Over close to 30 years repairing firearms, I have used a variety of bedding compounds including, but not limited to, Devcon steel, Bisonite, Acraglas, Marine-Tex and Steel Bed. Most of my bedding jobs are M1- or M14-type service rifles with occasional pillar bedding of bolt actions.
The characteristics I look for in bedding compounds are ease of use, lack of shrinkage and a decent working time. What follows is a description of my two favorites. I’m not claiming they are the best bedding compounds, but I have had good luck with them and use them regularly with excellent results.
Bisonite: Saturn Products (719-846-7362) claims its epoxy was originally developed for military rifle teams and I tend to believe that claim since I first encountered it as a young Ordnance NCO learning to build national match M14s for military rifle teams in the 1980s.
It is dark brown with a mix ratio of approximately 10 parts compound to one part hardener, and looks good in walnut stocks. Consistency out of the container is a liquid and it is commonly thickened with powdered fiberglass as necessary to avoid dripping. It attains a semi-hard rubbery state in a couple hours, so it can be trimmed with a knife prior to hardening overnight.
I generally use Bisonite for wood stocks on service rifles. A good bedding job will last for a few thousand rounds and then it can be touched up with a skim coat if the rifle begins to loosen in the stock.
Two things I don’t like about this steel-impregnated epoxy are limited availability and its tendency to separate when stored. The only retail vendor I’m aware of that sells Bisonite is Champion Shooter’s Supply in Ohio. It can also be ordered over the phone from Southern Colorado Gun Products.
When stored in its plastic container for a while, the compound separates with the heavy solids on the bottom and oil at the top. It can be restored to normal consistency by warming it a bit in a pan of hot water or simply by placing it under a bright light. Once it is warm you may stir it to blend the ingredients.
Marine-Tex: I believe this epoxy was originally developed to repair boats and it can in fact be found at marine supply stores as well as Brownells and industrial suppliers. It’s available in gray and white–I use the gray version to bed synthetic stocks. It has the consistency of cake frosting and is easy to apply. Mix ratio is five parts resin to one part catalyst. The only thing I don’t like about it is it isn’t available in brown for wood stocks. If I could only have one bedding compound in the shop, this would be it.
An effective release agent for both of these epoxies is Brownell’s Acra-Release Aerosol.