Summary:
At 100Y Gen 2 avg. was 0.626" with a velocity of 1,099fps, SD of 5.9, ES of 22.9 taken over 46 shots. Better than my Semi-Auto Benchrest Precision (SABP) "control group" (which is my current go-to at 0.738-1.75" (but weird things happened Sunday with the SABP that I think opened it up a bit from what I'm used to during testing which I'll explain below).
Result
Needs more testing as the slow fire vs rapid fire strings were more than a little disconcerning having almost 3/4" INCREASE in group spread on the slow fire(?, which seemingly should be the opposite). If the groups end up being accurate though, the $7-8 per box price increase over SABP would buy me just under 1/4" reduced group sizes. So $8 to go from just over 3/4"down to just over 1/2".
Testing Details
Let me preface this by saying I definitely wasn't feeling "steady" on any of these. Only time I had a chance to test was during a Recreational Rimfire Match at my club last Sunday. I arrived almost too late to shoot cause I had to chase down the Fedx guy in my neighborhood delivering these from Killough because Fedx missed my scheduled delivery date (was supposed to be Sat. so I could leisurely test these all weekend). Arriving at the match I ended up rushing to get my equipment setup, put out my targets, get my gear in order, etc. and even during the barrel conditioning shots I could tell I was waggling more than usual off a bench, where I usually like to shoot testing stuff like this relaxed prone on a mat.
Rifle is a Bergara B14r with DI Precision 24" barrel with a Stiener T6Xi set at 30x in an MPA JAE Gen5 stock, shot off an Atlas and rear bag on a wooden shooting bench. Conditions were: 91 degrees F/29.3Hg/59% Humidity.
Keep in mind although this is a 50Y UIT Smallbore target I was shooting these at 101Yards.
First Volley: 5 shots on each except for 4 shots on top left target as I miscounted. Top 2 slow fire targets I had 10 minutes time to complete. Bottom two targets are Rapid Fire, 5 shots in 30 seconds. Last lower right target I made a 0.1 click adjustment down (and possibly right, don't recall but looks probable). What's interesting is the Raipd Fire sequences on the bottom 2 targets were much better. Possibly shooting them all in a lull in the wind?
2nd Volley: Again, top two taregts slow fire in 10 minutes. On both those left hand flyers it was definitely NOT me. It "could" have been wind but the gusts that day were super small, like maybe 2-3mph coming from our 4 o'clock which
may account for it? Again, interesting the rapid fire shots on the bottom 2 targets were excellent.
So just for yuks on the thrid volley I threw in some SABP. I was thinking, lube is probably the same right? So I only did 5 sighters and made a slight scope correction for what I thought would work. What I got was a jam-o-matic. Almost every other round failed to extract. Not sure if it was Gen2 lube related or possible carbon ring build-up pressure from the Gen2 switchover, but never had THAT happen before in this rifle with SABP. On the bottom rapid fires I was trying to toss them in one-by-one and extract by running the bolt two or three times. Finally gave up on that last target as I could feel I wasn't lining them up properly by hand and was getting lead shavings in my results. BTW: ~3/4" groups @ 100Y out of SABP is about the norm that I usually see shooting our clubs NRL-style matches. And my SABP velocity is ~1,070fps on average, so the Gen2 stuff is definitely faster by about 30fps.
Hopefully I can get out and try it in my CZ457 (Whidden Lothar Walther barrel, Vanquish stock) but I still am having trouble with MPA's new side mag. release mechanism properly angling the rounds into the chamber without shaving the lead a bit. I may just feed them by hand very delicately into the chamber as I want to see results from another rifle since I still have 2 1/2 boxes of this Gen2 stuff remaining.