At what range shooting does one need to use a 20 MOA base. Can a 0 MOA base be used say out to maybe 500 yards for a .308?
Rifle Scopes Range for 20 MOA base use?
Re: Range for 20 MOA base use?
It really depends on how much internal adjustment the scope has since some scopes have enough internal elevation to take a .308 past 1000 yards on a 0 MOA base.
It really depends on how much internal adjustment the scope has since some scopes have enough internal elevation to take a .308 past 1000 yards on a 0 MOA base.
Re: Range for 20 MOA base use?
a 0 moa base will theoretically get you to 600 yds + with a 308; if your using a 100 yd zero; if your using Federal GMM w/168 gr MK; if your scope has at least 40" of adjustment, in which it has 20" up adjustment and 20" down adjustment.
See Below:
Range Drop Drop
(yd) (MOA) (1/4" Clicks)
0 *** ***
50 -0 -1
100 -0 -0
150 -1 -3
200 -2 -8
250 -3 -13
300 -5 -19
350 -6 -25
400 -8 -32
450 -9 -39
500 -11 -47
550 -13 -55
600 -15 -64
650 -18 -74
700 -20 -84
750 -23 -94
800 -25 -106
850 -28 -118
900 -31 -131
950 -35 -145
1000 -38 -161
Note there are a alot of "if's" in the above statement. Note: there is <span style="font-weight: bold">NO</span> range for a base. There is only a range (amount of drop) for your load at "x" range. Your scope must have the adjustment range in inches to "come up" to offset that drop.
Given the above to reach 1000 yds. with that 308 load, you will need a scope and or base combo that will compensate (come up) for the 38 MOA drop at that range.
Some examples:
A scope with 40" of adjustment (20"up & 20"down) will not have enough adjustment to reach 1000 yds. If you add a 20 MOA base, you will have 40" up and 0" down, which might get you there, but you will most likely not be able to zero @ 100 yds.
A scope with 50" of adjustment (25up & 25down)+ a 20MOA base will get you to 1000 yds. That's because you now have 45" up (25" scope + 20 MOA base) and 5" down. It's very close, and should work, for the above load.
A scope with 60" of adjustment would be "better", with a 20 MOA base. Because you now have 50" up (30" scope + 20 MOA base) and 10" down. This will cover most abnormalities in your receiver, scope or load.
Got it?
Bob
a 0 moa base will theoretically get you to 600 yds + with a 308; if your using a 100 yd zero; if your using Federal GMM w/168 gr MK; if your scope has at least 40" of adjustment, in which it has 20" up adjustment and 20" down adjustment.
See Below:
Range Drop Drop
(yd) (MOA) (1/4" Clicks)
0 *** ***
50 -0 -1
100 -0 -0
150 -1 -3
200 -2 -8
250 -3 -13
300 -5 -19
350 -6 -25
400 -8 -32
450 -9 -39
500 -11 -47
550 -13 -55
600 -15 -64
650 -18 -74
700 -20 -84
750 -23 -94
800 -25 -106
850 -28 -118
900 -31 -131
950 -35 -145
1000 -38 -161
Note there are a alot of "if's" in the above statement. Note: there is <span style="font-weight: bold">NO</span> range for a base. There is only a range (amount of drop) for your load at "x" range. Your scope must have the adjustment range in inches to "come up" to offset that drop.
Given the above to reach 1000 yds. with that 308 load, you will need a scope and or base combo that will compensate (come up) for the 38 MOA drop at that range.
Some examples:
A scope with 40" of adjustment (20"up & 20"down) will not have enough adjustment to reach 1000 yds. If you add a 20 MOA base, you will have 40" up and 0" down, which might get you there, but you will most likely not be able to zero @ 100 yds.
A scope with 50" of adjustment (25up & 25down)+ a 20MOA base will get you to 1000 yds. That's because you now have 45" up (25" scope + 20 MOA base) and 5" down. It's very close, and should work, for the above load.
A scope with 60" of adjustment would be "better", with a 20 MOA base. Because you now have 50" up (30" scope + 20 MOA base) and 10" down. This will cover most abnormalities in your receiver, scope or load.
Got it?
Bob
Re: Range for 20 MOA base use?
Thanks guys. I appreciate your help.
Thanks guys. I appreciate your help.
Re: Range for 20 MOA base use?
Given that many 20 moa bases are the same price as 0 moa bases, you're much better off getting the 20 to start with. Hopefully this leaves you room in your scope to play with.
Given that many 20 moa bases are the same price as 0 moa bases, you're much better off getting the 20 to start with. Hopefully this leaves you room in your scope to play with.
Re: Range for 20 MOA base use?
If I go with a WO Tac Scope 4-14X50, will I have enough adjustment with 80 MOA total to zero at 100 yards and a 20 MOA base?
If I go with a WO Tac Scope 4-14X50, will I have enough adjustment with 80 MOA total to zero at 100 yards and a 20 MOA base?
Re: Range for 20 MOA base use?
I have a 20 M.O.A base on my 338 and a Nightforce 3.5-15x56 and @1800 yards I am maxed out on my scope and useing the hold marks.
I sight my rifle in at 400-600 yards depending on what use I will be doing with it.
I have a 20 M.O.A base on my 338 and a Nightforce 3.5-15x56 and @1800 yards I am maxed out on my scope and useing the hold marks.
I sight my rifle in at 400-600 yards depending on what use I will be doing with it.
Re: Range for 20 MOA base use?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: alien319</div><div class="ubbcode-body"> If I go with a WO Tac Scope 4-14X50, will I have enough adjustment with 80 MOA total to zero at 100 yards and a 20 MOA base? </div></div>
alien,
Sure you will. 80 MOA is 40 up and 40 down. Add a 20 MOA base and you now have 60 up and 20 down. 20 MOA down should allow a good 100 yd zero.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: alien319</div><div class="ubbcode-body"> If I go with a WO Tac Scope 4-14X50, will I have enough adjustment with 80 MOA total to zero at 100 yards and a 20 MOA base? </div></div>
alien,
Sure you will. 80 MOA is 40 up and 40 down. Add a 20 MOA base and you now have 60 up and 20 down. 20 MOA down should allow a good 100 yd zero.
Re: Range for 20 MOA base use?
Thanks Bob. I appreciate your help. I just didn't want to get a 20 MOA base and not be able to zero at 100yds. I want to at least start at 100 yards. I will then move up to 300 yards.
Thanks Bob. I appreciate your help. I just didn't want to get a 20 MOA base and not be able to zero at 100yds. I want to at least start at 100 yards. I will then move up to 300 yards.
Re: Range for 20 MOA base use?
I just bought a NF 3.5-15x50. I'm getting ready to buy base and rings, and this question is related to my situation. according to NF specs I have 110 moa in elevation on this scope. Is this 55 up and 55 down? I'm mounting mine on a Rem. LTR .308 and realistically won't be shooting past 600-700 yards max possibly a little bit further at deer at a particular stand where I can see close to 1000 yards. Should I buy the 20 moa base? with the amt of elevation on this scope, if i buy the 20 moa base can i still sight in at 200 yards? I've been a hunter for 20+ yrs, but I'm a rookie at long range. I am eager to learn and will listen to any advise from experienced LR shooters. thanks
I just bought a NF 3.5-15x50. I'm getting ready to buy base and rings, and this question is related to my situation. according to NF specs I have 110 moa in elevation on this scope. Is this 55 up and 55 down? I'm mounting mine on a Rem. LTR .308 and realistically won't be shooting past 600-700 yards max possibly a little bit further at deer at a particular stand where I can see close to 1000 yards. Should I buy the 20 moa base? with the amt of elevation on this scope, if i buy the 20 moa base can i still sight in at 200 yards? I've been a hunter for 20+ yrs, but I'm a rookie at long range. I am eager to learn and will listen to any advise from experienced LR shooters. thanks
Re: Range for 20 MOA base use?
should be able to,if you can zero @100yards with a 20moa base and a scope with 80moa total
should be able to,if you can zero @100yards with a 20moa base and a scope with 80moa total
Re: Range for 20 MOA base use?
should be able to,if you can zero @100yards with a 20moa base and a scope with 80moa total
should be able to,if you can zero @100yards with a 20moa base and a scope with 80moa total
Re: Range for 20 MOA base use?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clifford44</div><div class="ubbcode-body">I just bought a NF 3.5-15x50. I'm getting ready to buy base and rings, and this question is related to my situation. according to NF specs I have 110 moa in elevation on this scope. Is this 55 up and 55 down? I'm mounting mine on a Rem. LTR .308 and realistically won't be shooting past 600-700 yards max possibly a little bit further at deer at a particular stand where I can see close to 1000 yards. Should I buy the 20 moa base? with the amt of elevation on this scope, if i buy the 20 moa base can i still sight in at 200 yards? I've been a hunter for 20+ yrs, but I'm a rookie at long range. I am eager to learn and will listen to any advise from experienced LR shooters. thanks </div></div>
Cliff,
If your have 110 MOA (55 up and 55 down) you don't need a 20 MOA base to reach 1000 yds. A flat zero MOA base will do you fine.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clifford44</div><div class="ubbcode-body">I just bought a NF 3.5-15x50. I'm getting ready to buy base and rings, and this question is related to my situation. according to NF specs I have 110 moa in elevation on this scope. Is this 55 up and 55 down? I'm mounting mine on a Rem. LTR .308 and realistically won't be shooting past 600-700 yards max possibly a little bit further at deer at a particular stand where I can see close to 1000 yards. Should I buy the 20 moa base? with the amt of elevation on this scope, if i buy the 20 moa base can i still sight in at 200 yards? I've been a hunter for 20+ yrs, but I'm a rookie at long range. I am eager to learn and will listen to any advise from experienced LR shooters. thanks </div></div>
Cliff,
If your have 110 MOA (55 up and 55 down) you don't need a 20 MOA base to reach 1000 yds. A flat zero MOA base will do you fine.
Re: Range for 20 MOA base use?
Thanks for the info. It's actually pretty neat to get in here and get good, solid info from guys that trully know what they are talking about. This sight is becoming addictive! Thanks again.
Thanks for the info. It's actually pretty neat to get in here and get good, solid info from guys that trully know what they are talking about. This sight is becoming addictive! Thanks again.
Re: Range for 20 MOA base use?
Hi Guys
I was wondering if you could help me out too. I recently purchased a Leupy 8.5-25x Mark 4 LR/T from a fellow hide member and am curious to know your thoughts on whether I should purchase a Flat base or a 20MOA base. The scope has 75MOA adjustment in elevation.
I'd like to be able to zero in at 100 or 200 yards and eventually be able to take long range shots up to 1000. Should I purchase a flat base or go with the 20MOA? Your help is greatly appreciated!
Thanks!
Hi Guys
I was wondering if you could help me out too. I recently purchased a Leupy 8.5-25x Mark 4 LR/T from a fellow hide member and am curious to know your thoughts on whether I should purchase a Flat base or a 20MOA base. The scope has 75MOA adjustment in elevation.
I'd like to be able to zero in at 100 or 200 yards and eventually be able to take long range shots up to 1000. Should I purchase a flat base or go with the 20MOA? Your help is greatly appreciated!
Thanks!
Re: Range for 20 MOA base use?
20 MOA. There's no downside to it, and you'll be sure to have enough elevation to shoot as far as you care to.
20 MOA. There's no downside to it, and you'll be sure to have enough elevation to shoot as far as you care to.
Re: Range for 20 MOA base use?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hill billy</div><div class="ubbcode-body">Given that many 20 moa bases are the same price as 0 moa bases, you're much better off getting the 20 to start with. Hopefully this leaves you room in your scope to play with. </div></div>
I disagree. If you dont need an extra 20 minutes (or 10,15) for your application then dont get it. Its baest to keep the scope as close to mechanical zero as possible. That being said, I have a 30 MOA base on my 50....
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hill billy</div><div class="ubbcode-body">Given that many 20 moa bases are the same price as 0 moa bases, you're much better off getting the 20 to start with. Hopefully this leaves you room in your scope to play with. </div></div>
I disagree. If you dont need an extra 20 minutes (or 10,15) for your application then dont get it. Its baest to keep the scope as close to mechanical zero as possible. That being said, I have a 30 MOA base on my 50....
Re: Range for 20 MOA base use?
i have the Mark4 4.5X14X50 on a armalite super sass with Mark4 rings, no problems dialing out to 1000mtrs with the flat base, I slo have a NF 5.5X22X56 on my SR-25 and it's max is right under 40min, so i just ordered the NF 20moa unimount, I shoot SMK 175 with both guns.
i have the Mark4 4.5X14X50 on a armalite super sass with Mark4 rings, no problems dialing out to 1000mtrs with the flat base, I slo have a NF 5.5X22X56 on my SR-25 and it's max is right under 40min, so i just ordered the NF 20moa unimount, I shoot SMK 175 with both guns.
Re: Range for 20 MOA base use?
There are a lot of assumptions involved when figuring what base slope angle to employ.
The first one assumes that the degree of elevation required for the nearest distance zero adjustment can be predicted. In my experience, it does not follow any consistently predictable pattern. Having 80MOA of adjustment available does not equate to having 80MOA of useable adjustment.
That 100yd adjustment may occur at halfway up the adjustment range, more likely will occur somewhere lower in that range, and, almost certainly, will not occur very close to the bottom of that range, and may not even do so with a 20MOA base slope.
Typically, a .308 shooting 175's can zero at 100yd and reach 1000yd with 30-35MOA or so of additional elevation. Or thereabouts. My .260 shooting 142's at 2850fps will do it with about 28MOA.
My approach is to mount the scope using a borrowed base without any slope, zero it for 100yd, and then count down the clicks to bottom. If there's at absolute least 22-25 MOA, a 20MOA base is good, and if there's at least 32-35MOA, a 30MOA slope is even better, if it's less than 20, use a 10MOA base, and so forth...
Once you've got a slope value determined (and if it's more than what's available commercially, consider shim testing and a custom bedded a base), then you get your base.
It's not about how much you should add. It's about how much usable adjustment you should allow your mounts to waste below the short distance zero's vertical adjustment point.
Typically, I use 20MOA bases, and fairly often end up custom bedding them for somewhere around a total of 33-35MOA slope altogether.
My goal is to achieve a 100yd zero at an adjustment point somewhere around 5MOA from the bottom of the extreme adjustment range.
This permits some bottomout clearance, and limits the usual restriction an extreme elevation adjustment places on windage adjustment; while simultaneously freeing up nearly all of the vertical adjustment range as usable for longer distance applications.
Greg
There are a lot of assumptions involved when figuring what base slope angle to employ.
The first one assumes that the degree of elevation required for the nearest distance zero adjustment can be predicted. In my experience, it does not follow any consistently predictable pattern. Having 80MOA of adjustment available does not equate to having 80MOA of useable adjustment.
That 100yd adjustment may occur at halfway up the adjustment range, more likely will occur somewhere lower in that range, and, almost certainly, will not occur very close to the bottom of that range, and may not even do so with a 20MOA base slope.
Typically, a .308 shooting 175's can zero at 100yd and reach 1000yd with 30-35MOA or so of additional elevation. Or thereabouts. My .260 shooting 142's at 2850fps will do it with about 28MOA.
My approach is to mount the scope using a borrowed base without any slope, zero it for 100yd, and then count down the clicks to bottom. If there's at absolute least 22-25 MOA, a 20MOA base is good, and if there's at least 32-35MOA, a 30MOA slope is even better, if it's less than 20, use a 10MOA base, and so forth...
Once you've got a slope value determined (and if it's more than what's available commercially, consider shim testing and a custom bedded a base), then you get your base.
It's not about how much you should add. It's about how much usable adjustment you should allow your mounts to waste below the short distance zero's vertical adjustment point.
Typically, I use 20MOA bases, and fairly often end up custom bedding them for somewhere around a total of 33-35MOA slope altogether.
My goal is to achieve a 100yd zero at an adjustment point somewhere around 5MOA from the bottom of the extreme adjustment range.
This permits some bottomout clearance, and limits the usual restriction an extreme elevation adjustment places on windage adjustment; while simultaneously freeing up nearly all of the vertical adjustment range as usable for longer distance applications.
Greg
Re: Range for 20 MOA base use?
I've a Remington 700 Police DM in .308win with a Nightforce 20 moa rail with up a Nightforce NXS 5,5-22x56 mil-dot of 110 moa elevation. With a Fiocchi USA 180 grs (Sierra MK) I work at 30/110 moa of elevation, at 910 mt (1000 yards) I work at 71/110 moa. With a Norma 168 cartridge (2578 fps) the moa at 100 meters is little different, not more of 2 moa but a I don't remember correctly, and I put in the turret 43 moa for 1000 yards.
A my Police sniper friend use a TRG 22 with hinterberger 190 hpbt and no moa rail with a S&B 3-12x50, no problem of elevation range at 1000 yards. All depends of the excursion of your optics and the bulleth path of your cartridge.
By by
I've a Remington 700 Police DM in .308win with a Nightforce 20 moa rail with up a Nightforce NXS 5,5-22x56 mil-dot of 110 moa elevation. With a Fiocchi USA 180 grs (Sierra MK) I work at 30/110 moa of elevation, at 910 mt (1000 yards) I work at 71/110 moa. With a Norma 168 cartridge (2578 fps) the moa at 100 meters is little different, not more of 2 moa but a I don't remember correctly, and I put in the turret 43 moa for 1000 yards.
A my Police sniper friend use a TRG 22 with hinterberger 190 hpbt and no moa rail with a S&B 3-12x50, no problem of elevation range at 1000 yards. All depends of the excursion of your optics and the bulleth path of your cartridge.
By by
Re: Range for 20 MOA base use?
Why not study up on your scope's internal range of elevation, and the ballistic curve of your ammunition? Figure you have about 45% of the reticle travel to work with which could be anywhere from about 20moa to over 50moa depending on your scope.
Look at the ballistics table to decide where your zero should be. With a 300yd zero and a 168gr SMK at 2700fps you likely won't need a canted scope base.
Probably lots of good ballistics software sites out there, but if you have a Sierra manual and some graph paper, you can just plot your bullets path from muzzle to 1000yds. Just plot the numbers given and draw the arching line. Confirm at the range.
With the ammo described above and a 300yd zero, you need 37moa of elevation to get on target at 1,000yds. Unless you are a Palma shooter, there is no real need to push your .308 to 1000yds. 800yds is more doable and then you are looking at about 21moa of elevation. Could probably use Weaver or Warne steel scope base and be all set with a lower sitting scope to boot, if you work out the math ahead of time and know your gear.
Why not study up on your scope's internal range of elevation, and the ballistic curve of your ammunition? Figure you have about 45% of the reticle travel to work with which could be anywhere from about 20moa to over 50moa depending on your scope.
Look at the ballistics table to decide where your zero should be. With a 300yd zero and a 168gr SMK at 2700fps you likely won't need a canted scope base.
Probably lots of good ballistics software sites out there, but if you have a Sierra manual and some graph paper, you can just plot your bullets path from muzzle to 1000yds. Just plot the numbers given and draw the arching line. Confirm at the range.
With the ammo described above and a 300yd zero, you need 37moa of elevation to get on target at 1,000yds. Unless you are a Palma shooter, there is no real need to push your .308 to 1000yds. 800yds is more doable and then you are looking at about 21moa of elevation. Could probably use Weaver or Warne steel scope base and be all set with a lower sitting scope to boot, if you work out the math ahead of time and know your gear.
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