Weapon-mounting a PVS-14 is not really a great idea.  I don't like doing it and don't recommend it.  I think it creates more issues and opens the door to more possible problems than it is worth.  Plus, you can duplicate the results and protect your goggle way more while keeping it on your head.  All that said, there are still a lot of people that want to weapon-mount a PVS-14.  We sell weapon mounts for PVS-14's, but I always suggest keeping it on the head.

The PVS-14 was designed to be the standard issue NVG for infantry units.  As such, it is supposed to be on the head 99% of the time.  Warfighters are already carrying a ton of gear, so efforts were made to keep it as small and lightweight as possible.  No shock mitigation.  Weapon mounting the PVS-14 is a distant secondary application.  The PVS-14 is a night vision goggle.  As such, it is designed only to replicate your daytime vision capability.  This means you're looking at less than 200 yards PID range.  While detection and recognition ranges will be much further, 100% PID is still under 200 yards - even to the naked eye at noon.  Anything more requires magnification.  But, walking around with a magnified NVG at night is a good way to fall flat on your face or walk off a cliff.  So, the objective lens is only big enough to gather the amount of ambient light needed to provide a good image at the necessary PID range.

All this being said, NVG's are really only good for use with non-magnified red dot optics.  The PVS-14 is not collimated, so you cannot put it in front of an optic and expect to maintain POA/POI.  It will shift considerably even though you will still get what appears to be a usable image.  This means it must be placed behind an optic that has already dealt with parallax.  Now, light will be degraded every time it passes through a lens.  The more lenses light must pass through, the more degradation it suffers.  A magnified optic has several more lenses than a red dot, so you're asking more of the light that passes through all of them.  By time it gets through the scope and is gathered by a PVS-14 mounted behind, the small objective from the NVG will have less to work with.  This equals a worse performance and requires a lot of added ambient light or IR illumination.  So, if you're going to weapon mount it, you want to use a red dot which will have a lot less light loss. 

But, let's think objectively about why you would want to weapon mount a goggle in the first place.  The first thing to remember is that night vision and thermal are extremely mission specific tools.  They are essentially, one-trick ponies.  Asking them to perform outside their design parameters is a recipe for disappointment.  If you want a goggle to wear on your head, buy a goggle and a laser for aiming.  If you want a weapon-mounted NV device, buy a dedicated NV scope.  If you want something to use with your existing optic, buy a CNVD.  What is your mission?  If you're a hunter who wants to sit on his ass and call prey in or attract them with a feeder, then a night vision device that is designed for weapon mount is your answer.  Don't buy a PVS-14.  But, if you're a hunter that stalks your prey, then buy the PVS-14 - but for the love of God, keep it on your head.  Why would you give up the mobility and versatility afforded by a night vision goggle by bolting it to your gun?  Doing that, marries your objective lens to your muzzle.  Now, you have to keep the weapon hefted and shouldered just to see in the dark.  That's exhausting.  What's more, you will invariably break one of the 4 principles of safe firearms handling because you're too busy being sucked in by the night vision image.

If you're really anti laser, then you should still keep the goggle on your head and just look through the optic on your gun.  If you keep the goggle on the gun behind your optic, you run a risk of doing permanent light damage to the tube.  Current production Gen3 image tubes are autogated, which provides protection from a reasonable amount of battlefield light exposure.  But, it doesn't make the tube invincible.  If you mount your goggle on the gun, behind any optic with a lit reticle or dot (including those with a night vision setting), you are exposing it to light.  What's more, you're exposing it to concentrated light in the same exact spot for a long time.  This will damage your tube.  When I tell people this, I am sometimes met with the "but my Aimpoint/Eotech has a night vision setting, so it will be ok" response.  Nope.  That night vision setting is only projecting the reticle or dot in near-IR.  It's invisible to the naked eye, but is designed to not completely bloom out your night vision.  It does not mean that it will not harm the tube if prolonged exposure occurs.  In fact, it is designed so you can keep the goggle on your head and still aim through the weapon optic if your laser goes down.  Let me say this again: The night vision setting on your optic will still cause permanent damage to your image intensifier tube after prolonged exposure.  The reticle will continually burn into your image tube because the goggle is fixed in place behind a permanently shining light source.

Now, let's talk about recoil damage.  Because the PVS-14 is designed to be on your head 99% of the time, there is no shock mitigation system that would have created extra weight.  That means the tube is directly exposed to the G-force.  Not good.  The thin-film image tube is really only rated to withstand small caliber recoil.  We are talking 5.56x45 here.  L-3 tubes have a slightly thicker film that allows them to stand up to 300Blk.  But that is it.  Anything heavier and the manufacturer will not warrant the tube.  Filmless L-3 tubes can stand up to much higher levels such as .50BMG.  BUT: that is only referencing the tube.  The housing will be destroyed much faster.  Think about it: you're placing a lot of faith into a metal mount, attached to a plastic housing, undergoing exposure to a rapid and violent motion.  The housing is designed to withstand bumps and occasional impact in the field.  But, repeated violent recoil from a heavy caliber firearm is too much.  Again, it was designed to be on your head.

Night vision weapon sights are designed to handle shock from recoil (well, milspec/issued sights are.  all bets are off when you roll the dice on cheap commercial units).  If you're going to buy night vision, you want to first establish reasonable expectations for the device based on your mission.  You're not going to buy a drill press and be happy with its performance as a band saw.  You're not going to buy a pistol and be happy with its precision capability at 600 meters.  Don't buy a night vision goggle and expect it to be a scope.