Hi 10mm lovers! I have a gen3 glock 20 with a lone wolf .40 conversion barrel. I shot it at the range the other day and as hard as I tried not to, I kept shooting high and left. Then when i changed the barrel back to the stock glock barrel and shot Hornady 180 I shot low left. I had recently put a 21lb wolf guide spring in it. Could the .40sw be to slow for the 21lb spring and it's making the bullet stay in the barrel to long? I always shoot more left than right with my glocks and the ammo was 180grain mag tech.
What I think you are suggesting is the bullet is still in the barrel when it begins to tip and unlock. And that the amount of barrel/slide travel is different because the 180 grain 40 S&W is slower than a 180 grain 10mm. The answer is nope. It's physics. Guy named Newton. All 180 grain bullets will stay in the barrel the same distance of slide movement regardless of velocity. Bullet goes faster? So does the slide. Bullet slows down, the slide slows down proportionally.
A really close approximation of slide movement can be calculated by this simple formula: (barrel length"/slide+barrel weight grains)*bullet weight grains = slide travel". (Yes, physics nazi's I know it is actually slide+barrel mass and bullet mass, but for out purposes here weighing and using grains is good enough.)
So, for a 180 grain bullet in a hypothetical gun with a 5" barrel and a slide+barrel weight of 17.5 oz (7656.25 grains) the slide will move 0.1306" before the bullet leaves the barrel. Velocity doesn't matter. Our hypothetical gun doesnt' have a recoil spring or friction. Also, the frame is assumed to be completely fixed. These variables result in less slide travel, but they act the same for the distance traveled regardless of velocity, so for our example they don't matter.
Different barrels will shoot to different points of impact with the same sights. That is just it. Doesn't take more than a thousandth or two of difference in the way a barrel block locks up to change the impact noticeably.