Thermo fit by JP

[Djgrendel]

Good rule of thumb is .001" of press fit per inch of diameter. So a 1" bore would be served with a 1.001" bushing. You can get away with a bit more, but usually .001 per inch is plenty. I use liquid nitrogen to freeze the barrels. It will shrink the extension .004 under size in about 3 minutes. The thermal press fit will happen in less than a minute.