Was This to be Expected?

TL;DR What would cause my 130g cast reloads to impact higher than 115g plated or factory?


Just got back from the range shooting some freshly loaded 9mm. The load today was a Lee 358-125 RF sized to .356. These drop at about 130 grains. Powder coated with Eastman Ford Light Blue. These were loaded on top of 3.8g of 231 at 1.026" I've chronographed these at an average of 1030fps. These were hitting much higher than my standard load or any factory fmj rounds out of my CZ75 SP01. Standard load being 115g Berry's plated 4.5g Bullseye @ 1.155" ave 1160fps.
Being heavier and slower, I'd expect them to hit low. I know 38spl out of a revolver will hit higher than 357 out of the same gun typically, but I didn't think anything similar happened in autoloaders.
Groups with the cast loads were pretty good, just consistently high and to the left. Thought I may be having an off day so I switched over to the 115g Berry's. Those were dead on @ 30yds.
I could come up with some theories for the elevation, no idea why they would bear to the left.
Just wondering if you guys had some ideas, or if this is already a known phenomenon.

Howland said:

The slower velocity means the barrel has risen more before the bullet leaves the barrel.

Click to expand...

This is what I understand about revolvers, I didn't think the same held for automatics, as the slide recoils straight back. But that does make sense. Now would this account for the drift to the left? And, then, if I were to boost the velocity, should I expect the impacts to come back down?

Well, there you go, looks like I'll need to bump that up to 4g 231, and hopefully get me shooting somewhere near my point of aim. Glad I figured this out now before I loaded up a mess of them.