Normal or not, I can't say, but it does happen on a lot of rifles. The Choate varmint stock my 10FP is currently on has special hardened screws that can be torqued over twice as hard as a lot of common specs call for, and they have never come loose. But the stock does need metal between the screw head and the rifle to do that as wood and plastic will give under that much pressure.
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Patron Member