Home Forums Hunting & Shooting Ask The Gunwriters Bedding the lug

I've bedded my fair share of rifles but I have never really grasped the reasoning behind only bedding behind the lug. Why would bedding the whole thing hurt accuracy?

Bedding only behind the lug prevents any any extraneous particles from allowing the action to seat fully in the inletting, which can definitely affect accuracy. Since the rear surface of the lug is what actually presses against the inletting during recoil, this can work pretty well.

On the other hand, in many actions fully bedding the lug prevents the front of the action from flexing during firing--at least theoretically.

I know more than one custom gunsmith who beds both front, rear and sides of the lug, but leaves some space at the bottom to prevent particles from allowing the lug to seat fully.

When the lug is part of the action you want the action to stay or settle back to the exact same spot.

If there is no room in front of the lug it may not be able to settle or may work it's way up during firing.

To me, bedding the action and a couple of inches of the barrel shank helps stiffen the action. You can see this, stock in padded vice with wet glass. If you flex the barrel back and forth, you can see the wet glass bulge as the action flexes. Once the glass sets up, there is no flex.

Gotta see this to believe it.

DF

i have heard that many times, but then why are benchrest rifles, with very heavy barrels, typically bedded with the barrel completely free-floated? And the most accurate factory rifle I've ever owned was a Rem. 700 varmint-barreled .223 with only the back of the lug bedded.

There is a reason to bed the first couple inches of the barrel on a 98 Mauser, because the front action screw is in the middle of the lug. When the screw is tightened, the front of the action can bend if the barrel isn't supported. But most bolt actions have the front action screw behind the lug.

A recent build, a 7RM MkV/Brux/McM Woody Express, is bedded like that per my smith's recommendation. And it shoots great.

Either way, bedding the full action seems to me to help stiffen the action. The shank as part of the bedding may help with the stiffness. But, my smith said the full free float to the receiver is better for even vibration harmonics vs. the shank being involved.

I guess,old habits are hard to break. My latest build, a 26 Nosler 700 BDL, is bedded the old way, full action with 2" of shank. And, it shoots good, too.

DF

I think The bigger problem with bedding is that people put stress on the action by putting too much torque on the screws when doing the bedding job.

Put that on top of bedding up into the barrel change and things can't get out of whack quick.

Spotshooter,

Oh, I've seen that too, even from supposedly professional gunsmiths.

I pillar mine, and take great care to have nothing in a bind especially the box mag, making sure it moves some.

DF

MD,

Yes Sir, I learned that in Gunsmithing class from one of the best smiths in then industry. Best class I ever took.

I pillar mine, and take great care to have nothing in a bind especially the box mag, making sure it moves some.

DF

Does stressing or flexing really matter so long as it stresses or flexes exactly the same way every time? My objective in accuracy bedding is to get that precise repeatability, not that I'm an expert by any means. Neutral bedding is desired but not an imperative. Insofar as bedding behind the recoil lug only, bedding the sides and front make for more contact points which makes for more potential variables. If you consider the stresses in firing they are mostly back and in rotation vertically. Other forces like twisting are relatively minor and should be handled by the friction between the stock and the action - if properly inlet or bedded and torqued. No?

In the final analysis many bedding methods seem to work just fine.

As an aside one benefit of bedding is to couple recoil forces from the lug into the stock equally across the entire area of the lug. Wood is not homogenous in compressive strength. The weaker parts yield first and more force is borne by the stronger parts. You can get splits doing that.

It does.

a few common issues are the release agent being too thick, which results in wiggle room, and varied friction points.

think about the way you move a springy piece of metal, you clamp it down, and then bang it and get it to move and hold. That's something you really don't want here.

Getting a stress free, now wiggle where it counts bedding job is the key to getting a rifle to settle down and run.

Spot

I think we're talking about two different things. Take the M98 action mentioned above and how bedding the shank of the barrel relieves stress on the action. IF the action is perfectly bedded (meaning no change in the action/stock interface from shot to shot) with the barrel free, does stress on the action affect accuracy SO LONG AS the stress on the action is the same for every shot?

Now I mean this as a general example regarding the state of the action from shot to shot. Floating at the shank means the barrel is a longer moment arm and forces can as a result cause more variation at the muzzle. Shorter is stiffer. So normal shot-to-shot variation in forces causing the barrel to vibrate may (may) cause more variance in how the muzzle reacts.

I bed both behind and in front of the lug however when I put the rifle back together I put a tiny bit of grease on the lug and have no problems at all. My bedded rifles have all shot under an inch and most of them are factory barreled rifles not customs.

Shod

JB pretty much nailed it in his first 2 posts...

Even on the 98 Mauser, I prefer to float the whole barrel because there is enogh receiver ahead of the lug for support. On a Sako or Howa, on the other hand,I'll bed a short section of barrel because the lug is at the extreme front of the receiver. I like to clear the bottom of the lug on virtually everything and the bottom, front, and sides on a Remington. For at time, I bedded the sides of the lug on Remingtons in the belief that it would prevent twisting of the round receiver in the bed from torque. I really can't say that it did any good. Since clearing everything but the back of the lug had worked so well, I reverted back to that technique and have been happy about the choice. GD

At KofO I was taught on walnut to bed all around the lug up to belted magnums which then it was necessary to relieve at the bottom of the lug. On the real big heavy recoiling rigs relieve infront of the lug also. These variations were for protecting the stock only. Bedding out the first couple inches of barrel, the chamber area, was never detrimental. But we only did that thousands of times - so it mighta been a fluke. The heavy barrels don't benefit from that, because they're heavy. IMO, it's not done for vertical support, its for stability where a bit of flex, where the big boom happens, translates to the most change at muzzle, whip. I've also developed the opinion that it doesn't have to be pretty and perfectly filled to the rails and it doesn't have to be uber-specialty glue. Just get some Loctite gel, which is readily available and very high quality, and dump it in there with the intent to keep everything consistent and neutral. #1 Acquire rifle, #2 float barrel, #3 make fit neutral, #4 bed lug area without glueing action to stock, #5 mount optics. Then you're on your own.

This is true but the other unspoken fact is that some bedding compounds shrink and lose the mirror reverse fit.

There is a reason Devcon Steel is popular with those that have a lot of bedding experience, it is proven and reliable. I have also used Devcon Aluminium at it was equally good though I didn't own the rifles as long to say whether it was still good after 20 years, like I have been able to quality with Devcon Steel. As the aluminium version is to provide a color change option, it should/looks to be just as good.

John

One reason is that a lot of bench rest rifles are switch barrel rifles and bedding under the barrel/chamber would screw up the ability to change barrels.