Yes. Our barrel extensions are installed but not torqued during QPQ. After QPQ, the barrel extensions are torqued to spec and the gas ports are drilled.
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Yes. Our barrel extensions are installed but not torqued during QPQ. After QPQ, the barrel extensions are torqued to spec and the gas ports are drilled.
I originally tried it with the full size gas port...IIRC a 0.078" drill bit fit it pretty close. I think I posted this observation earlier in the thread, but it seemed to function pretty closely to my 10.5" MRP like that. It seemed to be usable with most any ammo unsuppressed, but obviously not optimal with a suppressor. I did shoot it a little with my mini-4 on the full size gas port and it functioned fine though. With an 078 gas port I think an H3 or A5H3 buffer is probably a good idea whether suppressed or not.
I've had adjustable gas blocks as well as fixed port gas blocks on the barrel also, as I've been using it to experiment with limiting the gas feed and shooting mostly suppressed. I'm pretty much done experimenting for now and I'll probably end up going back to a configuration that is more likely to run unsuppressed in any condition. When I do that I'll likely put a standard gas block back on and let it rip with the 078 port. I still think 078 is maybe a bit overgassed, but I'd rather have it a little overgassed than undergassed. What I've seen lately is that combinations that I thought were tuned to run across most any conditions completely choked in cooler weather...I had no idea how much impact ambient temperature would have and I thought I had some extra safety margin with the gas feed when I really didn't.
All things considered, the gas port the barrel comes with isn't as large as some 10.5" barrels come with, and it still allows for function across varied conditions. It'll work as is but won't be optimal for everyone, which is an understandable compromise to be made on a barrel like this. I know it's larger than some people want on their 10.5" 5.56 gun, but I can't fault AP for the size they picked. Hey, it's a better size than a commercial DD MK18 barrel, I think.
Cool. Yeah.. I think you did mention your observations earlier, but I got too lazy to look back.
I'm trying to reconcile the .071" LMT port against this .077". I have an FN 10.5 that runs a touch on the rich side, but like you said, I'm cool with it for reliability. I've yet to pop the FSB and check the port size on that barrel.
Are the barrels dimpled? Thinking about ordering one of their 300 blk complete uppers, but I can't find any word on how the gas block is secured.
Mine wasn't dimpled so I made a dimple for one set screw.
Mine wasn't dimpled, but has been running great. I should be putting my 10.5" through some high volume fire over the next week, so I'll try to report back. To date it's been flawless with a mixture of different ammo (in small quantities).
My 10.5 FSB will be here tomorrow. We'll get to sling a few rounds this weekend.