I have a walnut stock where the original barrel channel has been opened up for a sporter barrel and I have a fwt barrel to use! Any ideas or tricks on how to fill in the area as discretely as possible? Is it as simple as acraglass (gel) and a bit of stain to try to match the original stock?

Even though Brownells says their accra-glass is supposed to be walnut color. I find it to not match any walnut I've seen. Do some mixing of different batches to try and match your stock. powdr

Fuggetaboutit.

The best I have managed is to add a lot of actual walnut sanding dust into the mix but even then its not great.

mixing oak sawdust with clear epoxy works pretty good. trick given to me by a cabinet maker friend. play with it a little to see what you can come up with.

Ed

if it is a blued barrel I find that filling with acraglass that has been dyed black contrast makes it look ok as opposed to a brown dye that matches nothing.

It can be done. Years ago I had a Ruger 77V rebarreled with a #2 contour Douglas, leaving a wide open channel. The gunsmith, Lex Webernick, filled in the gap with a color blended material that I thought was acraglass. The color match isn't exact, but it's pretty close.

I have done it a few times.
Get a walnut dowel from Woodworkers Supply of Woodcarvers supply and spin it down to the contour and size of the channel for a good pres fit. Glue it into the channel, and when it's dry plane off the top of the dowel. Now you have a solid walnut forend again and you can simply inlet the new lighter barrel.

buy another stock

I have had very good results by glueing in thin strips of a matching walnut (about 1/4" wide) along the top inside edge of the barrel channel using a clear epoxy adhesive. Use strips thick enough to fill in the excess gap and then, when dry, re-open the channel to better fit the barrel. I then bed the entire channel as usual using a mixture of the same epoxy adhesive and an appropriate lightweight fairing filler such as West's #407. You can float by fitting 1 - 3 layers of 10 mil vinyl tape on the barrel as needed. Properly done all you will see is a thin glue line at the wood joint. Of course the stock finish will need repair along the top edge but that is normal even if just using straight bedding compound.

Used black Devcon that was sanded flush with the top surface of ones stock. Has the appearance of a full length bedded barrel, but everything is floated. Not unattractive at all.

This. Use wood sanding dust of a lighter color than your wood that you are trying to match. Mix a good amount of dust into your bedding material and bed as usual. Lightly sand with fine sandpaper when dry. Then apply a light touch of finish and you are good to go. IF you are using Accraglass get a new batch. Older stuff can give you some pin holes on the surface ......

This. It looks better than one would think.

I've used walnut sawdust, brown dye and walnut pieces. All work fine depending on the size of the gap. It will always be somewhat noticeable.
An option is to sell the current stock and replace it with another wood one.
I've got a vanguard stock I bought to replace a synthetic with. Small sliver out of the barrel channel at the forend and a larger chunk at the safety where bubba thought he was a craftsman.
I'll post pictures as I attempt repairs.

I have used a walnut strip (about 1/4' thick) glued into the barrel channel then re-inletted for the barrel. Works out fine. GD

Bed with accra-glass and then paint the stock with Rust-oleum.