Bedding

[The Sodbuster]

I see frequently where forum readers have created semi-custom rifles and accurized their hunting rifles by glass bedding the action.  If an action is already pillar-bedded and barrel free floated, is there anything to be gained by glass-bedding the action in addtion to the pillars?  Should a barrel only be glass-bedded for the first couple inches, or is there any benefit to bedding the barrel the entire length of the stock.  I'm talking about lighter, sporter barrels; not heavier, varmint style barrels that vibrate less by virtue of their mass.

[Ramrod]

I doubt there is much to be gained by fully glass-bedding an action that is pillar bedded. It might be worthwhile to glass the recoil lug and an inch or two of barrel.

[goodconcretecolor]

Glass bedding can enhance pillar bedding by providing a tighter, more precisely fitted bedding of the action into the stock. I have experimented with several different types of bedding for the barrel of my favorite hunting rifle. I glass bedded the action into a synthetic stock and used a pressure point at the tip of the forearm. Groups were nice and tight but point of impact could shift by several inches at 100 yards depending on how the rifle was held. The barrel was then free floated, groups opened up from 1 to 2 inches but point of impact was much more consistent.  
I then tried what has been called "dampened free float" where the barrel channel was filled with expanding polyurethane foam( sold under the name "Great Stuff" in the insulation section of home improvement and hardware stores). This has yielded the best of both worlds; tight groups(1 moa or less) and rock steady impact point.

[conrad101st]

how did that expanding foam stand up to the heat of shooting?  will it melt?

[goodconcretecolor]

Urethane is not thermoplastic, it is thermosetting. You have to get above 350F to start to degrade it and then it is by decomposition or charring, not melting. Automatic or high capacity gun barrels may get that hot but sporting barrels rarely do.

[KRP]

The pillars only job is to give something non-compressable for the action screw to tighten against.  Glass bedding provides a solid, tight fitting surface for the action and recoil lug to rest against.  If I had to choose only one I would choose glass bedding although both is the way to go.

[usherj]

In your situation, glass bedding can provide additional support that pillar bedding alone can not. It can help support against the twisting forces, and possible shifting, from the repeated cocking of the bolt. Only a well bedded flat bottomed action or tightly bedded recoil lug (sides of) can resist such forces. Keep in mind the guard screws should not contact the insides of the pillar, therefore can't provide much lateral support againt such twisting. The good news is that the pillar bedded action is the easiest to glass bed since the position of the action in the stock is already set. It is not likely that bedding more than the first inch or two of the chamber end of the barrel will yield better results.

[ardeekay]

"Dampened-free-float"... I like that idea !!   I will try it on a mannlicher stocked 7mm-08 that I am playing with... I tried free-float.. 2-3 inch groups... and a press. point... 1 to 2 inch but not dependable.. my next trip to Menards, I will get a can.. thanks.. Bob