doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com On face?

I recently examined an Army Navy sidelock that has me wondering if the gun is "on face". When held up to a light and examined from the side, I could detect a gap between the standing breech and barrel face - I could see light. I could not see any light between the water table and the barrel flats, but I could not detect any "wear" on either when I had the gun apart. There was no play in barrels/action with the forend removed.

Is this gun on face?

More importantly, will it need(or soon need)to be tightened up?

Forester

Light between the barrel flats and water table is fairly normal, I think. Less desirable is light between the breech and standing breech. If there's no shake with the forend removed, I'd be inclined to ignore it. You didn't say how thick a feeler gauge it would accept between the space. My biggest concern would be that "vicious recoil that might result if the shell is able to move .001", toward the standing breech, when firing". Check with "Guff" Thomas on the principle involved. he'll 'splain it to you.

The gun has been re-jointed badly. There should be no light visible through the barrel breach end and the standing breach. It may not wobble because it has been re-gripped and is being held tight by the bolts.

Poor re-jointing can leave a gap between the barrel flats and bar flats (what you Yanks call a 'water table'). Also look at the radius, there can often be a gap left there as well.

Then check the doll's head fit. amateur gunsmiths struggle to get it right on all the surfaces that need fixing straight when multiple bites are involved.

Also worth checking to see what the headspace is like in the rims, sometimes you will find the barrels have been filed uneven and the rims are deeper on one side than he other and the barrels effectively slanting to one side.

The barrel breach ends should be a sliding fit (metal to metal contact) but not an interference fit that hampers opening and closing. There should be a "couple" of thousandths clearance between the barrel flats and the action bar flats (AKA water table). This allows the bars to flex ever so slightly under the asymetrical loads on the faces and the hinge pin and/or jointing circle. If there is no clearance, the flex will knock the action off-face in short order; the bars are going to flex.

For a definitive explanation of "jointing" with excellent illustrations see Vic Venters Gun Craft column in July/Aug. Shooting Sportsman.
I just received my copy today.

You have problems.

Homelessj0e
Thanks, could you be more specific?
Thanks again
Mike

Vic's excellent article (including engineering drawings) suggests that the clearance between crosspin and circle on the lump be between .0005" and .0015" and that there should be no visible clearance between the breech end and the standing breech. Clearance between the action flats and the barrel flats is listed as .002"-.004". That is why you can often see a bit of light there but the clearance between the barrel breeches and the standing breech (or "detonating" as it's charmingly called in the UK) should be "the thickness of smoke" and you really should not be able to see light.

That's what I said

If you expect anything other than a smart-a$$ed, useless post out of Hojo, you'll be disappointed. Better chance of getting ObamaCare being repealed, followed by his resignation.