My Model 10's

[Tupperware]

They started marking the bull barrels as +P with the -10. But realistically any bull barrel 38 is +P

Where would this be stamped? My heavy barrel model 10-10 is not marked

 

[b737lvr]

Where would this be stamped? My heavy barrel model 10-10 is not marked

Interesting... looks like the last -10 I saw had its barrel replaced then because yeah the -10s I'm seeing online all have the traditional roll marks

 

[Doriangray6]

What makes it a +P barrel?

The barrel is stamped +P which, according to S&W , means that it's rated for higher pressures than regular barrels.
It was one of the firearms I ended up with after my old man croaked and was made in 1994, exported as a PD firearm to someplace, and then imported back into the states by CIA - Century International Arms.
As far as I know the 10-10 series all had heavy "bull" barrels but among the disorganized paperwork in his gun safe was part of a receipt from S&W indicating that they had replaced the original barrel because it was cracked but I don't know if it had a cracked barrel when he bought it or if he cracked it as he did have a tendency to build hot loads for most of his firearms.