I have been pissing around with a 10-22 for years that had the same problem. It's had 2 or 3 scopes on it in the last 15 years or so. I used to shim the scope mount with tinfoil. The 20 moa scope bases were always to high for my budget back then. The last time I put a new scope on it I just corrected the problem, which was the stock to receiver fit. It was a hogue overmold stock. I just piller bedded it and it solved the problem of the receiver sitting slightly higher than the muzzle. Seems like I used to shim the front mount to raise the front of the scope since it would shoot low. A fellow could also shim the forward portion of the receiver to get the barrel higher.