Loading for the .45/70 Bridger Line Throwing Gun.


January 23, 2011, 07:29 PM
I have a Naval co. Bridger line throwing gun and was wondering if anybody knew anything about the blank cartridges for it. They are black power and come in different loads, Heavy, Medium, Light and Extra Light. I am interested in reloading these and have 3 boxes of expired shells I want to refresh with a new primer and powder. I have experience loading for smokeless powder and all the equipment to do so. Just wondering if anyone else has looked into this. Thanks

Naval co. Website for the Bridger http://www.navalcompany.com/linegunkit.htm

I hope I put this in the correct place.

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January 23, 2011, 08:08 PM
I saw an older version of this about a year ago in a gun shop, also in the Seattle area. It was based on a 1886 Winchester lever action, chambered for the .45/70 blanks, & was in a fitted wooden crate with extra lines, etc. Very neat, hope you find the information you're looking for.

January 24, 2011, 09:05 PM
The 45 denotes caliber and the 70 denotes 70 grains of black powder,the correct max charge should be 70 gr black powder,contact the manufacturer of the linethrower first for a recomended load.

January 25, 2011, 08:54 PM
I have a line gun that's older than dirt. It uses a small bp charge to set off a rocket to carry the line.

I would contact the mfg. and see what they recommend and I would not use smokeless unless they approve it.

January 25, 2011, 10:26 PM
I pulled the cartridge apart and poured the powder onto the scale and it weighed out at 54.2 gr but I am still not sure what kind of black powder it is. also the cartridge had a small piece of 1/4 inch thick cork with what looks to be wax over it. It could be salt water residue though. I will try and contact someone at Naval Co. again and ask them. I called once already and got the run around about how I should just buy the ammo they make. Thanks again guys.

January 26, 2011, 02:06 AM
"Life Saving" is for line-throwing guns. It looks like your best option is the slowest brand of Fg powder you can find, or some FA or 2FA blasting powder, if you can find it.


I found this on a thread on the DoubleGun board. I know I've seen similar elsewhere, but I cannot find it at the present.

From an old NRA Handloaders Guide; Screen opening for DuPont sporting BP;
Screen Opening (square mesh)
Whaling ----.4410"--.1560"
Life Saving-.1310"--.0650"
FG ---------.0689"--.0582"
FFG --------.0582"--.0376"
FFFG -------.0376"--.0170"
FFFFG -----.0170"--.0111"


I just found this, edited down from http://thefiringline.com/forums/showthread.php?t=356628

or another source, possibly the original at http://www.freepyroinfo.com/Pyrotechnic/Black_Powder/Blackpowdergrades.txt

Sporting Grade Black Powder -- "g" type powders

Powder Grade pass screen, holding, stays on, passing

Whaling 32/64" mesh 3% 4 mesh 12%
Lifesaving 6 mesh 3% 12 mesh 12%
Cannon 6 mesh 3% 12 mesh 12%
Saluting 10 mesh 3% 20 mesh 12%
Fg 12 mesh 3% 16 mesh 12%
FFg 16 mesh 3% 30 mesh 12%
FFFg 20 mesh 3% 50 mesh 12%
FFFFg 40 mesh 3% 100 mesh 12%
FFFFFg (no longer manufactured by Goex)


"A" Blasting Powder
used mostly by pyrotechnicians and for some specialized quarry work

Powder Grade passes screen holding stays on, passing

FA 20/64" mesh 3% 5 mesh 12%
2FA 4 mesh 3% 12 mesh 12%
3FA 10 mesh 3% 16 mesh 12%
4FA 12 mesh 3% 20 mesh 12%
5FA 20 mesh 3% 50 mesh 12%
6FA 30 mesh 3% 50 mesh 12%
7FA 40 mesh 3% 100 mesh 12%
Meal D 40 mesh 3%
Meal F 100 mesh 3%
Meal XF 140 mesh 3%

*** Shows maximum percentages held or passed by the sizing screens.


Commonly used Black Powder Grain Mesh Sizes
FA 3 - 5
2FA 4 - 12
3FA 10 - 16
4FA 12 - 20
5FA 20 - 50
6FA 30 - 50
7FA 40 - 100

Sporting Grades (G) Grain Size (in mm) mm)

Cannon Grade
1FG 1.68-1.19
2FG 1.19-.59
3FG .84-.29
4FG .42-.15
5FG .149

Blasting Grades (A) Grain Size (in mm)
1FA 8.0-4.0
2FA 4.76-1.68
4FA 1.68-.84
5FA .84-.297
7FA .42-.149
Meal D .42
Fine .149

Except where noted in inches, the screen sizes are in wires per inch. The
higher the mesh number the smaller the opening size. Note that, for any
given number of "F"s, that the blasting powder is much coarser.

If you ignore the 'F' numbers, for a given measured grain size, the blasting
powder burns faster than the graphite-inhibited sporting powder; That's
partly because of the inhibiting action of the graphite, and partly because
of the geometry of the grains.

Blasting powder is less dense because the grains are more irregularly
shaped; they take up more volume for a given weight of powder. Blasting
powder grains also have a lot of rough edges. Rough edges both inhibit
packing of grains, and offer lots of easy-to-ignite sites on each grain.
The combination of more air space between grains, and the rougher surfaces
of the grains promotes faster burning.

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