I've been using these bullets in my 243 now for a couple of months and have had a chance to assess how effective they are on muntjac and roe. I've had about 5 or 6 muntjac with them, but, to date, only 2 roe, a doe and a buck.
All the muntjac have been H/L shots, and all have fallen on the spot, whether or not they were aware of my presence prior to the shot. Niether of the roe died on the spot, though niether would properly be classed as a runner.
The doe had seen me and was in the process of trying to decide whether I was a threat or not. I took the shot before she could make her mind up. She ran 50 or 60 metres, but was in view the whole time, and I'm sure she was dead as a doornail by the time she hit the deck. The bullet had passed close above the heart. 5 weeks later sees me out for a buck, giving the Sierras another outing. The buck hadn't seen me, but the doe he was with had, although she couldn't work out what I was. Her suspicions roused the buck from his bed and he was pacing around uneasilly unsure of what she was fussing about. I shot him in front of his nearside shoulder in order to have the bullet exit behind the opposite shoulder. it didn't quite work out that way and the buck needed a second shot to finish him off although the first one had put him down.
In all cases the Sierra bullets have caused extensive damage, usually consisting of an entry wound, an exit wound and a secondary exit somewhere else on the body, telling me that the bullet is fragmenting at some point during it's passage through the animal.
Today I butchered the roe buck I shot yesterday and managed, unexpectedly, to recover the remains of the bullet. Bellow are a few pics to add to my ramblings.
These three pics are of a muntjac shot last week and show the entry wound, the entry and secondary exit wound (both on the same side), and the primary exit wound. This seems fairly typical for this bullet. This is the kind of quartering shot I tried to execute yesterday on the roe buck.