I have been playing around with slugs and the H&N shoot fantastic but when I shoot a squirrel it just goes through them and dose'nt mushroom, anybody have the same problem?
That's pretty typical with higher powered guns and slugs. Hybrids, AVS, Neilson all make softer slugs than the lead used for H&N but I typically still get just a pass through on the higher powered guns.
AVS is among the softest lead, get a version with large hollow point will give best expansion close to hybrid and RS. Now I don’t know the range your shooting, but if under 40 yards, try polymags for body shots, they will not pass through.