Apache
Harbor Freight's long-gun case: IP65 weatherproofing, pick-and-pull foam, and wheels at the lowest credible price in the field.
The Apache 9800 is Harbor Freight's Pelican knockoff, and for storage and ground transport it is the price-to-protection benchmark the budget field cannot beat. The polypropylene shell carries an IP65 rating, which means dustproof and resistant to water spray and low-pressure jets from any direction. That is genuine weatherproofing, but it is a step below the IP67 submersion rating of the Pelican, Nanuk, Seahorse, and SKB cases, so do not treat it as a dunk-proof case.
A built-in purge valve equalizes pressure after elevation changes, pick-and-pull foam lets you cube a custom fit, and the 50-inch interior with wheels handles a full-length rifle. Padlockable latches make it airline-legal for checked transport. At $150 MSRP, and frequently under $120 with Harbor Freight coupons, it is the case to buy when you need three or four boxes for storage or a beater for the truck and cannot justify Pelican money on each. The honest limit is the seal: IP65 handles rain and splash, not submersion, and the latches are lighter-duty than a Pelican Vault.
Add the Apache 9800 Weatherproof Rifle Case to your build and see how it enhances your platform.