Did a little digging into this foam thing and found out some things. One, of course is the OEM custom cut which is absurdly expensive unless your rifle/pistol is over the top in price in the first place...
The second option is pick-n-pluck foam inserts but you won't get the exact shape because the pull out sections are square. Works for ammo boxes and such, not so good for rifles and pistols.....
Third option is the electric carving knife as illistrated on You-Tube in various video's and the way I went this time. It's an exercise in patience to get the exact shape and carving knives aren't really meant to cut sharp corners so it takes lots of time and the end result might still not be that good. I lucked out and mine came out acceptable.
The forth option and the one I like best and will use from now on is the Hot Wire Method. An outfit by the name of Proxxon (and others) offers a hot wire knife for hobby foam cutting. It seems as though guys that have model railroads use foam to make scenery and crafts people cut foam to different shapes (for what I have no idea) but the hot wire knife is the preferred method and quick I might add.
It's basically a thin wire supported between a metal base and a metal standoff and it's charged electrically and gets red hot, instantly. The Proxxon is a handheld tool that 'slices' (melts) the foam with a thin kerf and seals the pores as it goes through the foam. It's capable of square corners or any shape or tracing so all the little shapes on your rifle/pistol can be faithfully reproduced in the foam, quickly and easily (or as close as you trace the part on the foam.....
The wires are replaceable on all the tools and attach to the posts easily so all thats needed to start an inside foam cutout is a small hole in the foam for the wire to go through.
You want to cut in a well ventilated place because the hot wire makes the foam stink a bit and of course, don't touch the wire, it's red hot.
The tools cost about 50 bucks for a real good one down to 15 for a cheapo. Goggle up Hot Wire Cutter or Proxxon and have a look. I have a Proxxon now and plan on using it from now on. There are some enlightening vids on You-Tube showing the hot wire cutter, cutting foam to give you an idea.
I'd rather spend 50 and have the tool handy than spend a couple hundred to have someone else cut the foam.
Hope that helps.....