What's the difference between a "heavy" M4 buffer and a "regular" M4 buffer other than one being heavier than the other?
I'm assuming it would have something to do with slowing the cyclic rate, so in a semi auto only, it wouldn't make a difference - or would it?
Also, does anyone happen to know the weights of each?
Thanks!  

The solution to most of lifes quandries, biggerhammer
IIRC the heavier buffer is indeed intended to slow the cyclic rate.

I have an M4gery that suffered from bolt overspeed.  

It would rebound so fast that the round couldn't get up out of some magazines in time and the round would get jammed between the bolt and the feed ramp with the bolt lugs putting 2 nasty dents in the brass right behind the shoulder.  

Sometimes, the round would somehow bounce up into the chamber with those dents on it and the bolt would jam just short of locking.    I'd have to dissasemble the rifle and hammer the bolt carrier to the rear (using a big brass punch on a ramped part of the bottom of the BC.

Bill Alexander saw me tinkering with it at the local range, diagnosed the problem during a cease fire and told me to get a heavy buffer.   I got the DMPS buffer that looks like the Colt 9mm SMG buffer in that biggerhammer link and that solved the problem with all but one of the 20 or so mags that I have tried.   I'm guessing that a new mag spring would fix that one.

I have shot a M4 upper on a full auto lower with the old buffer.  Man, that was hard to hold on to.  Must have been running 1,000 rpm.

I picked a Colt heavy buffer + Wolff spring in the hope of reducing felt recoil in my 16in.  And honestly I think the extra weight causes MORE felt recoil due to increased inertia.  

Gonna try the stock buffer + Wolff spring combo the next time out.  

Does anyone know what comes w/ the RRA 6 pos. stocks?  There is no H on the buffer.  I don't have a scale to find out.

Thanks.

The "H" buffer prevents bolt bounce in full auto.

If firing full auto you find that after 2 to 3 rounds the gun stops firing and the hammer is resting on the firing pin, caused by the bolt is bouncing slightly out of battery.  When the bolt is slightly out of battery when the hammer falls...the gun will not fire, just a slight dent on the primer or none at all.

In semi-auto this is not a problem because you can't pull the trigger fast enough for this to come into play.

Found this out the hard way, converting full sized M16A1s into 11.5" with collapsible stocks, when we switched to the "H" buffer they worked like a charm. Some needed it some didn't, if you really want to slow it down try a SMG buffer. This was confirmed by the instructor at a Colt armorer school. Don't waste your money on this, if you have a semi auto.

If I remember right....
regular carbine buffer is 85 grams
"H" buffer is 105 grams
and the SMG or 9mm buffer is 155 grams
didn't weigh the full buttstock buffer.