So I had several Type 4s today, couldn't get the charging handle back after a failure to fire and had to mortar it.
PSA upper and lower, reloaded ammo. Each time was after firing multiple rounds, ie. wasn't that I pussey'd the handle on charging it.
Problem I:
    Primers on those several rounds were dimpled but no ignition. After clearing it I loaded those rounds a second time, they both fired. Sellier & Bellot (Zapalky) primers.

Problem II:
    The type 4 malfunctions. My reloaded rounds were once-fired casings that had been sized with an RCBS Small Base X-die. They all passed muster in a Wilson case gauge and a Lyman case gauge. So I don't think they were bulged. Were definitely not over-long

I then tried factory ammunition. All rounds fired, but if I tried to eject a round without firing it, the charging handle was stuck. But the rounds would still fire normally and the rifle cycled and chambered the next round.

The AR15 is relatively new, probably has about 500 rounds through it, and maybe 250 since cleaning.

Chamber doesn't match your bullets or they are loaded too long.

I would check headspace.

Having to mortar unfired rounds to free them from the chamber is always caused by ammunition headspace problems.

You need to bump the shoulder another .003"+ on your brass in order to get the clearance needed for reliable feeding and extraction.

Thank you all.  First I'll throw out the Lyman case gauge and keep the Wilson. Then I've got some re-reloading to do.

If you cannot manually cycle quality factory ammo, you may have a chamber problem. If it's a factory built PSA upper, I would contact them. You can also go to their ar15.com Industry page, Industry - PSA. Josiah is their rep and would be more than willing to help.

Something is wrong.  You should be able to eject unfired factory rounds without any problems.
I recommend cleaning the rifle and then lubing the bolt carrier group especially the cam pin and bolt lugs.