Hey, Wow your on the right track! And your right I think you would still batter the gun with a steel bushing.. But you know what your doing that's for sure!! I would think a scrap piece of nylon would work it's tough stuff..PVC too.. Maybe a tough rubber that could be laminated together with contact cement.. If you need size let me know I'll pull mine and use a digital micrometer to check what you need..Good man! George