Tim.
It has been a concern from the start, we are putting together a piece to add on to verify if this could be a problem area. The way the rifle is shooting it doesn't seem to be a problem. We will continue to test different ideas.
harro,
Both barrels are straight .900. The barrel block and front block are delrin. The new front block has 3 1/2" of adjustment to move fore and aft on the rails, and uses a adjustable tension pad for tuning(like a mid-barrel tuner). The first stage in the rifle build, the rails extended to 1 1/2" behind the crown with a 1" barrel block that gave 10" of movement fore and aft. It didn't pan out where the block was finally placed once the barrel got some heat in it. Also both of the rear stock tubes are injected with foam to help dampen the vibration along with the middle dampener.
Bill Thanks, It's a on-going fun project, with as many possibities as your imagination allows.
Joe