Best way to sell an M2 machine gun barrel?

I don't have much experience with the M2 machine gun but we recently found an M2 .50 cal machine gun barrel in grandpa's barn (he thought it was a truck axle and was about to scrap it). I'm trying to figure out what might be the best way to go about selling it (I doubt I'll ever be able to afford an M2 and i'd like it to go to a good home). It appears to be in unissued condition (it was in a protective wrapper and still has a cosmoline coating). As best I can tell, the wrapper is labeled:
J941-B-674
PART NO. D353404
BARREL QTY. 1
METHOD 1A 8/23/51
Anyone know exactly what this is (I think it might be an aircraft barrel)? Anyone have any guesses on value and where to best sell it? Many thanks!

Thank you to everyone for those suggestions. I've posted to those forums. It appears to be an M3 aircraft barrel and I'll attach an image below for confirmation. Does $350 seem a reasonable price (I've seen some on gunbroker for $500 but that seems far too high)?