How much difference do most of you see in POI when using different loads from a big bore. I have been noticing a lot of vertical change between loads, even the same bullet but more/less charge. No changes in windage though. Is this a normal thing with big bores?

Hi NBHunter,
I think you will find that with different bullets your POI could change in any direction. This is why handloading pays off when trying to have soft and solids hit to the same POI. Often you will end up with a velocity difference in your loads in order to gain the same POI. You may have to start by getting the velocity and sighting the way you want it with your softs as they will be the most used bullet and then try a couple different types of solids and vary the velocities in order to bring it to the POI of the softs.
Good luck
470 Mbogo

One other point is work up these loads the way your going to shoot your rifle in the field. If you have a muzzle brake and plan to take it off when hunting this can effect your POI with both bullets. I had a 416 Rigby that I tried with a muzzle brake and the POI changed by more than three inches when I took it off.
Take care,
470 Mbogo

What 470 said.. other than some advice..

to get "Started" you can look at the reloading books (or use a drop calculator) and determine WHERE you want them to be the same poi. I did some work on this with my svt-40, in that I wanted 150s and 183s to hit the same spot, at 100. the 183's where pulls from "cheap" ammo, reloaded. I had to play with the velocity, but I did get them to hit just about the same spot... I've done the same with my 416, and my friends 416s, and my 358 winnie... and other than hornady bullets in my 416, it's all been hit or miss, no pun intended.

it DOES help if they are the same weight, fwiw.
jeffe

All rifles observe this rule to a different degree, some change drastically, some not at all, and the rest in between...

Over the years, and after going through a multitude of guns, I have kept only those that shoot all loads to the same POI or close enough for Government work and were accurate...My only double rifle will shoot almost any reasonable load to the same POI and that is really rare, that's why I kept her...She also shoots under and inch at 50 yds on a good day.

Some will tell you that the 375 is known for keeping all loads near the same POI, Jack O'Connor wrote of this, but it certainly has not been my experience...With some work I have been able to make some shoot a soft and solid close enough, if not they went down the road to some gunshow.....

Most of the rifles I have owned, seen, or observed showed a wide despersion between different loads. It all has to do with barrel harmonics...

Lots of folks seem to think there rifle will shoot all loads to the same POI, or so they tell me at the SCI and Gunshows. I take this stuff with a grain of salt, try'em before you buy'em if they make that claim..

If you find one that shoots all loads to the same POI, then keep it if it will shoot'm all within say a 3" group.....it is a rare rifle that will do so..

Another thing I have noticed is that if your selling a person a rifle and mention this fact, they put little value on that asset in a rifle and you will get all kinds of uneducated/unknowledgable replys..mostly it is a non issue in their minds when it should be first and foremost....

An example of a perfect bolt gun is my .338 Win. Mauser action Custom rifle:
300 gr. Woodleigh RN zero at 100
250 gr. Nosler 2" high @ 100
230 or 225 gr. Failsafe, Swift or Barnes X is 2" high at 100 yds.
210 gr. Nosler 3" high @ 100

What more could you ask considering it shoots an inch or better with any of the above loads...

To me the above is what makes a hunting rifle and I have several that will do this to one degree or another, else I would not still have them, my 300 H&H, 30-06, 6x45, 8x57,416 Rem, 450-400, 404....I think my 9.3 may very well join the ranks...It has taken me 50 years to put the above guns together and bunch didn't make it and went paya muy rapido.

Just my thoughts on the subject for what it's worth...others perfer and are satisfied with a gun that will shoot one load where they want it, and that works too, I suppose.