Competitive shooters putting 10 rounds dowrange in 60 seconds with light, skinny barrels see no accuracy change doing that then again a few minutes later.
7.62 NATO chambered Garands tested for accuracy in an accuracy cradle put three full clips (24 rounds) into 2 inches on the 300 yard target with good commercial match ammo. All shots fired about 8 seconds apart.
Barrels properly heat treated and fit to squared up faces on receivers don't bend from the heat caused by most sporting rifle use; even rapid firing many shots 15 to 20 seconds apart. If bullet impact shifts from barrel heat, that's because the barrel's hard against one point around its shoulder on the receiver. Both barrel and receiver expand from heat, but that high point puts a stress line on it that bends the barrel.
Have your receiver faced off a few thousandths, then a few thousandths shim put in between barrel and receiver so the barrel clocks in for proper heaadspace.