20 MOA bases?

[DaveTN]

I want to switch my Remington VLS 308 over to a Picatinny rail.

I’m using a Leupold VX-III 6.5-20X40 LR. I wonder if I need the 20 MOA base? The longest I’ve shot it so far is 300 yards, but I will get the opportunity to shoot 1K. If I use the 20 will I still be able to dial in 100 yards?

[CM1021]

You should be able to...it just gives your more vertical travel upwards...

[RWF]

i would not think so, i am thinking most VX-III are 1" tubes and do not have the adjustment range. i thinking you will need at least 80 MOA in the scope. but your dope will tell you the answer to your question.

[Dolomite_supafly]

With most guns zeroing at 100 yards will be an issue without a lot of down travel.

I know I put a 20 moa base on my savage and my scope bottomed out about 2-3 feet above the target at 100 yards.

I too though I needed one but for 90% of the shooters out there they do not need or can use the extra moa.

Inside of 600 yards you should not need a moa base even with the crappiest scopes.

Dolomite

[Alleycat72]

You need at least 40 moa of movement plus some on both sides.

Edited June 3, 2012 by alleycat72

[RWF]

who zero's at 100 yards? i am curious on that. on gaming guns a 50 yard zero is mostly used beause it is still good zero at 200. when i deered hunted my zero was 2.5 -3" high at 100. and as a rule most any gun with a spitzer type bullet will stay in the kill zone on deer sized game out to about 300 yards +/-. so more or less if i could see it i could kill it.

i use a 200 yard zero on my 1000 yard gun,

with a 100 yard zero you could easily miss at 175 i would think, if not the whole deer but kill zone for sure.

even for L.E. i do not now why they would want that.

just me.

[mikegideon]

The specs on the leupold site say it's a 30mm tube with a 90 MOA adjustment range. That's a lot. Your scope will handle a 20 MOA riser with no problem. Looks like you're going to need it too at 1000.

I zero my long range rifle at 100. Doesn't matter, since it gets dialed in to whatever range I'm shooting.

[RWF]

thanks

[alwaysonjohn]

Just note that most manufactures offer custom bases such as 0, 10, 20, 30, 45MOA cants. Just go look on Brownells.

I would think that if your scope is already zeroed at 100 then you can count how many clicks are available in elevation. Then calculate that number into MOA's and use a ballistic calculator to see how many MOA's of elevation you need to shoot something at 1000. To use a ballistics calculator accurately you need to know the fps/weight of your bullets, etc. but even without that information it will get you decently close. If you don't have that many MOAs of elevation then adding a custom base cant will raise your zero that many number of MOA. I hope this helps. 20MOA is the most popular for Remington 700s using the 308 caliber. My custom Rebel Defiance (based of the 700 platform) that is being built will have a 20MOA cant.

[mikegideon]

Assuming the scope is in the middle of it's range (good assumption with a VXIII), he has 45 MOA to play with. Taking 3 random .308 loads with published muzzle velocities, and a 100 yard zero, here's the sight adjust chart. Note that the scope is already up 4 MOA for the 100 yard zero, which only leaves 41 MOA of adjustment. Also note that factory loads are going to run slower in a barrel shorter than 24", which will require still more elevation. As I said in an earlier post, he's gonna need the riser, even though it's on the edge.

BTW: These traces were run at 80 degrees outside temp.

[Guest nowheretobefound]

who zero's at 100 yards? i am curious on that. on gaming guns a 50 yard zero is mostly used beause it is still good zero at 200. when i deered hunted my zero was 2.5 -3" high at 100. and as a rule most any gun with a spitzer type bullet will stay in the kill zone on deer sized game out to about 300 yards +/-. so more or less if i could see it i could kill it.

i use a 200 yard zero on my 1000 yard gun,

with a 100 yard zero you could easily miss at 175 i would think, if not the whole deer but kill zone for sure.

even for L.E. i do not now why they would want that.

just me.

This just shows how different requirements and backgrounds influence different shooters. I don't know of anyone that zero's at 50, sometimes on a close combat weapon i.e. M16/M4, AK, Steyr. Most hunters I know who are not tactical shooters also zero at 200, pretty standard. On my rifles I use a 100 zero mainly to be able to dial in for better accuracy at 400 meters and closer. 2 1/2 to 3 inches from POA is not acceptable for me in certain situations.

To the question, you have a scope that has the travel so why not put it on a rail, unless total weight is a factor for you. That way if you do ever want to crank out the MILS (or MOA) you can.

[fastbs]

With the mentioned scope you should be good with a 20 moa base. Even if you never need the extra elevation adjustment it will be there and 20 moa bases normally cost the same as a 0 moa.

As the old saying goes "better to have and not need than to need and not have"

Not really a reason to not get the 20 moa base unless your scope will not zero at 100 which is RARE.

Zeroing at 100 gives you a good place to base your scope adjustments off of.

[Guest 556or762]

I have 20 moa bases on all my rifles even my .22 (I do shoot it farther than most people would 300yds.) I think a 20 moa base on a 700 in .308 is a great investment and you should be able to zero just fine if not go to a 200yd zero and just make a range card for adjusting your scope or "DOPE" , I can say from experience that you should purchase a GOOD base made from steel ot aluminum and make sure the screws are torqued properly with BLUE (not red) lock tight. I have had issues with aluminum bases and under or over torqueing the mounting screws will lead to the base getting loose and possibly pulling the threads out of the action. I have used Nightforce bases which have a machined in recoil lug to take the strain of a heavy scope off of the mounting screws during recoil, I also use leupold and other name brands, my Savage MKII is the only aluminum base I have left by EGW its the only manufacturere I found with a 20 moa base for a 22 and there is not a lot of recoil to deal with.

[DaveTN]

Thanks for all the information and opinions.

I am not a hunter, just a shooter. I have multiple rifles and multiple optics that I switch around. I am now in the process of trying to make all my rifles a common platform. That platform will be a Picatinny Rail. I know I won’t be able to switch without rezeroing each time, but different bases and rings is a hassle.

I think the 20MOA base would be a better choice for my 308 VLS than the standard base.

[RWF]

This just shows how different requirements and backgrounds influence different shooters. I don't know of anyone that zero's at 50, sometimes on a close combat weapon i.e. M16/M4, AK, Steyr. Most hunters I know who are not tactical shooters also zero at 200, pretty standard. On my rifles I use a 100 zero mainly to be able to dial in for better accuracy at 400 meters and closer. 2 1/2 to 3 inches from POA is not acceptable for me in certain situations.

To the question, you have a scope that has the travel so why not put it on a rail, unless total weight is a factor for you. That way if you do ever want to crank out the MILS (or MOA) you can.

well, that's kinda of what i was trying to say. A 50 yard zero (as a general rule) will = a 200 yard zero, not perfect but you will be within 1-3 inches at 200. most closer to 1-1.5" inches and very easy to dail it in. i do understand that in some situations 2.5 - 3 high at 100 will not work but i was talking only about big game hunting, where most things have a 6-8 inch kill zone. that way i do not have to worry about the range, just aim and shoot. i no longer sight in my hunting rifle like that any more only because i no longer really have a place to try to hunt at 300+ yard range. and if i did my part most deer dropped on the spot.

but like you said more or less it just what you are best at. (the back ground)