I used them for two years. They shot wonderfully tight at 100 yards with 100 grains of 777 pellets. However, when I increased the charge to 150, the groups were doubling, and tripling in size. I need the 150 grains for my trip to Illinois where shots may be longer than home, so I switched loads. It may be that my rifle doesn't like that particular load, or may be the the sabot cannot stand up to the 150 grain charge.
The Lock-N-Load is a great idea, and the bullet performs very well. You may need to experiment to see what shoots best. Also, they are extremely convenient to carry extra loads afield with.