Yeah, you're left guessing some with the Belgian DRs.

What do the proof marks say? If there's a lion rampant over "PV" and "B. Blindee" (jacketed bullet), or "B. B"., then it MIGHT be a full nitro. If it has the PV with "B. Plomb" (lead bullet), or "B. P.", it's definitely a nitro for black. Note that with respect to the proof marks on rifles proved for NFB loads, the term "Nitro Proof" is meaningless. Nitro for Black proof is black powder proof, period.

If the rifle has PV and B. Blindee on the flats and is 6 3/4 lbs, then the only reasonable conclusion is that it's a NFB, which is the same as a BPE. Yes, the Belgians built some full nitros terribly light, but a little common sense needs to prevail. At 6 3/4 lbs, I can't imagine it being a full .450 Nitro Express.

This isn't the Boland, is it?