They make different grades, lite, standard, and heavy. I've found that the heavy stuff is really thick, a little too thick. All the gun greases in my arsenal perform the same and I can't really tell the difference between any of them. Regular wheel bearing grease would work just as good.
With that being said, the only handguns I like to use grease on are Sig's and 1911's. I would be more inclined to use a good gun oil on a HK. They have tight tolerances.
10 Acura TSX 2.4 QS 5W30 syn
13 Yamaha XT250 Valv 20W50
09 Chrysler TC 4.0 Chevron 10W30
06 GMC Sierra 4.8 QSGB 5W30
02 Suzuki DRZ400 Valv 10W40