captbill,
I think your friends are probably guessing and guessing wrong. Do your target pullers report sub-sonic impacts or yawing bullets? What's your vertical like. Plenty of folks shoot your combo in 1K benchrest with great results.
F-Class is a different kettle of fish because of the much longer interval between shots and the resulting much greater change in condition between shots. In benchrest you can get your shots off in less than 30 seconds but in F-Class we're talking about 10 minutes or so. So the problem that confronts you is that your bullets drift more, a lot more at 1K than at 600 in moa in an identical condition and in 10 minutes you get a lot more condition change than a benchrest shooter deals with. You can't address this with a minor change in velocity. An additional 150 fps won't turn a mid-nine into a ten.
Just as an aside, without running the numbers I'd bet that the small reduction in drift that you get from the Dasher's greater velocity would be completely undone by the lesser bc of the 108's you want to try compared to the 105's you're shooting now.
The difference in your results between 600 and 1K are universal. Everybody shoots better scores at 600. At the Nationals this year I was in the top 10 at 600 with my 6BR. Much different story after we moved back to 1K. If you want to minimize that difference between 600 and 1K you'll have to do it by improving bc. The top dogs are running 7mm's in spite of the recoil for the higher bc -reduced drift they offer.
These pictures are a 600 yd target from the last BR match at Piedmont and the last NC 1000 match that I shot that same month, both shot with that same 6BR as the F-Class Nats. Conditions were not much different for the two targets. And I don't think that these targets show any meaningful loss of acuracy between 600 and 1K. Both five shot groups went down-range in about the same time it takes to get one shot off in F-Class. The first three shots made the wad in the middle of the 1K group according to my target puller. Who knows what faster shooting might have produced. Fishtailing wind are tough. A little more velocity wouldn't have changed much for me though and probably won't for you either.
For F-Class I need better wind reading skills and strategy as most of us do. But I'm screwing a 7mm together for F-Class to help. If you want to change your rig to reduce drift increasing caliber and bc will be more rewarding than increasing velocity.
Greg
