anyone make an AR10 platform 22-250?

If I’m not mistaken, and I probably am, but I believe Armalite made a limited production run of AR 10 rifles in the early 90’s…
Calling Sinister Dave…!
 
Olympic Arms used to make an AR-15 with a modified Magwell and special magazine. The backside of the magazine well where the forward part of the trigger guard is had machined reliefs in it to where it cut through the Magwell. It wasn’t ideal.

iu
 
Black Rain Ordnance made a 22-250 AR. I shot one at an LE demo and it shot well. Yes its the magazine and feeding which is the normal issue with that round in an AR, which meant highly specialized and expensive magazines.
As stated, the 22 creed is probably the easier choice, but if you have a lot of 250, or like a shorter varmint bullet, it can be done.