grottulf

To take fully advantage of the possibility to use a smaller diameter handguard, I would definately choose the PCC model. But if you prefer a handguard with a larger diameter, you should choose the AR version.

I forgot the picture... I use one piece clamp style shaft collars to be able to adjust or block off the ports. I only found them in metric dimensions though, so we had to turn the inner diam up slightly, for them to fit the barrel. Another word of advice is to push a lead slug inside the barrel, where the hole is going. Thats a good way to minimize the risk for burrs inside the barrel, when drilling.

Time for a late update on the porting matter... I did the usual mods, the comp and a kynshot buffer. The gun shot ok, but I felt there was still room for improvement. So I tried installing a couple of opposing neodym magnets in the rear of the buffer, which made it a bit more soft to shoot. Next step would probably be to start reloading, and figure out a load with a lower PF that works well. But since I'm just about as fond of reloading, as I am of eating worms, I started thinking of porting the barrel again. But this time mostly to reduce the PF of factory ammo. I decided to try porting really close to the chamber. I didn't want to put it too far out, since I didn't want the blast to interfere with my grip for obvious reasons. I started very conservative with a 2mm (~.08") hole 90mm from the breech face, but I was surprised at how little it affected the velocity. I drilled it out little by little, and chronoed it after every time. Eventually I ended up with a 6mm (~.24") hole 73mm (~2.9") from the breech face. This really made wonders with the recoil. I would estimate that I have about half as much dot bounce, than a comped mpx. Not as soft though, not that it matters.

Thanks for the advice, but it's not the hiperfire trigger that causes the light primer strikes. I've already ascertained, that it's because of the headspace. It would probably not hammer the bolt as badly though, due to the hammer being flat... But I've heard of many others using hiperfire triggers in 9mm without problems. And I would very much like to be able to keep it, since it's the fastest trigger I've shot. I can shoot splits down to 0.10-0.12 with it (as long as I don't have to hit anything...)

Brownells still haven't solved the shipping/export problems, so I still use the old bolt. It works as long as I only use ammo with soft primers. But I'm starting to consider milling down the mating surfaces on the bolt or turning down the mating surface on the barrel, to decrease headspace... And/or buying another bolt... But I'm wondering how that would affect other things. If I mill the bolt, it will sit more towards the barrel... If I turn the surface on the barrel, I could also turn down the surface on the "ring" that mates against the upper, to compensate for that... Any ideas? I can add that I'm also having a problem now with the hiperfire-hammer (I swapped out the stock trigger), hammering the rear of the bolt, so it's become mushroomed. So I can't get the firing pin out anymore... (See pic) Considering the shape of the hiperfire hammer, I'm not really surprised that it has happened, but I'm not sure of how to fix it... Should I just grind out the problem areas, and hope it won't happen again, since the hammer won't reach it anymore? Or should I try to get the bolt to lock further to the rear (by turning down the ring on the barrel, so the barrel sits further to the rear? Or is it just crappy material in the FM-bolt, so it will solve itself with a better bolt? Any input would be appreciated

Like most turkish shotguns it requires break-in, or that you disassemble it and polish any burrs and edges, that might cause friction. But if you can fire it while the safety is on, you should definately return it, and get another one

Stoeger and RIA VR80 have huge threads here, and there are some threads on the Tigris/Orthos here as well. And probably a lot more, that I can't recall at the moment. Is there a particular brand you're interested in, just ask. Someone will probably know something.

None of those are available in 5/8x24 like the OP requested.

Unless you can find a .308 comp with vertical ports, it wont be very effective though.

Yes, it's important to use a barrel vise when loosening barrel devices. Don't ask me how I know... When it comes to vise blocks for the upper receiver, I like JP's blocks: https://jprifles.com/buy.php?item=JPVC I'm not sure I would fully trust a vise block that only clamps to the take down lugs...

Just to be clear though. The Utas XTR 12 is a completely different shotgun from another manufacturer. No side-charger, etc etc... Not saying that either is better or worse though...

What comps have you tried? It isn't a night and day difference like with a .223, but the comps I have used definately makes a difference. (Except for the stock one on my FM9B) Even with a 16" barrel it makes a difference, but it works better with a shorter barrel. And like Tony says, only use comps with vertical ports on a 9mm.

This is really interesting If I understand correctly there will be some play in the locked position (Up to one buffer tube thread) I would think that no play would be better, both for wear and function? but maybe it needs that play to get the speed of the bolt up before the rollers can disengage? Is the blue bumper(?) part of the buffer, spring loaded? Will there be an A5 buffer tube version? Finally and most importantly, can you ship to Europe?

You could always buy a 1/2" comp of your choice and have it re-drilled and tapped to 5/8". I bought my Armanov comp pretty cheap, with busted 1/2" threads, and had it re-drilled and tapped to M14x1

It weighs 4 oz, just like the JP vertical comp, for instance. I haven't thought about it as heavy, but maybe it is...? If you compare it to aluminum and titan comps, it definitely is though