My 20 ga. Encore will pierce the primers on 3 of 5 of the Lightfield slugs. Best one I've found so far is Federal Premium 3" with the Barnes sabot slug. 4 shots in 1 7/8" the fifth opened the group to 4 1/8". Second best is Federal Premium 5/8 oz 2 3/4" sabot 4 shots in 3" and 5 in 5". These are 100 yd groups with a Leupold 3-9X scope at 9X.
Are you saying that the primers were pierced due to high pressure of the Lightfield slugs? Were you usuing 3" ? I noticed the 12 gauge slugs had a muzzle velocity of 1900 FPS.....way too hot for any shotgun in my opinion.
I bought some of those Sauvestre 12 gauge 3" disgarding sabot slugs
that were fin stabalized and based on an anti-armor round fired in tank guns. These things were SO HOT that I couldn't open the action of my Mossberg 695 without using a rubber hammer. The primers were pierced and flattened. These clocked at almost 2000 FPS. I also tried them in an NEF single shot Ulti-Mag. Same deal. Wouldn't eject and had to be driven out with a wooden dowel.
I tend to stay away from the magnum stuff. Lightfield Hybrids (2-3/4") clock at over 1400 FPS.....more than enough for whotetail out to 100 yards.
That's what I used to take the deer in my profile picture but the distance was only about 25 feet.