Has anyone used this site: www.mycasebuilder.com ?

You can pick from a huge number of different cases and use their online tool to design your own foam inserts.

I'm going to do one for my Mauser M03 in a Pelican 1700 with two barrels and two scopes.

Ask about the density or a sample of the foam. Realy soft or mushy foam does not hold up well when compartmentalized. Also leave lots of room in-between each part as the sideways tensile strength of foam is low and will tear if the compartments are too close. ...Dave

You can get the normal Pelican form or the newer harder foam. Here the two types they list.

BTW - I've had no issues with the standard Pelican foam ever.

PE foam is fairly dense (similar to the feel of a "pool-noodle"), yet forgiving. It offers a secure, snug fit. Finger-notches are recommended in order to retrieve items.

Ester foam (commonly used in upholstery cushioning) is more spongy and pliable, exhibiting excellent shock absorption and malleability.

Go for it. I've used Pelican cases for a long time to protect my cameras. Found it bomb-proof but heavy.

There is an outfit called something like pelicancasebuilder, some derivation of pelican case, who sells custom foam inserts. They sent me a grid matched to my Pelican case to lay out my components and trace them on a insert. Not cheap but excellent seldom is.