i've got both an uzi sub( when we coild fire such things) and a beretta 92 as well as a tok( rinco) i found that 4.5 of 231 and a 130 grain bullet would NOT push A CERTAIN BOLT back far enough to engage the sear- went up to 4.8, and finally to 5 even - that's where i'm at right now- i know both the beretta and the tok can handle that- lighter guns may not- my old speer lists 5.2 as the top end for this bullet- again, another instance of data being LAWYERIZED as time goes on- pretty soon, if this keeps up, published loads woun't have enough "ooph" to push the slide all the way back, and we're all wondering why?- my advice it to get at least 2 manuals as well as to check out the "net " loads, do up a bunch of charts, and see what works IN YOUR PISTOL- look for any loads- esp the top end - that widen the ends of your spectrum- in my case i found that 4.5 will not work in every application- she "doubles" as well as does other things at that grainage-