I made my own carbine out of that really long 24" barrel on a M141 .35 Remington. Being a kind of squirrel like tree climber/hunter in my youth, those long barrels caught on way more branches than the 18-20" versions. I did have one of those 18.5" .308 Remington 742 semi-autos when I thought that I needed to shoot fast and I didn't shoot it often enough to realize that it was overly loud. Just not real well made with stamped parts and a short lifespan because that breech bolt worked those receiver rails like a milling machine.
