Hi there, I'm posting on behalf of a friend who recently purchased a new FX-9. Gun ran fine for the first ~500 rounds, but since then, the bolt refuses to hold open most of the time, whether there is a mag inserted or not. We have tried various 10-round single-stack and 10/17 double-stack Glock and Magpul mags, and none of them reliably engage the last round bolt hold open; but then it doesn't seem like a magazine issue, because the bolt won't stay open with no magazine inserted either. You can pull the charging handle back and engage the bolt hold open, but the slightest bump or movement and it slams shut. Really annoying when the RO calls "open and empty" and you can't get the bolt to hold open, and equally annoying to have to hold the charging handle back in order to load a magazine.
I've read all over the 'net about people having problems with the hold open not being engaged by single-stack magazines and the recommendation is always to use double-stacks with the higher spring tension to push that follower up a little more - but I want to emphasize that in this case, the bolt won't stay open even with no mag inserted. You can lock it open and just give the gun a light tap and the bolt slams shut.
Any ideas? Any aftermarket solutions? Any point in trying a different bolt hold open (can you use one from an AR)? Anyone know of any "upgrades" in the aftermarket, M*Carbo maybe? I see you can buy the factory LRBHO from Wolverine, but is it likely that this part is worn out and replacing it will fix the problem, or is this a design flaw in the gun and they all do this?
Sorry for all the questions but I vowed to help this person get this gun running smooth and I'd love to be able to do so. Last resort is to send it in for warranty but that's always a PITA that takes way too long and often doesn't fix the problem. I really appreciate any help you all can offer, thank you very much.
I've read all over the 'net about people having problems with the hold open not being engaged by single-stack magazines and the recommendation is always to use double-stacks with the higher spring tension to push that follower up a little more - but I want to emphasize that in this case, the bolt won't stay open even with no mag inserted. You can lock it open and just give the gun a light tap and the bolt slams shut.
Any ideas? Any aftermarket solutions? Any point in trying a different bolt hold open (can you use one from an AR)? Anyone know of any "upgrades" in the aftermarket, M*Carbo maybe? I see you can buy the factory LRBHO from Wolverine, but is it likely that this part is worn out and replacing it will fix the problem, or is this a design flaw in the gun and they all do this?
Sorry for all the questions but I vowed to help this person get this gun running smooth and I'd love to be able to do so. Last resort is to send it in for warranty but that's always a PITA that takes way too long and often doesn't fix the problem. I really appreciate any help you all can offer, thank you very much.
