Gamma Core - bolt guide top o-ring going missing

[The Jayster]

Once in a very rare while (maybe 2-3 times in 6 years so far), I'll encounter an odd issue where the top 013 o-ring on the bolt guide goes missing. It's no biggie because I have plenty of spares and adding one requires 20 seconds, plus it stays there for a long period of time but I find it weird. I'm talking about this fellow:





Has anyone ever had the issue? The only other weird thing is that often when I gas up the gun (Emek), the first shot pops off really loudly. Whenever I replace the o-ring once it goes missing the issue seems to go away for a while then comes back.

I consider this a very minor issue but I'm asking because I'm curious.

[flyweightnate]

Sounds to me like it's sticking in the bolt, maybe not cut deep enough on the guide? Then, eventually, it rolls off the guide and makes a little trip downrange.

I would try being a little more intentional about greasing it, checking for burrs on the bolt ID, and maybe going to a harder duro urethane so it's less likely to roll off. A90 might be good. Going down a size or using a metric 1.5mm might be an option if you want to tinker. A tiny dot of glue at 2 or 3 positions on the oring groove is another option.

Or leave it alone if it's only a minor nuisance.

[MrBarraclough]

Are you using the stock bolt?

[The Jayster]

Indeed I am

[Trbo323]

I'm wondering if you have something going on with your reg. That first loud shot sounds like an overpressure issue which would be a contributing factor to this ring wearing out/going missing

Sent from my motorola edge 2024 using Tapatalk

[The Jayster]

Makes sense. Otherwise I keep it well-maintained (o-rings in good shape, super clean, well-lubricated, reg seat in good condition, etc.)