Here's my Sig P290 in an open top that I wear at the 4 o'clock "FBI" position...all but invisible with an OTW T-shirt. The 2nd pic shows my carry position with a S&W M36 with a 3" barrel, again in an open top OWB "FBI" position. With the shirt worn outside the pants, it's no more visible than the P290. Both holsters are home made, but Galco and others offer something similar, but usually with a thumb break, a feature that I don' t care for...reason being, at 66 yo, I"m no longer doing cartwheels in the Wally World parking lot, nor running down BG's.
Best Regards, Rod
Best Regards, Rod