Advanced Marksmanship 165- or 168-Grain .308: Accuracy Through Long-Range (Duh!) Glass-Penetration

[BillyJack]

This is a general question, but assume the ammo in question is no-frills match-grade (highest-accuracy ballistic characteristics like no exterior scoring to promote expansion on impact, NO HOLLOWPOINTS) used by a shooter who needs penetration at moderate-to-extreme angles through non-armored glass. (I'm checking something I saw on an idiot-box show, i.e., TV)



I read an old post closely related to my question, but none of the respondents seemed to grasp the PURPOSE (practical application beyond [quod erat demonstrandum] accuracy) of employing divergently-weighted loads, that there're REASONS different loads are/were standardized. Shooting under different conditions and ultimate desired effect of shot (do you want target to suffer maximum hydrostatic damage, or do you simply desire point penetration?) will determine which load should be used.

I would TEND to think that the slightly more powerful round would ensure minimal deviation of ballistic trajectory after passing through a sheet of glass, but I don't KNOW I'm right...as I'm not military-trained on a rifle more sophisticated than a bolt-action M14, which isn't exactly a sniper rifle.

 

[Erud]

This is a general question, but assume the ammo in question is no-frills match-grade (highest-accuracy ballistic characteristics like no exterior scoring to promote expansion on impact, NO HOLLOWPOINTS) used by a shooter who needs penetration at moderate-to-extreme angles through non-armored glass. (I'm checking something I saw on an idiot-box show, i.e., TV)

View attachment 38074

I read an old post closely related to my question, but none of the respondents seemed to grasp the PURPOSE (practical application beyond [quod erat demonstrandum] accuracy) of employing divergently-weighted loads, that there're REASONS different loads are/were standardized. Shooting under different conditions and ultimate desired effect of shot (do you want target to suffer maximum hydrostatic damage, or do you simply desire point penetration?) will determine which load should be used.

I would TEND to think that the slightly more powerful round would ensure minimal deviation of ballistic trajectory after passing through a sheet of glass, but I don't KNOW I'm right...as I'm not military-trained on a rifle more sophisticated than a bolt-action M14, which isn't exactly a sniper rifle.

i don't know the answer to your question, but I'd like to see pics of the bolt-action M14.

 

[JBNj]

You may want to contact lowlight on here and your intention. Personally I would use tactical thumbs for deflection purposes. When done right, Each groove on your tactical thumb can measure the right amount elevation defeating deflection to help get on target. If you do not know what I'm talking about. Then you need to educate yourself in the art of OAF

 

[JBNj]

I REALLY want to see pics of a bolt action M14

i don't know the answer to your question, but I'd like to see pics of the bolt-action M14.

Ask and you shall receive.
TSD Sports SDM100B2 Airsoft M14 Bolt Action Sniper Rifle with Red Dot Scope and Flashlight:Amazon:Sports & Outdoors

But maybe he is referring to The model 1914 Enfield. The Brits referred to as the Pattern 14 Enfield
http://en.m.wikipedia.org/wiki/Pattern_1914_Enfield

 

[Blackjack988]

+1 for pics of a bolt-action M14.

EDIT:

Ask and you shall receive.
TSD Sports SDM100B2 Airsoft M14 Bolt Action Sniper Rifle with Red Dot Scope and Flashlight:Amazon:Sports & Outdoors

Well i'll be damned....now his question makes more sense...maybe?

 

[DeadSilence]

Quietly taking a seat. Thinking about getting some snacks. This might get interesting.

 

[damoncali]

Unconvinced. Not subtle enough.

 

[Rthur]

I'm gonna take this right foot and put it...........

Bullet scoring?

I guess you may need to elaborate more on the barrier to target distance.


R

 

[Hollywood 6mm]

The OP made by brain hurt. I'm just going to wait for DeadSilence to bring the snacks....

 

[Unknown]

Extensive bullet deflection testing has been done by various law enforcement agencies. Good luck getting them to give you copies of the testing though. Maybe the FBI testing would be available through the freedom of information act, but frankly, it isn't worth my time to search for the info until I need it...and I haven't needed it so far. I'll let someone else do all the digging for the information.

Another thought is why the hell would anyone outside of military or law enforcement NEED (VS want) that infomation?

 

[Bender]

I actually had a theory about shooting through glass. ....... Not that I ever intend to try. But wouldn't two shooters on the same target firing at the same time work? First bullet would break the glass, even at an angle, and the second would travel unimpeded to the target? Just a thought.

 

[gasdoc09]

Another thought is why the hell would anyone outside of military or law enforcement NEED (VS want) that infomation?

Why the hell would anyone outside of military or law enforcement NEED (VS want) a gun?

 

[Unknown]

Gasdoc09,
Point taken...(In retrospect, I agree with your point). I made my earlier comment after a friend asked me about wanting to try shooting a pistol underwater. I told him that all that had been done, and I wouldn't recommend it, rather I would recommend he look up the research other people have already done on that idea...I didnt' want him wrecking his pistol by trying something "unusual" and shooting with a barrel full of water. I asked him why he would need to shoot underwater, and pictured him trying to conceal his pistol in a swimsuit.

Bender's idea of using two shooters to defeat glass is a common tactic.

 

[JBNj]

Why the hell would anyone outside of military or law enforcement NEED (VS want) a gun?

The founding fathers would smack you around with that statement.

 

[gasdoc09]

The founding fathers would smack you around with that statement.

Yeah, that was the point of my post - that the entire gun rights issue isn't about NEED at all, but our inherent freedom to possess weapons (and by extension, the knowledge and skills to use them). And how we, as gun owners, should be very wary of statements that imply NEED ever comes into the questions, because history has shown gun owners can be their own worst enemies when it comes to diluting the core rights with seemingly small concessions and compromises. For example:

- hunters who say that nobody NEEDS a semi-automatic rifle
- little old ladies who say that nobody NEEDS more than a revolver in the purse for self-defense
- target shooters who say that nobody NEEDS hollow-point bullets
- and those who say that only military or law-enforcement really NEED any particular weapon (or skill, or piece of knowledge)

They're all wrong.

Context, man, context.

 

[VoxPatriam]

Slightly continuing the tangent here... I think the Founding Fathers would absolutely say we NEED firearms. After reading the Federalist Papers, it's pretty clear that they didn't intend for us to be worried about hunting and sport shooting. The important thing here is that there was no clause to say that we can keep and bear arms except the ones Big Brother decides we are competent enough to point in a safe direction.

As for shooting through glass, your volley fire theory would probably work, depending on the type of glass you're shooting through. Automotive glass, more specifically windshields, are designed with layers of plastic embedded in them so that when it breaks it doesn't shatter (from, say, one round going through). You'll wind up with a ragged hole in the glass and a spidered window that's more difficult to see through. The second round will likely just make the hole slightly bigger as the glass can flex once spidered. We had a guy in Iraq empty a 200 round drum into a car and the windshield was still more or less in tact, but full of holes. Granted that was 5.56 from a SAW, but I believe the effects would be similar.

 

[Advokaten]

Slightly continuing the tangent here... I think the Founding Fathers would absolutely say we NEED firearms. After reading the Federalist Papers, it's pretty clear that they didn't intend for us to be worried about hunting and sport shooting. The important thing here is that there was no clause to say that we can keep and bear arms except the ones Big Brother decides we are competent enough to point in a safe direction.

As for shooting through glass, your volley fire theory would probably work, depending on the type of glass you're shooting through. Automotive glass, more specifically windshields, are designed with layers of plastic embedded in them so that when it breaks it doesn't shatter (from, say, one round going through). You'll wind up with a ragged hole in the glass and a spidered window that's more difficult to see through. The second round will likely just make the hole slightly bigger as the glass can flex once spidered. We had a guy in Iraq empty a 200 round drum into a car and the windshield was still more or less in tact, but full of holes. Granted that was 5.56 from a SAW, but I believe the effects would be similar.

Still anything inside the car would be doing a great impression of a Dodo and have all life extinguished from them./Chris

 

[VoxPatriam]

Absolutely. Like Major Payne said. If he's still in there, he ain't happy. Just figured I'd address the effects on the glass for BDA purposes. I imagine it'd be difficult to establish a "best round for penetrating glass" without some more specific parameters. Wouldn't angle of incidence/angle of the glass, thickness and type of glass, and velocity of the round have a lot more to do with the final effects than the 3gr difference in rounds?

 

[ThatDarthGuy]

http://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=2834&context=jclc Hope this helps. Is mainly for police pistol calibers. And the glass was not on any kind of an angle.

http://www.dtic.mil/dtic/tr/fulltext/u2/a283575.pdf This is an Air Force Study on .308 and tempered glass. A little more along the lines you were searching for.

If I come across any more info I'll post it.