If the rifle wont shoot without a tuner a tuner wont make it competitive,if it shows promise without a tuner then it may be worth a try with one fitted......
.........if you actually tune the thing that is.
Barrels........................are a bit like ford vs holden some have a favorite brand and thats that,soon as someone cleans up at a comp the first questions are what ammo,what barrel.........................most if not all the current match grade barrel manufacturers are making some pretty good stuff.
As for the long and skinny barrels with tuners fitted as per the trend in the states,well that is more of a neccessity to make there weight limit of 10.5lb's where we have the custom class limit of 14lb..........
................and they worked out that the longer barrels when tuned shot pretty damn good.
Actions.............................I would love a custom action,a mate just got one and it is sweeeeeet to use and it shoots BUT I have spoken to some pretty good smiths here in Aust and most all of them say that yeah the customs are good to use,smooth,port/loading options but for flat agging ability offer no real advantage over a well setup 54 or the like.
If it has or can have a decent trigger fitted,has good ignition it more than likely can be made to shoot.
Mr Bill Calfee..........................................he is no doubt a world class smith,great sales person and an exellent self promoter and his rifles usually end up in the right hands to be used on the world stage..........he is not silly

I was having a conversation with a lady that was lucky enough to compete at the worlds in Italy and used a team USA rifle now only a fool would think that the ammo and rifle wouldn't work together but this lady said that it was unbelivable to use and shoot with.............................................she went alright with it as well.
If you have a good action,trigger,stock and smith to put it together then there is no reason for it to not be a shooter if only it was that eazy.
Another thought pin or thread the barrel to the action,some smiths say that threading is not required and more work for nothing and yet others say threaded is the go......................I am undecided on this one.
A smith in Victoria reckons that the 2000 series Annies are a good candidate for a screw and glue job,he filles the screw holes with epoxy so that the temptation is reduced to fiddle by the owner..........have seen one that was barrel blocked and it went alright as well.
And if you havent got the right ammo,cant interpret what a flag is telling you all the Calfee rifles in the world wont help ya.
Disclaimer.................the above opinions are by Chris who has won nothing of note,and they may just be worth what you paid for them

Regards Chris.