I've been wanting to make sure my equipment is as good as I can get it. I have an Aimpoint Pro that I've sighted in for 30 feet for home defense and a room clearing environment. I have an Eotech 512 with laser for distances to around 50 yards. I have a Hi-Lux 4-16 mil-rad scope I've had trouble getting sighted for 100 yds. Took it to a LGS to get boresighted and that was a waste. Wouldn't cut paper. So wanting to get on target, and wanting to do it myself, I bought the Wheeler MFG laser boresighter. That thing is great. I dialed it in at a distance of around 20 yds, then took it to the range at the SO. It was a windy day and the crosswind didn't help. Later I found out we were having gusts of up to 50mph. So to get a steadier hold on target I got a Caldwell Lead Sled Solo. I just assembled it today and it looks like it will fill the bill to take the unsteadiness out of the sight in process. Should have done it the first go round.

Caldwell Lead Sled Solo

The tray can hold up to 25 lbs of weight material. Since I have the lead shot pouches used for diving, I'll use those as needed. My SOLGW M4 fits perfectly with a 30 rnd mag. Hopefully I'll get it out to the 100yd range this weekend

that lead sled ought to help get that sighted in.

Lead Sled is fine for your purpose.  I have a Solo, too.  Good for general sighting in.  But, POI is likely to shift slightly with the rifle against you shoulder, so confirm your zero.

Lead Sled Solo is not as repeatable for sub MOA capable rifles, however, as a good front rest and rear bag.

I bought a lead-sled years ago, but rarely use it anymore.

IMHO it is best to sight-in your optics in the most stable position you will ever shoot "in the field".  For me that is prone with the rifle on a bag/backpack or on a bipod.  I don't carry a lead-sled with me in the field, so I no longer use it, except to choose the best performing (most accurate) ammo in a particular rifle.  In the latter case, you want to eliminate human sources of inaccuracy.