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Posted: 6/2/2012 3:15:48 PM EDT
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I replaced a bolt in one of my carbines a year ago
with the highly recommended Bravo Company bolt. I had the same extraction problems today, but I can't remember if it was the same rifle. Questions as follows... 1) Can I tell from markings on the bolt if it is the Bravo bolt? 2) If it is the Bravo bolt, what can I do about it? Do they offer a warranty? 3) If they don't, or if it's not the Bravo bolt, what's the oring trick behind the extractor trick? Any nitrile oring of that size, or is a special oring? What size is it? 4) Any other suggestions for correcting this issue? I hate it when they don't work, but I really like getting them corrected. Thanks! John |
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The O-ring band aid trick only works if the problems is the extractor dropping the spend case on the pull.
Could be problems with the head space, short stroking, the ejector bound up in the channel, or even the face of the bolt retracting behind the back of the ejection port window during cycle that could be the problem instead. So having said that, what is the current ejection path and what distance is the spent casing being thrown. Next, pull all the way back on the charging and confirm that the face of the bolt does not retract back past the back of the port window (face of the bolt should stop about 1/4" to 3/8" in front of the back of ejection port window). From there, using a spent case, hook it on the extractor and cam the ejector into and out of the bolt face a few times to confirm that the ejector is not binding up. From there, it just a mater of checking head space, that the extension lugs are lined up with the bolt lugs, and that that there are no problems in the gas system. |
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It was the bolt I bought from Bravo as shown
above, so that leads me to a gas problem and short stoking occasionally? Or maybe a bad chamber? I have had no ripped rims, no primers out or pierced that I have noticed, but there was a lot of un-used powder in the locking area of the barrel shroud. The barrel has no markings anywhere, and I did look under the hand guards. The failure was leaving the spent rounds partially in the chamber about every 20 to 25 rounds. The same as it was doing before I replaced the bolt. I have pulled the gas tube, to run some solvent through it, and I will order a few new ones asap. I was shooting .223 in it yesterday. Edit to add, the lower is a Bushmaster, but I am not sure about the upper. I bought it used from a dealer. The face of the bolt stops about an 1/8" in front of the rear part of the ejection port. I did not watch for the directon or distance of the spent brass on good cycles. Edit #2 to add, I have never fired any steel case ammo in this rifle, nor any of my other rifles, for that matter. Also, The is a lot of black smudging on the heat shields in the hand guard. Edit #3 to add, the gas key is staked correctly, and spent cases eject correctly & the ejector is free running. I found a few flakes of brass under the extractor, but not much. Thanks again for the help. John |
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After reading This and some other threads, along
with the smoked upper shield it has become apparent that I am losing gas from the front sight base where the tube goes in. So I hope a new tube will fix it, but what are the chances that the sight base could be out of spec? Is there a different tube available to make up for that? Great info here. Thanks! John |
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I noticed the "o" ring and extractor thing came up again in this thread. My Rem. VTR came with the "o" in it and it's in the manual too. Most of the comments I've read on here seem to lean towards that it is a NEED only thing. If so, why did they use it in this "factory" assembled rifle?
Thanks, Motor1 |
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I noticed the "o" ring and extractor thing came up again in this thread. My Rem. VTR came with the "o" in it and it's in the manual too. Most of the comments I've read on here seem to lean towards that it is a NEED only thing. If so, why did they use it in this "factory" assembled rifle? Thanks, Motor1 Remington is a relative newcomer to the Black Rifle world. What they do or don't do does not set policy. |
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I noticed the "o" ring and extractor thing came up again in this thread. My Rem. VTR came with the "o" in it and it's in the manual too. Most of the comments I've read on here seem to lean towards that it is a NEED only thing. If so, why did they use it in this "factory" assembled rifle? Thanks, Motor1 Remington is a relative newcomer to the Black Rifle world. What they do or don't do does not set policy. I understand but everybody knows it's not really a Remington and the company that made it has been making "black rifles" for many years. |
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I noticed the "o" ring and extractor thing came up again in this thread. My Rem. VTR came with the "o" in it and it's in the manual too. Most of the comments I've read on here seem to lean towards that it is a NEED only thing. If so, why did they use it in this "factory" assembled rifle? Thanks, Motor1 Remington is a relative newcomer to the Black Rifle world. What they do or don't do does not set policy. I understand but everybody knows it's not really a Remington and the company that made it has been making "black rifles" for many years. Short answer, if the ejector spring is strong enough, and the chamber not tight cross walled sectioned/rough, then there is no need for the added O ring. |
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The description for This says
it will help with eroded ports. Has anyone tried one of these? John |
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As you can tell I have been working toward a solution for this issue. I thought that the front sight bases & barrels had to be machined to match when installed with the conventional taper pins. If This will work, I am willing to go this route. Will the taper pin holes in this sight match the ones in my barrel? Input please. John John |
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As you can tell I have been working toward a solution for this issue. I thought that the front sight bases & barrels had to be machined to match when installed with the conventional taper pins. If This will work, I am willing to go this route. Will the taper pin holes in this sight match the ones in my barrel? Input please. John John FSB's and the barrels they are mounted on are unique sets. This troubleshoot seems like it's going all over the map. Try to keep it logical and linear. I'll go back and re-read the thread and see if I can follow what is going on. Edit: So it's not an extraction problem, it's under-gassed due to a gas leak at the FSB ? Where is the leak...gas tube connection or FSB/barrel ? |
| Load one round in the magazine and fire. Does the bolt lock back? Every time? If so, its not short stroking. Where does it eject using the barrel as 12 o'clock? On your fired cases, are there any signs of extractor cutting into the rim? Does the fired case body have any abnormal scratches or gouges? |
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Ok. I'll take a deep breath & start again.
I get double feeds about every 20+/- rounds. I will have to shoot it agin to see where the correctly cycled brass goes. I have lots of spent brass, but I also have several AR's so I can't be sure what rifle fired what brass. I will rest fire again, but I have been working the bugs out of this carbine for a while. The double feeds are the spent case extracted about halfway out of the chamber & the fresh round stripped & under the spent case. Things I know... 1) I replaced the bolt a year or so ago because of failures to extract completely out of the chamber, thinking it was the extractor, however, I could not get the extractor pin out of that bolt to check the spring, so I bought the Bravo bolt. Thinking that would correct the problem, I haven't shot it since then, until this past Saturday. 2) When I pulled it apart to verify it was the carbine with the Bravo bolt, I pulled the hand guards off to check the gas tube, when I saw that about 2/3's of the upper shield has black sut on it with a pattern that points directly at the area of the gas port on the front sight base, so that's why I am keying in on the front sight base now. I bought this rifle used, my first AR, and I do recall that it was on top of a class III lower which leads me to the likelyhood that the port has erosion issues. John |
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Is the gas leak at the base/barrel or gas tube/FSB ?
Another check to try is the flex tubing check. Get some flex tubing (aquarium) that will fit tightly over the gas tube end that is inside the receiver. Blow on it. Helps to have a healthy AR to do first so you have a baseline for comparison. |
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If it really was on a full auto lower, than that is further leading me to my first thought that this upper is OVER gassed not under. That's why I said looked at the rims of the case to see if they look bent or cut by the extractor. Before you messing with the gas block, get an H2 buffer and an extra power buffer spring from Wolff and put that in your lower.
If you shoot it before you do the above, I will bet you your brass is ejecting at 1 o'clock or so, indicating an over gassed situation. |
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Is the gas leak at the base/barrel or gas tube/FSB ? Another check to try is the flex tubing check. Get some flex tubing (aquarium) that will fit tightly over the gas tube end that is inside the receiver. Blow on it. Helps to have a healthy AR to do first so you have a baseline for comparison. I was gonna post a pic of the inside of my handguard, but I can't log in to tiny pic... It's leaking where the gas tube goes into the sight base. Edit to add, I just pulled the handguards off of my my other carbine, that I shoot about as much as the one above, and the shield in that one looks new. No sut at all. John |
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Is the gas leak at the base/barrel or gas tube/FSB ? Another check to try is the flex tubing check. Get some flex tubing (aquarium) that will fit tightly over the gas tube end that is inside the receiver. Blow on it. Helps to have a healthy AR to do first so you have a baseline for comparison. I was gonna post a pic of the inside of my handguard, but I can't log in to tiny pic... It's leaking where the gas tube goes into the sight base. Edit to add, I just pulled the handguards off of my my other carbine, that I shoot shoot about as much as the one above, and the shield in that one looks new. No smut at all. John It may be pushing out that joint because the tube's partially plugged. Flex tube test results ? |
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If it really was on a full auto lower, than that is further leading me to my first thought that this upper is OVER gassed not under. That's why I said looked at the rims of the case to see if they look bent or cut by the extractor. Before you messing with the gas block, get an H2 buffer and an extra power buffer spring from Wolff and put that in your lower. If you shoot it before you do the above, I will bet you your brass is ejecting at 1 o'clock or so, indicating an over gassed situation. I will shoot it again to check for torn rims before I do anything to it. I will watch for the brass pattern, too. What else? What would make it over gassed if it was a FA upper? Thanks again. John |
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If it really was on a full auto lower, than that is further leading me to my first thought that this upper is OVER gassed not under. That's why I said looked at the rims of the case to see if they look bent or cut by the extractor. Before you messing with the gas block, get an H2 buffer and an extra power buffer spring from Wolff and put that in your lower. If you shoot it before you do the above, I will bet you your brass is ejecting at 1 o'clock or so, indicating an over gassed situation. I will shoot it again to check for torn rims before I do anything to it. I will watch for the brass pattern, too. What else? What would make it over gassed if it was a FA upper? Thanks again. John Will it (bolt catch) lock back on the bolt (not carrier) on the last round ? |
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Is the gas leak at the base/barrel or gas tube/FSB ? Another check to try is the flex tubing check. Get some flex tubing (aquarium) that will fit tightly over the gas tube end that is inside the receiver. Blow on it. Helps to have a healthy AR to do first so you have a baseline for comparison. I was gonna post a pic of the inside of my handguard, but I can't log in to tiny pic... It's leaking where the gas tube goes into the sight base. Edit to add, I just pulled the handguards off of my my other carbine, that I shoot shoot about as much as the one above, and the shield in that one looks new. No smut at all. John It may be pushing out that joint because the tube's partially plugged. Flex tube test results ? I did the tube thing on both carbines, and they seem the same to me. I did it several times. Model airplane fuel tube works perfectly. When I pulled that tube Sunday, it was clear. No debris as far as I could tell. I would think that with the pressures & temps involved, not much can live in there... John |
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If it really was on a full auto lower, than that is further leading me to my first thought that this upper is OVER gassed not under. That's why I said looked at the rims of the case to see if they look bent or cut by the extractor. Before you messing with the gas block, get an H2 buffer and an extra power buffer spring from Wolff and put that in your lower. If you shoot it before you do the above, I will bet you your brass is ejecting at 1 o'clock or so, indicating an over gassed situation. I will shoot it again to check for torn rims before I do anything to it. I will watch for the brass pattern, too. What else? What would make it over gassed if it was a FA upper? Thanks again. John Will it (bolt catch) lock back on the bolt (not carrier) on the last round ? If you mean during live fire, I will watch for that when I test fire it later this week. I did not shoot to an empty mag Saturday. I kept topping them off between drills. John |
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Stove pipe jam (double feed with a live round and a spent round are ejection problems, not a feed or cycle problem.
So, start by pulling the charging handle all the way back, and confirm that the bolt face does not retract back past the back of the ejection port window (face of the bolt should be about 1/4" to 3/8" in front of the ejection port window with the CH pulled all the way back. Also on the CH pull, the last inch of pull should be the same tension as the middle to last of the pull just before that last inch. If the last inch of pull is harder, then either you have the wrong length recoil spring in play, the butt stock screw is protruding into the back of the receive extension, or you are getting hammer wedging between the top of the trigger/disco and bottom of carrier. Next if could be either the extraction spring weak, of you are just doing a crappy job at getting the chamber clean (read use a chamber brush) and lubing the rifle correctly. From there with the bolt in hand, take a spent case off the extractor, and cam the ejector into the bolt face a few times to confirm that the ejector is not binding up in the bolt face. While you still have the bolt in hand with the spent case, use the tip of your finger on the mouth of the case, cam the ejector all the way in, then remove your finger. The spent case should clear the bolt face. If the spent case is not coming off the ejector cleanly, then take a look at the rim relief cut in the ejector and compare it to the face of the bolt. The bottom of the ejector rim relief cut should be flush with the inside rim face of the bolt. If he rim relief cut is below the face of the channel, then it going to pinch the rim, causing problem with a clean release of the spent case off the bolt face and extractor. As for cleaning the rifle, you need CLP to clean and lube 99% of the bearing parts (including the chamber with CLP and a chamber brush), with the last 1% of the cleaning the actual barrel bore with something like sweets since CLP will not dissolve copper. If you are using something like Hoppes (which leaves behind a residue that just collets fouling and turns into a sticky mess), or using another type of lube (one that does not have a cleaning agent in it, allowing the fouling to bind to the surfaces instead of just being disolved before it can collect), then this could be your problem alone, with the gun quickly fouling out in less than a mag. And no, it not that I don't like Hoppes solvent, I use it all the time to clean the bores in my shotguns. It's in auto loaders where it should be avoided. |
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I have checked a case in the bolt for ejector function & it seems correct. I also pulled the CH back & the bolt face stops about 1/8" infront of the back of the ejection port. I will have to check for the rest of what you posted tomorrow. Time for bed. I'll be back... John |
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A failure to extract can be from over gassing as well because the bolt blows rearward while the case is in full obturation and this can cause the extractor to slip off. Hence, the suggestion to look at the rims of the case.
Since he is using a BCM bolt, that comes with the proper 5 coil extractor spring and the O-ring, so he definitely has MORE than sufficient extractor tension (for a properly gassed system). ETA: He is having the same problem with different BCGs, so that eliminates a bolt issue. So far I'm betting its overgassed. ETA2: OP, you asked why would a full auto potentially contribute to over gas, its because if the barrel has had thousands of rounds through it, the gas port can/will erode, meaning enlarge. The larger the gas port, the more gas is being siphoned into the system, and thereby increasing cycling speed. ETA3: Do one more thing for us, measure the buffer spring and post the length. |
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chewbacca, I think that you are on to something here.
With thousands of rounds through the rifle, a weak recoil spring will allow the rifle to over function, and with the increased speed at unlock, his buffer may not be correctly dead blow effecting to allow the spent case to be ejected rearward at the back of stroke. Also, there is over tension of the extractor, and if the spent case is not coming off the bolt alone via the finger removal from the case testing, try the test again with the O ring removed, and maybe even some live fire with the O ring removed as well. |
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Guys,
I am at work on my lunch break, so I don't have acces to the rifle, and I don't have a lot of time. A few comments from your responses. I did pull the extractor out of the Bravo BCG, and I am sure it didn't have an o-ring. Also, the case does leave the BCG when when I test it by hand. It seems to function correctly for that test. Also, While I'm not quite ready to give up on this upper due to the education I am receiving on the detailed workings of the AR firing cycle with your help, one other thing I have will consider, if i do have an erroded port in the barrel, would be to send this barrel off & have it cut down to pistol length & just buy a new 16" barrel for this carbine. I am open to suggestions in that direction as well. Gotta go. Thanks again! John |
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Yes to both. See with the eroded port, more gas is entering the system thereby causing the bolt to unlock prematurely when the fired round's case is still at full expansion and swelled against the wall of the chamber (obturation). This (I'm theorizing) is why you are getting failure to extracts, because the bolt speed is so high that the extractor is slipping off the rim while the case is in obturation. By putting in a h2 buffer, it will slow down the timing of bolt unlocking, which will allow the case to contract slightly and therefore your extractor is not fighting the friction of the obturation like it is no
w, and should be able to maintain its grip. However, if you go out tomorrow and load one round the magazine and it fails to lock back after firing, then the entire over gassed theory is out. Posted Via AR15.Com Mobile |
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I would grab an O ring. You may not need it but if you do its a lot better to have one on hand than to order it separate. With the O ring added the extractor should have enough force to rip through the rim of the case if the rifle is over gassed and the chamber is opening early. |
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An H2 sounds good to me if it will allow reliable operation. That spring measures 10-3/8" No H2's in the house. I'll have to order one, and if I am gonna do that, are there any other items I should order to split the shipping for this project? Thanks! John If you have a CAR (standard) buffer and an H3 you can take them apart and make an H or H2. So with the correct 2 buffers you can cover the set. Without knowing if your over or under-gassed, there are reduced power as well as extra power action (buffer) springs. It's all guesswork though, until you get back to the range. H3, not in the pic, has all tungsten slugs.... 
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The range trip seems to fitting into
the schedule pretty well, so far. Things I will check. 1) Single round in the mag several times to check for LRBHO. 2) Angle of spent rounds from ejection port. 3) Distance of spent rounds. 4) Recover & inspect cases, and take particlar note of FTE or FTE cases. 5) Multiple rounds in the mag to watch for double feeds & inspect those FTE rounds. What else? John |
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An H2 sounds good to me if it will allow reliable operation. That spring measures 10-3/8" No H2's in the house. I'll have to order one, and if I am gonna do that, are there any other items I should order to split the shipping for this project? Thanks! John If you have a CAR (standard) buffer and an H3 you can take them apart and make an H or H2. So with the correct 2 buffers you can cover the set. Without knowing if your over or under-gassed, there are reduced power as well as extra power action (buffer) springs. It's all guesswork though, until you get back to the range. H3, not in the pic, has all tungsten slugs.... http://www.ar15barrels.com/tech/buffer-construction.jpg Too much good info! I never thought about what was in the buffers, or that you could take them apart. John |
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No malfunctions.... 
I shot 10 rounds single from the mag. All of those locked back. I then shot about 45 more rounds from 2 mags. All but about 10 rounds went about 10' at 3 o'clock. 2 went to about 4:00. A few went to 2:00. I do have a some curved score marks on some of the brass like it was being dragged as the bolt was unlocking. No marks from ejector pin hole, and no ripped rims... Now what? John |
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No malfunctions....
I shot 10 rounds single from the mag. All of those locked back. I then shot about 45 more rounds from 2 mags. All but about 10 rounds went about 10' at 3 o'clock. 2 went to about 4:00. A few went to 2:00. I do have a some curved score marks on some of the brass like it was being dragged as the bolt was unlocking. No marks from ejector pin hole, and no ripped rims... Now what? John Sounds good...I'd put a happy face up there. Wha ammo ? What buffer ? |
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I guess it should be a happy face, but I was really looking forward to getting the gremlins out of this one. Ball .223 factory, and the carbine buffer that has been in it... Should I take the front sight off to look at the port? I am a little dissapointed, actually. I suppose I'll take it to the next 3 gun, but I will take another one as back up. Any more thoughts, anyone? John |
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"Ball .223 factory" is sort of a misnomer and definitely not enough information.
Ball is an old term almost always associated with military ammo. .223 is typically civilian ammo loaded to lower pressures. So if it was some flavor of .223, and you're cycling well, you would likely be a little over-gassed with full power military ammo. Sounds like it would run an H or H2 buffer with .mil ammo easily. Settle on what ammo you like and adjust from there. |
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Good Day,
Thought I'd share my recent experience with a one year old Stag Mod 1, 16" barrel 5.56 chamber, 1 to 9 twist. First thousand rounds Fed 223 55 grain had no issues. Got a hold of a can of Green tip Lake City XM855 62 grain and started having FTExtract issues with spent brass being left in chamber and next hot round jamming behind it. No short stroke since would always lock open on last round. Upon advice from another member, RedFalconBill, went to heavier buffer, using H buffer, and threw in a D-Fender ring. Haven't had any FTExtract issues in last 100 plus rounds. Cycles the 223 with this configuration as well. I just posted this the other day wondering if others had similar issue with hot ammo requiring a heavier buffer. Stag went both ways on this, first saying I should send it back and didn't need to modify anything, then said if it's working then maybe leave it alone. Seems that just that little bit of extra mass in the buffer slowed down the whole operation by enough microseconds to allow the extractor to hold onto the rim of the shell until the case contracted enough to be able to get pulled out and eventually ejected as per plan. Believe the Colt M4's are being shipped with an H buffer or heavier? Not quite sure if you have similar or same issue, as I believe I'm having a slight over gassing situation and the H buffer along with D Fender (could have used O ring same same) takes care of it. Hope this helps. Walt B |
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