I agree with
@Rimfire Jesus mostly.
I have a lead sled laying around somewhere not been used in 15 years or more.
IMHO they will not have the same impact point or produce the same groups as your shoulder.
A pair of heavy bags are also a good alternative.
His advice to dump the Hornady bullets is also sound and I have found they are hard to get running well.
Quality bullets will group with less hassle and be more consistant.
Sierra 168g or 169g are both easy to get running, well worth the price difference. Just be aware the ogive on the two of those are different lengths from base and tip.
I have improved my load development by using Eric Cortina's methods and agree with his premise that if 2 shots don't group 5 certainly won't.
In fact the only reason I use 3 with initial ladder tests is to see the shape of the 3 shots to help eliminate stringing.