I would not suggest running a cleaning rod down the barrel and pushing anything out at this point, as if there is an obstruction then I would suggest leaving it. The obstruction will often give an idea of what happened, and by removing it you could mess this up. When we see a barrel obstruction, we generally will mill out the side of the barrel where the obstruction is at, as this will allow you to see the obstruction from the side, and see what else is around it, often times you can see a squib or where a squib was hit by another live round, and we will see where someone has shot a 300-Blackout in a 5.56 barrel. You mention that the rifle is a .223 Wylde chamber, as this may also be a contributing factor, so again I would suggest not removing any obstruction in the barrel or cleaning it, until a proper and thorough inspection can be done.
There are many reasons that a rifle can blow up, a detailed and thorough inspection will need to be done to figure out why.
It could possibly an ammunition issue, but could also be something else or a recipe of things that contributed to the issue, so I would not suggest just jumping to the conclusion that it was the ammunition is at fault without a thorough examination of everything.
IMHO of how to figure out what happened, a detailed inspection of the rifle, ammunition from the box, and empty shell casings will need to be done. After a thorough inspection of everything, most times you can come up with physical evidence of what happened and why.
The ammunition should be inspected on both the live rounds, and empty fired shell casings. The live ammunition needs to be examined for many things like bullet weight, bullet shape, bullet set back, crimp, powder type, powder weight, powder consistency, should be pressure tested, internal case dimensions, etc. Fired shell casings also need to be thoroughly inspected for signs of over pressure, weak casings, stressed casings, bad primer pockets, stretched casings, deformed casings, internal dimensions, deformities, etc.
A thorough gauging and inspection of the rifle should also be done. The bolt should be measured to make sure it is within proper dimensions, as I have seen similar blow outs where the bolt faces internal circumference was too large and didn't support the casing. The firing pin hole dimension should also be inspected and measured. The tail of the bolt and internal gas chamber area of the bolt carrier should also be gauged to make sure they are in proper spec dimension, and don't have a large fouling build up that would cause the bolt carrier assembly to unlock too early. Headspace should be gauged for minimum and maximum, as too short or too long you can cause things to blow up. I would also do a chamber cast, as we have seen several blown up rifles that checked correct for proper headspace, but the chamber cast showed that the chamber was offset to the bore, most likely caused by someone using a reamer with no pilot, and in the case with 5 blown up rifles we have seen after the shooters had put several thousands of rounds down each barrel with the only issue being some blown primers, and eventually they blew things up. A chamber cast may also show that the chamber has no free bore, see this quite often.
The barrel should be inspected thoroughly inside and out. Put it on a gauging table and run a depth gauge down it, and it may show a slight deformity that cannot always be visually seen where a live round was shot behind a squib or other barrel obstruction, seen several of these. Run a bore camera or borescope down the barrel may might show bad machining of the chamber, free bore, of any type of deformity where a live round was shot behind a squib or other barrel obstruction. A bore scope or camera run down the barrel may also show where a bullet may have had jacket separation which we see occasionally on frangible and plated ammunition. A bore scope would also allow you to see if there was a squib, and a live round was shot behind it, as there will be evidence of fouling or damage that can often be seen. A bore scope or camera close up look at the chamber and free bore, may show maintenance issues, where there is a build up of fouling that caused or attributed to the over pressure. We have seen several hundred blown up AR15 / M16 type rifles, and one of the common things we see is a heavy fouling build up at the end of the chamber and free bore area. This build up is kind of like the fouling that is on the tail of the bolt, but it has a a glass like appearance and is very hard, my guess is from people not cleaning or thoroughly cleaning a chamber or possibly not getting the dirty solvent out. I am a big fan of using a chamber brush, and a bore brush, and not a fan of a boresnake or other pull through cleaning systems that don't do a good job of cleaning a chamber. We also see a build up inside the chamber and/or bore when people use solvents that get gummy or varnish things up when it isn't thoroughly removed, hence why I am not a fan of using banana oil based solvents in the AR15 / M16 type rifles. Lube and/or solvent in the chamber and bore and cause pressure issues (usually extraction issues), and in a rare situation can result in damage or firearms blowing up. The gas port should be gauges to see what is is and where it fits into the specs. A barrel should also be checked for straightness, as a bent or warped barrel can cause pressure issues.
Other things that should be inspected is the rifle for any signs of the rifle unlocking too early or violently. The receivers should be gauged to check to see if things are in proper spec. Hammer & trigger pin holes can be gauged to show if they are in spec, and will often show signs of the rifle unlocking too quickly or violently. The receivers should also be inspected to make sure they are machined properly, and not off set out out of proper alignment. The buffering system should also be inspected to see if they are within spec, and show any signs of stress or the action cycling too quickly or violently. I have seen rifles that people have built that had no clue what they were doing, and had them unlocking too early and blew them up. I have seen rifles that people suppressed, didn't realize that adding a suppressor can change the timing cycle, and blew them up. I have also see 3 blown up rifles from the same LE Agency, that their in house Armorer (trained by another company) built using piston conversions, that were unlocking too early. And one of the more common causes of blown up guns in the last couple of years that we have seen is when someone puts a 300-Blackout in a 5.56 chamber.
Greg Sullivan "Sully"