Coning

[Dphariss]

In the Antique forum in Herbs post on the  trip to Santa Fe there is a drawing of what someone thinks is the interior of the the Hoffman and Campbell rifle featured in chapter 7 of John Baird’s “Hawken Rifles..”. They have misplaced a decimal point.
Enclosed is the description from Pg 42 of my rather worn first edition. The “coning” is very slight according to this.

[Daryl]

Interesting indeed, is  the 1/2 thou enlargement for 1 1/4", then last 1/4" and additional .002".  Wow - not much enlargement at all, certainly no where near the bottom of the grooves.

[flinchrocket]

If the bore is not worn, it seems it would require a separate operation to round the tops of the lands.

[Panzerschwein]

Nowhere near as much coning as the historically incorrect type used today.

[James Wilson Everett]

Guys,

This written description of an original barrel bore is quite consistent with the bore we still get today when using 18th century tooling.  The final polish of a smooth bore barrel (that is before rifling) is done using an armory reamer.  This tool gives a very slight taper to the bore with the breech end being a few thousands of an inch larger in diameter than the muzzle end.  My barrels tend to be about 0.003 inch in diameter smaller at the muzzle than at the breech.  Master gunsmith Gary Brumfield reported his to be about 0.005 smaller.  The coning opens up the muzzle quite a bit, but up to the start of the cone there will be the slight taper.

Jim

[Bob Roller]

Only one thing missing.The ARKANSAS choke,tight in the middle and loose on both ends.
Bob Roller

[Daryl]

Bob, even in 1860, the/some Brits thought that tight in the middle and relieved at both ends was the "best" for strong shooting with a smoothbore and shot.

[Dphariss]

Only one thing missing.The ARKANSAS choke,tight in the middle and loose on both ends.
Bob Roller

Tight on both ends and loose in the middle does not work well either.
The thing that gets me is the time it takes to lap one out very far. But I tend to not use very coarse compound.
And Daryl is correct and its illustrated in books of the time. Not sure how this was supposed to work but the Brits put a LOT of work into shotgun performance.
Dan

[Daryl]

Seems to me even W.W. Greener mentioned in retrospect, the tight middle, loose both ends choking in his 9th edition of The Gun.
Of course, by the time he wrote that edition, he's pretty much perfected choking, for lead shot.

[tecum-tha]

On my Jaeger from around 1745, it seems to be the case as well. Loads harder at the muzzle than down the rest of the barrel.

[Clark Badgett]

On my Jaeger from around 1745, it seems to be the case as well. Loads harder at the muzzle than down the rest of the barrel.

That is pretty standard on most.

[Clark Badgett]

Nowhere near as much coning as the historically incorrect type used today.

And just what is the "historically incorrect type used today"?

[Daryl]

 A funnel, I suspect, running 1 1/2" to 2 1/2" deep.
I tried a short cone or funnel, about 1/2" long. I had to cut the end off the barrel and re-crown it to get my accuracy back
that disappeared with the cone.

[Dphariss]

This is as deep as I ever go.  This was done on the lathe and is a 2 angle. I usually do just one angle but I got carried away.





This can be used to put a a tapered crown in a barrel a with double stick tape and 320-400 grit wet to dry. I used it on my 16 bore rifle. Its a shallow, wide groove barrel and I can load hard lead with no problems.

[rich pierce]

Nice crown. I’m not surprised it loads easily.