Stock Stiffening: A New And Effective Way

In our never-ending search for supreme accuracy and precision from our best rifles, no stones should go unturned. I was reminded of this while shooting with one of my 13.5 pound target rifles, chambered in 6mm PPC and equipped with a 20-power scope. The rifle has a composite stock with a rather slender section extending through the small of the stock, including the curved pistol grip forward of the comb. The stock is actually small enough in this area for my first three fingers and thumb to completely encircle it.

One day as I was shooting from benchrest, I was getting a few annoying vertical groups for no reason I could immediately identify. Then, as a test, while I was viewing through the 20-power scope with the forend and buttstock resting solidly on the front and rear supports. I placed my hand on the rifle stock in the same fashion as used to fire the rifle, thumb on top, three fingers below and extended index finger on the trigger.

This was all the hand contact that was needed to noticeably spring the stock downward enough to cause scope reticle movement on target. Normal procedure in firing a rifle is to apply even thumb pressure to the stock equal to that of the trigger finger during trigger squeeze. Such pressure is not always equal between thumb and finger, resulting in uneven pressure to the stock, which was exactly what I was seeing.

Following this I shot a five-shot group while encircling my right thumb on the stock with somewhat varied contact firmness between shots, but not enough to discernibly 5 inches, which is the weakest area of bridging support as a rifle is placed across sand bags in preparation for shooting. The guide tape is pictured here used to direct the drill. disturb the scope reticle position, which was carefully centered on the aim point at the start of each shot.

Sure enough, the group resulted in vertical change from the shots fired with no thumb contact. I then tested one of my Model 40X Remington rifles with a heavy walnut stock and could not duplicate the scope reticle movement. I immediately decided to make a careful evaluation to see if any corrective measures might be applied to the offending stock. Stock Stiffening Idea The idea struck me to place three spine-like rods into the small of the stock diagonally upward through the pistol grip, straight up to the

The rods are then marked for length to fit each hole. Along, thin stick is used to apply bonding material to the walls of each hole. integral aluminum bedding system used in this type of stock. Entry for the three rods would be at the lower border where the grip cap would normally be. As rod material I used lengths of round steel files 5/16 inch in diameter. The rods would be bonded in place with J-B Cold Weld material, which has a tensile strength and stiffness near that of steel.

I felt all this should serve to help stiffen the stock in this weakened area. Final tests would tell. As a gunsmithing procedure, the work was straightforward. Apiece of masking tape was placed along side the pistol grip as a drilling guide. Three equally spaced entry marks were placed at the lower border of the grip cap for the start position of each hole. The three holes were then drilled, being sure to stay near grip center and not too close to the sides of the stock.

The holes were drilled to a depth of about three inches, or until contact was made with the metal bedding block. The material inside the stock turns to powder with no apparent strands as used in some fiberglass application. The material is very lightweight. I used compressed air to clean up the holes. With the J-B Cold Weld mixed, the sides of the holes and the rods were coated. Warming the material makes insertion easier. If necessary, use a punch to help insert the rods so any air can be pushed out.

As a finishing touch, use J-B Cold Weld to fill the holes flush and finish to the same color as the stock. Similar to endoscopic surgery, the holes are small. As an alternate method of covering the holes, I ap- Paint was later used to match stock color. plied a decorative brass grip cap to the stock on one of the two rifles. Testing The Work The rifle was set aside in a warm place for 24 hours for the Cold Weld material to set firmly before testing it.

With the rifle placed in a padded vise, I could immediately feel there was an increased stiffness in the involved area. This was further borne out as I placed the rifle on firm sand bag rests. The stock definitely withstood hand pressure better as I pushed down on it with the reticle of a 20-power scope fixed on a oneinch aim point at 100 yards. It also

Adding stiffness to the narrow area of the stock helps reduce flex while shooting. made shooting those small groups on target noticeably easier. Would I recommend this stock stiffening procedure for all rifles? Perhaps not. But where pinpoint accuracy is sought after, as in benchrest shooting or long range varmint shooting, it gets my nod. Where we can improve accuracy without a great deal of cost or effort, it should be done. The two pairs of groups shot at 100 yards clearly show this.

The targets showing vertical grouping, compared with the near perfect groups, were made by purposely applying uneven hand pressure to the stock while shooting. The weaker the stock in the pistol grip area, the greater the vertical grouping is likely to be. Heavy trigger pull is a primary offender here. In benchrest shooting there should be as little hand contact with the stock as possible.

But, where a heavy trigger pull is present, thumb and hand pressure must be commensurate to the trigger pull force or the rifle will surely move as the trigger is pulled or squeezed. This is where added stiffness to a stock really pays off. AG American Gunsmithing Association