On the 98 Mauser the "Handle" is completely to the rear of the receiver bridge & locks into "Nothing". The third "Safety" lug which ordinarily had a slight clearence & did not actually add to the strength of the action, was there only in case the two front ones sheared, is relied upon to bolt these conversions. They thus become a rear bolted gun rather than a front bolted one. The strength of the receiver rails combined with that of the lug itself is what determines whether they are safe or not. As mentioned some guns designed& built from scratch as bolt action shotguns used a single rear lug in conjuction with the handle. The handle being attached to the lug neither adds to or detracts from the strength of the bolting.
