A cursory search for 6mm Dasher guns didn't turn up any except high $$ custom guns. Who makes them for normal people?
The 6 Dasher is not a standard rifle caliber, but any good gunsmith can chamber one for you. I chamber my own, and have a chamber reamer for my needs so it will only cost me the price of about $400 plus $20 shipping for a new barrel blank to chamber the next 6 mm dasher barrel when I shoot this one out...so I don't get concerned about barrel life. I understand that most shooters are not retired machinist with a machine shop... so they must depend on others to do the work for them. I use mostly Bartlein 5 R barrels these days because they tend to shoot. Order from Bugholes or Southern Precision rifles. Go to their site they not only have a variety of barrels but chamber them for certain actions and you can assemble it with a go-gauge and Ramage style nut, with their bugnut...
Others provide this check with barrel makers, it's probably the least expensive way to get into 6 dasher. A machinist is the best job in the world. I recieved my Bartlein barrel blank at noon, took the barrel off an old Remington action, trued the action, threads, face reciever, threads & lugs and bolt lugs, bolt nose, check bolt face for square. Mill & Install m16 Extractor, mill down bolt knob, and thread 5/16" x 24. Turn bolt knob on lathe, and mill a grenade pattern in it. Next to the barrel threaded it chambered it, threaded for a Area 409 break, torqued the barrel to the reciever...check headspace again, assemble the rest of the rifle, install into an aluminum chasis and torqued in the barreled action. With out skim bedding this time. Rifle done 8 hrs or so load up some ammo ...and shoot it the next morning with in 20 hrs, ..from barrel blank and parts, to complete rifle along with reloaded match ammo ...in 20 hrs. My 6 mm Dasher, was shooting tiny groups right from the start. Did I say, "machinist, the best job in the world." Right next to being a tank commander....for sure.
And ya never have to wait months for someone to build you a rifle...and you can do crazy things no one else would do....got an idea build it. Thats how ya run 230 gr ATIPS at 2620 fps out of a 308 case. A 308 case will develope over 3600 ft/ lbs of muzzle energy with 200 gr SMK at 2856 fps my go to load. Also a ulterd 300 RUM reciever to feed 4" cartridges running 250 gr ATIP over 3000 fps, or 3100 fps in a 30" barrel... Or a roughing die to bring 30-06 or 308 down to 8.6 Blackout one pass no lube required no annealing and beautiful 30 degree shoulders ...I should patent this one, it is a good idea. But people don't do that anymore just let someone else make it for them.. and if acquired the skills and a productive logical thought process, you can make it yourself...and, better, alter it, improve it ... Life is a learning experience I've never stopped learning. And maybe it's just a hobby, but it's more rewarding when you can carry out your ideas in metal...its solid...and your efforts will be here, long after you're gone. Todays lesson...