The same adaptor is used on both M16, AR15, and M4, IIRC, with minor adjustments. Or have fun with this -- Amazon.com : NcStar AR15 Golf Ball Launcher (AGOLF) : Sports & Outdoors Just make sure you use blanks when you do. Military Ammo Blanks .223 AR15 / Mini 14 / M16 / 5.56MM
The electrical department at the mine where I used to work had a line gun. It was a single shot that used .45-70 blanks loaded with black powder.
Well, what started me on the line launcher was one leg of my SSB antennae had came down from the tree top and I needed to get it back up into the fork where it secures. I started with a weighted line but decided there were just too many windows within the rebound area so I tried a wrist rocket but the line and weight just reached the apex of their arch a few feet below the fork. I next tried a bow and wooden arrows with a messenger line, hit the fork every time but the arrow just didn't weigh enough to get the messenger line back to the ground. That is when I remembered this old line launcher I had under my desk at work, retrieved it, loaded it, and ...click...damned firing pin was just missing. I ended up using my fishing bow with a fiberglass fishing arrow to get the antennae back up. There is another 12 guage launcher on the market too but I haven't seen one in a few years, made by Mossberg on one of their 500 series pump guns.
About 70 years ago I saw the Guard put a field phone line across a swamp with a bazooka. Being a young kid, I wasn't allowed any where near the operation, but it impressed me to the point I still remember it. They were just back from WWII and it was before Korea, so there were a lot of crazy guys there with all kinds of weird stories and games. They also had jeeps with 50's and 106 or so recoil less rifles that were impressive.
The black powder 45-70 blanks for line throwing guns were made by Western Cartridge Company (Winchester) during WWII. They used 45 grains of black powder and were designated 45-70 MK I. I have some of these blanks. In the 1950's they made the M32 that used smokeless powder with three wads. Here's a comparison of the MK I and the M32. 45-70 line throwing guns are still being made and sold. H&R makes one that Bridger sells in a case with all accessories. Here's an older Remington 45-70 line thrower.