Having trouble wrapping my brain around this, hoping someone’s got a good system figured out.

I’ve got a Cadex Kraken multi-caliber rifle, 6.5 Creedmoor and .338 Lapua barrels. The way I see it, it should be fairly straightforward, zero one barrel at 100m, then put the other barrel on and shoot at the same distance. In theory, I should be able to measure the shift in elevation then see what distance corresponds to that hold. Once I have that, I would just set that distance as the zero range in my ballistic solver (I use GeoBallistics).

Today I went out and tried it out. The scope (gen ii razor 4.5-27) was zeroed for the 6.5 barrel. With zero elevation dialled above the 6.5 Creedmoor zero, I installed the 338 barrel and shot a group. I figured the shift would be easier to see past 100m so I shot a group at a 270m target. The rounds were impacting .9 mils low, dope chart says the elevation adjustment should be .6.

I ran out of daylight so couldn’t get everything figured out, just got myself a little more confused. Thinking about it now though, I’m thinking I should zero the scope with the 338 setup, then work backwards from there. My thinking is, by starting with the 338, I won’t have to worry about hitting the zero stop when dialing to the 6.5 poi. Once I know how many clicks I need to dial to the 6.5 poi, I can look for a distance in the dope chart that matches. That would become my 6.5 zero? Ultimately I’ll have the scope zeroed at 100m for the 338. That zero stop will also correspond to a 250m (for example) zero for the 6.5. From there I shouldn’t have to modify my dope or zero when switching calibers?

Am I going about this the right way?

Another way to do it OP is with some o the ballistic programs.. the AB program in my kilo 2400 range finder will do it using zero height and zero offset.....you input your 100 yard corrections and then it automatically outputs the correct adjustments.. I have not used it but as well as everything else in the program works I am sure it works fine..

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Thanks gentlemen, I’ll have to get back out there and see how it goes

I think a dedicated 6 5 and a dedicated 338 will save you a lot of trouble especially since changing barrels may change your zero anyways.

Fixed

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