurate.

In other words, the loads given by the manufacturer are for Cowboy Action loads. They are NOT meant to be full pressure loads. Most CAS shooters use light loads. You can go over their recommendations if YOU know what you are doing, what to look for, and work up slowly.

[Kansas Ed]

I've been experimenting with TB in a couple of obsolete rounds...like the 38-72. What we noticed was that the chronograph started showing a fairly substantial LOSS of velocity when the powder got to the max fill line as calculated by the .7 to case full rule. My assumption was that the powder was starting to slightly compress due to minute calculation error. As has been stated above, accuracy seemed to be best substantially below that point and closer to 100fps under what velocity maximum was. It does amazing accuracy though out of some of the larger calibers but seldom over about 1300 fps. Everything we've tried it in so far the velocity maxes out about 1300 fps. A good powder with limiting factors.

Ed

[fouronesix]

Qs about Trailboss come up often. Usually the same questions with the same responses. No big mystery about Trailboss if you treat it like any other very fast powder in the Bullseye/700X class of powders. It is very fast and it has very low density.