Hello All,
2 posts as I am limited on characters.

My son and friends took out the firearms this weekend and not everything went glowing.
labeled the rifles below, to help organize my thoughts.  All 4 are AR15 models, 3 PSA's and 1 S&W.

Rifle 1 - Built from scratch with Mostly PSA Parts - 2010
Rifle 2 - Prebuilt PSA 8.5 inch .300black - 2023
Rifle 3 - Prebuilt PSA 12.5" 5.56 - 2022
Rifle 4 - S&W 16" - 2013

1st Issue - Excessive Gas Pressure
This one is probably on me. The Rifle appears to have no functional issues. We had originally installed a standard A2 Front sight.  
We decided to drop the A2 for a floating guard and and adjustable gas block.  I have shot it a few times, very accurate and no issues to me.

One of the girls this weekend, made a statement that Riffle #3 and #4 felt easier to shoot and kicked less then Riffle 1.  Her boyfriend, commented that he felt left there was more pressure on the recoil on Riffle #1.
Could I not have tuned or setup the gas Block correctly?  

2nd Issue - bad bolt - rifle #2

The Army Kid shot around 30 rounds out of Rifle #2, no issues, then had a jam.  They cleared the Jam, fired another Round, Jammed again.  Cleared the around, would not fire.  Tried to pull back charging hammer and the BCG was Locked in place.  Stopping using it.

I had to use a Hammer and Wood to forcibly drop the BCG back and eject the round.

With No Round in the weapon, the BCG will slide into place with little issue.  
With Round in the Chamber, the Bolt will not twist and seat in place.

I swapped out the BCG with the BCGs from the Rifle #1 and #4, and everything appeared to be work as it should with Dummy Ammo.  
I then bolt swapped the bolt from Rifle #1 into the GC on #2 and it appeared to work correctly, with and without Dummy Ammo Chambered.
I do not See any external damage on the #1 Bolts though, I have not full disassembled it.
Is this worth digging in and trying to repaired, or just replace the Bolt?

Ultimately, I figure if I have to replace the bolt, I will probably just get a whole new BCG.  How are Sons of Liberty BCGs?

Thank you all, for any assistance.

Shorter barrels have heavier buffers?     If the rifle runs, and is accurate, no problem that needs fixing.    Most AR's are over-gassed, a heavier buffer would be an adequate band-aid.

Break down the bolt and inspect.  Cheap ammo?   Any damaged FCG parts?   The bolt may have had something jamming it that worked its' way out.    Any casing missing the primer, or shows signs of shaved brass?      I have a spare bolt for every AR, and bring the extra in my shooting gear.

Rifle 2 probably has a tight chamber or ammo out of spec which is not uncommon in 300 blk.  PSA is kinda rare for not passing the guage test, still i would guage the chamber and run the ammo through a case guage.  Doubt it is the BCG.  

Rifle 1, adjustable gas block or heavy buffer or live with it.  Over gassed is not really that bad, just not desirable.

RE: rifle 1, I run superlative arms AGBs. The gas required to run a new build reliably is not always the gas required to run after break in. There's no harm in tuning the gas down a click or 2 and testing for function. Adding buffer weight is an option but I get the same result with less gas. Why not take advantage of the AGB?

As for.the BCG malfunction, strip it, clean, inspect. If it looks good and nothing is obviously broken, lube it up and function check the weapon. As previously mentioned, could have caught some brass shavings and bound up but come free. Definitely invest in a spare.