Partition vs Accubond

[Raghorn]

I've been shooting 225 Partitions in my .338 for a few years with good results, 3/4 M.O.A. Last year I tried a box of 225 Accubonds, and the accuracy was great, 1/2 M.O.A. but with the exact same load, M.V. was off by about 80 F.P.S
Any ideas why ? I would like to use the Accubonds, but I want to keep the veloicity up around 2800 and the best I could get with the Accubonds was about 2750 without exceeding the recommended max load.

 

[Val]

An 80 FPS variation in muzzle velocity is pretty small. That could have been caused by temperature variation, chronograph set up, or any number of causes. The 80 fps is pretty neglegeable with respect to bullet drop and the effect on game. I wouldn't worry about it.

 

[Raghorn]

Thanks Val.
I tested the loads side by side, and repeted the test several times, the Accubonds are defaintly moveing slower.
I just can't figure out why. The only thing I can think of is some pressure is slipping past the boat tail. The main reason I wanted to go to the AccuBond was the reduced downrange drop of a boat tail design, but the lower velocity produces about the same drop at longer ranges.