I would have thought that AA machining would be uniform, perhaps its not, your HW seal may have sorted the problem but if you do go back to the factory seals it is easy to check if its right, first check with some feeler gages that the gap on the shoe is 25 thou/0.6mm then smear some grease on the breech close the lever and open it and look to see if you have a even seal mark ( remember the mark will get wider when the gun is fired as the tube moves forward squashing the seal more) this is quite a reliable way to check if the breech seal is leaking and the shoe gap is the right size
I solved my o-ring wear by making sure there's not too much crush. With the factory shoe, there is usually never too much crush, so I get an over sized tool steel shoe from Maccari. When the lever gets near the detent you will feel the seals start to touch and squish as you pop into the detent. I just file a tiny bit at a time until I feel the seals touch the breech just as the arm touches the detent ball. My seals last for a long time and I'm confident they're sealing with single digit velocity spreads. While not perfect, the o-ring set up does the job, in most cases. A friend has a TX that takes 2 full seals and one sanded down to half. I found this by watching him shoot and seeing the slop. Strange part is the gun was and still is very accurate.