We have some strange rules.
One piece rest. I think it would be a great advantage (Ben might chime in here as he used one in the USA when he was there).
Another rule that is strange is the reflective tape. You can use it if it is glued or sewn on. You can't just sit it there. It seems there would be a great advantage if it just sat there but I can't figure it out.
Kim

I think you'll find the one piece rest is not the only difference in the rules. ARA has an 8.5lb sporter class and everything else is un-limited in the truest sense. No dimensional, scope power, rest or weight restrictions. Bit like our emperimental class in centrefire. Are the rests an advantage. Well once you get your gun setup for them, absolutely they are. Takes all the fun out of it really.
Everyone is transfixed with barrel tuners these days but there is as much to be gained from correct bag and rest setup. I halved a shooter's group the other day in the tunnel by merely adjusting the placement of the rear bag

Guys
Up until around 2011 or so RBA in Oz was run as unlimited class and the one piece rest was legal but nobody used one.

I’v used them in the US and compared to a joystick rest the one piece are very slow to move to and from the sighters quickly.

One thing that would be a problem on some of the smaller rangers here is, where would you store them between details? They are heavy and take up a lot of space behind the firing line.

Peter

I found them to be terrific
Know that is not a technical term but I will explain
The one piece rest with the return to battery occy strap is a no brainer you don't have to be gentle on the thing at all
Just twist and shoot and it all stays exactly where you put it on point of aim
But it isn't just the fact that its a one piece solid rest, the one I shot didn't have a sand bag at all
It had polyester type plastic with bearings in the bottom and sides on the front (spring tensioned)
The back slide between two rounded pieces of plastic

With these rests forget about pushing on the back of the trigger guard or free recoil, just squeeze the trigger and move to the next target
You can shoot fast with these rests but as Peter said the travel time is slightly longer to and from sighters

Kims stocks work very well on these one piece rests as they are parallel
But the fact is one piece rests are against the rules so we simply can only dream

Saw one rest that had a piston driven return to battery which I thought was a great idea
There is more to ask of the shooter with our separate front and rear rests which makes our style more of a challenge

Just like a one piece rail a one piece rest will remove one aspect that can affect alignment.

Rimfire is becoming a game of trigger pulling. With the magnificent equipment now available I wonder how much skill remains. The constant need for perfection is almost up to computerised shooting without all of the human skills. One piece rests remove so much of the technique needed to get good scores and again basically remove contact with the rifle, kind of like sitting in the loungeroom and using a remote control. Let's keep competition literally in our hands and work the rifle. I really don't think we need one piece rests where the rifle is basically locked in. Just my thoughts.