When I first started shooting rifles at the range, I'd build sand castles with the sandbags ... that works well 'nuff ... but they shift at every shot ... so it's kind of a pain if yer gonna make an afternoon of it!
I ain't ever bought one of them "
sleds" ... I'm sure they're nice ... but ... 1. I almost never see anyone else with 'em at the range ... 2. with all I already got, I can't see luggin' that much more ... even from the truck to the bench!
I bought one of these more than a few years ago ...
http://www.dillonprecision.com/#/content/p/9/pid/24652/catid/27/Protector_Model_Rifle_Rest ...

I've got no complaints!
It fits in a smaller bag ... it ain't light ... but it is, compared to luggin' my pistol range-bag!
Somethin' like this is purdy nice, too ... when the range is busy, and there's almost no (
decent) sandbags left!
I'll usually either shoot off this alone, 'er lay a bag 'er two under the grip, as well! Ya could get somethin' to bring along, to put under the grip ... but I either use an available sandbag, 'er go without!