Bruni 8mm Glock reliability

Does anyone know the best way to make the Bruni 8mm PAK Glock (UK top venting version) more reliable? I've always found the 8mm top venting version to be a hit and miss affair and have never had a full mag fire without some sort of stoppage.

I've been toying with the idea of enlarging the breach by 1mm to accept 9mm PAK as the 9mm is more powerful, and slightly enlarging the existing top vent hole as neither of those mods are illegal as it doesn't have any bearing on the factory fitted barrel blockage material, and also because there's no law in reboring blank firers to larger calibre size's so long as it does not have a diameter larger than 1" (25.42mm) as per 1968 Firearms Act.

Any thoughts?

It could well be the extractor or the the ejector that is the problem the extractor may need a bit of filing so that it grips the round well or may need a better stronger spring in it. The ejector may be to short, worn anything in fact but those are the most likely culprits maybe also the mag but that is usually for feeding problems. The 8mm blank is well powerful no need to mess with the gun to make it 9mm the 8mm has more than enough oomph to do the job.

Good points. I never thought of looking at the extractor or spring issue. I'll check those first before any attempt at reboring. Another issue is it could also be the spray painted metal could be a bit too thick and may just need smoothing down.......