doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Is this considered off face?

Every time I look at a gun I might be interested in I check for light at the standing breech. When I've rejointed guns, all by fittting new hinge pins, I'll keep at it until the gun will just barely close with the forend off. I wouldn't want to see light anywhere between breech face and barrels. If you see light at one side and not the other it can only mean one of two things, well maybe both but unlikely, either the frame has stretched unevenly from one barrel being fired more or the original fitter did a lousy job. In either case if the quality of the gun warrents it, corrective measures should be taken. I couldn't abide a gun with a gap at the breech and have passed on several that I would otherwise have bought. So many Brit boxlocks have difficult to replace crosspins. They don't have slotted hinge caps, the pins are press fit instead of screwed so that it's easier to shim or tig the hook or other Rube Goldberg method which always leaves the problem of trying to fit the hook to a possibly worn out of round crosspin. Not the best situation.
npm

eeb,

Please re-read my response regarding "spring space." Without it, a gun may shoot loose in a few hundred rounds.

Phil

Phil - This gun had 1/32" to 1/16" worth of a space in the aforementioned area. Quite a bit more than .001".

Fox guns came from the factory with about .002 or so between watertable and barrel flats at rear.This allows the rotary bolt to pull the barrels down and back a little when wear occurs. If barrels could not be pulled down any farther there would be play in the fit. It states this in their catalogs. Bobby

"WHY"!!
On the few I have bothered to check the standing breech formed an angle of "Less" than 90°, IE the top of breech was tilted Forward. Elementery geometry would show that if it will close with an angle of less than 90° it would close with a 90° or greater angle. This angle is quite obviously put there for a purpose other than the ability to close the gun.

Eeb,

I would guess that the action is warped on this gun. Barrels could be mis-regulated at the muzzle. But, that is highly unlikely.

Phil

2-Piper,

I quote from the Journel of the Custom Gunmakers Guild, "88.5 degrees is about average for most guns. This allows the needed room for the bottom edge of the barrels to clear...", "and the fact that the wear on the breach is a bit uneven, and the standing breach may not be perfectly flat, it is unrealistic to expect full 100% contact...98% is doing well."

Phil

Phil;
With all due respect I think you have misinterpreted their reason for the cutting of the breech face tilted forward 1.5° (90-88.5). The pivot point upon opening the bbls is the center of the hinge pin, which lies some distance below the watertable. If one connects a line from the pivot to the lowest point of contact between the bbls & the breech & then extends a tangent upward & forward, then any point on the bbls which does not cross this tangent line will move away from the breech upon opening. I rough scaled the distance form pivot to breech on one gun & came up with a length of 2 3/4" & ½" below watertable. Figuring the tangent for this triangle gives 10.3°. Thus for a hinge located to these dimensions one could say with certainty that any breech cut to an angle with the watertable of 80° or "Greater" the bbls would open with no interference. It is quite patently obivious that "Journel of the Custom Gunmakers Guild" notwithstanding, tilting the breech forward to an angle of less than 90°, decreases rather than increases opening clearence. Incidently the above measurements were taken from a 16ga Lefever which is quite tight & on face. The corner of an ordinary .0035" piece of paper inserted in just above radius on either side of bar is gripped very tight & lever stops farther to right than mormal. A square with blade which can be set to clear radius shows standing breech is cut to a lesser angle than 90° with watertable, but have not yet put the precision protractor on it to determine exact angle. It is however "Not" cut this way to aid in opening the gun. It could be cut square or tilted Back to the same amount & open with equal ease in any case.

barrel hooks are softer than case hardened hinge pins. a lot of british box locks have a non removable hinge pin,if you use smoke on the hook and finish by blacking the barrels down you get a really nice fit.( after piecing or welding the hook)and if properly fit and finished you have a permanent and acceptble repair. nialpatricmac how do you repair a LC or NID with nice colors or finish on the action.if properly done tiging is invisable and permanent mc

Like Miller, I'm of the thinking that the watertable to breach angle is irrelavent. I (also) believe it's the angle 90 degrees from the line between the axis of the barrel hinge and lowest breachface contact point that is relavent. The breachface must be over 90 degrees (more open) from this angle to open and close.