I have a custom autococker pro stock. I always used a WWA freak barrel back on it. But i bought some other barrels online with AUTOCOCKER threads and i tried to put them on but they wouldn't. I tried everything i could think of. I do have a hard time getting the WWA back on because the body is a lil tight and with the oring the barrel back is really tough to turn but it threads on just fine once you get it started, i know this cus without the oring it threads on and off with no trouble.
Please can you help i have never had this problem with barrels with all the other cockers i have owned.