Generally speaking, out of the same rifle, will a lighter, faster, lower recoiling bullet hit lower than a heavier, slower, higher recoiling bullet?

Yes

It depends on the individual barrel. -Al

In my testing of different bullets weighs, say a 130 vs 150, and the lighter has more speed, it will hit lower in my tests. Not sure if that holds for all weighs, but just what I have experienced.

Yes, mostly due to longer barrel time so the bullet leaves the barrel higher into the recoil cycle

My experience mirrors yours

I don't see any hard-and-fast rules in rifles regarding bullet weights and impacts on the target. Sometimes heavier bullets shoot to same point of impact, more or less, sometimes lower, sometimes higher. There are a lot of other variables than bullet weight that would determinative, or at least significant. But the rule bears out a lot more in handguns, particularly the big ones.

And the distance. Within 100 yards, yes. After 150, no.

Biggest difference that I ever saw was helping a guy sight in a Browning BAR during our annual sight in days. Without touching a thing and only changing brands of ammunition and maybe the bullet weight, his .30-06 was grouping into the next target over.

I had a Remington once, I've since been cured of my affliction, that grouped different bullets so far apart that you had to come back tomorrow to check your targets.

The worst I've ever seen was a .30-30 lever gun. My brother in law brought his son in law's rifle to check zero. He had a box each of factory Remington and Winchester ammo of the same weight bullet. We shot the rifle at 100 yards. The rifle was plenty accurate enough, but the groups were 8 inches separated vertically. So we set it for one or the other and told the owner to only use that ammo.

This past week, my 38-55 Marlin shot 200 grain bullets four inches higher than 255 grain bullets at 50 yards, both loaded pretty warm. I've generally found that the big, slow calibers (38-55, 44 mag, 45-70) vary more from bullet to bullet than the smaller, faster calibers do. I had a Ruger 77 30-06 years ago that would shoot almost everything from 150 to 180 grains to about the same point of impact at 100 yards.

I have a Rem. M700 that shot most any bullet to about the same point of aim and was more than accurate enough. Through my neglect the bore became pitted and cratered and the more I cleaned it the bigger the groups became. It ended up where it was only luck to get a decent 3 shot group. It has been re-barreled with a stainless Douglas barrel and has returned to accuracy but in the meantime I acquired a very accurate Weatherby Vanguard 2 stainless that goes everywhere with me now. Point of impact with different bullets is varied with the Weatherby so I just stick with 180 SST and consider that I'm well armed for anything in Louisiana.

"Generally speaking" the op is correct but it depends on the individual gun. The only way to know for sure is to shoot the particular weapon.

That is true, but a lot of hunters will swap brands and weights and never think to check point of impact. I once investigated a hunting accident and the rifle involved had 4 rounds left in it and all 4 were different and there were 3 different brands of ammo. The shooter told me there was no way he shot a man because he was a precision marksman and very careful. It was a cheaper Remington bolt gun and a Simmons scope.

Not in my 9.3x62. It is a Ruger Number 1S. I sighted it in with Norma 232gn bullets about 1 1/2 inch high at 100 metres. 250gn Woodleigh PPs go about seven inches low and 286gn PPU factory loads are 20 inches low. I've never seen a rifle that groups different weight bullets so far apart.

A mate has a Tikka and his groups the 286gn PPU and 250gn Accubond about the same at 100m.

Don't know why my Ruger does what it does. ???

I was trying to develop .458 Winchester 350 grain loads at 2750 fps to take on an African hunt with 450 grain loads at 2200 fps. At 100 yards the 450 grain loads shot about 6" higher than the 350 grain loads. Why? Because recoil raises the muzzle and recoil starts when the bullet is in the barrel. Heavier slower bullets stay in the barrel longer. The barrel was pointing higher, with the heavier slower bullets, when they left the muzzle.

This was kind of contradictory to conventional wisdom that faster bullets don't drop as much as slower ones. That's true but after they leave the barrel.

Since then, I don't take two kinds of ammo on the same hunt. With two different calibers, I found I could take solids and soft points on the same hunt but only if they were the same weight.

I have seen this to be the case with handguns over and over and came to the same conclusion.... seems even more pronounced in a revolver vs a semi-auto pistol, which would make sense. Given the same recoil impulse, the bullet that leaves the barrel the soonest is less impacted by muzzle flip.

Follow up question.

If POI for different bullet weights and types is several inches apart left and right, what can be deducted from this?

I would deduce that you can't use those loads interchangeably for accurate shooting at extended ranges. It happens to me all the time when shooting factory rifles with light-taper barrels, with scant exceptions. I've loaded for and shot some heavy guns and heavy barrels that behave differently, as a rule.

The rifle starts to recoil as the bullet starts to move, and so POI is affected by, among other things, how much recoil and how much time between the bullet starting to move and it leaving the muzzle. Just to complicate things, the rifle doesn't recoil straight back, but tends to pivot up at the muzzle (because the recoil is transferred via the butt, below the line of the bore on most rifles). It can also pivot laterally due to things like cast and the effect of the shooter's cheek and other aspects of how the rifle's held. In fact it is for this reason that you can get different POI from different shooting positions, even without changing loads.

As well, with all of this movement the barrel is not infinitely stiff, and it tends to flex as all of this is going on, and this in turn can be affected by contact with the fore-end.

All of these things can contribute to different POI, including lateral shift.

Usually all of this doesn't matter all that much: you zero for the load you'll use, and (if you're smart) from the position you'll favour for the longer shots, and leave it at that. It only really starts to show up if you are shooting different loads, positional matches, or trying to regulate a double rifle.

All of the above or none of the above. You just have to shoot them to find out.

Had a similar experience but then saw I had one 4 shot group and one 6 shot group, wasn't an equipment problem.

I feel lucky if different weight bullets DO impact close together. I have a 35 Whelen that puts 225 Accubonds about 1/2” higher that the 200 Accubond that’s a bit higher velocity. That puts them pretty close together down range.

What powder(s) are you using?

One thing I've found during my experiments at very different temperatures is that POI can vary considerably with temp-sensitive powders.

An example from 20+ years ago was working up two loads for my .338 Winchester Magnum, one with 200-grain bullets and RL-15, and another with 250s and H4831 Extreme. They shot close to the same place at 70 degrees Fahrenheit, but not at 90 degrees in Africa--or at around zero F. in Montana.

I have an extremely accurate, custom, heavy-barrel AR in .223. It shoots bugholes with 60 grain Sierra HP’s over Varget. It also shoots bugholes with 65 grain SGK’s over Varget. The 65 grain bugholes are 3/4” from the 60 grain bugholes at 2 o’clock.