I hate to tell you this, but the deer at 100 yards wasn't a miss, and the one at 150 might have been, but based on your powder load, it too was probably a hit. I say this based on what you reportedly did at the range, and the fact you used a rest.
Your load is a pretty hot one even with a 250 grain bullet, and it is possible that you might have shot a bit low at 150 yards. The gross sights that you get often with fiber optics on an inline really leave room for some error in sight picture, but if you had practiced out to 100 yards, and were getting good groups, and you used a resting position when sighting and firing, you likely hit the deer right where it counted.
I have shot deer from 10 yards to 110 yards with my muzzleloader, and I have found that deer, even when hit with a soft lead .530 diameter projectile that goes through and through, taking out the lungs, can go 100 yards from where they are hit, and not bleed or leave hair for the first 60-80 yards. My most recent deer, two weeks ago, left only a tuft of hair, and went 80 yards before blood trail, and dropped about 20 yards beyond that. I have also seen deer drop where they were standing, or watched them go a short distance and watched them fall. It's unpredictable.
One thing that I have learned the hard way..., you must wait a full 30 minutes after taking your shot. If the deer went a short distance and piled up, you lose nothing, but if you reload and go a trackin' after about 10 minutes, and the deer isn't quite dead, the deer will see you long before you see it, and will bolt another 100 yards or so. It may do this so far from you you don't even hear it go. So the deer will have gone about 100 yards, leaving a blood trail for about the last forty, and you will spook it for another hundred. What you will find is a spot of blood, a blood trail, lots of blood, and then nuthin'.
The large amount of blood will be caused by the deer coughing, as it lies down, while the small trail leading up to that large amount will be from the wound or from blood dripping from the deer's mouth. But you may have to track the deer for 60-80 yards first, maybe a bit farther, before you find that first blood, and it may be pretty small.
Waiting 30 minutes gives the deer time when it first lays down to succumb to the trauma. It more than likely will expire in that time, and you only need to find it.
So give waiting a full 30 minutes a try. Mark your spot from where you shot when you leave to get the deer, so you can look back for a visual reference. Mark the spot where you think the deer was, again for a visual reference, and be prepared to go at least 100 yards from that second point before you expect to find the blood. You may have to slowly zig zag along the path you thought the deer took to find this trail, depending on the brush conditions, and don't forget to look under low piles of hedge etc for sometimes they will crawl up under that stuff to hide, and you won't see the white of the tail.
LD