As stated, if in a shoulder to shoulder match, especially benchrest, when the difference between 1st place and "also ran" is measured in 1/10's of an inch, a wise man stays sub-sonic from the get-go or starts out super-sonic and guarantees it stays that way the whole way to the target (and good luck finding HV ammo that shoots in that league). In situations like that, one swallows one's gut and springs for the $15-20/box stuff. The matches I attend see everybody shooting high end low-vel match stuff. Everybody.
The major suppliers of Eley Tenex, such as Killough's, publish the lot numbers they have available and exact velocity (supplied by Eley) obtained by those specific lots. Speed numbers vary, but fall into a very narrow band of between 1065 and 1080 fps typically. A lot of .22 BR shooters are very fanatical about such things. I shoot in single shot/Schutzen matches where .22RF competition is conducted at 100 yards, both offhand and benchrest, group size and score - and I'm here to tell you that putting ten into the 3/4" 10-ring is no mean feat, especially if there's even the slightest breeze. (The best I ever did was a 249-9C that copped 1st place that day - with a BSA Martini International + Eley Tenex. I have yet to witness a perfect score of 250 although a few such scores pop up around the country during a year.)
