300 BLK Feeding and Extraction Issues
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    300 BLK Feeding and Extraction Issues

    Totally in the dark with this gun. Running a NiBr slab side BCG in it never had issues early on with the MilSpec BCG that I originally had in it, running the same hand loaded 147 grain .308 FMJ rounds. When we shot at McMiller last summer I had a round jammed in the chamber and could not extract it with the charging handle. The RO came over to help and said that he could probably get it open and the unfired round out of the chamber if I would indemnify him against potential damage. Faced with having to bring it home with a live round in chamber I said have at it. He jammed the butt against the bench a couple of times and the BCG flew back extracting the round. I put it away and haven't taken it out since.

    Today I fired three rounds with no issue and the fourth was caught in the chamber...without the bolt engaging the rim. I tried to pry it out with a screwdriver..to no avail. I brought it home with the BCG locked back and was able to knock it out with a cleaning rod. Took a quick look at the bolt face to see if there was any discrepancy evident with the extractor and it looks normal.

    I suspect that the ASC magazines might be a part of the problem. When I was packing to go out, I tried to load one more with my UpLula loader and the fourth round was catching on the rear rib of the magazine. I bought them to use for the 300 BLK as I figured that the silver metal might be a clue to help keep the ammo separate from the .223.

    I have five of these crappy mags and may send them a nasty gram...just to make me feel better.

    My thought is to clean the chamber very well in the event there's something gunking up the extraction and to try running Magpul mags next time out.

    Any other thoughts are appreciated.
    “…democratic socialism, the great utopia of the last few generations, is not only unachievable but that to strive for it produces something utterly different – the very destruction of freedom itself. As has been aptly said: ‘What has always made the state a hell on earth has been precisely that man has tried to make it his heaven.'” F.A. Hayek

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    There could be several reasons for the FTE.

    1. Not enough gas pressure. If your rounds are marginally producing enough gas to operate the action, adding a heavier BCG may have made it a little worse. For the Blackout, a lightweight drive train allows you to better operate at lower pressures, so always look to go lighter in the BCG or buffer and weaker in the recoil spring.

    2. Burr, or rough, or dirty chamber is holding the case in the action. Normally an AR is running pretty high gas and just powers through most chamber issues. But if this is a relatively low pressure target round, if may not be getting enough gas pressure to extract with a dirty chamber.

    3. Headspace is off and dwell is not proper. If you did not change the bolt this should not be an issue. Check BCG for gas leak in the key. Also, make sure your gas block has not moved.

    I have adjustable gas blocks on all my .300BLK ARs. That way you can set up for running with low gas pressure (like with subs) and turn the gas down for the high pressure stuff.

    FTE is not usually a magazine issue. BTW, for running .300BLK I would either run straight GI mags (make sure they either have the new FDE GI followers, or MagPul followers), or the poly Lancers. The Blackout (bullet) uses more room inside the mag tube than the 5.56mm, so ribs that are just off from MILSPEC can cause them to bind. I see many places running sales on new Okay, D&H, and Brownells GI mags with the proper followers for $7-$8 all the time. Lancers can be harder to find and about double the price for the translucents.

    That Range Officer had the right idea about bouncing the butt of the AR to use the weight of the BCG to extract the case. I have also put the charging handle on the edge of a table top and hit the butt to dislodge a case.

    I have friends sometimes give me their old worn out GI mags. I take them apart, replace the follower and/or spring. I check the tube for cracks around the lips and the spot welds along the seam and throw out the ones with issues. I knock out any dents, clean and degrease them and then paint with hi-temp exhaust paint. I paint my floor plates some distinct color so I know which ones are mine at the range. I have also seen people use thin colored tape, like for auto detail painting, to mark their mags for whatever purpose, like which ones are .300BLK. You can also just stencil 300BLK on the side.
    Last edited by GreenWolf70; 06-10-2019 at 10:46 PM.
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    Battle of Wanat: 10 years ago last 13 July, 1LT Brostram was killed in combat killing the last enemy combatant in the outpost. The LT went to the point of decision and made the difference that turned the tide of the battle. The original investigation found the Bde Cmdr, the Bn Cmdr and the Co Cmdr at fault for dereliction of duty. If you want to see what a sarcastic silver star citation reads like, pull up the company commander's silver star.

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    I've had FTE's due to two issues - powder didn't burn completely and left crud in the chamber which caused the following round to fail to extract, and a corner of the rim broke off, preventing extraction.

    I always take a cleaning kit and bore light with me to the range just for these sorts of occurrences (especially since I reload).

    The part here:

    and the fourth was caught in the chamber...without the bolt engaging the rim.
    did you just pull the bold back and release it again on the round? That will almost always get the extractor engaged on the case head and allow you to fire it - unless the round is out of spec and doesn't fit in the chamber -- which brings me to another question: You also mentioned reloads - what cases are you using? Which head stamps stuck?
    GreenWolf70 likes this.
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    Quote Originally Posted by Yissnakk View Post
    I've had FTE's due to two issues - powder didn't burn completely and left crud in the chamber which caused the following round to fail to extract, and a corner of the rim broke off, preventing extraction.

    I always take a cleaning kit and bore light with me to the range just for these sorts of occurrences (especially since I reload).

    The part here:



    did you just pull the bold back and release it again on the round? That will almost always get the extractor engaged on the case head and allow you to fire it - unless the round is out of spec and doesn't fit in the chamber -- which brings me to another question: You also mentioned reloads - what cases are you using? Which head stamps stuck?
    I tried releasing the BCG again in hopes of catching the case rim. Seems the lugs were not in alignment. Not sure what headstamp it was, but it was certainly a case that I re-formed from 5.56. After I clean the chamber well, I'll plunk a bunch of the rounds to see how they are fitting.
    Yissnakk likes this.
    “…democratic socialism, the great utopia of the last few generations, is not only unachievable but that to strive for it produces something utterly different – the very destruction of freedom itself. As has been aptly said: ‘What has always made the state a hell on earth has been precisely that man has tried to make it his heaven.'” F.A. Hayek

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    Quote Originally Posted by Czechbikr View Post
    I tried releasing the BCG again in hopes of catching the case rim. Seems the lugs were not in alignment. Not sure what headstamp it was, but it was certainly a case that I re-formed from 5.56. After I clean the chamber well, I'll plunk a bunch of the rounds to see how they are fitting.
    BIG thing - make sure you only use domestic .223/5.56 cases to form your brass from. If you are using Wolf, IMI, PMC....then it's really to be expected - case walls are too thick. I sorted my .223 brass and only use Lake City and FC brass just to be safe. Any brass, once formed, will fit just fine, but once the bullet is seated, the neck will be out of specs and too thick to properly chamber.
    GreenWolf70 likes this.
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    I am not sure I understand "Seems the lugs were not in alignment." Could you explain a little further?

    Unlike some rifles the AR bolt pushes the cartridge from the mag to the barrel and the extractor slips over the case rim as it drives the cartridge into the chamber. The bolt lugs are held in alignment by the bolt cam pin, which is held in alignment by the firing pin. While you have the BCG out, extend the bolt and then set the BCG down on the bolt, as you release the BCG, it should NOT go down over the bolt just from its own weight. If it does, you need to replace the gas seals/rings on the bolt tail.

    Also, when you full length sized those cases, did you use a small base sizing die? It just occurred to me that I have 1,000 once fired Lake City cases that I am slowing trimming to length. They were a pain to full length size because most of them seem to have been fired through a SAW, or M-249, which has a much larger chamber than an AR and I did not use a small base sizing die, so I am pretty sure I will need to go back and size with a small base die. I ran into the same machine gun issue with some once fired Lake City 7.62 NATO, but since my .308 is a bolt gun it is not an issue.

    Got this off the details for a Redding small base sizing die, "Redding Small Base Full Length Sizer Dies were designed for use with semi-automatic firearms for improved feeding. These dies size the brass down to minimal specifications. Due to the fact that this product sizes more than regular dies, it is crucial to have a sufficient amount of high quality lubricant to prevent stuck cases."
    Last edited by GreenWolf70; 06-11-2019 at 10:10 AM.
    Yissnakk likes this.
    Battle of Wanat: 10 years ago last 13 July, 1LT Brostram was killed in combat killing the last enemy combatant in the outpost. The LT went to the point of decision and made the difference that turned the tide of the battle. The original investigation found the Bde Cmdr, the Bn Cmdr and the Co Cmdr at fault for dereliction of duty. If you want to see what a sarcastic silver star citation reads like, pull up the company commander's silver star.

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    Quote Originally Posted by GreenWolf70 View Post
    I am not sure I understand "Seems the lugs were not in alignment." Could you explain a little further?

    Unlike some rifles the AR bolt pushes the cartridge from the mag to the barrel and the extractor slips over the case rim as it drives the cartridge into the chamber. The bolt lugs are held in alignment by the bolt cam pin, which is held in alignment by the firing pin. While you have the BCG out, extend the bolt and then set the BCG down on the bolt, as you release the BCG, it should NOT go down over the bolt just from its own weight. If it does, you need to replace the gas seals/rings on the bolt tail.

    Also, when you full length sized those cases, did you use a small base sizing die? It just occurred to me that I have 1,000 once fired Lake City cases that I am slowing trimming to length. They were a pain to full length size because most of them seem to have been fired through a SAW, or M-249, which has a much larger chamber than an AR and I did not use a small base sizing die. Got this off the details for a Redding small base sizing die, "Redding Small Base Full Length Sizer Dies were designed for use with semi-automatic firearms for improved feeding. These dies size the brass down to minimal specifications. Due to the fact that this product sizes more than regular dies, it is crucial to have a sufficient amount of high quality lubricant to prevent stuck cases."
    You can also get RCBS SB dies for less than half the price of Redding and they work just fine. I do my first time conversion resizing in a single stage press and use lots of spray-on case lube (home brew 10% liquid lanolin, 90% denatured alcohol)
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    well my Few and minor function probelms with my 300 BO seem to be worked out. actually the only problem that i had was the bolt locking back after the last round was fired from the mag.
    then there was the total waste and complete wash out of trying to load the Raniers 180 grain projectile, simply DOES NOT WORK in my gun not a single one would even start to chamber.
    . but i have shot Remington subs, Berrys subs in 200 and 220 grain, Hornady A max 208 grain at sub sonic and super sonic.
    and the gun runs 100% and is as accurate as you could imagine, more than i would have guessed for a 7.5 inch barrel.
    Mine has never failed to chamber, eject or fire even on extremely low power rounds that the case basically just dropped at my feet when they ejected.
    can't help you or offer suggestions as I am definitely the New Kid on the Block with this gun/caliber but I sure do like it so far.
    let us know what you find the problem is.
    OH and I full length resize with my regular old Lee Dies too!
    Yissnakk likes this.
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    Quote Originally Posted by olfarhors View Post
    well my Few and minor function probelms with my 300 BO seem to be worked out. actually the only problem that i had was the bolt locking back after the last round was fired from the mag.
    then there was the total waste and complete wash out of trying to load the Raniers 180 grain projectile, simply DOES NOT WORK in my gun not a single one would even start to chamber.
    . but i have shot Remington subs, Berrys subs in 200 and 220 grain, Hornady A max 208 grain at sub sonic and super sonic.
    and the gun runs 100% and is as accurate as you could imagine, more than i would have guessed for a 7.5 inch barrel.
    Mine has never failed to chamber, eject or fire even on extremely low power rounds that the case basically just dropped at my feet when they ejected.
    can't help you or offer suggestions as I am definitely the New Kid on the Block with this gun/caliber but I sure do like it so far.
    let us know what you find the problem is.
    OH and I full length resize with my regular old Lee Dies too!
    I am creating my brass with the Lee dies also. Need to check the brass OAL also. That could be at the root of some problems.
    Yissnakk likes this.
    “…democratic socialism, the great utopia of the last few generations, is not only unachievable but that to strive for it produces something utterly different – the very destruction of freedom itself. As has been aptly said: ‘What has always made the state a hell on earth has been precisely that man has tried to make it his heaven.'” F.A. Hayek

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    Quote Originally Posted by Czechbikr View Post
    I am creating my brass with the Lee dies also. Need to check the brass OAL also. That could be at the root of some problems.
    OAL of the brass could be an issue but definitely check the head stamps. I also learned this the hard way by loading up about 50 test rounds with very mixed head stamps, including about 30 Wolf brass converts. I ended up getting a Lymans cartridge gauge as a safety check.
    Czechbikr and GreenWolf70 like this.
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