Self sealing rubber "plug", literally shreads the projectile, disintegrating it upon impact
No other part numbers with same form, fit, and function found.
NSN 6645-00-922-0886
NSN 5855-00-256-5562
NSN 6145-01-455-7524
NSN 5965-01-641-5810
NSN 2925-01-573-1067
NSN 6145-01-371-2101
NSN 5990-00-843-2063
NSN 6130-01-408-5814
NSN 5930-00-834-8136
NSN 6135-01-217-8810
NSN 6130-01-324-6468
NSN 6620-01-015-2470