Saw an AR15 yesterday where the bolt carrier group was stuck mostly to the rear. It took a while to finally get the rifle apart, then it still took some time to identify the problem.
The issue turned out to be that the forward assist broke.
This makes for an interesting problem. Now this makes for a good argument to have more then one firearm. At the range, if you can’t clear the issue, you can still plink or train with the other firearm. In the fight, you just transition to the other firearm when Immediate and Remedial action don’t work. It is also a good reason to buy quality parts. While a fluke like this can happen with any brand, it is less likely to happen when you buy quality.
The rifle this occurred too was home built from Spikes parts. I have no doubt that Spikes will replace their forward assist.