I'm not too aux fax with many of the rules, but for sure; the palm shelf has to be flat, my OR 10 failed due to sculpting on it. The box is still used as is the 500g weight for trigger pull. I think you would have to have a single shot mag or be able to load manually. There are a lot of regs about grips. I think the best first off is to check out the rules using the link provided to be sure.