I've been working on a long term project testing a variety of rifle bullets in ballistic gel and I had a chance today to fire a few shots from the muzzleloader into the gel at 75 yards. The rifle is a Knight Bighorn .52 cal and both bullets were shot with 130gr Triple 7.
275gr Knight Bloodline. This is the top-down view.



I was amazed that the bullet exited the second block, that's 32" of penetration before exiting. I fired a 275gr copper HP from a 45-70 into the gel blocks with a similar impact velocity and it barely made it through the first block. All of the petals exited the first block by about the 8" mark. This is consistent with what I saw on a deer I shot with this same load last season; I saw exit holes in the hide from the petals. The entrance hole looks like it was cut with a cookie cutter!
405gr Rem FP. I use these for plinking and when somebody else wants to shoot the muzzleloader.



This bullet curved up and to the left, exiting the second gel block after 22" of penetration. I found one fragment of the jacket and small bits of lead through the bullet's path, so the bullet did expand.
The initial damage done by the Bloodline in the first 8" of penetration was pretty spectacular and the remaining shank left a good wound cavity. The 405gr jacketed bullet just left a very consistent wound cavity the full length of penetration, similar to what I see from hard cast lead bullets from a handgun.
I plan on testing more bullets whenever I have time during the other testing. If anybody has a specific bullet they want me to test, let me know. I have .458 and .475 sabots on hand, so I'm going to run through whatever other bullets I have on hand. It might be hard to beat that Bloodline though!