The "J.A.C.K." Uppers

*NEW* 10.5" J.A.C.K. 5.56 Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 11.5" J.A.C.K. 5.56 Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 12.5" J.A.C.K. 5.56 Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 13.9" J.A.C.K. 5.56 Mid-Length Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 14.5" J.A.C.K. 5.56 Mid-Length Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 16" J.A.C.K. 5.56 Mid-Length Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 16" J.A.C.K. 5.56 M4 Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...

*NEW* 14.5" J.A.C.K. 5.56 M4 Upper

The J.A.C.K. (Just Another Carbine Kit) is designed to provide a solid foundation for your next build by using high-quality, US made components. The barrel and gas system are the heart of your rifle and TNTE takes the worry out of your build by...