I recently had the opportunity to run my PWS piston conversion AR upper through the Viking Tactics Street Fighter class taught by Kyle Lamb.
Right side of gas block with Daniel Defense Lite 9.5 FSP rail
Round count for carbine in the class was slightly less than 800 rounds. The PWS upper performed impressively for the first two days of the class without a single malfunction shooting crappy Brown Bear Classic .223. Despite being shot from a variety of positions including in variations of prone where plenty of dirt and debris were being kicked up. I had fired an estimated 400 rounds on two different range days prior to this class.
On Day 3 the problems began when I was attempting to complete a shooting drill around vehicles. I shot it strong hand only with no problems but when I went to shoot support hand only, it appeared that the weapon was short stroking, I would fire a round and then manually cycle the bolt before firing again, still doing this with just my support hand. The drill also required a single magazine change which I completed but the multiple repeated malfunction clearances took a toll on me. At one point I had to “mortar” the weapon in order to get the charging handle to go back.
It was frustrating and much of the drill’s value was lost as I had to fight the weapon to complete the drill. I cleared the weapon and took it off the line to investigate and found that the gas block was loose, enough that it would wiggle with just finger pressure.
Note scratched to barrel due to shooting around vehicles and barricades
I emailed PWS that evening and they immediately offered to have it sent in for repair. The plan is to install a taper pin to keep the gas block fixed. So far all 3 problems I’ve had with this weapon have been related to the gas system. The first time PWS opened up the gas port, the second time they stated that their was a subtle taper to the barrel and finally, the gas block was shot loose. I suspect the Daniel Defense Lite 9.5 FSP rail may be making it difficult for them to properly secure the gas block using the set screws. I may have them change it out to a Larue 7.0 rail when I send it in to see if that makes it easier.
I remain extremely impressed by the customer service at PWS but am starting to lose confidence in their system, both in design and execution. I look forward to getting my upper back and running the gun through its paces. I hope that PWS can finally resolve these teething issues to deliver the enhanced reliability it was advertised for.