Re: manners t-4a bottom metal
Yes. It's a 700 clone.
Pacific Tool looks good. That's where the reamer, bushings, etc came from anyway.
But, if someone was able to recommend a specific DM system that works really well (especially with 6br ...not sure if it's more or less prone to feeding issues) then, I would take a closer look.
I'll check out the ones you listed.