Choosing an AIRGUN Scope vs. a POWDER BURNER Scope — 
What's the Difference?!?
Maybe you just got started with airguns after years of firearms shooting. This post is for you.
Maybe you're shopping for a scope and wonder what features you should look for that will make a difference. Though not a complete list, here are some important points.
Actually, it's kind of hard to divide scopes in "airgun scopes" and "powder burner scopes."
I really depends on the features and the shooter if they are more usable for airguns (AG) or only powder burners (PB). Scopes for AG have to fulfill more requirements than for PB.
After comparing the specs of over 150 scopes last year I find that manufacturers mix and match all kinds of features with each other, so the lines are blurred....
Here are some features that might make a difference for you as an airgunner (vs. a PB shooter). This post might take some blurr out ouf your shopping decision, I hope:
(1) The Scope Must Have Parallax Adjustment, and a Close Range Minimum Parallax = Most Important Difference AG vs. PB
Airgun ranges are short, as short as 5-10y for ratting, 55y max. for field target competitions and typical longer range hunting. With powerful PCPs/ high qual pellets/ slugs, lately more people are stretching it out to 100y and some even further.
At these short distances we need to have a clear scope image.
And with the small targets we try to hit (squirrel heads, not deer lungs!), we need to eliminate parallax errors as much as possible, as it will throw off our POI.
Therefore, for AG the scope should have (a) a parallax adjustment, and (b) that should be down to 10y — or whatever minimum range you shoot at.
(2) ONLY IF You Have an AG that Is Spring-Powered: The Scope Must Be Springer Approved = the Most Important Difference of Springer—AG vs. PB
Spring-powered AG (both coiled spring and gas piston spring) have a double recoil, the gun/scope move both backward and forward — PB only backwards. And the following AG could care less, their recoil is minimal: PCPs, pumpers, and CO2.
Scopes must be build to withstand both of these recoils of a springer AG. Not many do.
The Diana Bullseye ZR Zero Recoil Mount might allow you to use a scope on a springer that was not build for it. But I've never tried it. Other can chime in.
(3) To Change the POA: The Scope Must Have Dialing Turrets — and/or — a Holdoff Reticle
The reasons for this:
(a) AG Need to Make Frequent Adjustments to the POA
If you zero a PB and and AG at 50y and then shoot them at 100y the PB will hit very close to bullseye. But the AG will hit waaaaaay low.
The reasons for this are that AG have much less power than PB, and AG pellets (and slugs) have a much lower ballistic coefficient (BC) than PB bullets.
And therefore their projectiles (pellets and slugs) have a much more loopy trajectory.
And so, to keep hitting bullseye (or squirrel head) at ranges other than what you zerod the rifle at, you will need to make frequent adjustments to your point of aim (POA) — adjusting for elevation.
Similarly, with AG you also need to make frequent adjustements to your POA for windage. Because AG pellets suffer a huge amount of winddrift in comparison to PB bullets (again, because of their low BC).
(b) The First Way to Adjust POA: Dialing the Turrets
To adjust your POA you can dial the turrets a predetermined amount of clicks — which will move the scope's cross hairs so that your aim will compensate for projectile drop and/or wind drift.
The amount of clicks for a certain range or a certain amount of wind you either find using a ballistic calculator (Strelok Pro, ChairGun, etc.), or by test shooting at different ranges and making a dope chart.
If you choose to dial your turrets [the "first way"] you need finger adjustable turrets (not requiring a coin or tool to turn the turret [however, needing a tool to reset the turret to zero is fine as this happens seldomly]). You'll probably want exposed turrets (not capped), as capped turrets seem to be the manufacturer's way of saying: "Don't dial these turrets all the time — they're not made to withstand that."
You want turrets that will "track," i.e., they are good enough in quality that they will change the POA consistently by the same amount every time you dial the turret to a certain position.
(c) The Second Way to Adjust POA: Holding the Crosshairs Off the Target with the Help of the Reticle Hash Lines
Instead of dialing the turrets you could hold the crosshairs off the target by a predetermined amount. The right amount of holdoff is the same as the right amount of turret clicks, you'll get it from a ballistic calculator or the dope chart that you previously made.
Now to move the crosshairs just the right amount above or the the side of the target is impossible unless the scope reticle has evenly spaced hashlines or dots. These help you to hold off that predetermined amount.
If you choose to aim with holdoffs [the "second way"] you'll need a reticle with hash lines and/or dots that are evenly spaced (not an unevently spaced BDC reticle, those are calibrated to certain PB cartridges...! [BDC = bullet drop compensation, or "ballistic reticle" or some similar name]).
(d) Advantages/ Disadvantages to Both Methods of POA Adjustment
Dialing turrets is usually a little more precise as you don't have to hold a non-existent cross hair intersection onto the killzone (or bull's eye). A gridded reticle, "Christmas tree" style can help.
Using holdoffs is a bit quicker, esp. for constantly changing ranges in hunting situations, and in constantly changing winds.
If you choose to both dial turrets (e.g., for elevation) and use holdoffs (e.g., for windage, to adjust quickly to changing winds), your scope will need to meet both requirements, and the turrets and the reticle should use the same unit of measurement — either both should be in MOA or both in MIL.
And avoid turrets that are calibrated in SMOA (Shooter's MOA), which is 1.0" at 100y, instead of a true MOA which is 1.047".
Hope this helps some!
I wished I had found such a guide when I first got into airgunning...!
Matthias
PS: If you want other forum members to find this post..., may I suggest you write a very short reply....?
That way this post doesn't get totally buried under the pile of more recent posts....
What's the Difference?!?Maybe you just got started with airguns after years of firearms shooting. This post is for you.
Maybe you're shopping for a scope and wonder what features you should look for that will make a difference. Though not a complete list, here are some important points.
Actually, it's kind of hard to divide scopes in "airgun scopes" and "powder burner scopes."
I really depends on the features and the shooter if they are more usable for airguns (AG) or only powder burners (PB). Scopes for AG have to fulfill more requirements than for PB.
After comparing the specs of over 150 scopes last year I find that manufacturers mix and match all kinds of features with each other, so the lines are blurred....
Here are some features that might make a difference for you as an airgunner (vs. a PB shooter). This post might take some blurr out ouf your shopping decision, I hope:
(1) The Scope Must Have Parallax Adjustment, and a Close Range Minimum Parallax = Most Important Difference AG vs. PBAirgun ranges are short, as short as 5-10y for ratting, 55y max. for field target competitions and typical longer range hunting. With powerful PCPs/ high qual pellets/ slugs, lately more people are stretching it out to 100y and some even further.
At these short distances we need to have a clear scope image.
And with the small targets we try to hit (squirrel heads, not deer lungs!), we need to eliminate parallax errors as much as possible, as it will throw off our POI.
Therefore, for AG the scope should have (a) a parallax adjustment, and (b) that should be down to 10y — or whatever minimum range you shoot at.
(2) ONLY IF You Have an AG that Is Spring-Powered: The Scope Must Be Springer Approved = the Most Important Difference of Springer—AG vs. PBSpring-powered AG (both coiled spring and gas piston spring) have a double recoil, the gun/scope move both backward and forward — PB only backwards. And the following AG could care less, their recoil is minimal: PCPs, pumpers, and CO2.
Scopes must be build to withstand both of these recoils of a springer AG. Not many do.
The Diana Bullseye ZR Zero Recoil Mount might allow you to use a scope on a springer that was not build for it. But I've never tried it. Other can chime in.
(3) To Change the POA: The Scope Must Have Dialing Turrets — and/or — a Holdoff ReticleThe reasons for this:
(a) AG Need to Make Frequent Adjustments to the POAIf you zero a PB and and AG at 50y and then shoot them at 100y the PB will hit very close to bullseye. But the AG will hit waaaaaay low.
The reasons for this are that AG have much less power than PB, and AG pellets (and slugs) have a much lower ballistic coefficient (BC) than PB bullets.
And therefore their projectiles (pellets and slugs) have a much more loopy trajectory.
And so, to keep hitting bullseye (or squirrel head) at ranges other than what you zerod the rifle at, you will need to make frequent adjustments to your point of aim (POA) — adjusting for elevation.
Similarly, with AG you also need to make frequent adjustements to your POA for windage. Because AG pellets suffer a huge amount of winddrift in comparison to PB bullets (again, because of their low BC).
(b) The First Way to Adjust POA: Dialing the TurretsTo adjust your POA you can dial the turrets a predetermined amount of clicks — which will move the scope's cross hairs so that your aim will compensate for projectile drop and/or wind drift.
The amount of clicks for a certain range or a certain amount of wind you either find using a ballistic calculator (Strelok Pro, ChairGun, etc.), or by test shooting at different ranges and making a dope chart.
If you choose to dial your turrets [the "first way"] you need finger adjustable turrets (not requiring a coin or tool to turn the turret [however, needing a tool to reset the turret to zero is fine as this happens seldomly]). You'll probably want exposed turrets (not capped), as capped turrets seem to be the manufacturer's way of saying: "Don't dial these turrets all the time — they're not made to withstand that."
You want turrets that will "track," i.e., they are good enough in quality that they will change the POA consistently by the same amount every time you dial the turret to a certain position.
(c) The Second Way to Adjust POA: Holding the Crosshairs Off the Target with the Help of the Reticle Hash LinesInstead of dialing the turrets you could hold the crosshairs off the target by a predetermined amount. The right amount of holdoff is the same as the right amount of turret clicks, you'll get it from a ballistic calculator or the dope chart that you previously made.
Now to move the crosshairs just the right amount above or the the side of the target is impossible unless the scope reticle has evenly spaced hashlines or dots. These help you to hold off that predetermined amount.
If you choose to aim with holdoffs [the "second way"] you'll need a reticle with hash lines and/or dots that are evenly spaced (not an unevently spaced BDC reticle, those are calibrated to certain PB cartridges...! [BDC = bullet drop compensation, or "ballistic reticle" or some similar name]).
(d) Advantages/ Disadvantages to Both Methods of POA AdjustmentDialing turrets is usually a little more precise as you don't have to hold a non-existent cross hair intersection onto the killzone (or bull's eye). A gridded reticle, "Christmas tree" style can help.
Using holdoffs is a bit quicker, esp. for constantly changing ranges in hunting situations, and in constantly changing winds.
If you choose to both dial turrets (e.g., for elevation) and use holdoffs (e.g., for windage, to adjust quickly to changing winds), your scope will need to meet both requirements, and the turrets and the reticle should use the same unit of measurement — either both should be in MOA or both in MIL.
And avoid turrets that are calibrated in SMOA (Shooter's MOA), which is 1.0" at 100y, instead of a true MOA which is 1.047".
Hope this helps some!
I wished I had found such a guide when I first got into airgunning...!
Matthias
PS: If you want other forum members to find this post..., may I suggest you write a very short reply....? That way this post doesn't get totally buried under the pile of more recent posts....