Firing a bullet through glass

Question
QUESTION: does firing a bullet through glass, ie: windshield, window, ect.. affect its trajectory, will it pass through unscathed, or will it essentially stop it.  

I have heard that it mushrooms on impact and fly's like a slug, however im not sure.

Thank you for your time.

Austin

ANSWER: Yes, passing through glass can strongly affect the bullet and its trajectory. The effect can vary greatly.  It's possible that a bullet fired through thin glass at exactly a right angle could have minimal effect on its trajectory if the bullet has a heavy full metal jacket. But the same bullet could be deflected and not even pass through the glass if the angle is sharp.  Bullets designed to deform (e.g. mushroom) will tend to do so when passing through glass, the degree of deformation also depends on several things (bullet shape, bullet jacket type, bullet mass, bullet velocity, angle to glass, glass thickness, etc.)

So, all we can really say definitively is that yes, passing through glass can affect the bullet trajectory and it can cause deformation of the bullet.

Hope this helps!

Dave

---------- FOLLOW-UP ----------

QUESTION: Thank you for your quick reply Dave.

Just one more thing, would it be prudent of a shooter, to attempt to shoot a target behind glass, I'm speaking mostly of a sniper, seeing as their shots have to be so accurate.  

Answer
On TV, police or military snipers often shoot through glass. But in real life, a trained sniper knows that deflection of the bullet will be somewhat unpredictable. If the target is very close to the other side of the glass, the trained sniper may be able to take the shot, but probably would do that only if there is no other alternative.

Hope this helps!

Dave