I bought a used AR. Vulcan Lower unknown upper(was told it was a complete Vulcan when I bought it) anyway. When I shot it it wouldn't group. 6 inches at 100 yds. I thought, well the barrel is shot out so I bought a whole new upper. DPMS 223. Floated bull barrel and it is a tack driver. 1/2 inch groups or less. ( i can shoot) Now- I tried to get old upper shooting. Thought barrel was shot out so I ordered a new barrel Still no shoot. Hmmmm. I has a composit receiver so may be it is not strong enough for a floated barrel- New Aluminum receiver- still No shoot. I think well maybe it is the bolt- took bolt from DPMS- still no shoot. It also has a new gas block. The only thing that has not been replaced with brand new is the handguard. Is it possible that a FreeFloating hand guard would effect the way a gun shoots?
I have tried a Red Dot Scope
A 3x9x29 Tactical Scope
And a 3x9x32 Tasco
The Red Dot and the Tasco are prov-en shooters. The Red Dot had been on a 357 Pistol and the tasco was put on a 243 after removing from the AR. Less than one inch Groups
This is my first Ar but not my first gun. I have over 40. I am scratching my head on this one. I don't know what else it could be. The Handguard just has a big nut that holds the barrel on then the handguard screws on it. That is all that is holding the barrel on. Is it missing something? The Schematics I see are all for a regular handguard and they show a Barrel snap ring, a Delta Ring and a Weld Spring which this one don't have. As I said this is my only AR so I have never took apart anything other than this one.
I thought about taking the new DPMS apart and looking at it but it shoots to good. I don't want to mess it up.
I have tried Rem, Hornady, Win and a couple generic brands of ammo along with several of my own handloads.
Any Ideas