Gen5 Glocks in 40SW are heavier?

[Sandspider500]

My .40 throating reamer was delivered today.....

[gloob]

If the action starts to move before the bullet leaves the barrel how can there be any accuracy? Wouldn't shot to shot velocity variation mess with your timing equations?

M1 Garands have their gas port right next to muzzle, the bullet must be away from the firearm before anything starts to move.

AR-15's and M1A's have their gas ports quite a few inches from the muzzle. If those actions started to open while the bullet is in the barrel could they hold MOA to 600 yards and beyond?

I don't think you'd be worrying about your group size if the action unlocked on any 50k psi rifle while the bullet was still in the barrel! The gas from the port starts moving some parts with significant mass. And then those bits do the magic after the bullet leaves!

Every gun starts to move as soon as the bullet starts its way down the barrel. That's why the front sight is significantly higher than the rear sight on longer barrel revolvers, to adjust for the muzzle rise that occurs before the bullet exits. The only difference in the semiauto pistol is the slide is free to move separate from the frame aside from the effect of the recoil spring. As long as the bullet is out before the barrel starts to unlock and tilt, accuracy shouldn't be affected by much other than play in slide to frame and barrel to slide.

[gloob]

My .40 throating reamer was delivered today.....

Me too, I hope. I starting thinking about this experiment. And then I realized I been shooting the same loads for almost a decade. I have my system with calibrated inserts. And I just do that. I thought about all the work involved making accurate ladder loads and it's a lot.

I thought maybe just starting with a top end load, then use a 0.1 grain scoop. And add that to the next 5. Then 2 of these to the next 5, and so on. But then how much cumulative variation do you get after 10+ of doing this? Making new loads takes a lot of effort!