I have two PE 510-4 kits (Chilean Navy). I also have two receiver sections so I need to remove the old receiver remnants. The rear trunion I can do with a wire machine but for the front section removal I need to remove the barrel. I have read all sorts of bewares and don't clamp it in a padded vise and its only on with 40 ft/lbs or torque but requires a million to get it off and there is a special tool to support the trunion during removal. Has anyone removed one of these barrels and have any real world advise.

I have two of the same kits and have the same problem, barrel removal. What I did was to first remove the two roller lock recesses from either side of the receiver. Be careful. There are two small steel balls that key the recesses in place. If you don't realize they are there you may lose them. They are real small. The first receiver I put in a regular vise just tight enough to keep the receiver from rotating. I clamped on the roller lock openings. The big holes that the lock recesses go into. I then supported the muzzle end of the barrel. The barrel flats are 28MM and real narrow but like you I had heard that the barrel was only on with 40 Ft-LBS of torque so I thought just go slow and don't get crazy. I had a big adjustable wrench that I tightened on the flats and popped it with my palm. The barrel broke loose and spun right off. I wanted to remove the carry handle and found that once the barrel is off you can tap the roll pin thru the receiver and into the barrel channel. The second barrel has been a different story. Not near so easy. Since the roll pin opens into the barrel threads I have put Marvel Mystery oil down the center of the pin to let it soak and just warmed it a bit. As I was warming it all sorts of liquid came out of the roll pin. The adjustable wrench won't stay on the flats on this barrel near as well so I haven't tried loosening it but once or twice. A friend who does gunsmithing and has replaced a lot of barrels says he uses brake cleaner and heat on stubborn barrels so I plan on trying that next plus I ordered a 28MM wrench. Here's hoping.