A few of us are using it on a Grand, I believe that vsummer uses a fuse (not sure which one) on a 2.1. The spring is compressed too much to effectively collapse on the Grand, not sure of the 2.1. Personally I have not had a short yet to determine how efficiently the VS2 works, so I must withhold judgement for later. Best to meter your resistance while atty is attached from firing pin to ground before using any atty, I do, even while having the VS2. For me its an
insurance in case I forget to meter, which is more frequent as I get older. The REOs also are so dependable that they lull you to complacency more times than I like to admit.