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Page AR-15 » AR Discussions
AR Sponsor: bravocompany
Posted: 7/23/2017 9:29:05 PM EDT
I recently bought a Radical firearms complete upper with 16" 300 blk aac and put it on an ATI Omni lower. I didn't have any issues with ammo feed using the cheep stuff from Cabelas. I then replaced the A2 birdcage out for a tanker muzzle break and I used a rifle bench vice instead of the barrel lock vice block. Now I have an issue with the spent brass not leaving the breach before a new round is being chambered and the two jam up the bolt. It's like the 3rd or 4th round everytime. My question is; did I torque the upper or is it the ammo, because this ammo is different from the ammo I was buying from Cabelas? This new ammo is stuff I'm buying from a cheap ammo distributor online. The ammo I'm using now is Homeland Munitions 148gr FMJ 1850 FPS. I originally thought it was the hexmags I was using so I bought a few pmags gen 3 and it's still doing it. Any help would be greatly appreciated.
Link Posted: 7/23/2017 9:32:40 PM EDT
[#1]
Sounds like you're overgassed. Bolt is outrunning your mags.
Link Posted: 7/23/2017 9:50:29 PM EDT
[#2]
They put a pistol gas block on it even though it's 16" I'm guessing so that the subsonics will fully cycle the bolt. Could that be the issue?
Link Posted: 7/24/2017 5:29:46 PM EDT
[#3]
What buffer weight are you running in the lower?
Link Posted: 7/24/2017 5:35:30 PM EDT
[#4]
You have a gas problem.  Not uncommon on the .300 with the various combinations.

You might need to pick up an adjustable gas block and learn how to use it with the various loads.
Link Posted: 7/24/2017 8:29:08 PM EDT
[#5]
You also have to factor in that the entire upper was made by Radical.  Their stuff has encountered about any issue you could think of and some that you probably wouldn't.

Sounds to me like a gas issue, but it could be a number of other things.

ETA:  Just saw you switched ammo.  Try the original ammo you were using before doing anything else.

ETA2:  When you say the brass "isn't leaving the breach", do you mean that it's not extracting from the chamber at all?  Or is it extracting and just not ejecting?
Link Posted: 7/24/2017 9:41:37 PM EDT
[#6]
make sure the gas block is still centered.  if it's not, you have have backed the barrel out of the extension.  I believe Radical had issues early on with that.
Link Posted: 7/24/2017 10:29:30 PM EDT
[#7]
The new round is being loaded into the chamber right as the spent brass is being pulled from the barrel. The new round shoves the old brass up towards the gas tube and the two get jammed as the bolt tries to feed the new round into the barrel.
Link Posted: 7/24/2017 11:01:48 PM EDT
[#8]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
The new round is being loaded into the chamber right as the spent brass is being pulled from the barrel. The new round shoves the old brass up towards the gas tube and the two get jammed as the bolt tries to feed the new round into the barrel.
View Quote
Theoretically, the part in red is impossible.  The only way for a new round to be chambered is for the bolt to travel far enough rearward to catch the rear of the round in the magazine and start pushing it forward.  If the bolt is that far rearward, the round should be completely extracted from the chamber (so long as the extractor maintains control of the empty case throughout the entire extraction cycle).  If the extractor is slipping off the case rim, that could be the cause of your problem.  So could an ejector issue.    

Check your extractor and ejector tension, it sounds like the round is (probably) completely extracting and just not being ejected from the upper.  Radical has had known issues with shit parts going into their rifles.
Link Posted: 7/25/2017 7:45:24 AM EDT
[#9]
Look like this?
Link Posted: 8/20/2017 9:46:16 AM EDT
[#10]
yes exactly...That a 300 or 223?
Link Posted: 8/20/2017 11:06:52 AM EDT
[#11]
Radical is known for poor quality, but aside from that, it sounds like your extractor is slipping off the case rim. Is this a Radical bolt carrier group, as well?
Link Posted: 8/20/2017 11:15:03 AM EDT
[#12]
More and more of these threads starts with "So I got a radical......"

Seems like a pattern or something.
Link Posted: 8/20/2017 11:17:48 AM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
More and more of these threads starts with "So I got a radical......"

Seems like a pattern or something.
View Quote
Exactly. I don't know why that company can't get their shit straight. Manufacturing a decent quality AR isn't a tough thing to do these days.
Link Posted: 8/20/2017 12:45:46 PM EDT
[#14]
I would guess it is somehow the ammo, but ive had troubles with a 16 300 too but it had to do with running subs without a suppresor
Link Posted: 8/20/2017 1:36:08 PM EDT
[#15]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
The new round is being loaded into the chamber right as the spent brass is being pulled from the barrel. The new round shoves the old brass up towards the gas tube and the two get jammed as the bolt tries to feed the new round into the barrel.
View Quote
Yeah that is not possible. The bolt needs to move all the way back, ejecting the spent case from the chamber, then moving forward the bolt strips off a new round from the mag and chambers it ready for the next trigger pull. If you have a round leaving the mag as the bolt is ejecting a spent case then you have a mag issue, feed lips are bent weak or damaged. Try the ammo that worked for you and try different mags. Early Pmags had feed lip issues, Hex mags are junk imo and GI mags will spread  apart at the rear of the feed lips. 300blk can be picky. I would have an adjustable gas block if I did a 300blk build. Also check your extractor, get the BCM extractor upgrade kit. In most cases extraction issues are caused by incorrect timing of the gas system aka over gassed
Link Posted: 8/21/2017 8:21:54 AM EDT
[#16]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
yes exactly...That a 300 or 223?
View Quote
300 blk.
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