I don't blame you for trying to talk him out of it. Many of my good friends work for MPD and they are all bitter about their department and the morons running it. No doubt the majority of crimes in all the suburbs are thanks to Memphians. You couldn't pay me enough to work for Memphis. To have to deal with the extremely violent community with a serious lack of support from the brass isn't worth it. The worst part is that the courts here are handing out slaps on the wrist. You can take someone to 201 Poplar (the county jail) for their 18th violent felony and they get a $1000 bond and walk out the front door before you finish your arrest report! They the plea bargain their aggravated burglary charge down to theft of property and get probation (which they promptly violate with no serious consequences). Something's bad wrong here.
As far as the original topic, I got the following standard boiler plate text response from Sportsman's Guide:
"Thank you for your question on items that have mailing restrictions.
We have placed restrictions on specific items listed in our catalog and our web site.
Due to the various state, county and municipal laws that exist, we are not always able to comply with each individual guideline.
Not all of the restrictions are based on laws on the books, but could be a company decision based on other particular concerns. These may include whether the state has law suits pending involving gun owners and recent court decisions that may affect businesses like ours.
Also, it may be that the states' laws are so vague that they could be interpreted unfavorably in the event a court action was ever involved.
We do apologize for any inconvenience this may have caused you."