Sideways trauma may certainly be the cause of some 99 cracks, but from what I've seen, at least half of all 99's have a tang crack, so they all couldn't have experienced sideways trauma.
If you remove the buttstock, you'll see that there isn't much wood at the upper tang.
I believe there is more than one contributing factor, wood grain, stock bolt working loose, wood that has dried and shrunk over the years, improper inleting from the factory, etc
By making a brass shim (about the same size as the recoil lug) to ensure the recoil lug is transferring the recoil to the lower tang, where there is much more wood, then it makes sense that most cracks will be avoided.
I own about 25 99's and have owned over 40 over the years,
Since I started using shims , no more cracks!
As I mentioned, I'll have pics posted here when I get home on Thursday.
Last edited by EGSavage; 04/22/14.
