There were 2 versions of this bolt.

The first has a few more milled ribs on the back end which made it much longer on the back end. This early version also came with a stainless pull pin.

The second version shortened the back end which made for less milled ribs. it also came with the delrin matching pull pin as well.

both stainless and delrin pull pins were ribbed to match the bolt and jackal vertical asa and cocking rods.
enjoy,
Kmac