Air gun optics, is there a functional difference?


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gamestalker
February 25, 2014, 10:52 PM
My Son mounted a Leupold fixed power scope on one of his air rifles and something on the inside of the scope failed. I don't know exactly what happened, but that's not really important.

According to a person behind the counter at Sportsmen Warehouse, you can't use a scope intended for a firearm, on an air gun. He said the guy told him because air guns produce a reverse recoil, from that of a typical firearm, that even a scope capable of enduring the recoil of a magnum cartridge will break internally if used on an air gun. I've never heard anything like before and have also used many different firearm scopes on my air rifles, and I've never had one break, so for the moment I'm calling it B.S..

Anyone ever heard this before, or is this just some type of selling hype to try and sell more air gun scopes?

GS

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rcmodel
February 25, 2014, 11:47 PM
Not BS.
That's exactly true.

Firearms recoil to the rear violently.
And scope internals are designed to withstand it, and resist recoil with it in the same direction, in spades.

Spring piston air-rifles recoil to the rear in the normal direction when the piston flies forward.

Then when the piston hits the end of its travel it stops sharply against the front of the cylinder compressed air column, and jars the gun the other direction, HARDER.
Along with a high frequency vibration in all directions from the powerful spring rattling around inside the receiver.

That loads the scope internal parts with unusual forces in directions not produced by any firearm.

And that loads the scope internals the wrong direction from what they were designed to withstand.
HARDER!

Leopold is one of the few that says it won't harm their scopes.
But still, they design them for recoil going the normal direction.
Not going the other way, and sideways at the same time.

Some rifle scopes may take it forever without breaking.
But some won't that would have lived happily forever on a hard kicking Magnum rifle forever.

The thing is, you won't know until you find one that won't.

rc

gamestalker
February 26, 2014, 03:14 AM
RC, I just want to say I really appreciate you on this forum. What you said makes perfect sense as you explained it.

But at the same time, you also clarified a supporting point I made when discussing this with my Son last night. That being, glass such as Leupold and a number of other top shelf optics are designed to handle most variables regarding a broad range of use. And range optics, though most may be perfect for BR or other similar range use, they would be far less appropriate, and as well, vulnerable to damage resulting from exposure to the typical elements associated with hunting.

For instance, I always remove those package deal optics and mount them on my air rifles. Like most of us who know the difference, I simple won't shoot a high powered rifle with bargain brand glass. That said, I now know why those cheap scopes always seem to fail after being put on my air guns, never would have figured it out.

Thanks again RC!

GS

Chevota
February 26, 2014, 07:05 AM
The scopes on airguns fail in several ways and not always repairable, but I would consider trying. Find what let loose which might be a lens or the crap for an illuminated reticle and use some good epoxy or something.
As mentioned it's the reverse recoil. The normal rearward recoil and vibration won't bother it, it's the harsh high-G reverse of piston slam. A firearm is a firm but low G push, the airgun is less forceful but a much sharper higher G. Like how you can throw grapefruits at a glass door all day and never break it, but one steel BB with a fraction of the energy can. Some bad news is an airgun rated scope is no guarantee it will last on the gun, those things break all the time. The good news is you can reduce or fix the problem by properly tuning the gun so it isn't harsh. Eliminating seal leakage is #1 imo, then you can go further by raising the compression. It isn't hard to do, but you have to take the gun apart to do either. Heavier pellets help too, so stick with a medium or heavier weight, no light weights, alloys, no lead BB's either. For .177 I'd use 8.3gr at minimum, and .22 I'd use 14.3. For magnum guns I'd go up a bit, so maybe 10.3 and ~16? Never dry fire the gun which is the harshest thing you can do to your scope. Cleaning pellets are like a dry fire unless used with a pellet. Kids often like to stick other things in there too which are usually very bad as well, like steel BB's, paper wads, wood, darts, whatever. The gun needs the weight and cork like fit of a lead pellet to allow pressure to build inside and soften the piston slam, and tuning helps by increasing that pressure. I tune all my guns and have never broken a scope. Maybe 95% of my scopes are cheap too, about half are cheap airgun scopes that come bundled, and half are cheap firearm scopes so that says something about tuning. If you plan on taking it apart to do the work I have the info, just email me at chevota at hotmail

Sa-tevr
February 26, 2014, 02:50 PM
The Diana RWS 54 Air King (http://www.pyramydair.com/s/m/Diana_RWS_54_Air_King/398) has a reputation for eating scopes. If you search for it you'll probably get some recommendations for tough scopes.

Here an example: http://www.gatewaytoairguns.org/GTA/index.php?topic=46380.0

gamestalker
February 26, 2014, 04:23 PM
Cool guys. Really appreciate the information. I never would have guessed an air gun would trash any scope, much less a firearm scope.

GS

Mousegun
February 26, 2014, 08:16 PM
Even air gun scopes can have a rating. Some are for medium or low powered rifles and others brag they hold up to the magnum rifles.

I have an RWS model 48 which borders on a magnum rifle. It was a rifle/scope package deal with a Leapers scope 3X9 X 40 and it has held up very well over thousands of shots. All it takes is one and it could all come to an end but even that scope has a lifetime warranty.

When I put the Vortek spring kit in the gun, it became very wild. The kick increased considerably and I attribute that to the more powerful Vortek spring even though the kit provided a very tight spring guide and a tube that encompassed the spring to keep it straight. The design concept is great so I decided to cut the spring down a bit.

I took 2 turns off it and calmed the gun down to the point I no longer felt it was going to toast the scope or any scope I put on it. Even with the cut spring, it still delivered almost 900 FPS; good enough for me.

AKElroy
February 26, 2014, 10:07 PM
I have a Beeman S1 with this BSA mounted. I got a few thousand rounds out of a Bushnell prior to mounting this one before it failed internally. I have it going back for warranty repair, it was rated for magnum spring piston guns, and this Beeman qualifies with 1,000 FPS.

I paid $75 on optics planet for this BSA, a 3x9x40 AO. it holds zero perfectly, at least so far at 400 rounds or so. The optics claim to be coated, but you won't confuse it for a Leupold. It catches glare, which makes if difficult to use with the sun in front or behind. Other than that, it is clear and bright, sharp edges, and easy to dial in focus. The AO is off a bit, 5 yards or so. Not a big deal. It is overly heavy and feels well made, definitely not BSA's normal work. I suspect they farm this specialty item out to a sub with better quality. That, and the extra tube thickness allows for a bit more ring torque necessary for the mechanical recoil. I put 35 inch-lbs on it with no marks or creases.

I would invest in a "cheap" air-gun scope made specifically like this one. You are not shooting at distances with an air gun that require clarity at 200 yards, and you will destroy every high-end scope you mount not made for this specific purpose.

Mike Kerr
February 26, 2014, 11:33 PM
Gamestalker,

Like you I thought the airgun recoil problem for conventional rifle scopes was a myth. Its not. Don't ask me how I found out.

RC Model did a very good job of explaining the differences in recoil actions. His explanation is the best I've seen, or read.

:):):)

hso
February 28, 2014, 11:43 PM
Anyone ever heard this before

Yep, pretty common point of knowledge on airgun forums and scope manufacturers will also point out that a scope is or isn't suitable for air rifles.

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