doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Off-Face -- When is it bad enough to fix?

Just took out all my old hammer doubles from 1900 to 1938 and checked the looseness with foreend off and lugs unlocked. All but one with a new breech face show some amount of play and a bit of rattle. Much, much less than with my "new" gun having approximately 0,003 shim needed on hook and about 0,005 inch off face. These guns have been this way for as long as I have had them and we have shot each for at least 10s and 10s of rounds of trap and SC. These are a mix of guns with cross bolts or "dolls heads" and those with only double underlugs. Some have been used heavily with CIP-spec hunting loads, usually with 28 grams shot at 1250 pfs or less, sometimes with 28-30 grams at 1300 fps. The target loads have generally been under 8K psi and 24 grams shot. I never considered these guns to be "off face" when I bought them and still do not. I sure do not expect any of them to "hammer itself apart" anytime soon.

I simply do not buy your statement that gun with 0,001 inch off face "hammers itself apart, in short order." Not with sub-CIP and CIP loads, mostly with 24 gram shot loads in 16 and 12 gauge. Maybe with "magnum" loads to SAAMI specs or handloads at SAAMI max.

Niklas

Phil, actually I have read your posts and you are also incorrect in assuming that I've no experience with putting guns back on face. I'm a machinist and did lots of precision work over many years. The last gun I put back on face was a best British boxlock built on the Smith assisted opening action. It was off face a few thousands so I fitted a new crosspin. I wouldn't dream of cutting into the hook on such a nice gun. Moreover, when I removed the old pin it was apparent that most or all of the wear was on the pin and the new one only needed to be made to the original size or a tiny bit bigger. The most difficult part was making sure that the shoulders and thread of the new one were as tight as possible. Nor would I harden such a pin, I used O1 steel which in it's anealed state is plenty hard and tough enough. Obviously you need a thread cutting lathe and experience cutting threads right up to shoulders, etc. so perhaps not every gunsmith wants to get into doing this. BTW. you got your facts a little backward, pressed in pins rarely go all the way thru the frame and consequently don't have engraved ends. It's the caps in the outside wall of the frame that get the engraving. You couldn't harden a pin, press it into the frame and then engrave it. Pressed pins mostly got hardened when the frame was case hardened. Hope this post doesn't get you upset.
npm

Niklas I've got several hammers guns built between 1871 and 1881...no looseness what so ever with the forearm off.

I have a 1915 sidelock that was slightly loose...after several hundred rounds it was really loose.

Nick,

If it was not clear, what I said was that once a gun has lost springspace, it would hammer itself apart. In the case of your hammerguns the forend pressure may be enough to prevent hammering. There are three forces, in opposition, involved in a breach locking double: the forend, the bolt, and the hook/pin.

Phil

Spud,

I'm not upset. There are alway an exception to the rule. I never said that replacing the hinge pin was a bad idea. I think that it is unnecessary, in most cases. Finally, taking a .009 - .011 dovetail around the bearing surface of the hook is not going to weaken it. BTW, the dovetail can be delivered to a customer for around $275 - $300. Is pin replacement comparable?

Phil

Obviously, there is quite a bit of looseness in the claim that "slightly" loose barrels are gonna get really loose fast. Mine have not.

This thread has been quite educational for me. I will be keeping a close eye on my favorite old doubles. At some point perhaps a few will get new hinge pins. The nice old 1890s Husqvarna might be one -- it did quite well today at an informal bit of SC. The "scotch" tape on hook took a beating but performed much as RWG reported -- it was good for about 25 rounds of 7.500 psi, 24 gram loads at 1200 fps.

Niklas

When yOu have a flat tire do you use a bandaid ?

Actually, I did once. Got me back to where I could get tire fixed properly.

Wouldn't one decide whether to replace the hinge pin or weld (or dovetail) the hook, hinge (pun intended!) on whether the pin was fixed or removable? Seems I recall reading that Winchester made replacement pins for the Model 21 in increasingly larger sizes, to compensate for wear. Certainly if you could get a new pin from the factory, fixing such an off-face gun would pretty much be a no-brainer.

If I had a "best" gun with a removable pin, I think I'd go with the replacement pin. But none of the 3 or so guns I've had put back on face met either of those criteria.