John T,
I was tying to figure out why you are having problems with your Sled so I went to my garage, pulled out the Sled and looked at it for a few minutes.
There is really not much to look at since it's a simple piece of equipment. I noticed though that I had cut the bottom of the 4 front bolts as they were longer than necessary and I didn't want them to touch the bench. I should also mention that when I am shooting past 200 yards I have to raise the front bag to the point that it wobbles and makes the Sled less stable. So instead I place a 1/4" piece of plywood under the front legs.
If your Sled is not broken and it was assembled correcly, I would shoot each rifle with a load they like, from both the Sled and your other bag, on the same day and preferably under the same weather conditions.
If your Sled keeps opening your groups I would return it for a replacement.
,
.
