Would anyone know where i can buy a 0 gauge shell
this one was used in the Vietnam war, would anyone know what shotgun they used?

I believe you are asking about the M79 Grenade
Launcher and the 40mm 00 or flechette shell.
The 00 shell used 27 buckshot in a 40mm sabot and the flechette round used 45 flechettes.

WC

I have three of the "0" Gauge shells , different headstamps R-P , W and LC. But - it is my personal view that these are spurious , and made by some creative soul for the collector market .
Mine all came with a badly copied page purporting to be the results of military testing at the Lone Star Ammo plant in Texas , dated 03-86 . Conversations with Bill Woodin supports the theory that these are fake , and were never issued for use in any known firearm .
I agree with Captnemo that the shells are cut down 40mm flare cases , mine have a fresh look to the cut edge at the mouth out of proportion to the aged look of the casewalls .
So BigAl , sorry to disappoint you , these are fakes , and were made for us mugs to get excited over . Also , the things were supposedly used in a large bore machinegun , not a shotgun . If you want a copy of the literature that comes with them let me know and I will send you a scan .

Just made a phone call to my friend whom carried an M79 in Vietnam from mid 68-mid 69.
He told me that he carried 5 buckshot shells for the M79 for the whole year without firing any of them.He said the shells were M576 Personal Defence Rounds.He stated that the only buckshot 40mm that he had seen were made of plastic and looked like an oversized 12 gauge shell.All other rounds used an aluminum case.The color was green and they had a folded crimp.

According to him the buckshot shells were used only in the M79 as they would not feed through the automatic launchers.

There should be a few on these boards whom are familiar with the M79.

WC

Since the original query was where to locate a specimen of the "0" gauge shell , you might try contacting Victoria Gilbert at Liberty Shooting Supplies P.O. Box 357 Hillsboro OR 97123 - ph (503) 640 5518 - e mail LISHU@AOL.COM .

I got one of my cartridges from Victoria , she may still have some , although it was a while ago . Otherwise study Auctionarms.com or Gunbroker.com or use the wanted column on either of those sites . You may well turn something up fairly quickley . Good luck