Barrel shimming is old school. Just another method of stabilizing the barrel.
Only testing in your rifle will determine if it improves or worsens results.
I shoot a fully bedded barrel in 17 hmr, here's a couple of 30 shot runs at 50 yards.
Only problem I have is with ammo quality. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/_KOpahXBN-lITrZajnBA8nkukXiQMsudFw4IsfAG9Pli_QmGTipwCMcwwJ5uI8lrJIKhNxDXrM-dVg=w513-h660"}[/IMG2]
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/NFJ28XO-ZHuIZXbeopfEniieKX95j4Arb4UCIHV4rEzqtxbelXLVhkUFh8eNSV_pHaqhrrAxYiyb-w=w516-h660"}[/IMG2]
At the end of the run where heat build up is the greatest, no shift shows up.
Those were shot with this setup [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/8B-0JL-YiAOqflkNS4zrbgZx0Kh0hCDqyiYw_QQu5ex8QN6eU8TDHPT13TwVIA-hOTO-JNd-rrrnbw=w448-h220"}[/IMG2]
atop these shims [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/DDkMHIAXcruQCJGJT8NzUYmVP0xDtvz2z1b9doChrpyDqYf08okAdQueF4QzLW6cdFKIhcs0fni8cA=w248-h440"}[/IMG2]
All you can do is try it.
If it works, keep the shims.
If it doesn't, remove them.
Here's a 30 shot run at 100 yards
from the 455 barrel block SOF
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/CPz5W0ylKfirapaUnAR-dn1OGRojSWTO9H0nNISC_VX-Uo7M-OiOCBqxXJReRf1HGWa5YYDbEeeouQ=w522-h660"}[/IMG2]
Ammunition quality has more effect than temperature change.