Okay, fair enough. But how do we go about changing the rules and/or codifying  new techniques?

I'm working on a breech seating project with a Stevens, both rimfire and centerfire, .22LR (yes) and it would be nice to compete with it after the bugs are worked out.

All though I don't have any personal interest in Benchrest 22 Breech Seating myself. And if there are no current ASSRA or ISSA Rules to support it. I personally would not let it deter me in the very least. Sometimes we tend to get all caught up in all of various Rules. But rules are indeed a must to keep the playing field even for all and rightfully so. But sometimes we also tend to forget about what it is that actually gives a tremendous amount of shooting pleasure. And that is what we should all pursue in life and it just being the love of shooting even if it has to be outside of being competitive with anyone other than just ones self. I would any encourage anyone to go where few have gone before and to then share their successes or the lack there of with everyone else. But that is just me and how I personally feel. 
That is what I actually highly  appreciate about the CBA the free advancement to achieving the ultimate advancement in cast bullet accuracy without any restrictions in the plainbase bullet class.   

It seems to me that under the current rules, the worst case scenario would be competing in the centerfire class, where anything other than what is defined a 22, long, long rifle must compete.

Agree with CF it is not as if Breech Seated 22 Rimfire has an unfair advantage by any means. Probably just the opposite of and with the cost of un-affordable match ammunition for one to be able to be competitive.. Maybe more folks could then come out and afford to compete. I personally don't see a need for a separate match just let them shoot with all of the rest. The only reason I stopped shooting Rimfire competition was because I could no longer afford to buy the match ammunition required to be competitive. And there is a lack of freedom to adjust the less expensive Rimfire ammunition. But Breech Seating would allow one to be able to do just that and to also be able to promote one's self seeking personal accuracy. I also feel it goes hand in hand with Singleshot Falling Block rifles of the same time period as is called out in the Mission Statements by both the ASSRA and ISSA but that is just my own personal opinion. What both those organizations choose to do is simply up to them and as it should be.

" 4.4 22RF ammunition may be used in CF matches but may not be disassembled on the range proper, i.e., shooting bench or immediate area. "

Interesting and thanks Randy. The way I read it is if you bring the components, powder, measure, bullets, breech seater and empty cases one would be good to go would that actually be correct? 

I don't understand why anyone would want to breech seat rimfire ammo when you can do it so much more easily with a 22 Hornet?

Bingo! In order to go where no man has gone before.