My Rifle is at the factory getting worked on and I had to pull ALL the accessories, per their instructions. I'm running a Vortex Diamondback that has 60moa, so 30moa down max mins zero. with my current load (30-06) at 1000yds i will have 30moa drop. The retical has marking up to 11moa built into the reticle but I will still be near the end of travel on the scope. I won't be able to shoot beyond 500yards but maybe once per yearO can shoot 500yds regularly. I'm worried I might not be able to do it without the extra MOA. I'm debating on dropping on a 20moa rail when she comes back from the factory. My main concern is I am currently in low rings and I may have to go to medium rings. It would be about $40 for the rail plus another $20 for new rings if my lows don't work. If I have to go medium rings that also puts me higher over the bore and I really prefer to stay as low as I can. Should I go with a 20MOA rail, is it worth is?
20 moa scope base or flat?
- Thread starter Shadow9mm
- Start date
I had plenty of clearance, close to 1/4in in the low rings before I sent her in, it should still clear with a new rail.
stagpanther
New member
Correct me if I'm wrong--I think (meaning guess) what Bart might be referring to with the low rings is that by getting the line of sight of the scope as low as possible relative to the bore axis that gives you more "wiggle room" in down elevation for closer-in zeroes (especially with scopes that have limited elevation)?
Scope heights above the bore is not critical for elevation adjustment range. For every tenth of an inch difference, there's a 1/10th MOA change in zero setting at 100 yards. At 1000 yards, it's a 1/100th MOA change.
For every MOA the scope is adjusted to move point of impact up, the LOS several inches in front of the scope goes down a few thousandths of an inch and 1 MOA down on target. Reaiming on target then moves the LOF up to raise point of impact 1 MOA higher on target.
Sight zeros require the line of fire (barrel bore center axis) be an up angle from the line of sight to the line of fire that compensates for bullet drop at target range plus line of sight height above the bore.
Keeping the scope as low as possible keeps your head more stabilized as it rests on the stock comb.
Too bad that most of the web sites explanations of how scope adjustments work are wrong and confusing.
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So i'm a bit confused, are you trying to guarantee you can dope out to 1000 yds or 500 yds ? If your scope has 60 MOA of adjustment that doesn't necessariarily mean you have 30 MOA of additional elevation from your zero. Most people like to have a 100 yd zero and I find that on many of my high end precision scopes a 100 yd zero is factory set pretty low in the elevation range (meaning you can actually end up with 40+ MOA of additional elevation. When I shoot my 300 Win mag with my Sightron 8-32x at 1000 yds I am able to do so with a "0" MOA rail (with about 5 extra MOA). Every rifle combo is different so run your ballistics , find your max needed elevation dope, add another 6 or so MOA for some error room and check your scope for adequate (or not) available elevation.
No, I'm not trying to guarantee you can dope out to 1000 yds or 500 yds with a scope with 60 MOA elevation adjustment range.
How did you verify high end precision scopes a 100 yd zero is factory set pretty low in the elevation range?
I ask because new scopes are typically shipped with the line of sight on their mechanical and optical axis that's centered in the outer main tube. This is not the midpoint in the elevation and windage knobs mechanical adjustment range.
This is most unusual....
.... unless the barrel is crooked to the scope mount ring axis. Or someone moved the elevation adjustment from its zero before you used it.
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stagpanther
New member
I usually slap a 20 MOA Warne steel base nowadays on most of my rifles that that get x16 scopes or better out of habit (assuming the cartridge is capable of 600 yds +). Scope bases often come with rinky-dink screws and I try to minimize the frequency of changing them out. Friends don't let friends use weaver aluminum bases.
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unfortunately my only option is an EGW aluminum base but it is picatinny. its a TC Compass (same as venture from what I understand) I do have a in lb torque driver and loctite though. I'm gonna bolt it on, shoot a few rounds to settle it, double check the torque, and call it good.
stagpanther
New member
Just me--but I find it's more important to thoroughly degrease the receiver base holes and mount and then locktite the base screws to the receiver but generally don't torque much beyond 20/25 inch lbs unless specified--when it comes time to change the barrel over-torqued base screws are a curse. I wait at least 24 hours after mounting the base before using the gun. I hate aluminum bases.
stagpanther
New member
I personally prefer the durability of steel bases on steel receivers compared to aluminum bases. I can't prove it--but I feel that the steel base is better at maintaining true over the long haul (at least with the big bangers) compared to an aluminum base.
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Are your scope's two tubes made with steel? They bend more during recoil than the base does.
Is the rifle receiver one of the stiffer ones?
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stagpanther
New member
I have two concerns when choosing scope bases--the bridging from front to back attachment points to the receiver, and reducing the flex/deformation of the ring to base contact point over time.
What if the front and back ends of the scope bend and flex more from recoil than the base does?
If they go back to their original position after firing, is that ok? That's what barrels and actions do.
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stagpanther
New member
All of that is way above my pay grade--but judging from your level of experience I'll take your word for it that is what is actually happening. Stuff moves and gets knocked out of alignment over time--and aluminum bases deform fairly easily in my experience. Aluminum is great at bending and returning to form--not so good and absorbing impacts (e.g. aircraft structure).
What about the impact from recoil that shocks aluminum scope tube front and back ends bending them? They're inches away from the mount rings
stagpanther
New member
I take impact as meaning something hitting something--hammer head on nail head--or aircraft encountering solid ground, bullet contacting target. Recoil hit in a rifle I take to be more of a "system" force absorption. Slack or asymmetry in the system can conceivably cause loose tolerance which can result in a "hammering" effect over time.
Bottom line--even if the steel base structurally makes no difference at all at how the scope absorbs recoil force--I'll take a steel base over an aluminum one every time on my rifles if I have a choice.
Bottom line--even if the steel base structurally makes no difference at all at how the scope absorbs recoil force--I'll take a steel base over an aluminum one every time on my rifles if I have a choice.