Recently purchased a proof research MTR 300wm. It comes from proof with the hawkins precision M5 detachable box mag. The M5 DBM seems a bit large, loud, and cumbersome for hunting. I purchased the Hawkins hunter DBM and one of their 3 round mags for a flush fit. However it seems I need to shim the hunter DBM as it sits "too deep in" and the mag does not click into place. Any tips or has someone else paired the MTR with the hunter DBM ? Thanks in advance.