Echo 3 Ordnance's buffer tube kit is manufactured to Mil-Spec dimensions. 

Buffer Tube Kit Includes:

• Buffer Tube, 7075-T6 6 Position, Hard Coat Anodized
• Carbine Buffer— Choice of buffer weight 
• Castle Nut, Phosphate
• Endplate, Phosphate 
• Buffer Spring, Standard Music Wire
• 100% American Made