The steel frame model 10s are all fine with +P ammo.
Load them full of it!

Elmer Keith did a vintage gun test that I love to quote.
Back in the 1940s and later, the ammo companies loaded
a 38 special with a 158 grain bullet to 1150fps- near 357 Mag.
This ammo was called 38-44 Hi Speed.
He fired a whole 500 round case through a first year production
J FRAME with no trouble whatsoever. If a 38 J fame will take
near 357 ammo, the k frame M10 will have no trouble.
Source for that story is Elmer Keith's book "SIXGUNS."

Just for the record, I will put any 38, +P or +P+ load made in my Model 36 J frame.