If this is only happening with the second grind, it is very common. First steps to avoid it is as others have said: cold (nearly frozen meat), better trimming of tendons and sinew/fascia, and putting grinder parts in freezer before grinding to help keep it cold.
Second step that has worked for...
I do the pvc pipes. Haven't had that problem yet. I did fill them with water with room to expand and froze them standing up on end. Capped after froze solid and ice flush with top. Maybe that prevented this?
I own a knight ultralite that I procured to hunt Washington State. I upgraded the sights to a peep and was very accurate on the range at 100 yards. I didn't work the gun past that point for the hunt I had in mind, but I am sure with load prep and practice it would likely be capable of a but...