Thanks Pete for comments. I know how good the Walther is, mine is in 22 cal. I bought it knowing the fps it produces and it was solely purchased as for a target rifle.
I was just wondering if there was a conversion out there as I thought an extra 100 fps would give more reach. It still would be very accurate with the Walther barrel. I myself would not put it in the magnum range and I can honestly say that the shot cycle is very comparable to The gas rams I own. Thanks again