doublegunshop.com - home Forums General Discussion Classic & Custom Single Barreled Sporting Rifles @ doublegunshop.com .461 Gibbs barrel specification?

I'm planning a .461 Gibbs No. 2 build on a Martini action and cannot seem to nail down bore and groove diameters of original rifles. I have heard specs ranging from .452 up to .470. The Imperial War Museum gives .448 as the diameter of a bullet in a .461 No. 2 cartridge in its collections, but my guess is this is the naked lead bullet that was paper patched up to a larger diameter.
Does anyone have reliable information on groove and land diameters, and possibly rate of twist?
Many thanks.

Bill, I think that you're going to have a difficult time getting the Gibbs .461 No. 2 in the Martini action. The No. 2 is a pretty long cartridge and I don't think it will make the corner. Any falling block action should work well though.
In the 1870's, Gibbs wrote Halford that he was using .460 caliber barrels at that time and I believe by then, he was using Metford rifling. There is a picture in Kirton's book with a mould for the Gibbs bullet. It is marked .461 Gibbs, 570 grains,
.453 diameter. Depending on what thickness of paper was used, it was probably wrapped up to .460" or .461". The Europeans tended to wrap there bullets to groove diameter while the U.S. shooters wrapped to bore.

they varied quite a bit over time. I would settle on .458 as it would fall within the specs. Call the shop next week and I can go over some documentation with you that I have regarding this matter.
Steve

Thanks gentlemen. I had considered going with a Krieger barrel for the .465 NE, with specs of .459/.468 and 1:18 twist, based on reports that Ross Seyfried wrote up an original Gibbs in the chambering with a groove diameter of .470 or larger in the Summer 2004 Double Gun Journal. I just ordered that back issue.
Bob, I am absolutely certain the longer No. 2 case will fit easily "round the bend" in a Martini. based on the Greener I once owned chambered in .577 3-inch BPE. This large, straight case, loaded with a 650-grain Woodleigh to the cannelure, fit the Greener just fine.

By the way, for comparison's sake:




From left, 9,3X74R, .450 3 1/4 BPE, .577-450 Martini Henry, .461 Gibbs No. 2, .50-90 Sharps and .577 3-inch BPE.

OK, that would be the large shotgun action, correct?

Think so Bob, although I no longer own the gun, and the guy I got it from was sketchy on the details. Shot it a couple of times with a compressed load of FFg under that big Woodleigh, and it was quite manageable.