[Unclenick]

A really common cause of pressure is a component change. If you worked your original load up with Winchester brass, which is typically light on brass and roomy, then switched to almost any other brand, you will need less powder to hit the same pressure, but will get less velocity.

Note that a tighter chamber will do the same thing. Peak pressure in guns firing above around 30,000 PSI, will depend on chamber dimensions rather than re-sized brass dimensions. Compare the water capacity of a fired case from the new gun with one from the old gun. If it is lower, then less powder is needed to hit the same pressure numbers.

QuickLOAD shows a case with 43.5 grains of water capacity is 98.1% filled with your 760 load when that Nosler bullet is seated to an OAL of 2.350". Peak pressure is just below 50.000 PSI. Muzzle velocity is predicted to be 3523 fps from a 24" barrel and 3597 fps from a 26" barrel. It also shows a lot of unburned powder (8% and 7%, for the respective barrel lengths), and high muzzle pressure (10,000 PSI range). Ballistic efficency is 21.5% and 22.4%, respectively.

Calculations show the same peak pressure will actually give you 10 or 15 fps more velocity and over 25% efficiency using 32.0 grains of IMR 3031.
A more newly identified phenomenon, secondary muzzle pressure, can occur when too slow a powder is paired with too light a bullet. Unlike detonation, which is hard to reproduce, Texas gunsmith Charlie Sisk had been able to blow muzzles off barrels with regularity deomonstrating this pheonomenon. It often is undetected at the breech, but RSI's web site has pressure traces that show it on a strain gauge at the rear of the barrel, so apparently it can show up there. Moreover, since faster 3031 will actually do better in your gun with that bullet, there is no point in taking the risk.