How to make checks in the recoil lug area? Dark arts question.

[RJW NZ]

I have a new and good quality repro fore end thats going onto a target smle in stock configuration and I want to be really precise with the bedding of the recoil blocks. How does one actually measure the internal clearances? Bend a little right angle onto my feeler gauges? I can barely see in there, even with the sear and mag catch taken out.

What would an armorer do?
Could I put a squeezable substance like modeling clay in there, tighten everything up and then open it up again? I could see how that would show if there was any clearances but probably not give me a precise thickness as it will pull to bits as I open it up again.
Any ideas?

The purpose is to get the recoil blocks firm and even, and then to firm up the fore end fit onto the wrist. I didn't want to set the wrist up without knowing what the recoil lugs were like.

Also; is there a school of thought either way of whether to leave the recoil lugs as wood only or should I put the brass/copper plates on? What I do like about the brass plates is that I can easily shim under them to take up any gaps.

Has anyone devised something that transfers the recoil shock from the lugs to the wrist with bolts ala the Canadian Team system? I've seen what appears to be rear fore end recoil plate (the U shape plate that engages the butt bolt) the with two bolts protruding towards the recoil lugs but haven't seen any text about it.

Information

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[Thunderbox]

About the only way to fit a forend is by trial and error, using some sort of substance to leave "witness" marks to give evidence of wood-to-metal fit. I dust the forend internals with talcum powder, and lightly oil the metalwork. After placing the two together, you have a series of witness marks that enable you to start scraping or filing wood away to get the correct fit. For a very precise fit, you remove just a scraping of wood each time. A No4 forend usually takes me about 10-15 assembly cycles, a No1 can be 20-30. The final fit can be incredibly tight, if you wish. Old gunsmiths used a wooden drift to tap the forend onto the receiver - thus causing a slight compression fit of the wood between the recoil lugs and the butt socket (I once had a 1913 LSA DP rifle where the original forend was still so tight that it took about an hour to get it off the rifle...).

I would have thought it counter-productive to attempt to fit metal blocks. With bare wood you can achieve a perfect tight fit, and the forend should last for decades of use. By contrast, it is very fiddly and difficult to get a perfect mating surface with metal blocks - and the fit/refit process can weaken the forend if you end up stripping out or enlarging the holes for the plate screws.

[Son]

When you say "good quality repro foreend" do you mean it's about 95% finished and needs to be fitted from there? If so, there's a lot more to it than just fitting the recoil blocks (if they are needed)

[Peter Laidler]

Just why do you need to measure the clearance between the recoil lugs and the draws Son? There shouldn't be any clearance. The fore-end should be fitted so that the draws 'draw' - hence the name - the fore-end back, hard between the draws and against the butt socket. Then after a period of firing there's a relaxation where a very small gap is permissable between the rear of the fore-end and the face of the butt socket.

Thunderbox is right. Armourers had a wood drift (Drift, Armourers No1) to drive the fore-end back and down. Don't forget that metal blocks were a palliative and not a cure, allowed because of the fiberous nature of the wood in use in Australian production so I seem to remember being told in Australia many years ago (look how the screw threads strip to emphasis the point....). And that's why when we rebuild draws, we insert patches with the grain in the direction of the draws and not in the direction of the wood.

In short, there is no need to measure the clearance between the recoil lugs and the draws when fitting a new fore-end because there shouldn't be a clearance. It should be a tight fit that requires you to knock the fore-end off the body, from the top ledges, using the tail end of a hammer handle

As for the Canadian method of loading the draws with bolts. I might upset some but in my humble opinion it's a frill, if not a complete fraud

Or am I missing the point somewhere?

[Son]

No need to measure anything. My fear is that a "reproduction foreend" will require a lot more fitting than first thought!

I'm afraid RJW, you may need to do some serious study about what you are getting into here. There's a couple of articles in the MKL... When I get a chance I'll link a few in for you to look at. I think I recall one of Peter's regards fitting a new foreend to start with...

[RJW NZ]

I'm afraid RJW, you may need to do some serious study about what you are getting into here. There's a couple of articles in the MKL... When I get a chance I'll link a few in for you to look at. I think I recall one of Peter's regards fitting a new fore end to start with...[/QUOTE]

Thanks, I'm pretty sure that the fitting a fore end instructions would cover my queries, so that will be interesting.

My train of thought was started when I realized how much I take for granted that the recoil lugs are in fact a good fit considering that they are totally out of sight. The difference between a good fit and no contact at all will only be a couple of thou. This thought has been brought about by observing how almost every other measurement around fore ends has variances, and I doubt very much if the recoil lug area is immune to them, so in fitting a fore end for a near to god perfect fit, it seemed the logical place to start is to make certain the recoil lugs have firm and even contact. Once thats established I'd feel more confident that next steps such as the rear fore end/wrist face fit can be addressed properly.

I mean, picture this, if the recoil lugs weren't in contact metal to wood, how would we know? And what would be any repercussions? I can imagine the group not being very tight for instance.

Do armorers simply assume that the lugs have good contact, or do they have checks that can be made? (and what are they?)

Checking for even contact in the recoil lug area must be a basic check if a barrel was sitting to one side in the barrel channel.

[S-A-M3]

Hi Roger, Had a bit of practice with this,I make them tight enough so you need to fit the fore-end with a block of wood too. If the barrel doesn`t sit in the middle of the barrel channel,
you know one side needs a piece of wood shaved off.[Assuming back face of stock is square to butt socket] Make sense?
Stuart.

[Son]

Mate, if the recoil lugs were not in contact metal to wood, then the foreend would fall off. The whole basis of the recoil transfer is the tight fit of solid wood between the (near) parallel surfaces of the butt socket and the back of the sear lugs.

This post of Peter's is for a No4 foreend, but the technique WRT the "draws" would do the job for an SMLE...

http://photos.imageevent.com/badgerd...0correctly.pdf

[Bear43]

If you do assemble the rifle and there is a gap between the sear lugs and the draws of the wood then the fore-end will be reduced to matchsticks in short order. I did an improper fitment once (my first attempt) and destroyed the fore-end in less than 10 rounds. If you fit the fore-end nice and tight (I use a rubber mallet to tap it into place) then the metal compresses the wood at the contact points and leaves witness marks on the wood. Just go by those witness marks in the draws, that will tell you if the initial fitment is evenly snug and bearing the same. That is what I go by in that area anyway.