Has anyone compared the penetration of the Lehigh solid brass bullets for the beowulf against the "regular" bullets like the XTP etc? I cant find any information online about it. I was thinking of buying some from Midway to try but they are 1.00 ea which I dont mind if they are significantly better at say hard target penetration.
https://www.midwayusa.com/product/1019442564?pid=109889

They offer significantly more penetration than an expanding bullet like the XTP.  Apples and oranges really and comparing a non-expanding bullet to an expanding bullet, well, there is no comparison.  But the solid does not expand and its spitzer shape would make it a very poor choice on soft thin-skinned game.  While I have not used them personally, and certainly not in the .50B, in the .458 SOCOM these bullets have a very good reputation on the 458 SOCOM forums for accuracy and penetration on hard targets.  If I were trying to take out an engine block, penetrate a brick or concrete block wall or wooden wall, these driven to about 1700 to 1800 fps would be my first choice.

By the way, I am talking ONLY about the bullets themselves.  I know absolutely nothing about the quality or accuracy of their loaded ammunition.

Yup, what he said.  A more apples to apples would be the Lehigh penetrator vs the AA solid brass Spitzer bullet.  

As mentioned, if you wanted to disable an engine or take down the neighbors I'll tempered rhinoceros that keeps getting out then the solid brass bullets are your huckleberry.  If you want to take out an elk or big gnarly hog, the expanding XTP is the ticket.

I keep a box or two of the AA 350 grain brass spitzer ammo on hand at all times just in case of giants, rogue elephants, dinosaurs and such critters ever start running roughshod over my property.  Never had to fire one yet but you never know.

Your reply reminds me of a conversation my wife and I had once after buying another elephant rifle.  She asked why I needed even one, let alone another elephant gun.  She continued to say she had not seen any elephant tracks in the garden lately.  I replied, “See how well having them works once the word is out?”

I thought I should have solids for my Beowulf when I went to work in AK, so I bought some of the AA ones. They shot okay and in my non-scientific penetration test (wet newsprint) way out-penetrated the 350 grain soft points I normally use for critters.

Well, I had to shoot an Alaska interior brown bear that had decided he wanted to eat me (I shoulda let him so I didn't have to deal with that clusterfuck!). Turns out, I had the gun loaded with 350 soft points and they worked just fine.

Given that, unless I was on a vehicle checkpoint and was using the rifle to stop vehicles in their tracks, I wouldn't- and don't- waste money on them.

I use 50 bmg to stop trucks so unless engine blocks or other hard objects really not needed ,and they ruin meat if you use one on a hog, in head out just below tail

Exactly.  All it takes is one elephant to ruin your day.  Probable? Nope.  Possible? Yes.  Better safe than sorry.

Thanks for the replies and I will use that elephant logic on my wife, hehe.