How much relief on recoil lug from bedding?

[chuckbuster243]

Hello,
I wrap 2 layers of tap around the edges of the recoil lug and bed the action and such. I sometimes put a pad under the barrel sometimes I dont, just depends on use and barrel. My main question is when I remove the action and clean up the devcon, chamfer the edges etc I relieve the front portion of the lug. Am I doing right in this? I dont relieve much just enough to make the lug slip back in easier without any chips. I would like to hear thoughts on doing this. Thanks, Matt

 

[Erik Cortina]

Put tape on the front, sides, and bottom of recoil lug, not the back.
The amount of clearance does not matter as long as the back has none.

 

[Preacher]

I use custom tapered, and semi tapered lugs and never worry about it...
I also only tape the bottom of the lugs....
If any of the sides of the lugs are taped off I would think it would have a tendency to create more wiggle room, and I don't want any of that partial bedding, fully bedded except for the bottom has always worked for me...

 

[chuckbuster243]

I always keep it tight to the back. I like the idea of tapering one on the surface grinder and just tape the bottom... Next one I do I may try that. Thanks guys, I always like trying different things. Matt

 

[Toby Bradshaw]

I use custom tapered, and semi tapered lugs and never worry about it...
I also only tape the bottom of the lugs....
If any of the sides of the lugs are taped off I would think it would have a tendency to create more wiggle room, and I don't want any of that partial bedding, fully bedded except for the bottom has always worked for me...

+1. On a round action, the only effective anti-torque surface is the side of the recoil lug, and the only thing stopping the action from sliding forward is the front of the recoil lug. The action screws should not be touching the pillars, so without bedding the sides and front the recoil lug you are counting on friction to hold the action in place (if it's a round action).

I doubt that it really matters whether there is clearance under the lug, but since the whole bottom surface of the action is available to keep it from moving downward, I always tape the bottom of the lug.

95%+ of short-range BR rifles have glued-in actions, and you can't get a tighter fit than that. So I'm not sure why anyone worries about bedding all the way around a recoil lug.

 

[Preacher]

I use custom tapered, and semi tapered lugs and never worry about it...
I also only tape the bottom of the lugs....
If any of the sides of the lugs are taped off I would think it would have a tendency to create more wiggle room, and I don't want any of that partial bedding, fully bedded except for the bottom has always worked for me...

+1. On a round action, the only effective anti-torque surface is the side of the recoil lug, and the only thing stopping the action from sliding forward is the front of the recoil lug. The action screws should not be touching the pillars, so without bedding the sides and front the recoil lug you are counting on friction to hold the action in place (if it's a round action).

I doubt that it really matters whether there is clearance under the lug, but since the whole bottom surface of the action is available to keep it from moving downward, I always tape the bottom of the lug.

95%+ of short-range BR rifles have glued-in actions, and you can't get a tighter fit than that. So I'm not sure why anyone worries about bedding all the way around a recoil lug.

My thoughts exactly.......

 

[sparky123321]

For expansion from heat I always use one layer of painters tape on entire the recoil lug. Some recommend two layers of tape on the front and the outside edges of the recoil lug. I've done it both ways and never noticed a difference except it takes a little more wiggling to remove the stock from the action with one layer. Recoil and the slight play in your stock holes will normally cause the action to butt right up against the rear of the recoil lug as long as you don't have too much play to the rear of the lug. I also remove all the tape the next morning, clean up any release agent used and tighten the action bolts to the recommended torque(sometimes even a little more). Most of the epoxies I've use seem to have a "little give" the next day, so this make the bedding fit like a glove.

 

[Toby Bradshaw]

For expansion from heat I always use one layer of painters tape on entire the recoil lug.

Steel has a thermal expansion coefficient of about 8x10-6 in/in. If a recoil lug is 0.250" in thickness, calculate the the temperature change required to expand the lug by even half a thousandth of an inch. Hint: it's not achievable by shooting.

In addition, when a lug us in close contact with metal-filled epoxy, the bedding acts as a heat sink. Not that it matters, if you do the arithmetic.

Most of the epoxies I've use seem to have a "little give" the next day, so this make the bedding fit like a glove.

If your epoxy has any "give," it's the wrong bedding agent. Devcon 10110 (which is what I use) has a compressive strength of more than 4 tons per square inch -- it doesn't "give" under the torque of action screws.

 

[sparky123321]

If there is any expansion to the recoil lug the greatest would be to the bottom and sides. I use an industrial steel filled epoxy. The give I'm referring to is before the epoxy is 100% set. I believe some epoxies can also expand due to heat, so a layer of painters tape on the front, sides and bottom of the recoil lug is not a bad idea. Painters tape is only .004-.006" thick. The most important and largest contact areas in a bedding job are the bottom of the receiver and the rear of the recoil lug. It would be a very bad idea to have the sides or bottom of the recoil lug contacting the bedding before the receiver is properly torqued and in full contact with the bedding.

 

[sparky123321]

We really are a crazy bunch aren't we. Discussing the thermal expansion of steel and the thickness of painters tape. I realize many of the steps I take when building a rifle or reloading probably add no "real world" value to the final outcome, but I just can't help myself. Being OCD can really suck at times, but it has allowed me to be very accurate and safe especially while reloading.

I hope everyone has a great Sunday. Unfortunately, instead of heading to the range today, I'll be spreading mulch with "the better half". Hope to get out latter in the week though.

I really appreciate all the great tips and assistance I've received on this site as well as all the purchases and sales I've made over the years.