All stocks are just like barrels; they both flex when the round's fired. Stocks moreso than barrels. Like barrels, if the stock flexes the same for each shot, accuracy will not be impared.
I once had a Win. 70 featherweight .270 rebarreled to .300 Win. Mag and its receiver epoxy bedded. Its stock was somewhat flimsy; the fore end easily bent as did the buttstock. But it shot no worse than about 1 MOA at 1000 yards. Sometimes wish I'd kept it but a friend wanted a long range hunting rifle and he paid dearly for it.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master