Yes, I reload for a BAR in 270. No crimping, and bullets don't change length after being magazine fed by firing previous rounds, so I see no reason to introduce another variable like crimping.
My question is what powders / bullets to you find to be accurate shooters in yours?
I think auto loaders limit powder selections because of burn rates and pressure on the gas system. Its much more complicated than a bolt gun, and seems persnickety. So far I have used W760 and H4350, but am thinking of going slower to increase velocities. I can't get over 2900 fps on a 130gr bullet without sacrificing accuracy. I've only loaded 130s of various kinds. Hdy SP, SST, and Barnes TSX all shoot pretty well. <1 MOA if I do my part.
Update on shooting with the BAR...I was always reluctant to use a bipod with my BAR because it is not a free floated barrel and I was concerned that the barrel harmonics would change. Recently I did try it and the consistency of groups increased while group size decreased. I am now capable of consistently shooting .5 MOA or less 5 shot groups. That's good enough for a hunting gun out to 550 yards.
I love the BAR because at 10 lbs loaded up, the reduced recoil of the auto loader is mild and its still capable from 0 - 500 yards of killing something substantial like a wild pig or deer, elk up to 300 or so. What I don't love is the trigger, but with enough practice you learn it...Nothing I have shot at with it has gotten away or needed to be chased. DRT every time so far.
In contrast, my Savage 7RM is no lighter, has a better trigger and perhaps is more accurate but I can't shoot it more accurately because of the increased recoil so its a lot less fun at the range. When people say a 7 RM doesn't kick very bad, I don't get it. On the bench it whacks the heck out of me and 20 rounds is max in a day for me. Maybe after all these years I still need some technique lessons. But I can put 40 rounds of 270 from the BAR downrange comfortably and still shoot 1 MOA at 300 yards at the end.
I have a older BAR 270 and have bin reloading for it .I found mine likes 51.5 grs IMR4831 with hornady 130 gr SST's. This load cronied around 2700 fps.I got to 52.5 grs and primers were starting to flatten but still good accuracy.I have also had good luck with IMR4350 , H4350 & H4831.It also likes the Hornady 110 gr V-max with IMR4350.