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Discussion Starter · #1 ·
Ever since switching to a longer, and better barrel (Ballistic Advantage 223 Wylde - 18") with a rifle length gas system, I have been having cycling issues. Figured an adjustable gas block might help. 5.56 ammo cycles no problem, but I cannot get .223 to cycle. I tried adjusting the block by starting all the way closed, basically turning the gun into a single shot set up, which acted as expected. Then opened the gas block one complete revolution at a time with only a single round loaded in the magazine, waiting for the BCG to lock open. Gas block eventually opened 100% and still no lock open. Tried 2 different BCG's (both functioning perfectly before this) and multiple magazines. No lock open ever reached with .223 ammo (PMC Bronze). Standard buffer spring and weight, and I'm 99% sure the ports are aligned properly on the barrel and gas block, so don't know what else it could be??
 

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Ever since switching to a longer, and better barrel (Ballistic Advantage 223 Wylde - 18") with a rifle length gas system, I have been having cycling issues. Figured an adjustable gas block might help. 5.56 ammo cycles no problem, but I cannot get .223 to cycle. I tried adjusting the block by starting all the way closed, basically turning the gun into a single shot set up, which acted as expected. Then opened the gas block one complete revolution at a time with only a single round loaded in the magazine, waiting for the BCG to lock open. Gas block eventually opened 100% and still no lock open. Tried 2 different BCG's (both functioning perfectly before this) and multiple magazines. No lock open ever reached with .223 ammo (PMC Bronze). Standard buffer spring and weight, and I'm 99% sure the ports are aligned properly on the barrel and gas block, so don't know what else it could be??
what angle are the rounds ejecting at? and what was the prior barrel length?, are the ammo specs? grain? etc
 

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Discussion Starter · #3 ·
what angle are the rounds ejecting at? and what was the prior barrel length?, are the ammo specs? grain? etc
When they do eject, is about 4 or 5 o'clock, so that's good. Prior barrel was 16" (1/8 twist) with a mid-length or carbine gas system, I don't remember. Ammo is off the shelf .223 PMC Bronze (55 grain, 2900 fps, FMJBT). As I mentioned green tip 62 grain 5.56 cycles great?!?!
 

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If you really have a rifle length gas setup with an 18-inch barrel, you have two inches less dwell time than a properly gassed 20-inch rifle. That could cause mediocre function with 5.56 and no function with .223.

A 20-inch rifle gets 4 inches during which time the bullet is still in the bore. You have two.
In the world of hundredths of seconds and thousands of pounds of pressure rising and falling in a heartbeat, that's a big deal to your rifle. I guess the adjustable gas block could help but I don't have any experience with it myself.

Good luck with this issue.
 

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Discussion Starter · #5 ·
If you really have a rifle length gas setup with an 18-inch barrel, you have two inches less dwell time than a properly gassed 20-inch rifle. That could cause mediocre function with 5.56 and no function with .223.

A 20-inch rifle gets 4 inches during which time the bullet is still in the bore. You have two.
In the world of hundredths of seconds and thousands of pounds of pressure rising and falling in a heartbeat, that's a big deal to your rifle. I guess the adjustable gas block could help but I don't have any experience with it myself.

Good luck with this issue.
Well... Here is the barrel I have now.


Also, a rifle length gas system and a rifle buffer extension and spring. So, I dunno??
 

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Ah, more info...

Aero Precision is pretty good. I would contact them and ask whether that thing actually has a rifle-length gas system, or some kind of "mid-length" thing they devised. It is a different animal.

Also... Why the rubber buffer thing for goodness sake? Screwy buffers and springs can cause unhappy AR15s. Have you tried it with a mil-spec buffer appropriate to your particular STOCK. In other words, we use a carbine buffer in an adjustable carbine stock, and we use a standard rifle buffer whenever we use a fixed A2 or A1 style stock.

Call me old fashioned but I am often hearing about all kinds of trouble with rifles running modern adjustable gas blocks, fancy hi-tech buffers and special improved gas rings, extractor springs and everything else. Meanwhile, standard 20-inch rifles with mil-spec everything run all day without issues!

Please check that out and report back! ;)
 

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Discussion Starter · #7 ·
Not sure where speaking the same language here... I don't know what you mean by the "rubber buffer thing" or the "screwy buffers and springs"? This is the buffer system I am running:


Combined with this barrel:


And a rifle length gas tube and adjustable gas block. By my understanding, this is all pretty standard stuff and configuration and should all play nice together!
 

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Howdy,
Sorry, I misread a line. Oops!

That buffer is a good rifle buffer. Are you running a solid A1 or A2 butt stock? It will not work in a carbine stock.

Also, I would be interested in what Aero says about a rifle-length gas system with an 18-inch barrel. Maybe they compensate for the reduced dwell time with that adjustable gas block?
 

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With an 18” barrel id be running 77 grain which is what the MK12 uses. That said i don’t believe in adjustable blocks for any 5.56 setup, just not needed. I have a MK12 i out together with a std A2 rifle stock, and milspec rigle tube and buffer and it runs everything. Throw a std buffer/spring in it, be it rifle or
Carbine and a std hss block amd see what happens as its am obvious gassing or buffer/spring issue. Optimum is 300-430 on ejection.

start from the beginning with std milspec stuff anf give it a wirl. And in an 18” 77s will give you the range it was meant to do
 

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1. Buffer and spring is matched to stock, not to barrel length or gas length, as stated earlier. You cannot use a carbine buffer in an A2 stock, or rifle buffer in a carbine stock. That's AR basics.

2. You don't need 77g bullets in an 18-inch barrel. If you like them, great. But you can use 55g, 62g or whatever in a 16-inch, 18-inch or 20-inch barrel just fine. A slow twist may have issues with heavier or longer bullets, but 1/12 is rare these days. Your 1/7, 1/8 or 1/9 will handle 55g, 62g and 77g OK.

Good luck.
 

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1. Buffer and spring is matched to stock, not to barrel length or gas length, as stated earlier. You cannot use a carbine buffer in an A2 stock, or rifle buffer in a carbine stock. That's AR basics.

2. You don't need 77g bullets in an 18-inch barrel. If you like them, great. But you can use 55g, 62g or whatever in a 16-inch, 18-inch or 20-inch barrel just fine. A slow twist may have issues with heavier or longer bullets, but 1/12 is rare these days. Your 1/7, 1/8 or 1/9 will handle 55g, 62g and 77g OK.

Good luck.
I didn't say you need them, but 77s are the prefered match round for distance, with any accuracy. 55s are great for 100 yard plinking but not much else.
 
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