Running Out Of Elevation? A 20 MOA Base Might Be Your Answer.
You're dialing your scope for a long shot and you hit the turret stop. Out of adjustment. The target is still out there — your scope just can't reach it. This is one of the most frustrating moments in long-range shooting, and it's entirely preventable. The fix isn't a new scope. It's a canted base — and understanding why it works will change how you think about your whole setup.
Quick Primer: What Is MOA?
Before we get into canted bases, it helps to understand MOA — Minute of Angle — the unit used to measure scope adjustments and shooting angles. The math is straightforward once you see it laid out.
1"
At 100 Yards
One MOA equals approximately one inch of adjustment at 100 yards
2"
At 200 Yards
The same one MOA equals two inches at 200 yards — it scales linearly with distance
10"
At 1000 Yards
At 1000 yards, one MOA equals roughly ten inches — making every click count
When you dial your scope to compensate for bullet drop at distance, you're adding MOA of elevation. The further the target, the more MOA you need. And your scope only has a finite amount of total travel — which is where canted bases come in.
How A 20 MOA Base Actually Works
A 20 MOA base angles the scope slightly downward at the front. That sounds counterintuitive — why would you tilt the scope down when you're trying to shoot farther? The answer is geometry. When the scope points slightly downward relative to the barrel, the barrel must point slightly upward relative to the scope to put both on the same target. That means your zero uses a lower portion of the scope's internal elevation range, freeing up more "up" clicks for dialing distant targets.
Think of your scope's elevation adjustment as a see-saw with a fixed center point. On a flat 0 MOA base, zeroing at 100 yards typically puts you near the middle — half the travel above, half below. You'll never use the downward half for shooting. A 20 MOA base shifts that center point lower, so nearly all of the remaining travel is above your zero and available for dialing distance.
Standard Setup
0 MOA Flat Base
Zero falls near the middle of the scope's adjustment range. Half the elevation travel sits below your zero — clicks you will never use. With only ~30 MOA above zero, many long-range shots become impossible before you run out of adjustment.
Extended Range Setup
20 MOA Canted Base
The 20 MOA cant shifts the zero toward the bottom of the scope's range. Now nearly all remaining travel is above zero and available for dialing distance — giving you dramatically more reach without changing the scope at all.
A Real-World Example: 6.5 Creedmoor At 1000 Yards
The numbers become very clear when you apply them to a real shooting scenario. Here's what a 60 MOA scope actually delivers at 1000 yards depending on which base you use.
0 MOA Flat Base
~30 MOA
Available Above Zero
~875 yds
Maximum Effective Range
A 1000-yard shot with this cartridge requires approximately 38.4 MOA of elevation from a 100-yard zero. With only 30 MOA available, you run out of adjustment at around 875 yards — leaving your target unreachable no matter how good your fundamentals are.
20 MOA Canted Base
~50 MOA
Available Above Zero
1150+ yds
Maximum Effective Range
The same scope on a 20 MOA base shifts zero lower, freeing up approximately 50 MOA of upward travel. That's more than enough to reach 1000 yards — with room to spare for even longer shots. Same rifle, same scope, dramatically more capability.
"Same Rifle. Same Scope. A 20 MOA Base Adds 275+ Yards Of Reach."
Which Base Is Right For Your Shooting?
The honest answer is that 0 MOA works perfectly well for most shooters. It's only when you start pushing distance — or building a setup specifically for long-range work — that the 20 MOA base earns its place. Here's a clear breakdown.
Recommendation
0 MOA flat base — you have more than enough internal adjustment and no need for a cantWhy
Modern scopes have plenty of elevation travel for typical hunting and target distances without any help from a canted baseRecommendation
Check your scope's total travel — 0 MOA may work, but 20 MOA gives you a comfortable bufferWhy
Some scope and cartridge combinations begin running short of elevation in this range. A 20 MOA base provides insurance without any downsideRecommendation
20 MOA base — strongly recommended for reliable dialing at these distancesWhy
Most standard scope setups will run out of upward adjustment before reaching 1000 yards on a flat base. 20 MOA gives the scope the head start it needsRecommendation
0 MOA flat base — a canted base provides no advantage for holdover shootingWhy
If you're compensating for drop by holding high with BDC reticle marks rather than dialing turrets, the scope's internal elevation range is irrelevantImportant Caveats Before You Buy
A 20 MOA base is a powerful tool — but it's not plug-and-play for every setup. There are a few things worth checking before you order one.
Verify Your Scope Can Still Zero At 100 Yards
Adding 20 MOA of downward tilt means your scope needs to dial up 20 MOA just to return to where it was on a flat base. If your scope's total elevation range is on the low side, you might run out of downward adjustment before reaching a 100-yard zero. As a rule of thumb: the added cant should be less than half your scope's total elevation travel. A scope with 70 MOA total handles a 20 MOA base easily. A scope with only 40 MOA total may struggle — consider a 10 or 15 MOA base instead.
Optical Performance At Adjustment Extremes
When a scope's erector system is pushed toward the edge of its adjustment range, image quality and tracking consistency can suffer slightly. A canted base moves your zero lower in the range — which means when you're dialing for long distance, you're pushing the erector higher than you would be on a flat base. With quality optics this effect is minimal, but it's worth knowing. You're trading a small amount of optical centering for a significant gain in elevation capability.
Very Flat-Shooting Cartridges May Not Need It
If you're shooting a cartridge with extremely flat trajectory — or shooting at high elevation where thinner air reduces bullet drop — you may need less elevation adjustment than typical. In these cases, a flat 0 MOA base might get you to your target distance with adjustment to spare. Run the numbers for your specific cartridge and conditions before assuming 20 MOA is necessary.
The Bottom Line On 20 MOA
A 20 MOA base is one of the best value upgrades in long-range shooting. For a relatively modest investment, it can give a mid-range scope the elevation reach of a much more expensive optic — simply by repositioning where your zero sits within the scope's adjustment range. It doesn't change how your scope tracks, it doesn't affect your zero, and it doesn't require any special technique. You just have more clicks available when you need them.
For shooters who are working inside 500 yards or using holdover reticles, a flat 0 MOA base is the right call — simpler, cheaper, and perfectly adequate. But if you're stretching toward 800 yards and beyond, or if you've ever touched the turret stop while trying to reach a distant target, a 20 MOA base is cheap insurance that solves a real problem. Better to have the adjustment and not need it all than to run out of clicks when the shot matters most.
"Better To Have The Elevation And Not Need It, Than To Need It And Not Have It."
Check your scope's total travel. Do the math for your cartridge and distance. If the numbers don't add up on a flat base, a 20 MOA base is one of the simplest, most cost-effective upgrades in long-range shooting.
Add the cant. Keep the clicks. Reach the target.