Stan pretty much covered it. An additional and important check since the 28" barrel is from a parts kit, is for headspace using a headspace gauge. Too tight is easily/carefully corrected with a piloted shell rim cutter. And although unlikely, excess headspace can also be corrected with the rim cutter by cutting a deep counterbore and soldering in a steel insert, then recutting - but that's all pretty involved for the average gent. Brownells has (or had) 20g rim cutters and inserts. frank