Try it here.
http://Simple Storage for a Semi Auto Rifle
The next pages are not as informative.
Step 1: Simple Storage for a Semi Auto Rifle
In the picture, you will see the steps to construct vertical storage for a semi-automatic rifle which is supported by the magazine well and the bolt. It allows for rapid removal, ensures there is not a magazine in the rifle (always ensure there is no round in the chamber before storage, cleaning or modifying a firearm.
Materials used are scrap bits of 1x 's and bolts I had on hand. Ensure the wall or surface you are mounting yours on is strong enough to support the rifle. When in doubt, locate the wall stud and mount to the stud. Drywall will not support this. In the photographs the mounting surface is a 1x book case so it is both solid and heavy enough to support the rifle. It also conveniently obscures the firearm from plain sight.
We do not have children in our home, so I recommend if you do, please ensure you either have a lock on the trigger or modify this design to accept a locking device. It the magazines/bullets are stored separately, your odds of having a horrible accident are minimized. Coupled with safety training and responsibility, the risk is minimized more.
Please do not consider me an expert nor responsible for what you intend to do with this design. It is for reference only and you will have to modify it for your rifle anyway. Spelling is horrible-for that my English teachers can hold me responsible. The Chihuahua is optional.