Went away with a friend on the weekend and he fired my 416sw which has a unidirectional muzzle brake, the concussion cracked the edge of his eyeglass lenses all the way round - both lenses.
Has anyone had this happen to them or anyone they know.

Will you make me feel real stupid and tell me what a 416SW is?

That is impossible....

Unidirectional? As in the gas goes in all directions? 360 degrees? I find this hard to believe.

Mickey1
416SW is my name for 505Gibbs necked down to 416 improved and shortened to 76.5mm(by about an 1/8) so can crimp in cannelure and fit in the mag.

Atkinson
To what do you refer, the glasses or Mickey

JR
I mean a brake that has holes 90 degrees to the bore axis all the way round the brake
as opposed to a brake that vents back towards the shooter like some of the 50bmg rifles do

What you been smok'en boy, concussion can't shatter glasses unless its explosive like in land mines and hand grenades!

Even grenades or artillery won't shatter glasses unles they are locked down in a vise. Usually just blows them off your face or at worse knocks the lens out of the frame. A 458 Lott taught me that.

had my hat blown off my mike's *&&(*&@#$@#$ 50 bmg....

shattering the glasses? I'll bet that, accepting it happened, it was either a picked up particle or a coinsidence that they had a hairline in them

jeffe

I killed a hummingbird with the sideblast from my .50BMG with a clamshell on it! Bet if someone was stupid enough to stand to the side of it, it would blow their glasses off. To the rear there is absolutely no concussion. I'll bet your friend broke his glass by dropping them on the bench.-Rob

The only way I can possibly imagine it happening without dropping them is if the frames were a really bad fit and clamped the lenses so tight they were already under a great compression load. Just speculation.

[ 11-06-2003, 22:00: Message edited by: tiggertate ]

Sorry for not be more clear on the damage.
The lenses are cracked around the edge, both lenses all the way round, these are small cracks less than an 1/8" long from the edge toward the centre. There may have been minute cracks there when they were made and have only been made longer by the concussion. the lenses are plastic prescriptions lenses and reasonablely thick.
About 10 weeks old, he claims did not drop them, clean them with solvent or any other abuse.
The frames are the type that do not go all the way around the lense. These are a warranty set of glasses because previous frame broke and the old lenses would not fit the newer frame, the previous lenses had been polished around the edge, but the new pair had not been, edge polished. He didn't notice damage at the time (over long weekend) it was not until we were driving home that he noticed.
Maybe the concussion didn't do the damage, but what else could have?
Shooting was the only thing that he did that he doesn't normally do.

I've worn glasses standing too darn close to 105mm tank guns, 105mm and 155mm howitzers, etc. I've yet to have them even move on my face although on one occasion my nuts hurt from the blast (but that could have been part of the pucker factor). I don't believe it had ANYTHING to do with shooting (except he was looking through them at the time).