U.S.- Mexico border tunnels.

[cbtengr]

Originally Posted by JJ_BPK

and a couple M3A1 shape charges..

Perhaps in concert with some of these.

40-lb-cratering-charge.jpg

[JJ_BPK]

Originally Posted by cbtengr

Perhaps in concert with some of these.

Attachment 27137

Why do most of the pictures of this charge have a couple block of C4 taped to the sides??

[cbtengr]

Originally Posted by JJ_BPK

Why do most of the pictures of this charge have a couple block of C4 taped to the sides??

I too noticed that as I looked for images, perhaps there are other applications that the younger demo guys can enlighten us to.

[abc_123]

The c4 is what initiates the "boom". A typical hole for cratering after you use one of those shaped charges will hold two of those cratering charges. you dual prime the system by putting 1ea C4 on each. if one cratering charge, then dual prime with 2ea C4.

place the c4 inside the dotted lines.

edit to add: naturally the depth of the bore hole created by the shaped charge depends on the ground/surface material.

The M180 cratering charge has a 15lb shaped charge and a rocket propelled cratering charge set up so that when cooked off, the rocket follows the slug from the cratering charge into the ground and detonates.. Creates a crater in one step vs the two-step process of blowing the bore holes and then coming back and putting in the cratering charges. The good thing about these is that the crater from the M180 will be asymetrical and still form an effective anti-tank obstacle since it's mouted on a tripod configuration and the munitions go in the ground at a an agle (<45degrees?)

It's beein a while since I was in an engineer unit and dealing with any of this stuff.

[cbtengr]

ABC thanks for the refresher, I need to dig out my 5-34.

As I recall the shape charge made a near perfect hole for the cratering charge to fit into, it was a pretty close fit, and if we were to tape C4 to the sides like in this pic it would not fit the hole. I now recall the dual priming but wasn't the charge made with a well in the top for a blasting cap for use as the primary ignition source? The dotted lines makes sense now that I have reread your reply and revisited m the pic I posted. I am pretty sure we never had those lines.

crater 2.jpg

[MR2]

Originally Posted by cbtengr

As I recall the shape charge made a near perfect hole for the cratering charge to fit into, it was a pretty close fit, and if we were to tape C4 to the sides like in this pic it would not fit the hole. I now recall the dual priming but wasn't the charge made with a well in the top for a blasting cap for use as the primary ignition source? The dotted lines makes sense now that I have reread your reply and revisited m the pic I posted. I am pretty sure we never had those lines.

Ditto

[mark46th]

U.S. troops also used a smoke generator to pump the tunnels full of smoke so we could find the other entrances/exits. Then the exits could be sealed, pump the tunnels full of acetylene and Ka-Boom...

[abc_123]

Originally Posted by cbtengr

ABC thanks for the refresher, I need to dig out my 5-34.

As I recall the shape charge made a near perfect hole for the cratering charge to fit into, it was a pretty close fit, and if we were to tape C4 to the sides like in this pic it would not fit the hole. I now recall the dual priming but wasn't the charge made with a well in the top for a blasting cap for use as the primary ignition source? The dotted lines makes sense now that I have reread your reply and revisited m the pic I posted. I am pretty sure we never had those lines.

Attachment 27138

Glad I put a qualifier in my response. Come to think of it, i think you are right about the well at the top. The last time I had one of those in my hands was something like 1993. But I do have a FM 5-34 in a box in my garage.