Ask 'em -- seriously -- if they can bench press 315 lbs. and then watch their reaction.

Mike Pouncey and Carlos Dunlap were so offended we had the audacity to call their strength into question, they shut us down right in front of Catch in West Hollywood!

Obviously, they were just playin' ... but you can tell they weren't ALL THE WAY playin'.

What's even funnier ... we asked if Odell Beckham's 315-pound bench press should count (because of the 2-finger spot from his trainer) ... and Dunlap hit us with the real talk -- HELL NO!

Don't get it twisted, both Pouncey and Dunlap think Beckham is a stud receiver -- but when it comes to weightlifting, they don't mess around!!!