"Clipped and Pinned"?

A semi auto receiver has a shelf to reject full auto trigger packs. That shelf is where the from pin would go through. A semi-auto pack rests on the shelf and the front pin is not used. "Clipped and pinned" means that the trigger housing has had the head an tip of a pin glued in to give the appearance that the front pin is installed. Also includes some milling work.

http://www.hkparts.net/shop/pc/Clipping-Pinning-Service-For-HK-Lower-Housings-9p923.htm

^^ As above, the "clipping" is the modification of a full auto trigger housing to mechanically interface with the shelf in a semi auto receiver so that it'll be held in place correctly, and the "pinning" is purely cosmetic, to fill in the unused holes in the housing and to give the impression that you are looking at a true full auto receiver.

Note that these modifications are done to the *housing*, not the actual trigger pack proper. The full auto trigger packs themselves need to have a small portion removed so as to fit the shelf in the receiver, and this portion, when "correctly" removed for use as a semi-auto trigger pack (for those using surplus parts for semiauto builds) also removes the hole locations where the portions of the pack offering full auto fire are normally installed. For registered NFA full auto installations the actual trigger pack can be machined so that it will fit the semi auto shelf but still maintain the hole locations for full auto functionality. A registered trigger pack will often be set up like this and at that point is essentially plug and play onto any semi auto receiver, which is why the HK series is so desirable (and valuable): One registered pack can fit a multiple of platforms and calibers.


Willie

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