Well I've gapped the 7700 rings for the 4000 they seem to slide nicely cant see any issues. Dont tell anyone but I used a 4inch angle grinder the file was going to take three years. Mite get the bottom end together tonight if i get a chance fun fun good times wahoo. Just like to thank all you good blokes on hear for sharing the great knowlage I couldn't of got this far without it.