20moa base necessary?

[coderlee]

Hello, I am building a 300wm as my long range hunting rifle. I have a viper hs lr 4-16. If I am wanting to hit around 1000yrd is a 20 Mos base needed or is a 0moa going to be just fine?

Thank you for your time.
R/s
Cody

 

[Broz]

With the proper bullet , from a 100 yard zero you will most likely need 20 to 24 moa of dial up to get you to 1000 for a center reticle hold. Your Viper with a zero moa base will have enough. I believe your internal elevation to be 86 moa. In a perfect world, with a zero cant rail, that would mean 43 moa up and 43 moa down from your hundred yard zero. Or close to it.

If you decided to use the 20 moa rail you would now have close to 63 moa of dial up from the 100 yard zero and that would get you to 1 mile plus dependant on some variables.

Jeff

 

[coderlee]

Thank you very much for your replay. Never really thought of shooting to a mile with the 300wm. The long range world is new to me. 5-600 is really the longest I've shot other then with a few big guns in Iraq and Afgh.

 

[FEENIX]

As Jeff noted, you have enough internal elevation for 1000 yards. However, you should consider 20 MOA canted base ...

Even though the scope adjustment range may be large enough to get to 1,000 yds, you should use a 20 moa base. That's because off-axis optical aberrations that degrade resolution increase with incidence angle. You should set up your rifle so that the incidence angle is minimized for long distance shots (where resolution matters most).

Assume the base is within +/-10 moa of alignment with the rifle bore. Let's also assume your bullet drops no more than 30 moa at 1,000 yds, and you like to zero your rifle at 100 yds. With a standard base, you would need up to -40 moa of adjustment to get to 1,000 yds. That means you need a total 80 moa of adjustment.

With a 20 moa base you would need up to -20 moa to get to 1,000 yds, but up to 26 moa to get to a 100 yd zero (worse case boresight alignment in each case). That means you need a total 52 moa of adjustment. With a 20 moa base, however, the incidence angle at 1,000 yds is 20 moa less, so the image will have less blur.

 

[Garycrow]

It's not necessary, but why would you not use one for the purposes you state?

A 20 MOA base generally doesn't cost any more than a 0 MOA one so you're not saving any money. You can still zero the rifle at 100 yds with one and the scope will be better centered within it's adjustment range when you're shooting 500-1000 yds.

All my bolt action rifles with picatinny rails get a 20 MOA one, there's just no reason not to.

 

[coderlee]

So the reason I asked is I already have a 0moa that I took off a armslist buy. I understand the concept of one and understand I don't need one on a 270. I just never have built a hunting rifle to shoot out past 600. I intend to shoot to a 1000 and plan on getting the 20moa. Just because maybe one day I'll want to punch paper past 1000.

 

[gohring3006]

So the reason I asked is I already have a 0moa that I took off a armslist buy. I understand the concept of one and understand I don't need one on a 270. I just never have built a hunting rifle to shoot out past 600. I intend to shoot to a 1000 and plan on getting the 20moa. Just because maybe one day I'll want to punch paper past 1000.

One thing nice about a 0 Moa rail is you can get the scope low on the rifle..
I'm discovering that a 0 Moa base and some Burris tactical rings are a nice way to get my scope low and use the Burris inserts to get my 20 Moa of slant..

 

[Catahoula]

Check out the Hawkins Precision one piece rings/bases.