Thanks Bill for the response. I was just about to drop you an email to get your input on the matter when I thought I'd take a look back here to see if there was any more info. I guess I'll post here now so others can also benefit directly from you.
When you say, "correct length buffer tube", are you referring to one that is "milspec"? If so, is a milspec CAR buffer tube/collapsing stock vastly different in material/dimensions than one not sold as "milspec" (i.e. Cavalry Arms, or ACE)? At least enough so that this may contribute to both the feed and accidental collapsing problems? In my particular case, where I have an older M4 collapsing stock from a Bushmaster, I'm not sure who manufactured it or if it is milspec, but it does seem robust and the adjuster detent pin is metal. Is there an easily observable way to determine if a tube/stock is milspec?
When you refer to experimenting with the M4 buffer, would this be a performance improvement over the standard carbine buffer? Would you recommend an "H" or "H2" buffer? I think both are sometimes used in M4's. Again, is a "non-milspec" buffer the same as a milspec one as long as it's an "H" or "H2"? I would imagine that the only way to make them heavier would be with tungsten (I guess some mfr's could cheese it with lead maybe?). I'm not sure if you have to be cautious about what you recommend for configurations due to contractual non-disclosure issues...
Have you given any thought about adding the specific components you mentioned to your accessory line-up? It may help to eliminate issues people are experiencing by using non-compliant/milspec items and give them confident access to compliant assured components.
For the magazine issues... I realize you made the generous offer to re-work anyones factory mag that exhibited the rough spot on the die indexing hole. However, could someone with a little ambition, mechanical intuition and a dremel/emery cloth buff out the feed lips, die index hole and feed ramp and give themselves a level of assured performance? Personally, I would feel comfortable doing so.
Thanks again Bill.