Recoil on the lightest Safety Harbour .50BMG should be about 750 G's absolute maximum...  Rather high - it's a very light rifle.

Although this is well past the "rated" 500 G's for a PVS-4 tube ( and 100G's for the scope itself ), I would not have any hesitation on assuming that a PVS-4 should handle it just fine in Gen2. They are very solid scopes. I would certainly risk my own under the circumstances.

They used to recoil test PVS-4 tubes with a hammer and 500 G's was the absolute minimum shock and had to be sustained over 0.3ms min. I suspect momentary peaks during testing would have approached 750Gs.

If anyone has a chamber pressure plot for .50BMG, I can make a more accurate calculation.

David.

Thanks

David

Still about 680 G's peak minimum...

I would still expect the PVS-4 to handle it just fine though.

Regards

David

That brings it down to about 580G's, which is probably under the peak when you consider the .3 ms requirement.

Though that's just the tube.

And we still haven't taken shock propagation into the equation which would de-rate the PVS-4 further.

But sometimes, the testing just isn't adequate for the application. This is one of those times. The PVS-4 was originally intended for the M16 but I've heard of it being installed on autocannons so in the scheme of things, the .50BMG should be fine.

However, I would not put a Gen3 on it, unless it was in something like a CNVD that was designed to mitigate the recoil....

David.

The min specs as listed above are from the Milspec for the tube and the entire assembled unit. They are test specs only.

There is no "upper limit" to the PVS-4 so you won't be able to compare it that way. You can only be sure about the test specs.

But I've heard of PVS-4's being used on .50BMG before, so it's not like you're doing something unexpected with it.

Most tubes have forces directed straight into the face of the tube, while the PVS-4 has it imparted to the tube via the plastic threads at the back, so not only is most of the shock wave dissipated before that, but the threads would likely break before the tube received anywhere near enough force to damage it. The recoil shock mitigation system within the PVS-4 is one of the best ever developed. Back then, they really didn't know how strong things needed to be, so they overdid it. There is absolutely nothing solid contacting the tube anywhere... And it's an inverter tube with solid parts that are well apart. Even the Russian's would be proud to have designed one.

I would be very surprised if you managed to cause any damage whatsoever with any rifle a human could fire.

They are even equally rated against transverse shock of equal magnitude... Simply put, you are not likely to break it with something as small as a .50BMG.  Unless you stick it in front of the barrel or there is already something wrong with it or it's been re-assembled with the wrong parts.

The weak point is probably the mount. Make sure it's a top-quality AN style bolt and all the threads are good, because it needs to stretch a little without yielding. And make sure it's well done up, because you don't want any whiplash effects there.

Regards

David