Original U.S. 1950s Era Rare Experimental X-51 “Universal Helmet” Shell With Incorrect M1 Liner - Missing Left Side Chinstrap & Bale Category_Receiver 3×36mmR and was adopted by

3×36mmR and was adopted by the Austro-Hungarian Cavalry in 1870

Both of these are inert and have been fully deactivated following guidelines provided by the ATF

In early 1951

The interior is lined with orange "service cloth" type fabric

Original U.S. 1950s Era Rare Experimental X-51 “Universal Helmet” Shell With Incorrect M1 Liner - Missing Left Side Chinstrap & Bale Category_Receiver 3×36mmR and was adopted byOriginal Item: Only One Available. Now this is a rare helmet to come across! There isn't much information out there at all about the X51 helmets, which were developed and tested during the 1950s. They were seen as an attempt to use new technology to improve upon the M1 helmet, which had served the U. S. Military well during WWII. Also with the post war budget cuts, they looked to create a "Universal Helmet", which would be able to meet the needs of