It may be possible that different runs of the same bullet have different properties. In my 270, I like shooting Sierra bullets because of the accuracy. Shot 130 grain with good results on deer. Decided to go with 150 grain as an all around round for moose and deer. As soon as I started using the 150s on deer, I saw all of my animals run. Took 3 mule deer and hit 1 moose 2 years ago all at fairly close range. 50 yard shot on a small buck and he ran a half a mile. Good thing it was all open country where I saw him. All three deer were double lung shot, all three sets of lungs looked like I pushed a pencil through their lungs. Hit the moose at 50 yards a little high just below the back bone as he was coming down a hill. Just made him shake for a second and a second shot from my son brought him down (180 gr WSM). Wasn't sure if I had a velocity problem or a bullet problem so purchased some SST 150s for the 270 to compare. Shot both Sierra and SSTs into pine logs (purchased some new powder and made loads up with both powders). All the Sierras entrance holes were noticeable only because of the mark the lead made at entrance. The SSTs started opening up immediately. Took the SSTs out and bagged one 8 point mulie at 300 yard and a whitetail 8 point at 75 yards. Both bang flops. When I talked to Sierra about the problem, they thought the bullets I had may be the problem and sent me 25 of a different batch to try late last year. Haven't given these new Sierras a test yet but will be doing so in the next month or so as rifle season opens up mid October. Like to do it sooner but my house needs residing and I wasn't ready to give up any fishig time to get the job done.