Pillar Bedding Article – Part II
Not long after the pillar bedding process was developed, fiberglass stocks came onto the scene.While benchrest shooters were convinced that pillar bedding had a positive effect on the accuracy of their rifles, they assumed the same process would help to improve accuracy of a fiberglass stock rifle. The process quickly adapted itself to “glass” stocks.When Chet Brown and Lee Six first introduced fiberglass stocks to the competitive world in the late 1960s, they used a process that left the stock with a “foam” core. The stocks were made officer glass cloth outer shells with the action area and barrel channels actually molded during the initial process. They used low-density urethane foam to expand the material from the inside and forced it out against the walls of the mold to form the gunstock. As a result, between the receiver area and the bottom of the stock (where the guard screws are) there was a foam core. The foam was lightweight to keep the weight of the stock within reason and when cured was rigid (unlike polystyrene of foam rubber) but had very little compression strength. In short order, it was found that pillars were absolutely required to keep from compressing the stock when tightening the guard screws
As a general rule, the same procedure was used to make the pillars as was used with wood stocks.Simply drill the guard screw holes over size and fill them up with bedding material. Thedrawback was that occasionally there would be some excessive shrinkage in the bedding materialdue to the volume of bedding compound that flowed down around the screws. While this resultedin a less than perfect job from a cosmetic standpoint, it had no adverse effect on the performanceof the bedding
When guys like my father, Wally Hart and Fred Sinclair started to take on this type of work fortheir fellow competitors they felt a need to produce a better looking product, and the use of precutaluminum pillars was introduced
When Gale McMillan introduced his fiberglass stocks in 1973, they were made pretty much thesame manner as Brown Stocks. Urethane foam was a major component; thus, pillar bedding wasa main ingredient in all benchrest stocks he made. (Gale made only benchrest stocks for the firsttwo years he was in business.) Due to the weight limitations in benchrest, light stocks were amust and the materials used were not nearly as strong as they could have been in a stock weighingmuch more. Pillar bedding was one way to make up for the lack of strength in the receiver area.