Gunsmithing Opening up grayboe barrel channel

[King_beardsly]

Does anyone have experience opening up the barrel channel on grayboe stocks, I'm attempting to run a rock creek medium Palma contour but the stock are set up for Remington sendero/varmint contour. I talked to the guys over at red hawk rifles and it seems to be astraight forward process with a wooden dowel wrapped in sand paper.

 

[ken226]

Not many gunsmiths here would use sandpaper wrapped around a dowel. Thats way too much work.

Just to open up the channel for a strait barrel, Id set the stock up in a vertacal mill and make a single cut with a 1-1/4 ball mill.

But typically, i prefer to set it up in my cnc vmc and 3d contour it to match the barrel contour.

If your stuck doing it yourself without the tooling for the job' id use emery cloth, backwards around a dowel.

 

[King_beardsly]

I figured as much, maybe I'll just being it to my local smith and have him mill it or possibly let me just use the shop.

 

[ken226]

If your time is eorth money, thats the cheapest route.

I did it once with aan old take-off barrel and emery cloth.

It took me and a helper 2+ hours. He held the action and controlled the depth of the action/barrel in the stock while i, holding long piece of sandpaper by each end, worked thr sandpaper back and forth untill i reached muscle failure. Several times!

 

[GH41]

He is talking about a fiberglass stock.. At some point he will run out of laminate and into coring. I think he should talk to Grayboe or someone like LRI about doing the job.

 

[ken226]

All the composite stocks on the market use fiberglass or similar in the outer shell. Pretty much nowhere else. Its initially made without an inlet or barrel channel.

It has an outer shell that completely encloses the infill material. Its flat across the top, no inlet, no barrel

The receiver inlet and barrel channels are milled right through the shell material and into the infill. The glass shell area that is in the location of the barrel channel and receiver inlet are simply milled away.

All composite stocks, which have a barrel channel and receiver inlet, are milled through into the core material.

They have a relatively strong core material made of epoxy/glass powder blend, except the buttstock, which usually hase a foam core.

 

[LRI]

We have a service that covers this. I make a 3D surface model based off of your barrel and we throw a tool path on it.

Have been meaning to get it up on our store, just haven't yet. Give us a call and we'd be happy to help if you'd like.

C.

 

[King_beardsly]

I'll give you a call tomorrow and we can figure something out

 

[King_beardsly]

I actually saw the full inlet you guys do and though I wonder if they can do that for just the barrel

 

[BR7.62]

if you have a buddy w/ a mill to use.... i use a ball end mill and shim the stock to get the angles i want for barrel taper.
if not... i half round wood rasp/file will get you going in the right direction quicker than starting w/ sand paper/dowel.
then switch to the sand paper to finish up. seal it w/ paint.
i like to run masking tape down the sides and draw the countour im looking for. hope this doesnt let the edges splinter or get jagged but this might not be needed.

 

[LRI]

I actually saw the full inlet you guys do and though I wonder if they can do that for just the barrel

We do it all the time. In cnc programming, this is really simple. Make what's called a revolved surface of the barrel contour, scale it slightly larger, then throw a scallop surfacing tool path onto it. Any CAM package worth a snot is capable of this. If there's to be any "Ouiji" board at this at all, it's figuring out what tooling works best for both surface finish and longevity. Carbon, glass, fillers, are all very abrasive and hard on carbide. Getting the geometry correct was the biggest deal in all this when I started pursuing it 15+ years ago.

 

[ken226]

I use Inventor and Autodesks integrated CAM software, HSM. I love their post processor. It makes jobs like this a snap.

LRI knows their stuff. They will give you a barrel channel that matches your barrel in a way thatll make your very happy you didnt take a dowel to it.

Buy once cry once. Its cheapest to do it once!

 

[jtate]

I have a similar question. Can the outside of a Greyboe stock be milled or sanded to a more narrow profile? I like their Renegade stock and you can get one without waiting six months for a McMillian A-5. The only problem is that I want a Game Scout or Game Warden forend instead of the A-5.

Has anybody ever tried this?

 

[LRI]

I have a similar question. Can the outside of a Greyboe stock be milled or sanded to a more narrow profile? I like their Renegade stock and you can get one without waiting six months for a McMillian A-5. The only problem is that I want a Game Scout or Game Warden forend instead of the A-5.

Has anybody ever tried this?

Never having actually held a Graboe stock in my hand, I don't know. However:

Most (as in, every single one I've ever touched) composite stocks have a core/shell construction. Think of a hard boiled egg. Its basically the same. You could reshape it, but you are opening a can of worms that will not be easy to resolve. You'd be money ahead to just hit the reset button and find the right stock.

C.

 

[ken226]

Every composite stock ive worked on uses somethink like a glass microballoon, chopped strand or similar type aggregate filler and epoxy blend inside the outer woven/roving composite shell.

The composite shell is the only part of the stock thats strong in tension.

Think of the stock as a beam in terms of the top being a tension cap and the bottom a compressio cap. When a load bends the beam downward the top becomes the tension cap. When a load bends the beam upward, the bottom becomes the tension cap. The same with left/right vector loads.

If you sand away the outer shell, the stock will be pretty easy to break for any load applied with a vector oppodite the side missing its tension cap.

No issue with the side in compression, as glass microballoon epoxy is strong in compression. Its why you can get usually get away without pillars.

Its like semimonocoque sircraft construction. The strength comes from converting bending forces into tension forces, and transferring those loads to the glass strands in the outer shell. As LRI said, the strength is in the eggshell.

In other words. Dont do it!

 

[XLR308]

This is an older thread but after reading through it there is a lot of misinformation about the Greyboe stocks construction.
The stocks are molded from an epoxy based composite material and are the same construction throughout the stock and there is no outer shell to worry about weakening due to modifications.
I just finished one up that I put a Kelbly Atlas action in and it needed quite a few minor modifications to work with that action and the barrel I chose to use.

The ejection port needed lengthened about .625" to the rear to match the action and a cut out added for the side bolt release.
The action inlet needed a cut out to accommodate the trigger hanger and material removed for a full length skim bed with marine-tex. I opted to also bed the first 2" of the barrel to stiffen the forearm of the stock and help distribute the weight of the barrel from the action.
I had to open the barrel channel up from the standard Rem varmint to accommodate the Bartlien M24 I chose to use.
Everywhere I had to cut, relieve or sand material it was of the same density and easy to work with but I wouldn't say it was soft and didnt encounter any voids or air bubbles in its construction.
Overall I'm very satisfied with the stock so far and plan on getting another one for the other Atlas action I have.