Fitting barrel keys and underlugs

[4ster]

I am building my first rifle, from a Rifle Shoppe Ferguson kit.  I am nearly done with the work on the metal parts and am beginning to think about fitting the stock to the barrel.  I can't get my head around fitting the underlug/key system the rifle uses.  It seems no matter how carefully done, the keys will get loose over a short time and not stay in place. 

I have read D. Taylor Sapergia's excellent tutorial on fitting barrel keys.  It looks difficult to get the slot cut perfectly but it cleared up some questions.  It still feels like with very little use these will get sloppy and not hold the stock tightly to the barrel and the keys will want to slide out of the underlugs.

What am I missing? 

[wetzel]

It seems like many rifles use the key system and don't have problems.  I have often wondered the same thing.  Can you put inlays in so the majority of the pressure is being taken by the metal or would it not be correct? 

[omark]

putting wedges through inlays is pc, though i cant say for sure what time periods. as far as loosening up, i always thought a slight tap with a hammer on the bottom center of the lug would tighten things up a bit. or slightly bowing the key. of course these adjustments should not be made  with a 3# hammer.      im sure others have better ideas.          mark

[Swampwalker]

4ster, I assure you a properly fitted dovetailed underlug in a barrel does not have a tendencey to loosen.  My advise is to take a scrap piece of barrel, follow the tutorial, and see for yourself.  Believe me, it works, and is a time tested system.  I trust them over soldered underlugs, but that is an alternative if you don't like the dovetailed underlugs.

[4ster]

Its not the underlug/barrel connection I am worrying about it is the Key/underlug fit.  As supplied in the kit the slot in the underlug is wider than the key.  I think this is a good thing, allowing the stock to move a little as the wood changes.  The key mortices in the stock will be placed (I hope) so that the keys hold the barrel down snugly.  I'm just used to modern guns with things like detents to hold things in place. 

Thanks for the idea about "adjusting" the underlug with a hammer tap.  I had not thought of that. 

As I understand it, the the Ferguson had no inlays to support the keys.  At least I have not seen any published examples. Except for its complicated breach, as a military rifle it has few niceties.  Everything else looks like it was designed to cost as little as possible to manufacture. 

Thanks for the help!

[Swampwalker]

Sorry, 4ster, I misread your question.  As to the keys, they actually work quite well.  It is important to get them to fit tightly in the wood, which is a bit of a challenge.  I usually drill 3 small holes in a row, open up with a tiny saw made from a hacksaw blade, clean that up with a tiny chisel also made from a hacksaw blade.  I try to end up with an undersized slot.  Then I heat up a strip of steel the same size as my keys and insert into the slot to achieve a perfect fit.  You might have to reheat the strip of metal and insert several times to get it all the way through.  Again, I would recommend trying this on a scap befor commiting to your stock. 
Another way to get a tight fit with the keys is to give them a bit of bend to increase the friction in the slot.  The untreated mild steel of the keys should have enough spring for this to work well.
Good luck!

[D. Taylor Sapergia]

Here's a few images of first, the Ferguson and second, the Baker, both sets from TRS, and similar in construction and purpose.

The wood holds the key snugly and does not seem to become loose over time.  The stock does not need an escutcheon to hold it tight...it's the wood that does it, not to mention they are inappropriate on these rifles.  If you follow the tutorial, and gently burn them in, they will be a perfect fit, and once the wood is dressed down later, there is no evidence of the fitting technique on the outside. 
If a key is a little loose in the lug, place a rod of about 3/8" dia. upright in your vise, and very gently squeeze the lug closed a bit.  This is better control than the hammer method.  If you go too far, a large screw driver has a nice taper for wedging it open again.

[Red Owl]

Well let's see. The wedge has to rest tight against the upper part of the wood in the wedge slot AND the bottom of the wedge has to pull down the tenon on the barrel and hold it down.  In other words if the slot in the stock is too deep- IMHO it really does cause too much trouble as the top of the slot is the bearing surface.  I angle the entrance of the tenon just a little as sort of a lead-in camming action. NOW, as far as fitting- I use a 1/16" drill and drill a series of holes maybe just a little below dead center of where the wedge should fit. I then connect the holes. At this point the slot is more narrow than the wedge. I now use a home made fitting or test wedge made from 1/16" stock and fit that. At that point I know where I have to remove wood (top or bottom) to make the actual wedge fit tight. For me at least- it seems to work pretty good but others likely have other methods.

[4ster]

Here's a few images of first, the Ferguson and second, the Baker, both sets from TRS, and similar in construction and purpose.

Thanks for the pictures.  Beautiful work!  Something to shoot for.

[NSBrown]

Does anyone have an easier process for wedges? I have no doubt that what has been described will do the job well…but, surely makers didn't pick up this barrel-securing idea for the fun of it.
Why would gun makers shift from barrel pins to barrel wedges? Pins prove quite adequate for the job; and wedges require more material and labor. Did customers begin demanding them over pins?

[4ster]

I'm going to speculate (without any research or knowledge really) that the keys were developed for ease of field servicing the weapon.  On the Ferguson the keys are pinned through a slot in the key so that they do not come free of the stock once the gunsmith completed building it.  What could be easier than sliding out 3 keys and unscrewing a tang screw to remove the barrel for cleaning?  

[NSBrown]

Punching out three pins and removing the tang screw.

[Dr. Tim-Boone]

Can you see a soldier crawling  around on his hands and knees in the dirt looking for the pins he dropped???   Keys that are retained in the stock might save a life... or at least a gun.....

I just did keys in one rifle I am finishing up. did it like Swampwalker & Taylor suggest. I like doing them.

[stuart cee dub]

That is why barrel bands on military guns were such a great idea as was interchangability .
But very troublesome to implement and costly especially if you needed to arm a bunch of cannonfodder double quick .

[caliber45]

4ster -- Once again, I'm venturing into non-HC territory, undoubtedly. But . . . since you asked for an easier way: I started using this method after losing a loose wedge key (not the finest fitter in the world, sadly . . .) while out shooting a new build. Rather than go home and giving up a half-day of shooting, I finally substituted a hunk of clothes hanger just to keep shooting. When I got home, I installed a new wedge key, but left enough sticking out the "far" end to drill a small hole through it. Then I assembled a small "bangle" with a tiny silver skull and a turquoise bead, which I attached to a likewise small fishing swivel. I attached the swivel through the small hole in the wedge key. The swivel/bangle keeps even a loose key from falling out, and gives the rifle a bit of added "character." I do that on all my rifles. Haven't lost a wedge key since. My apologies to the HC folks . . . -- paulallen, tucson az

[Pete G.]

Soldiers don't take barrels off of guns. Not then, not now.