I am installing a gracoil recoil buttplate on my kimber 8400 montana, chambered in 300WM, due to some issues and concerns with my scope. I lapped the rings, tightened everything to specs from IOR and Kimber regarding the base and rings. I also put locktite on all of the screws involved in mounting the scope. I have put a douglas premium barrel with drilled in muzzle break to add weight and reduce recoil already. Additionally I re-glass bedded the stock so everything is tight with the barrel properly free floating and the recoil lug tight fitting. The rifle will drive tacks (1/2" groups at 100yds) for about 100 rnds then innevitably one portion of the scope mounting system will vibrate loose, (with the most recent incident being the base itself). An additional measure I am taking is installing a gracoil recoil reducing butt plate (should arrive today). I noticed in taking the factory recoil pad off that the buttstock itself is hollow on the inside. I am not familiar with what the stock is comprised of, but it almost seems as though it is a rigid plastic as opposed to a composite resin or fiberglass compound. The walls in the buttstock are about 3/8" thick. The buttstock is filled with a rigid, and fragile, styrofoam. It does have tapped guideholes for attaching a butt plate, however with the gracoil buttplate having an internal piston it needs firm bracing within the butt stock. Here are my questions:
1. What compound would you use to fill the buttstock? ( I am currently planning on using an industrial two part epoxy with fiberglass fibers mixed in)
2. What in your experience is the best way to remove the styrofoam from inside the buttstock? (I plan on scraping it out, then prepping the inside with an MEK wash or mineral spirits)
3. What additional steps would you take along with installing this butt plate to reduce recoil? My main concern is no longer weight, (considering the time and money I have invested in this rifle), its reliability. I have slowly brought this rifle from the POS I purchased to fine tuned, but this issue with the scope is driving me insane. (No i do not want to replace the stock, have a Mac A5 on my 700 and I know this factory stock is flimsy from what I have seen, but the look and feel has grown on me)
In closing do not buy a Kimber 8400 Montana unless you want to put up with the frustration and heartache I have had to endure for about 8 months now. On the other hand it has been a nice little project. Thanks for your input!