Block bedding help

[rifletuner]

Guys

I need some advice from people with experience barrel block bedding a rifle. I have a heavy rifle in 308 Bear which is barrel block bedded. This is not a common method of building a rifle over here and I wonder if there are techniques we are not aware of. It has been very difficult getting detailed information out of those building rifles.

My rifle barrel is glued into a steel sleave with epoxy for the full length. I am not getting the accuracy that I would expect from quality components and tend to think its related to the bedding. The photo below shows a bronze sleave on my rifle, but this has been replaced by a straight steel cylinder of similar dimensions, however it does not extend back over the action. Can anyone talk me through the key aspects of this bedding method?

Thanks

Fergus

 

[Dan Conzo]

What length barrel is it? What is the length of the block? How close is the block to the receiver? What provision are you using for a recoil lug? How many guard screws does it have? Is the action free?

Dan

 

[rifletuner]

Dan

Answers as best as I can offer:

What length barrel is it?

It's a 32" blank with a finished length of about 31"

What is the length of the block?

Er… about 8" I will measure this and confirm

How close is the block to the receiver?

Will have to check exactly when I get home, but I would guess ¼" to ½"

What provision are you using for a recoil lug?

None

How many guard screws does it have?

Not sure exactly what you mean here. Do you mean on the block or somewhere else?

Is the action free?

Yes it is. No stock contact on the action or barrel.

Fergus

 

[Dan Conzo]

Fergus

The norm is 9" length block for Heavy Gun with 30-31" barrels with 4 guard screws in the center (evenly spaced) of block usually 1/4x28 pillar bedded. Our blocks are usually flat bottomed with a draft (taper) from center line of bore to the bottom in the front about 10 degrees and side about 2 degrees for ease of bedding and removing, the back is flat as this is the recoil lug. The bore hole is usually .050" to .100" (glue area)larger than the diameter of the barrel.The back of block is usually 1/4" to 3/8" from front of receiver. Most of the blocks are about 2 1/2" wide due to the availability of stocks. Scopes are mounted both ways extended from block and on the receiver. Tuning is done with handloading. Torques for guard screws (unless you have a glue-in) are anywhere from 40 to 80 inch pounds if pillar bedded. Barrel can be tuned with a tuning device if rules allow. I don't think an 8" block would hurt you or only 3 guard screws, and your action is free which is good but you need a surface for a recoil lug. On round glue blocks (the first ones that I saw in the early 70s made by Al Waldrop) I believe were machined flat on the back to act as a recoil lug. But I'm not sure of that. I do know that a lot of them were glued in to the wood with headless guard screws (for safety), people didn't quite trust the glue yet.
I hope this helps you.

Dan

 

[rifletuner]

Dan

Thanks for your comments on block bedding. I'll talk them over with my gunsmith and see what we can apply.

Fergus