Man I got a Shilen barrel for my varmint AR and I had issues chambering cartridges too.  Sucks.

When making AR 223 Ammo you really need to measure everything.  I even make dummy loads to test in the AR.

^^^I hear you..........now.  Before that the reloading was primarily for non match AR's.  No problem gobbling up the ammo that was a bit out of spec.  That Shilen - yup wacking the butt on the table to clear jams.  The stupid thing is you just clear the jam and put the same round back in................yup jams again.

A couple of tips for Match AR Reloading....

Full length resize only. Neck resizing is usually for bolt actions. The exception is is you bought virgin brass in bulk and it is all from the same lot. You will still need to feed every case into the rifle chamber to test for sticking.

Uniform flash hole. this is to ensure uniform ignition of the powder.

Measue length and trim to specs.

debur the case mouth.

Ream inside neck.

Weigh each case and discard those that are too heavy or light.

Do not use "Match"primers. I had a slam fire due to the sensitivity of the primer and lost 10 points instantly.

Inspect each bullet for uniformity and weigh each. Discard anything abnormal.

Seat bullets and crimp in separate operations.

Research on what the winners are using.

A couple of tips for Match AR Reloading....

Full length resize only. Neck resizing is usually for bolt actions. The exception is is you bought virgin brass in bulk and it is all from the same lot. You will still need to feed every case into the rifle chamber to test for sticking.

Uniform flash hole. this is to ensure uniform ignition of the powder.

Measue length and trim to specs.

debur the case mouth.

Ream inside neck.

Weigh each case and discard those that are too heavy or light.

Do not use "Match"primers. I had a slam fire due to the sensitivity of the primer and lost 10 points instantly.

Inspect each bullet for uniformity and weigh each. Discard anything abnormal.

Seat bullets and crimp in separate operations.

Research on what the winners are using.

That's some really good stuff. I should have full-length resized, but I made them intended for a bolt action, a year before buying this service rifle. Not happening again. I hope to get into this soon..