AR Cycling Issue

Str8Shooter

Str8Shooter

Member
I picked up a Radical Firearms .223 Wylde upper, cheap a few weeks ago... planned on letting my son use it for a plinker/ beater gun. When I took it to the range, I noticed that it wouldn’t cycle consistently. I know, “you get what you pay for”, but the dang thing shoots ridiculously well so I’d like to keep it. I’ve tried a different gas block, adjusted the position of the gas block, tried a different BCG, and nothing seems to help. Any ideas on how I can get this thing to cycle?
 
Str8,

Some barrels need the gas block a smidge forward of flush with the backstop. This is because some OEM barrels call for the original hand-guards. There is a little metal bracket that holds those in. (It sure isn't much though...)

Did you install an aftermarket "stronger" buffer spring? I did that one time with a mid-length gas system and had problems. I still haven't tested that rifle again. But i am dang sure that was the problem.

I am guessing you have tried some different ammo types?? Do you have access to any Federal/Lake City M193 or XM855?

Just some things to check:

BCG Oiled
Different brand Magazine
Lighter buffer
Lighter buffer spring
Full power ammo

It really is like winning the lottery getting a cheapo barrel that shoots. The odds are against you though, just like the lottery.
 
Yep, I’ve tried different ammo types and moved the gas block back a bit. Come to think of it, last time I shot it, I had it paired with a lower with an adjustable stock/ carbine buffer and got it to cycle a few times. The last few trips I paired it with a full length stock/ buffer and couldn’t get it to cycle at all.

Does a rifle length system send less force to the BCG?


Varminter... nope, it won’t lock back on an empty mag.
 
Originally Posted By: Str8ShooterYep, I’ve tried different ammo types and moved the gas block back a bit. Come to think of it, last time I shot it, I had it paired with a lower with an adjustable stock/ carbine buffer and got it to cycle a few times. The last few trips I paired it with a full length stock/ buffer and couldn’t get it to cycle at all.

Does a rifle length system send less force to the BCG?


Varminter... nope, it won’t lock back on an empty mag.

This tells me it's undergassed. The reason it will work with a carbine stock is the buffer is smaller and lighter and it can just barely overcome that weight. Put the rifle stock on and it can't push it back far enough. It sounds like everything else is ok, so the gas port is probably a little undersized and needs opened up. Easy to do if you have the right drill bits. It won't take much, just a few thousandths.
 
It’s an 18” barrel with a rifle length gas system, the gas port measured at about .090”

I’m shooting handloads... .223 Nosler 62 gr HP, 22.9 gr Benchmark... max load is 23.5 gr. That round cycles fine in all of my other .233’s

If I’m drilling out the gas port, can I just use a hand drill and open it up in very small increments?
 
Drilling it out .005" will make all the difference in the world.. be sure that you do not allow the drill bit to go in far enough to hit the rifling on the opposite side of the bore.. yes it can be done with a hand drill.
 
Originally Posted By: Str8ShooterIt’s an 18” barrel with a rifle length gas system, the gas port measured at about .090”

I’m shooting handloads... .223 Nosler 62 gr HP, 22.9 gr Benchmark... max load is 23.5 gr. That round cycles fine in all of my other .233’s

If I’m drilling out the gas port, can I just use a hand drill and open it up in very small increments?

I was going to ask if it was 18" with rifle length, there's just not much barrel beyond the port to build any pressure. I think those are typically meant to be suppressed, and it would likely work great then.

Yeah I've used a hand drill before. Use a dowel, or old cleaning rod in the barrel to stop the bit so you don't hit the other side of the bore. Honestly I don't know what size port it should have, maybe one of these guys knows. I haven't had to do that a lot, but I just found the largest bit that would fit, then bought one size bigger. A good hardware store that sells individual unwrapped bits is great for this task.
 
I found a drill bit that fit and it measures .090”, so at least I got the measuring part right. Great idea to put a wooden dowel in the barrel. I’ve got some time tomorrow so I plan on getting the next bit larger and drilling it out. I’ve also got a spare adjustable gas block, so I should be able to dial it in pretty well. Thanks to all of you for the info and suggestions, I really appreciate it. I’ll give it a shot and report back on how it goes. I should be able to hit the range on Tuesday.
 
one thing i would advise when messing with gas port changes - make small adjustments and test every change in size upward until it works. .

you dont wanna step several sizes and then go to the opposite side of things and now you're chasing an overgassed problem.

from what i'm reading on other forums from a google search.. 0.098 to 0.103 should be somewhere around the magic sauce though. i even found one dataset that claims a WOA 18" SPR rifle length uses a 0.108 port.



ive read a few things about using around 0.090 - 0.093 port size on the 18" rifle gas, but those seem intended for guys playing gun games and using lightweight carriers and buffers.

as noted, this is exactly why you make small changes and test every time and not just wahoo it and hope for the best.
smile.gif
 
Well, I went the next bit size up... 3/32” to 7/64” and that was the ticket! Took it to the range today and it cycled beautifully... no issues at all after 30-40 rounds and the bolt locks back on an empty mag. I probably just got lucky, but that’s what seems to be happening with this particular rig so I’ll take it. If I can figure out how to post a quick pic I’ll show the last 3 shot group. I know it’s not 5, but this is just a beater, so I wasn’t expecting too much.

Thanks for all of the advice and ideas, I really appreciate it!
 


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