Do American border guards have .50 cal rifles for anti-vehicle use?

Factual Questions
1

I forgot where I read this but apparently the US border patrol stationed at actual border checkpoints were apparently equipped with .50 bolt action rifles or even M16s chambered in a shortened .50 cal round (either .AE or Beowulf) because apparently a 50 round is the only round that can reliably penetrate an engine block to disable a vehicle from a frontal hit if a car tried to rush through the border barricades.

Any truth to this? Obviously inspired by recent events.

2

Not obvious to me. What recent events?

3

The almost-certainly-wasn’t-a-terrorist vehicle explosion in Niagara Falls.

4

Thread on that event here:

It starts out kinda schizo because the mods glued two threads together. After ~10 posts it settles down to sanity.