Sometimes the biggest problems looking at Hk parts is the slight differences in an item that seperate it from another similar one. Such might be the case with the M13 version of the 21E. The boltheads may be marked Hk21E - M13 but they may not be so marked. If they are not marked how would one tell if it is an M13 bolthead. Well, looking at the bottom of the bolthead where "the rubber meets the road" so to speak is the key.
In the picture below the bolthead on the right is the M13 one. The other 21E bolthead is made for German non-disintigrating linked ammo belts.
The other M13 difference can be forund in the feed mechanism specifically the sprocket. The distance between the points of the sprocket is smaller than the non-M13 to accomodate the smaller spacing of the M13 links. The sprocket also looks like its tines are "swirled" for want of a better term.
Will post a pic of the other sprocket tomorrow.
There is no difference in the bolt carriers between the two except that some are marked Hk21E - M13
I was going to IM you today to see if it would be ok if I used your pics but you beat me to it! Thanks for the addition.
P123 that is a "tweener" sprocket between the DM1 and the M-13.
The first 21E sprocket for DM-1 belts is different.
HKchuck your DM-1 bolt head is a tweener also.
First gen DM-1 bolt heads were flat sharp 90 degree on the "tooth".
See the slight chamfer which later became the large mill cut in the M13.
Some sprocket/bolthead combos will work for both links and some won't at all.
Thank you Chuck, being new to the belt-fed group here everything is a learning process, the passing on of information is one of the very special qualities to be found here on this forum.
would you happen to know at what approxamate date code they started makeing the "tweener" parts??? I imagine the HK21A3 feed mech is prob. for DM1 belts only.
OK, went looking at my feed mechs. I noticed a difference with one of them, my newest one. The first pair of pics are what clearly appear to be an M13 sprocket. The second pair of pics, my newest feed mech, I don't know, other than the spokes don't curl to the right, and there appears to be a much larger bevel to the tip of the spoke, on the inside. And, the bevel appears to be different between the left spoke, and the right spoke. Any ideas?
Newest feed mech: