Which has a bigger cup — Bob Reeves 42/M/s or GR Technologies 3M?

The GR Technologies 3M has a cup diameter of 16.76 mm / 0.6598 in compared to 16.67 mm / 0.6563 in on the Bob Reeves 42/M/s — a difference of 0.09 mm / 0.0035 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bob Reeves 42/M/s and GR Technologies 3M?

Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.

Bob Reeves 42/M/s vs GR Technologies 3M

Name: GR Technologies 3M
Brand: GR Technologies

The GR Technologies 3M has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

The taper behind the throat leading to the shank. Affects projection and tone character.

Mouthpiece A

Bob Reeves 42/M/s

• Trumpet

Backbores

Best suited for

🎵All-round versatile — balanced cup for general playing

Mouthpiece B

GR Technologies 3M

• Trumpet

Backbore—

Which is better?

Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.