OK, time for me to weigh in. Please bear with me as this might get a bit long-winded.
I purchased a Traditions Pursuit in-line this year but opted to continue with my roundball gun for hunting (took a really nice heavy-racked whitetail with it too!). But my hunting buddy doesn't have a front-stuffer so I loaned him my in-line. I've got a good load worked up for this rifle, 90 grains FFg TripleSeven under a 275 grain T/C MaxiHunter. If you've ever seen the MaxiHunter you'll know that it's not far off being a full wadcutter in design. My buddy shot several shots off in the back yard to be sure he'd know how to shoot the rifle and reload it - all went without a hitch so I sent him off to his treestand with a loaded rifle and three quick-shot reloads.
As I was working away in my home office I heard several shots which had to have come from my buddy's treestand. Sure enough, it wasn't 20 minutes before he was on the front step. But rather than his usual broad smile (he's got a long track record as a very proficient hunter, having harvested five deer this fall alone...), he looked, well, totally pi$$ed. He had loosed off all four shots available to him at one doe. Admittedly it was a long shot for a first-time m/l user, but he'd shot it enough at paper for me to know he would be accurate out to 100 or more yards. The real kicker is that he hadn't even raised one hair on that darned deer!
So we went back to the paper target and blew off another dozen or so shots, litterally obliterating the centre of the bulleseye in the process. Definitely not a question of accuracy or repeatability of the rifle, so what the heck was it?
We loaded up and headed back to the stand. My buddy went up into the stand with a nice maple stick, and directed me to where the deer had been standing in the snow. He "shouldered" his maple stick while I got down on my hands and knees to take a look at the path the bullet would have had to have travelled. We did this for each of the four shots taken. In each and every case the shot looked clear from his treestand location, but in each and every case I was able to locate the reason why he wasn't able to connect with the deer. The last shot was the most telling one...
In every instance I found where a twig had been hit by the bullet. It took over an hour to do this investigation, but boy, did we learn a lot. In the case of the last shot, it was taken at a range of 55 yards (laser measured, including slant range from the tree stand). The stand was fairly high in the tree by our standards, about 18 feet. The bullet had what looked like a clear path to the deer, but in fact never made contact with meat because it hit a small (1/8" dia) wild raspberry cane and was deflected downward into the snow. The shocker was that I found both the raspberry cane, located less than 5 yards from where the deer stood, and the furrow dug in the snow by the bullet. The bullet hit the cane just over two feet off the surface of the snow, perfectly on-path for a good chest shot, and was deflected downward at such a radical angle that it struck the snow midway between the cane and the deer. It would have been thrown off course by something close to 45 degrees after hitting a chunk of brush that I wouldn't have hesitated trying to shoot through, had I even been able to see it at that range!
In all four instances we found the twig, branch or raspberry cane that my buddy had shot, but only in one of them did we actually find the bullet hole in the snow. The evidence we saw provided irrefutable proof that the myth of the "brush buster" is nothing more than myth. You simply CAN'T SHOOT THROUGH BRUSH!
There will be those out there who have made shots through brush and brought the venison home - of that there's no doubt. But when one is presented with four abject failures of this technique in one day, one begins to believe that taking such a shot is, at best, a low-odds gamble. Given that we're shooting at living creatures that demand our respect and humane treatment, perhaps we're better to opt for the higher-odds shots?
PS: My buddy managed to tag a lovely fat doe the next day with that same muzzleloader, in almost the same situation, but at closer range which increased the downward angle of the shot such that raspberry canes were virtually taken out of the equation. The MaxiHunter punched through the shoulder, through the bottom lobe of a lung, through the heart, and out the bottom of the chest. Shot placement was as near to perfect as one would ever want, and the deer literally dropped on the spot.