Re: NRA .17 HMR High Power Rifle
OK, let's interject a bit of reality and experience here.
First off, the rules do in fact support you shooting the 17 HMR in Highpower. Secondly, in a 100 yard reduced match in light winds, the 17 HMR will be an outstanding chambering for the event. I shoot 100 yard Highpower practice with 22LR AR15 using the reduced targets on a regular basis and shoot good scores with it. Wind is an issue, but your 17 HMR will have approximately half the wind drift of my 22LR, so it should perform well at 100 yards.
Finally, regarding rules- unless the match bulletin specifically prohibits you from using a scoped rifle, the NRA rules themselves do support your use of this rifle, including with a bipod mounted, as long as you don't actually use the bipod to support the rifle. Now the match director has the final say, but the NRA rules themselves support you shooting in the match. If the match director says no then your recourse is to file a protest with the NRA, but he does not have to let you shoot even though the rules say you can and the bulletin does not prohibit it.
Here is an excerpt from the 2010 rulebook changes that clarify the use of your rifle for Highpower. In the past the scope was allowed with similar language, but they revised it specifically to include "tactical rifle" for 2010.
3.3.2 NRA Any Sight Match Rifle/Tactical Rifle - Same
as NRA Match Rifle Rule 3.3 except there is no restriction as
to sights. The following restrictions will apply:
(a) No person firing an any sight rifle under 3.3.4 will be
allowed to compete with any other group of shooters
who are also firing. A competitor using any sight rifle
under Rule 3.3.4 will only be eligible for awards in
their own division.
(b)Bipods may be attached but not utilized. Ammunition
will be restricted to no larger than .35 caliber.
Go for it and have fun! If your are any sort of a shot at all I'll suspect you'll score higher than some of the center fire shooters.