Bought a Browning 300 win mag in 2013. The guy I bought it from threw in 2 boxes of Winchester 180 grain Ballistic silvertip. So now I find myself down to 4 shells so I go to 2 of the big stores they don't stock them so I went ahead and bought a box of Hornady superformance 180 grain SST. So my question is will these change my point of impact on an 80 to 100 yard shot? I had it sighted in at 1 inch high at 100 yards.

Almost certainly, yes. You should sight in the rifle again.

For sure.

And you need to shoot more

yep

Shot the Hornady shells they hit 1/2 inch lower than the Winchester at 100 yards, I didn't change the scope should be ok with that.

Worst ammo Hornady makes.

Chances are even if you found the same weight grain brand and style of bullet you would be getting a different lot number and your point of impact would still change.

For a few years before I started handloading I was starting to wonder about my scope on my 270. I had to re zero every year even though I was still shooting the same brand and weight ammo rem 130 gain core locks. But the new boxes would be up to 5 or 6 inches off from the last years. When I started loading my own and paid attention to lot numbers etc. I haven't had to adjust the scope on that rifle since.

yep

Was the only other 300 win mag shells big store had.I finally found my original shells in Brady so hopefully good to go. Out of curiosity what's bad about the Hornady shells?

I'm sure you are good to go. I'm sure the deer won't like a 180 grain SST through the vitals.

If it'll hit vitals.

Across the board, Hornady makes good ammo, and good bullets, EXCEPT Superformance. They went into that ammo to make it go real fast, throwing consistent shooting to the wind.

I've seen your same ammo, in a .300 Win Mag print 3" or more at 100 yards. And it wasn't the rifle's fault. I later loaded for that same rifle and got it under 3/4" at 100 yards. Factory Rem 700.

Hornady Precision Hunter has been quite good in several cartridges and rifles that I have spotted for.