Thoughts on .40 caliber and 3/4 barrel

[Bill in Md]

With charges not to exceed 60 grains, what do the builders here think of a strait rifle barrel such as this  ?....Don't have one yet but am gathering ideas..........thanks.......b

[Daryl]

60gr. of 3F would be equivalent to about 70gr. of 2F. The 2F will develop the same speed, but at reduced pressure.
The .40 cal. barrel, with .012" deep rifling will have .163" of steel between the bottoms of the rifling grooves and the outside flats, for the distance the groove was opposite the flat in that split
second it was in the middle of the flat.
Those Indian muskets have .750" bores, with 1.0" OD at the breech. At the front of the plug, even less. With 1" OD and .750" bore, they have .125" between the hole and the OD, at the breech.
I've never heard of one blowing up, thus I suspect your .40 on the 3/4" bl. might be OK, but not for me. I prefer more weight of barrel, personally.

[Scota4570]

A long rifle?  I would not, but for safety reasons. 

I'd use an A-weight swamped barrel.  I spent a lot of time on a very fancy rifle with a 13/16" straight barrel. I feel like I wasted my time now.  After  owning rifles with swamped barrels I find them much better visually and in handling.  When you use a very thin barrel the area around the lock does not look correct.  You may need to add a spacer between the pan and the barrel.  It will look like a patch job.  The balance will not feel as good either. 

[Bill in Md]

A long rifle?  I would not, but for safety reasons. 

I'd use an A-weight swamped barrel.  I spent a lot of time on a very fancy rifle with a 13/16" straight barrel. I feel like I wasted my time now.  After  owning rifles with swamped barrels I find them much better visually and in handling.  When you use a very thin barrel the area around the lock does not look correct.  You may need to add a spacer between the pan and the barrel.  It will look like a patch job.  The balance will not feel as good either.

Your point about the lock area not looking right is well taken.....thank you

[Bill in Md]

60gr. of 3F would be equivalent to about 70gr. of 2F. The 2F will develop the same speed, but at reduced pressure.
The .40 cal. barrel, with .012" deep rifling will have .163" of steel between the bottoms of the rifling grooves and the outside flats, for the distance the groove was opposite the flat in that split
second it was in the middle of the flat.
Those Indian muskets have .750" bores, with 1.0" OD at the breech. At the front of the plug, even less. With 1" OD and .750" bore, they have .125" between the hole and the OD, at the breech.
I've never heard of one blowing up, thus I suspect your .40 on the 3/4" bl. might be OK, but not for me. I prefer more weight of barrel, personally.

Thanks Daryl ....your opinion is always valued by me!

[smallpatch]

I’ve built 3 of that description for my grand kids. They shoot about 50g FFfg, and do very well at our rendezvous and club shoots.
2 are Rice barrels, and one a Paris barrel.

[Bob Roller]

I agree with Daryl on this light barrel.The moderate powder charges and light weight round ball is a low pressure load.Too big for small rodents and too feeble for deer IMHO but a good gun for a grade school child to learn with and put holes in paper targets.I built a 40 caliber round ball gun and zero felt recoil but it was a heavier barrel with a drum and nipple.The last rifle I made was 40 caliber but it was not a muzzle loader.
Bob Roller

[B.Habermehl]

The 3/4 in barrel will build into a light gun. It however causes issues at the breech with shaping the stock. Plus getting the lock to fit properly. Even the smallest locks like the Bailes. If I were to build my tooth pic squirrel rifle again it would be built around a dainty swamped barrel. Plus it’s really interesting to fit a touch hole liner with that little wall thickness. BJH

[Daryl]

In that weight barrel, I would suggest a patent breech of some sort, no vent liner or drum.
A .36 cal. would be much more suitable, imho.

[L T Grey]

Bill,

I'd go with one of Rice's Squirrel rifle barrels. They are 13/16 (.812) at the breech, .650 at the waist and 3/4 (.750) at the muzzle. They are a delight! Jason makes them in lengths from 38 to 48 inches. The square groove barrels are only $25 more than their straight sided barrels.


 

[Bob Roller]

Assuming the breech plug threads are 1/2x20 I would make a chambered breech plug that could be used with a touch hole liner or a drum and nipple.This idea assumes the idea of having a machine shop or finding someone who can make the plug with integral tang.
Bob Roller

[Bill in Md]

I should have pointed out that the idea was the build a percussion piece as I have never built one. The "Squirrel barrel" suggested by LT is appealing as I want the gun to be an off hand shooter that is balanced but of small caliber......Any thoughts?

[okawbow]

I built a .30 caliber SMR with a 3/4” barrel. Very light weight and accurate. 42” barrel.

[L T Grey]

Bill,

If the gun is for small game I'd go with .36 caliber. To me .32 is very charge sensitive. A .36 will also do well for target work. If it's purely a target gun .40 makes sense. A rifle built around a Rice 38" Squirrel Barrel would handle like a wand making for a good woods gun. It would also have enough meat in the breech for installing a drum. For a pure target rifle I'd choose a longer barrel option.

 

[Osprey]

While I love light skinny barrels for hunting, I'll chime in that my favorite balanced rifle for offhand is a straight 13/16"  .40 Green Mountain in a Bedford pattern.  Just holds and hangs there perfect for me.

[Bob Roller]

I had a small scaled down version of an English target rifle and it was stolen when my shop was broken into,I know who did it but can't prove it.I still have a semi finished 4 screw lock I was going to use on it.It was a 40 caliber with 13/16 Bill Large barrel and I made a breech to match the lock.I might finish the lock and sell it on this forum.
Bob Roller

[wolf]

i have a 40 rice 3/4 and that is the load i have shot in it for years. 60gr. of 3f in fact i killed two 8 point bucks last year with that load. booth bucks were at 85yds,,,,,,,,,,,,

[Ian Pratt]

3/4" straight barrels make cool skinny guns. A few thoughts on how to deal with the shaping issues they create - 

If building a flintlock gun - to get better shape and have enough width so the wrist doesn't disappear, tip the bolster in at the nose end to kick the tail of the plate out. I suppose you could try this with a percussion lock , would probably take some creative filing of the drum slot in the plate and also the nipple seat before drilling.

tipping the lock fixes one problem and causes another - now the tip of your mainspring is even closer to the ramrod. Try to offset the groove a tiny bit so when you drill the rod hole it will head toward the side panel.

It also helps if you choose a lock with a not too narrow bolster and little or no bevel on the plate edge. Will make for more width of the panels from the centerline of the bore.

Lock height has to be right on the money - small side flats. First one I did , the bottom of the pan hung a touch below the side flat leaving a little hole through to the oblique flat below. Not a big deal, filled the bottom of the pan a little and shaped it out, but made unnecessary work for myself.

[Daniel Coats]

Here's how Jack Duprey solves the problem which is also what I'm doing on my current Soddy Daisy. Jack and I discussed this again last weekend at the CLA show and it adds width to the 3/4 inch barrel. I'll solder it on like he does.




image hosting sites

[B Shipman]

I have an A wt. Rice that they made a small run of years ago by reducing the whole barrel so the breech was 13/16. Their standard A wt. reduced. I get that this is a standard barrel now. Anyway back in the day 13/16 was popular. And I hated building them for alll the reasons stated let alone a 3/4. I did what Ian does. But that simple slab added solves everything. (Ithink). I will try it. Old dogs actually like new tricks.

[Daniel Coats]

I like it.




I have it inlet and working on the lock now and will post more pictures.

[whetrock]

What solder and flux did you use?

[Daniel Coats]

What solder and flux did you use?

I bought this as a set at Ace hardware recently and I hate it. Requires more cleanup afterwards than I think I should have to do. I'm looking for something better.