Panzer AR57 upper

[Toprudder]

I had always been intrigued with the AR57, so when I saw PSA was selling the new Panzer made AR57 uppers, I decided to get one. However, I think it has an issue with the chamber/bolt. I don’t think the chamber Was reamed deep enough, as the bolt is not fully closing.

The first ammo I tried was Federal, there was evidence the bullets were jamming into the lands. I tried FN and Speer ammo and did not see any evidence of jammed bullets, but the rounds still did not seem to seat fully. I made a chamber cast using Cerrosafe just for my own curiosity, and from that I could see a lot of unsupported case. The bolt doesn’t even come close to closing. An email to Panzer USA with photos resulted in this response:

“This is normal.
The case does appear to be at the proper depth as the case is not intended to sit flush with the chamber face. “

I still don’t think this is correct. Why would anyone design a gun with this much exposed case.

Comments?




Round fully seated.


Bolt when round is chambered. Without a round in the chamber, the bolt fully closes against the chamber face.

 

[mgmorden]

I don't think chamber cut depth would really effect whether the bullet touched the lands - merely the amount of the cartridge that sticks out. I'll admit that it doesn't look normal to me, but if the manufacturer says that's the way it normally operates and it does function then I'd probably take their word for it. It is a blow -back design so there with no locking lugs engaging there is the potential for there to be some exposed case.

 

[12Bravo20]

I had the older AR57 upper and I don't recall the rounds sticking out that far from the chamber. You do want the case to be fully supported especially with the 5.7x28 round. It can be very fickle on powder charge changes. one or two tenths of a grain can turn a safe round into something dangerous.