I have one of the new DAO model 37-2 revolvers, and the barrel is marked +P.

What I can't figure out is, why? They used the old style J frame, not the new magnum frame. As far as I can tell, this is identical to the model 37's that have been made since the mid 1950's, and we all know that S&W forbid any +P ammo in those guns.

Did they somehow figure out how to make these new guns stronger, or were these little airweights ok for +P all along?

I have one of the new DAO model 37-2 revolvers, and the barrel is marked +P.

What I can't figure out is, why? They used the old style J frame, not the new magnum frame. As far as I can tell, this is identical to the model 37's that have been made since the mid 1950's, and we all know that S&W forbid any +P ammo in those guns.

Did they somehow figure out how to make these new guns stronger, or were these little airweights ok for +P all along?

The science of metallurgy advances on.

Also, today's three dimensional computer aided design programs have the ability to perform an amazing number of stress caluculations (finite element analysis) that would blow the minds of engineers even 30 years ago.

Better metallurgy + better stress analysis (both in design and in testing) = more capable firearms.

Wyatt is quite correct. The puzzling thing is why are we still seeing some many cracked frame failures in aluminum framed revolvers?

I'm convinced the problem is the assemblers cranking down on the two piece barrels to get the cylinder-barrel gap into spec without having to "fit" the barrel shroud properly. S&W should take away all their wrenches and just give them a torque wrench that only goes up to the proper torque level (50-60 ft lbs?), then spins. Would save S&W a lot of cracked frames and mis-fit barrels that break and come off the gun. It's not just the aluminum framed guns, the steel ones are also having problems.