doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Jones underlever problem.

Has anybody tightened up a Jones under lever double? I have a Charles Osborn 12 bore with 32” barrels which is a bar in wood action. When closed, with out the underlever engaged, it is tight and on face. But when you close the underlever you can see it being crammed forwards, off face by .005-.006. It does not wiggle because the underlever has it cam,ed in place. It is still solidly closed, those Jones actions are very robust.

I seem to be collecting a few of these bar in wood or crab joint guns but they all seem to be from pre 1875 or so and everything wood-wise is needing repairs. They never were a robust action wood-wise, with a lot of wood 1/8”-3/16” thick. Sanded and refinished they become paper thin. Plus 150 year old wood gets very weak in unsupported areas which they have an abundance of.

This one needs a full restoration along with a bit of wood repair. For several years I just thought this gun was too far gone for a rescue, until I measured the barrels which were well within saving. They had been painted black many years ago, and that might have saved them. The bores were perfect other than some dumb azz lengthened the chambers, by elongating the forcing cones. Just load short shells people. Nothing makes a gun stronger by removing metal in the highest pressure areas.

The repair list is a bit long. Off face which should be a simple fix, left hammer not a good replacement, wood chipped, cracking and missing in a couple areas. I got lucky and found a left hammer, in my spares, that was almost a perfect twin of the right. Even the engraving was a close match with only the hole needing slightly to be welded up to reposition it, to time the hammer-axle-firing pin and then a new screw turned, threaded and engraved. I could get by with the old screw for now. Then a stock strip and finish. Fix the off face first.

It sounds as if the gun may have been Re-Jointed using one of the more common techniques suited to a Purdey double under bite, vis new pin or insert in the hook. Works well on a double underbite system but not on a Jones U/L. I would suggest removing the barrels and applying a liberal amount of lamp black to the two locking lugs,particularly the vertical face of each bite. Re-mount the bbls close a few times and check the smear pattern. If the cause is per my hypothesis the forward lump will be wiped clean indicating the Jones U/L is camming the bbls forward. Remove metal from the front lump to provide clearance. Keep us posted on what you find.

I thought the front lump on the lugs would be the problem. Has the rear lug worn so much it is no longer working and that allows the front lug to cam the barrels off face? If so is just removing metal going to allow both lugs to seat and keep the barrels on face? I’ll know in ten minutes about the front cam/lug. I'll need to verify the rear cam is seating properly because half a repair is no repair in the long run. And a 150 year old gun deserves decent treatment. Who knows 1880 might comeback and I’ll be in fashion with this Osborn.

Update, Well it is back on face. Thanks Hugh. When in doubt, follow the smoke trail, or lack there of. It now is back on face and well cammed down. I got to say the Jones action is a very interesting way to close a gun. Simple, strong and not that hard to work on if it is not buggered up.

I’m not so convinced of the strength of the Jones underlever concept, especially without a rib extension that keeps the barrels on the action face while firing. In most cases on a JU action the lockup is much closer to the hinge(than a typical underbite), this decreasing it’s advantage, even when considering the longer bar found on JU guns. Fitting on the draw/circle changes things, but let’s be real…most guns aren’t. You also have to consider the quality and deterioration of said guns. But that’s just one man’s opinion.

Consider what it replaced. Early closing systems like the thumb opener were not great. If they were so great they wold have been many makers using them after the patents ran out, or pay to use them before. It also theoretically has two incline ramps pulling things tighter. In truth, unless perfectly fit and not worn, one or the other will be the working one and the other just be just out of contact and nonworking.

The Jones under lever was used on a lot of double rifles for some reason

I was just sent a couple photos of a Henry with a Jones underlever. It's a .450-3.25". Since you had mentioned this distance from the hinge pin, I noticed that water table on this gun seems to be much longer than usual and the distance from the lever axel to the hinge pin is actually quite long. This is just hairy-eyeball guestimation, but it looks like that distance might be at least as long as a double underbite shotgun. I don't know if this is typical of Jones underlevers, of course, but might be something to look at.