Scope zero for multiple ammo types

[Skyyr]

Hey guys,

Dumb question, borderlining noobish, but I just encountered a situation I hadn't before and though I'd get input.

I was shooting today out to 400yds with a 16" 1/7 twist AR. I typically use 75gr SMK or equivalent. However, today I ran out (I wasn't planning on shooting that far when I initially got to the range and hadn't brought much) and switched to 69gr PPU. Obviously, this changed my impact point, and caused me to start thinking about zeros.

I typically run one type of ammo out of my scoped guns, so I've never really had to deal with changing zeros, especially for long(er)-range shooting. Should I zero for the most common type of ammo I'll be shooting and then adjust for other types? Should I zero for the lowest-velocity ammo and make everything a dial-up from that? Should I take the average zero and use that? Etc.

Any tips on the best approach for this?

[joedirt199]

Zero for the ammo you will most often be using and then record the differences in ammo you may end up with so that if you are forced to use a different ammo then you can dial in the difference. If you were using mixed ammo in the same mag then the average of those poi would play more of a role.

[Alaskapopo]

This is common in 3 gun. I have my 3 gun rifles zeroed for my 55 grain FMJ load at 100 yards and I have a dope card stuck on the stock showing me what to dial before a long range stage where I use 77 grain bullets and a 200 yard zero. Pretty simple and easy to remember.
So for example my turrets are set at 0 with the load i used most often and when its time to use the 77's I dial up 4 and over 2 to the left.

[TehLlama]

I zero for the ammo I care most about being POI=POA. Anything else I can dial in a different point of aim, or most likely just accept that I'm a bit off.
For me this is going from a 75/77gr match and feeding a carbine 55gr FMJ instead, which usually just means accepting the slight imprecision in POI, or dialing for that session to my previous load to load delta (for me this means going from a good 200m verified 77gr Mk262 zero to a decent 50yd zero with M193 that's a click down and two left, if I remember correctly).