With different loads, how much will the windage change?

[The Guide]

When you change loads in a sighted in rifle, how much will the point of impact change in the X axis (aka windage)? I know that there will be changes in the Y axis (aka elevation) but will it also change in the X axis?

The reason I'm asking is I want to have a big game round and a varmint/coyote round for the same rifle. If there shouldn't be any X axis change then I could just make 2 drop charts with each showing or using a respective zero for each round and then being able to dial from there. Saying that xxx grain round has a zero of 150 yards and zzz grain round has a zero of 235 yards by using the same cross hair setting.

Is this feasible?

Jay

 

[davkrat]

You never know until you try. I've had good luck with my .308 and .270 shooting the VMax varmit loads. For calling range coyotes they are close enough to my big game loads to not worry. I've had other situations where changing to another bullet might throw the POI off by as much as 4" at 100 yards. You can play around with loads to try and get the two loads to line up as well as possible.

 

[Mikecr]

'Feasible', but unlikely.
Load changes also affect horizontal, and it's a bad idea to discount it in ladder testing.

 

[jrock]

I've had other situations where changing to another bullet might throw the POI off by as much as 4" at 100 yards.

Ditto on that one. IMHO, I just load to the optimum performance of each bullet. Then just figure out where the two loads impact from each other and then add those adjustments to my drop charts. Then again, I don't varmint hunt with my gun during big game season. I change zero once for each season. Better yet, get another gun and then you don't have to change zero!!!