Furniture fits just fine, the fixed stock has about a 1/2 inch longer length of pull than the folding stock. The fore grip lower and upper will have some wiggle. espeacially based on temperature. I have had my 858 in minus 25, shot about 30 rounds in 5 minutes and was able to remove the lower handgrip and place it back on the gun due to the metal expanding much faster than the wood, was kind of a neat trick.
as for cleaning: clean ASAP same day as you shot. Shooting surplus ammo is fine if you do this. I have been in moist climates (nakusp) shot about 5 rounds of surplus and my barrel was orange about 4 hours later, cleaning cannot be overlooked using this ammo.