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 USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master