Obviously, lots of stuff will work and some form of sand is an easy choice.=
Years ago, this is how I filled my first set of range bags.
However, today I much prefer dried beans loosely filling recycled 25lb shot=
bags stitched shut. My range bags are filled with whatever type was cheap=
est at the discount grocer 15 years ago when I made them. At the time, on =
advice of my gunsmith I spent $1.50 on beans rather than use free sand from=
a pile in the back 40. The fact that I am still using them and quite happ=
y with their function speaks to whoever it was objected with the idea that =
beans might spoil. Of course, I don't leave them lying about in the rain a=
nd to the best of my knowledge my house is vermin free. =20
Bags of beans are much tidier at the range, in the car, and at home than sa=
nd (washed or otherwise)and much more convenient to carry because of their =
lighter weight, yet are heavy enough to well-steady a rifle.=20
Also, in my experience, a range-bag filled with beans will more readily con=
form to and provide a cozy nest for forearm or butt than sand (which does n=
ot have to sit for long before it compacts into a non-compliant and hard ma=
ss. Note that I have as well sand-filled leather bags pre-shaped to include=
"nests", but see bean bags as good in the "nesting" regard. =20
But I think my most important point is bags filled with sand in use often q=
uickly compacts to a hard, non-compliant, rest. In my experience, many rif=
les shoot away from a hard forearm rest (because rifle dynamics during reco=
il act before the bullet exits the barrel) comprised of a sandbag, leading =
to a misleading zero relative to shots fired from field positions. There s=
eems in my experience to be enough give in my bean filled range bags to pre=
vent this effect. =20
In an imperfect world the advantages I claim for beans are small. The rang=
e I use has sand-filled bags sitting about on site. But I cart my bean bag=
s from home to use in preference. =20