20" barrels with rifle gas?
I thought that was settled long ago, haven't heard of any reliability problems with a 20" rifle.
Yes.
Service Rifles are a different beast. They have really heavy barrels and parts, like gastubes, tend to get over-recycled.
IMO&E .093" 20" heavy barreled rifles don't have a particular affinity for powders like WC844, 845, SMP-842, 8208 and sometimes AR Comp & similar. A significant number of rifles simply won't run with those powders at that port size. If I were to speculate, I'd say it has to do with gas keys that were assembled without a sealant, but I'm not sure even that is necessarily 100%. .096" runs with any reasonable carrier and is what Frank White uses.
The heavier the barrel, the bigger the gas port needs to be.
I inherited the number drills, but I'll bet Harbor freight stocks them. You need to run them well lubed at high speed when using them to ream stainless.
