Walt Langendorfer

Walt Langendorfer from Rhino International Inc, was an American inventor. He designed a gas piston system to convert the AR-15 (M16) rifle to a more reliable operating system than the direct impingement that is the source of unreliability.More recently, the US Asymetric Warfare Group purchased the Gas-OperatedHK 416, a M4/M16 type rifle made by Heckler & Koch using the short stroke gas piston system after intensive tests demonstrating the superiority of this system in adverse conditions (dust, sand, intensive use without maintenance)Many new gas piston systems are being proposed by US companies. All of them can be traced back to the ArmaliteAR18, which was already a competitor of the AR15 and used such a system in the 50's.

References

* United States Patent Office, Patent number 4,244,273, Jan 13,1981
* SWAT Magazine 1986/4 Staff Report. Test of Rhino M16 and AR 15 Conversions, pages 64,65,66,67
* Army Times http://www.armytimes.com/news/2007/12/army_carbine_dusttest_071217/