I put together a complete RRA upper with a C product poly magblock and im having feed issues. The bullet is getting hung on the feed ramp. Their is no adjustment on the block. The mag is .0625 below the ramp when installed in the magwell. I know this was a cheap magblock. What is the best way to go. I looked for a better magblock and a possible dedicated lower this weekend at the gun show with no luck. Any advise from someone that has one that functions properly would be helpful. Thanks......