It's pretty clear from the syntax that he left the word 'no' out of his sentence by mistake. " There was signs of extreme pressure at all." was meant to be "There were no signs of extreme pressure at all."
Because you are using a fast powder, you have a high peak pressure that drops quickly as the bullet moves toward the muzzle, where a slower powder would have a lower peak pressure, but sustain pressure and acceleration down the barrel better to get you to the same final velocity with less stress on the gun. QuickLOAD is calculating 8.9 grains of TightGroup peaks at about 41,000 psi. Going to 9.6 grains of Power Pistol or to 13.6 grains of 2400 should give you the exact same velocity at only 22,000 psi and 20,000 psi peak pressures, respectively. That's about half the peak pressure of the TightGroup, so it is going to be a lot easier on the gun. Plus it leaves you peak pressure headroom to spare, which you can use to load up to higher velocity and energy. Alliant 300-MP should get you even more. With the right powder choices you can gain 20-30% in velocity and 40-70% in muzzle energy and still be at lower peak pressure than you have now.
The load should get more velocity from a rifle's longer barrel, but for the same reasons outlined above, if you want to be in the velocity range that load would produce in your rifle, it would be better to use Power Pistol or 2400 just to keep from beating up on the gun. 300-MP would give still more velocity, but needs to be operated at higher pressure to burn well. I would not run it at under 30,000 psi.
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