OK, this has probably been discussed before, but I didn't want to go searching thru several years of posts, so please be kind.

I bought a CMMG .22 LR conversion for one of my AR's and was thinking that I would just leave it in and use that one as a dedicated .22 that could be switched back to 5.56. Then I got concerned that shooting a steady diet of .22's thru it might mess up the gas tube with a buildup of lead.

Is this a valid concern? Would there be a difference if I stuck with ammo with "copper plated" bullets like CCI Mini Mags rather than just shooting the cheapest lubed lead ammo?