Trail Boss 70% Rule

[Spokerider]

I have a question about Trail Boss powdwer and the 70% rule

http://www.imrpowder.com/PDF/Trail-Boss-data.pdf


Is this formula appropriate, in other words....safe to use, when choosing a reduced load for a heavy boolit? Im wondering if the 70% rule assumes *normal* bullet weights. Would the weight of a heavy boolit cause pressures to rise to unsafe levels?

I am wanting to load 240gr boolits in .357 Max cases for 900-1000 fps.

[Bosshaug]

I would just give IMR a phone call. The tech people do answer the phone and can give you an answer right from the source!

[prs]

Good advice above, but I doubt your goal for that load can be met with TB; safely or otherwise.

prs

[Jim Flinchbaugh]

following the 70% rule, I loaded up some of my Argentine 7.65x53 a week ago. (14 grains)
Gave me 1150fps with 205 grain boolits. I dont think yer gonna meet your fps even with compressed loads

[DragoonDrake]

I thought you are not supposed to compress trailboss.

[rockrat]

I would think it might work. I have shot heavier boolits in my max. , 270gr. just not with TB, but 2400 powder, but at 1700fps.
If you have a chrony, try it and see. In other cases, I have found my best accuracy at more than 70%
Work up your loads and see what it does, you might be suprised

[zuke]

I loaded up 13 gr for my 303 brit inder a LEE 180 wearing a PP.
No sign's of pressure

[quilbilly]

If you compress TB, strange things will happen. In my 338WM, 95% give consistent velocities varying by less than 30 fps. When I increased that to 100%, average velocity went down and it varied by over 90 fps either side.

[r6487]

i have some penn bullets 230 grain 357 I want to run at 1000-1050 thru a handy rifle with 9mm can on it. I'd be interested in what you come up with. I am running 180 grain XTPs with 5.7 grains of unique, but use TB for 308 subsonic, so I have it available

[stubshaft]

I don't think you have the case capacity even if you go to 100% to get 900fps out of the 357 with a 240.

[MT Gianni]

From a friend who called the manufacturer and uses the stuff the 70% rule is for straight sided cases which is all that TB was recommended for.

[stubshaft]

The following is from the Trailboss website.

TRAIL BOSS

Trail Boss is designed specifically for low velocity lead bullet loads suitable for Cowboy Action shooting. It is primarily a pistol powder, but has some application in rifle. It is based on a whole new technology which allows very high loading density, good flow through powder measures, stability in severe temperature variation and most importantly, additional safety to the handloader.

The IMR data also suggests that the 70% rule is for the starting load.

[adrians]

following the 70% rule, I loaded up some of my Argentine 7.65x53 a week ago. (14 grains)
Gave me 1150fps with 205 grain boolits. I dont think yer gonna meet your fps even with compressed loads

jim, did you max out at 14 or is that where your at now,?
iv'e been thinking of trying TB in my 1891 argentine, :twisted:[smilie=s::evil:

[johnly]

From a friend who called the manufacturer and uses the stuff the 70% rule is for straight sided cases which is all that TB was recommended for.

There are recommended loads from Hodgdon/IMR for 30-30 and other bottleneck cases. I agree that you won't find loads for TB for bottleneck overbore cases like the 257 Weatherby, but 12 grains in a 30-06 case with your favorite CB will likely shoot a very nice group.

John

[uscra112]

Out of curiosity I did exactly as the O.P. planned - a subsonic heavy boolit from my 12" .357 Max Contender. Idea being to have a quieter load that would really clobber the chucks in the garden. A 100% density load of T.B. (7 gr. if I remember right) fell just short of 1000 fps., seating a 200 gr, boolit .400" into the case. Accuracy wasn't anything to write home about either. In a rifle barrel it might be better, both velocity and accuracy-wise. In the end my best was 6 gr. Unique. That also wasn't too terribly accurate. So far the next crop of chucks will just have to meet Mr. Hornet, like last year. The neighbours will have to get used to the noise.

Just ran that7 gr. T/B load thru Quickload - it calculated to 22K psi. OK for the Max., which is allowed to go to 40K.

[Fishman]

jim, did you max out at 14 or is that where your at now,?
iv'e been thinking of trying TB in my 1891 argentine, :twisted:[smilie=s::evil:

Somebody, who's name escapes me, posted some excellent information on pressure curves with a few powders including Trailboss. It has a very abrupt spike in pressure at first, although it doesn't produce high pressure. It is a very fast powder though. That quick spike in pressure made me think twice about trying it in my Argentines and Swedes. One of the theories about low numbered Springfields is that they shatter because the pressure wave hits them like a hammer strike. I am NOT an expert by any means and maybe someone who is can clarify. I am currently only using Trailboss in "modern" guns.

[NSP64]

I started using TB in my 45-70 14" contender and settled on 16.0 gr (out of 21.0 gr available) which is 76% load and it shoots good. 220 gr boolit 1350 fps.
I started with unique and was getting squib loads from the tree stand.

[Frank V]

I would just give IMR a phone call. The tech people do answer the phone and can give you an answer right from the source!

This is what I'd do too! Some of the loading manuals say that if a powder isn't listed with a particular bullet or cartridge it's often because the technitions found it unsuitable?
Frank

[Jim Flinchbaugh]

jim, did you max out at 14 or is that where your at now,?
iv'e been thinking of trying TB in my 1891 argentine, :twisted:[smilie=s::evil:


Thats all I've tried so far, like a bb gun-- pooot!

The range master liked it, said I'll never hurt his gongs :mrgreen:

[dnotarianni]

Light or heavy bullet won't matter as you will never get to the overpresure point. Compressing Trail boss lowers FPS as you are crushing and breaking the donuts. Trail boss while is a great powder for light loads is still a back Powder substitute.

[R.M.]

TB is not a BP substitute. It is a smokeless powder with lots of bulk.

[dnotarianni]

TB is not a BP substitute. It is a smokeless powder with lots of bulk.

I stand corrected. Being designed for lead bullets for cowboy shoots I mistakenly thought it was a black powder sub.

Dave

[PAT303]

I've shot lots of TB in the 303,6.5swede and 8x57 and I've tried the 70% rule but in the end I just fill the case up to the shoulder and shoot it.I've never got any pressure signs ever shooting TB in any case regardless of boolit wieght,for low power loads TB is the safest powder there is. Pat

[uscra112]

I've shot lots of TB in the 303,6.5swede and 8x57 and I've tried the 70% rule but in the end I just fill the case up to the shoulder and shoot it.I've never got any pressure signs ever shooting TB in any case regardless of boolit weight,for low power loads TB is the safest powder there is. Pat

Might be safe so long as you're using strong actions. A hypothetical 8x57 Mauser load calculated to 34,000 psi in Quickload, which won't blow up a 98 Mauser, but a 100% density load in an old .45-70 Trapdoor would very likely induce spontaneous disassembly. 34K psi is way more than any black powder I know of.

And those loads will run you through a canister awfully fast. A full case in either example is about 18 grains, and since there's only 9 oz. in a can, that's about 215 charges per can. Comparable performance using Red Dot would give 500 loads per can.

[PAT303]

I bought a bulk lot thats been going for a while,yes RD will work but like I posted TB is the safest powder for that type of reloading,I'd rather pay a few dollars more and be free of the threat of a double charge forever. Pat

[303Guy]

Over here it costs about the same per grain of powder as other powders. Comes in a bigger container with less weight at a lower price. But then we pay heaps for powder here down under.

That sudden pressure spike is something to be careful of. It's not the pressure attained so much as the rate at which it is attained. It's the shock factor. It's what shatters brittle substances like glass or perhaps over hardened steel actions. It's also what makes a small hammer created dents in steel - even hardened steel.