John Bass Big Bore Gun (Big pictures!)

[Mattox Forge]

I acquired a Bass gun, or what is left of it, from a friend last year. He purchased it from IMA. It was part of the large cache from Nepal.  It suffered near destruction during its time in Nepal, being the object of silver looters. I presume that the butt was broken off to expedite the theft of the silver buttplate, triggerguard, and escutcheon,  whereas the forend cap and wedge escutcheons were pried off the stock. Who knows what happened to the lock. In any case the relic offers a unique look at the architecture of a top quality English gun we would not otherwise get. Who would dare saw their big bore rifle in half and unsolder the rib off the barrel? The pictures are large, sorry.

Mike

Bass Barrel Notes
Bore: ~7 3/4; Land dia: .850; Groove Dia .890
Length: 32 1/32
Breech across flats: 1.393
Muzzle across flats: 1.289
Swamp waist located at 17.712 from breech 1.185 across flats (parabolic swamp breech to muzzle bore, muzzle to breech bore)
Rifling: ¾ turn in length of barrel

[Mattox Forge]

Breech and muzzle photos

[Mattox Forge]

I plan on building a gun using the barrel and a Mortimer lock I bought from my friend at the same time. I styled it after Mortimer's work.
Mike

[rich pierce]

Cool project!  If you haven’t re-cut rifling before, I or several others here could help walk you through it.

[Mattox Forge]

Cool project!  If you haven’t re-cut rifling before, I or several others here could help walk you through it.

Rich,

Thanks for the offer. What is involved in re-cutting the rifling? I am all ears so to speak. I have a number of restoration projects that need this.

Mike

[Daryl]

The first thing I would do with the bore, is to buy some maroon ScothBrite cloth and use a square patch of it, lubed with WD40 and push it on a jag up and down the bore about 40 times,
re-lube and maybe another 40 times full length pushes, clean the bore with wet then dry patches and have a look. It might not need re-cutting (freshing) the rifling.
Did you measure the bore from a slug down the bore a ways from the muzzle, or just measure the muzzle?
Reason I ask, is that the muzzle appears to have been filed in the grooves deepening them right at the muzzle. Measuring there will not give an accurate measurement.

[rich pierce]

Cool project!  If you haven’t re-cut rifling before, I or several others here could help walk you through it.

Rich,

Thanks for the offer. What is involved in re-cutting the rifling? I am all ears so to speak. I have a number of restoration projects that need this.

Mike

Daryl is spot on. My rule of thumb is whether after a good cleaning and scotch-brite treatment, a patched ball can be seated with even pressure to the breech, then pushed back out from the breech end, and the patch is intact.

The muzzle looks a little rough but the rifling looks strong.

If a re-cutting is warranted, the basic steps are to pour a lead slug about 3” long on a thick ramrod, much as one would for lapping. Then hardened toothed cutters are inletted into the slug. One in line with a groove which appears as a raised spline on the lead slug, and a wider one aligned with one land.

These are leveled and raised in their inlets until they barely start cutting with lube. Typically a plan is made to cut grooves and lands in a sequence till all are cut and the cutters no longer are making tiny shavings like those made with a fine file. Then cutters are raised by placing shims of about 0.001” thickness under the cutters and the process is repeated. Eventually it is cutting end to end with even resistance. Barrel is cleaned and inspected to see if all pits are removed. Lapping usually follows. Figure 8 hours of work for removal of 0.005-7”. A new lap will need to be cast if more cutting is needed to remove pits.

More detail can be offered if needed. This is just an overview.

[Mattox Forge]

I have some more detailed notes on the bore measurements I took. A linen patched .845 lead ball almost passes through the entire bore without too much dragging. The bore has not been scotch brited or polished at all, just bore brushed with a bronze brush.

Bass Rifled Barrel
31.1875 to breech face
31.4375 to touch hole
9 Groove ¾ turn in 31.1875 (32.0625-.882)
Pos from Muzzle   Groove dia   Bore Dia
0.000                   .955                   .870
.125                           .917                   Tapers down to
.250                           .901   
.375                           .896   
.500                           .896            .864
.625                           .896                   constant



It has a carefully filed out crown. Here is a clay impression of it.


I'll start with a good scotch briting.

Mike

[Mattox Forge]

Cool project!  If you haven’t re-cut rifling before, I or several others here could help walk you through it.

Rich,

Thanks for the offer. What is involved in re-cutting the rifling? I am all ears so to speak. I have a number of restoration projects that need this.

Mike

Daryl is spot on. My rule of thumb is whether after a good cleaning and scotch-brite treatment, a patched ball can be seated with even pressure to the breech, then pushed back out from the breech end, and the patch is intact.

The muzzle looks a little rough but the rifling looks strong.

If a re-cutting is warranted, the basic steps are to pour a lead slug about 3” long on a thick ramrod, much as one would for lapping. Then hardened toothed cutters are inletted into the slug. One in line with a groove which appears as a raised spline on the lead slug, and a wider one aligned with one land.

These are leveled and raised in their inlets until they barely start cutting with lube. Typically a plan is made to cut grooves and lands in a sequence till all are cut and the cutters no longer are making tiny shavings like those made with a fine file. Then cutters are raised by placing shims of about 0.001” thickness under the cutters and the process is repeated. Eventually it is cutting end to end with even resistance. Barrel is cleaned and inspected to see if all pits are removed. Lapping usually follows. Figure 8 hours of work for removal of 0.005-7”. A new lap will need to be cast if more cutting is needed to remove pits.

More detail can be offered if needed. This is just an overview.

This is a fascinating technique. I have a belted ball barrel that does need to be refreshed, and this sounds like the way to do it.

Mike

[Daryl]

.873 is a 7 bore. An 8 is .835" or so.
So - it appears the bore is .864 and the grooves are .896"?
Groove depth is .016".
That makes more sense. So - it is roughly a 8 1/2 bore or -7 bore.
An 8 bore ball of pure lead weighs 16 divided by 8 = 2 ounces or 436.5 x 2 = 875gr.
A proper mould for this barrel would be in the .850" range and somewhere near 930gr.(just a guess)

[Mattox Forge]

I have .850 balls that are a good fit with a .01 linen patch.
Mike

[Pukka Bundook]

That's a dandy barrel, and am sure it won't need freshing,  just polishing up a bit.

It will make a grand rifle, and you have chosen a good one to copy!
Looking forward to seeing your progress, Mike!

[Longknife]

FYI, Ther are no elephants in Virginia, 

[Mattox Forge]

Ahh, it's for bear.

[Daryl]

A .01" patch? 
I'm sorry but that is just hilarious.  A ball that is .014" smaller than the bore & you are going to use a .010" patch?

[smylee grouch]

  Yep, you might have to carry it with the muzzle up! 

[Mattox Forge]

A .01" patch? 
I'm sorry but that is just hilarious.  A ball that is .014" smaller than the bore & you are going to use a .010" patch?

No idea what I will shoot in it. That's just all that will go all the way through the bore right now without getting jammed.  With a 1:41 twist it doesn't seem like a ball will do well at all unless really light charges are used.
Mike

[smylee grouch]

I think there were Mortimer (sp) rifles of very large bore with that fast of twist that shot well but as you say I think that was with small for cal. powder charges.

[Mattox Forge]

I am not sure why they used such fast twists. So it will be interesting to see what it will take to get it to shoot well. A light charge for that gun will still be around 150 grains of 2F.
Mike

[Mike Brooks]

All germanic jeagers I have measured are 1 turn in the length of the barrel. It must have worked.

[Daryl]

I am sorry if I sounded condescending in my previous post. I see absolutely zero use for a .010" patch - for anything, in any bore size with any sized round ball.
In my .32, .36, .40 and .69, when using bore sized or even slightly larger balls, I still used the 10 ounce denim, measuring .021" to .0225 "- or the thicker yet ticking we had that ran .0235".
No loading problems ever & no fouling problems either and also loaded with each rifle's hickory rod.

About that "fast" rifling twist.
With very small powder charges at known distances, indeed they will work. Forsyth wrote of having a 13 bore double rifle (.705") than stripped if shot with anything heavier than 1 1/2 drams (41gr.).
He said it also had a 13" trajectory over 100yards.

[smylee grouch]

Curious what velocity a 41 grain charge would be in that bore?  Like a slap shot hocky puck. 

[mr. no gold]

This was obviously a grand gun in good English style. Thanks a bunch for showing it here. Curious to know though, is this a burned up gun? Wood has that look. Whatever, too bad that it was so damaged. Well, put it back right and then bring her back in for a standing round of applause.
Dick

[alacran]

All germanic jeagers I have measured are 1 turn in the length of the barrel. It must have worked.

Captain Johan Ewald's Jaeger Corps was comprised of Hessian game keepers and foresters who often times carried their personal weapons into battle.
As Mike states those rifling twists worked. The Jaegers gave the Patriot riflemen a run for their money and were rightly feared.

[taterbug]

Interesting!  And a fun project to watch indeed! 

Just curious, do you have any pictures of the face of the breech plug?  Wondering how the touch hole was handled for connecting to the main charge.