Trailboss in a 303 Brit


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challenger_i
October 2, 2009, 11:02 PM
Has any one used Trail Boss for a cast-bullet reduced load ?

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Gadzooks Mike
October 2, 2009, 11:37 PM
There are a few loads for that over on loaddata.com for 30-30. I would think one of those would work for a 303 Brit as well. I use Unique in my 303 Sav, have never tried Trail Boss.

challenger_i
October 2, 2009, 11:50 PM
Since my discovery of Trail Boss, I have converted to it exclusively, in my 45 Colt, 45 ACP (loads for a Webly Mk V) and my .38 Smith&Wesson, with very satisfactory results.

I had seen some cast load statistics, for Mil Surp cartridges, and most are low-volume powders. As Trail Boss is a high-volume, low-power propellant, I was curious as to its suitability in the 303 Brit, with a 170gr cast bullet.

I'm shooting this in a really slick Martini Enfield, so I am really not too anxious to try working up a load. Right about now, I am REALLY missing my P-14 Enfield!!!

rcmodel
October 3, 2009, 02:19 PM
Hodgdon shows one 30-30 Trail Boss load with a 160 grain cast bullet.

6.5 grain = 997 FPS @ 20,500 CUP.
9.0 Max = 1,195 @ 29,100 CUP.

A little extrapolation of case capacity's should get you in the ball park.

rc

navaide
October 3, 2009, 04:02 PM
I started loading my 338/378 Weatherby cases with 85% volume Trail Boss, and a .338 cal 200gr. gas checked bullet. The powder weight works out at 31.5 grains.
This combo is a hoot to shoot!

Robyn
November 17, 2009, 09:35 PM
Hi
I thought I would share this.
303 british
no4 mk1 rof
9 g trail boss
cci primer
lee 185g w/w gaschecked alox lube

first 15 shoots in 6 inch diameter at 200 yards...
I am still working on this load
but it looks great

Kernel
November 17, 2009, 11:44 PM
6.5 grain = 997 FPS @ 20,500 CUP.
9.0 Max = 1,195 @ 29,100 CUP.
:confused::confused::confused:
I wonder why Hodgdon calls 9 grains a “Max“. Pressure is only 29,100 CUP. The .30-30 is good to 38,000 CUP. Pressure wise, is 9 grains of Trail Boss really a maximum, or is it just an arbitrary place where Hodgdon decided to stop load development?

fireman 9731
November 18, 2009, 12:35 AM
I wonder why Hodgdon calls 9 grains a “Max“. Pressure is only 29,100 CUP. The .30-30 is good to 38,000 CUP

One of Trail Boss's best attributes is also its downfall. Its Bulk. You aren't supposed to compress it at all, so my guess is that 9grs in a 30-30 case is just about full.

Kernel
November 18, 2009, 12:49 AM
^^^^^
That's what I first thought, but come on. A empty .30-30 case holds 45 grains of H2O. Trail Boss can be THAT bulky.

Remo-99
November 20, 2009, 11:47 PM
but come on. A empty .30-30 case holds 45 grains of H2O.

And an empty 30-30 case holds 14 grains of Trail Boss when filled to the brim or ~12 grains powder capacity when allowing for seating a bullet. Therefore the IMR/Hodgdon listed max of 9 grains puts it at around the 75% of usable powder capacity.

When developing a lead bullet TB load for my 308win, there was no data for it, so I took the starting load for 30-30 and added half a grain to allow for the larger case and worked up from there.
A 308win has a full case of TB at 18 grains and powder capacity at ~15 grains. atm I'm at 14 grains with the load workup, but this seems to be moving further away from the accuracy point, where I found at 11 grains was the tightest groupings or approx 75% of powder capacity.

In comparison the 303brit has a full case of TB at 16.5 grains and ~14.5 grains at powder capacity. 75% of this would be approx 10.8 grains. I would suggest start at 7 grains and work up from there (150gr to 180gr lead).

btw, I found I didn't have need to use gaschecks with TB as it's a fairly low energy single based smokeless powder, but I am using lead bullets sized at .311" in a .308" barrel.

Sunray
November 21, 2009, 02:47 AM
Slug the barrel before you do anything else. Lee-Enfield barrels can measure between .311" and .315" and still be considered to be ok. Over .315" the barrel is shot out.
Go here. http://www.303british.com/id16.html
"...I thought I would share this..." Where did the data come from?
Neither a .30-30 nor a .303 Savage have anything whatever to do with the .303 British.

Kernel
November 21, 2009, 02:59 AM
Remo,

Thanks for setting me straight. Trail Boss IS that bulky. Got me curious. So I went to Lee’s web site and got the density of Trail Boss from their VMD chart.

Trail Boss is 0.2172 cc/gr. The inverse is 4.604 gr/cc.

Water (H20) is 1 gram/cc. 1 gram = 15.43 grains. So, the density of H2O is 15.43 gr/cc.

Volumetrically, a cc of TB per cc of H2O is 4.604/15.43 = 0.2984 gr TB/gr H20.

An empty .30-30 case holds 45 grains of water.

45 gr H20 x 0.2984 gr TB/gr H20 = 13.4 gr of Trail Boss

Which is what you said (more or less) what a full .30-30 case would hold.

Seat a 160 gr FN bullet (0.900” long) into that case, it holds 37.7 grains of water. A 80% load density is 30.2 grains. 30.2 x 0.2984 = 9.0 grains of Trail Boss. Exactly what Hodgdon said was the maximum load.

A 58% load density is 21.9 grains H20, which equals 6.5 gr TB. Hodgdon’s starting load. Interesting. I think we cracked the “Trail Boss Formula”, at least how it relates to the .30-30 Winchester.

Using this same methodology with .303 British, with the same 160 gr bullet, and a 2.800" COAL, the starting load would be 8.8 grains of Trail Boss (58% LD) and the max would be 12.2 grains (80% LD). Pressure would be no where near maximum. Velocity I’d guess to be somewhere around 1300 fps for the max load.

roo_ster
November 21, 2009, 10:24 PM
I started loading my 338/378 Weatherby cases with 85% volume Trail Boss, and a .338 cal 200gr. gas checked bullet. The powder weight works out at 31.5 grains.
This combo is a hoot to shoot!

So, there is hope for my .375H&H cast bullet load & TB and maybe even for my lead ball & TB load.

444
November 22, 2009, 02:07 AM
Probably not adding anything to the thread, but I worked up some subsonic .223 loads using Trailboss.
I started using 77 grain bullets and everything went great. Then I went to 100 grain bullets and started getting huge swings in velocity.
I didn't know that you couldn't compress Trailboss. I figured this out on my own and later read it.
So basically I am just confirming that you don't want to compress Trailboss. I guess I should have done more research into the matter before blazing ahead.

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