Virginia Gun Owners Forum - VGOF

does this device calculate MOA adjustment using the distance between the scope and rifle barrel?

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MikeVictor wrote:does this device calculate MOA adjustment using the distance between the scope and rifle barrel?

This is a device that calculates range to target. You would use a range card/drop tables to dial/hold the needed adjustment in the scope.

The distance between rifle bore, and optic is fixed, and already calculated into the drop tables.

This is the rangefinder I ordered. It calculates MOA correction for drop based on ballistics/other information stored in the device:

http://www.amazon.com/Bushnell-G-Force- ... B00HZGN9VO

Mike

Ok, now i know what range finder we are talking about.

Back to your original question, I'm not sure what you're asking about the device?

Yes.. an important input to accurately calculating the MOA is the distance the scopes line of sight is above the barrel (where the bullet starts from). Not accounting for this will result in an error in calculating the amount of drop or rise of the bullet at every range. I was wondering if the range finder I ordered will allow for this distance to be manually input and used in drop/rise calculations.

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I think you are overthinking it. If you rangefinder is programmable to tell you to add or drop your elevation, just make the adjustment the rangefinder tells you to make. If it tells you to add two MOA and your scope has 1/4 MOA adjustments, crank it 8 clicks and launch a bullet. Just because you have a fancy toy, it doesn't mean you don't have to practice. It means you have to practice using that toy to get the best results from it. Even if you think you know what you are doing, there is a 50% chance you will crank it in the wrong direction the first time you try to make an adjustment.

MikeVictor wrote: I was wondering if the range finder I ordered will allow for this distance to be manually input and used in drop/rise calculations.

No it does not, and I can't recall a rangefinder that did.

an important input to accurately calculating the MOA is the distance the scopes line of sight is above the barrel

Less important than you might expect. A 1.5" error in inputting your bore to optic axis is < 5" at 500 yds. The ballistics tables pre-built into the device have 6" of error for the flattest shooting cartridges, and 30" for the more 'rainbow' trajectories between cartridges on the edges of the groupings.

If you want the most accurate drop calculations, you are going to need to find the velocity of your ammo, out of your rifle. Then you will build your own drop table, based on your velocity, your bore/optic axis, your zero distance, and carry that chart with you. The range finder gives you the distance, and you look it up on your custom chart, and it tells you the drop compensation for that range.

ok.. tbanks for feedback. looks like i will use this app on my phone to calculate moa adjustments as it will consider all factors...even altitude and air pressure...

https://play.google.com/store/apps/deta ... Free&hl=en

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MikeVictor wrote:ok.. tbanks for feedback. looks like i will use this app on my phone to calculate moa adjustments as it will consider all factors...even altitude and air pressure...

There are a lot of nice phone apps that will do the calculations.

I use http://www.jbmballistics.com/cgi-bin/jb ... mp-5.1.cgi This is one of the more widely regarded calculators out there. Also they have a VERY extensive projectile database and the 'litz' versions have been field tested for actual BC. We know manufacturers BC's are a bit optimistic, and at longer ranges that can begin to become a significant source of error.