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Posted: 6/23/2025 10:29:25 AM EDT
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I'm thinking it's not the ammo, maybe it's really tight .223 chambers? My gut says the supposedly "nitrided" chambers might actually be only manganese phosphate and the chambers are sticky. I can't remembrer where I got them because I've had them for two to three years. The facts: * I have three Del-Ton uppers, two are supposedly nitrided and the third is chrome lined. All are marked for 5.56. * All three have BCM bolt carrier groups and spent casings have never showed any signs of overpressure (I checked frequently). * All three were 100% reliable until this weekend. * With two different types of 5.56 ammo, Winchester white box and Winchester USA with crimped primers, both nitrided uppers failed to chamber live rounds intermittently, and required me to "mortar" the rifle on the ground to extract the live rounds even if they were only partially chambered. * The chrome lined barrel upper cycled over 100 rounds of both types of ammo without a problem. * None of the three uppers have fired more than a couple-three hundred rounds between cleanings. * It is possible that up until this weekend the two nitrided uppers had only been shot with .223, since I had a bunch of it and wanted to rotate my stock. * I deadlined the two nitrided uppers pending determination of why both "suddenly" have a problem. What say you? |
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"If men define situations as real, they are real in their consequences."--W.I. Thomas
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"If men define situations as real, they are real in their consequences."--W.I. Thomas
_____________________
"If you ever really need a gun, you'll need it more than anything else you've ever needed in your life."
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What we teach Armorers to do is start with a thorough cleaning, which includes using a chamber brush with solvent to make sure there is no build up inside the chamber, then swab it out with a few dry patches, even follow it up with a patch soaked in denatured alcohol. The cleaning is done to make sure there is nothing like heavy carbon fouling, unburnt gunpowder, copper fouling or brass shavings hindering anything. There is often times a big difference the gunpowder used in premium ammunition that is usually cleaner burning, as compared to non premium which may be loaded with a dirtier ball powder that causes more fouling issues. Next look at any of the problematic rounds or brass that we removed, to see if there are any signs of deformities, scratches or gouges that is out of the normal. If something isn't looking right, try and figure out of the ammunition or brass casing is getting deformed, and what is causing it. You can always post pics of the brass or ammo, and even the feed ramps, as pics sometimes helps us see if there is an issue that we may spot. Have you checked the headspace, if not I would highly recommend it, as you should just not throw parts together in hopes it is correct, as if it isn't then you can experience problems like you are having, or more catastrophic where the gun blows up. As for a nitride finish as compared to parkerized (manganese phosphate) finish with no chrome lining, as compared to the nitride on the inside of the barrel, the parkerized finish can be rougher but that may depend upon if the chamber is polished and cleaned up afterwards, the nitride is much more slippery and doesn't add much for dimensional change as compared to chrome lining which can add thickness to the overall surface where the chrome is. CY6 Greg Sullivan "Sully" WeaponsArmorer SLR15 Rifles Defensive Edge Training (763) 712-0123 |
Surface finish of nitrite, And if chamber/ bore of barrel was not protected during parkerizing after, then going to be even a worse mess. As stated, run a chamber brush by hand in the the chamber with CLP/ bore brush through the bore, and if your pulling out black during such and barrel was not test fired, then more than just nitrite that was done to the chamber and bore. As for best carbonize treatment, that would be Tenifer, but can not be done in the states, since it requires arsenic to be used. https://firearmshistory.blogspot.com/2010/08/metal-treatments-ferritic.html As for chamber cross wall dimensions gauges (over just head space of chamber shoulders to face of bolt), I do have go and no go gauges for that, but are hard to find nowadays since it really just the head space gauges being sold instead. So looks like just chamber brush/bore brush cleaning (which should have been done before rig as put in service) and if still having problems, them time to get the barrel supplier on the phone. _______ On a side note, the one that kills me, is when barrel manufacturers will blue the chamber and bore of barrels, not that is a good idea in the first place or going to add protection to the bores, but used to hide about the worst produced rifling instead. |
Posted By PlaymoreMinds:
'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...
<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...
<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
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Originally Posted By Dano523: Surface finish of nitrite, http://accurateshooter.net/Blog/kendrpic00a.jpg And if chamber/ bore of barrel was not protected during parkerizing after, then going to be even a worse mess. As stated, run a chamber brush by hand in the the chamber with CLP/ bore brush through the bore, and if your pulling out black during such and barrel was not test fired, then more than just nitrite that was done to the chamber and bore. As for best carbonize treatment, that would be Tenifer, but can not be done in the states, since it requires arsenic to be used. https://firearmshistory.blogspot.com/2010/08/metal-treatments-ferritic.html As for chamber cross wall dimensions gauges (over just head space of chamber shoulders to face of bolt), I do have go and no go gauges for that, but are hard to find nowadays since it really just the head space gauges being sold instead. So looks like just chamber brush/bore brush cleaning (which should have been done before rig as put in service) and if still having problems, them time to get the barrel supplier on the phone. _______ On a side note, the one that kills me, is when barrel manufacturers will blue the chamber and bore of barrels, not that is a good idea in the first place or going to add protection to the bores, but used to hide about the worst produced rifling instead. |
Preferred Pronoun: Space Lord Mutherfucker
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Originally Posted By DVCER: A couple of these guys have forgotten more than I know. Is it OK to chuck the chamber brush in a drill, soak it in solvent and slowly give it 10-20 turns? Just regular duty grade ARs. NO!!! Do not use a drill to spin a brush to clean a chamber. The traditional AR15/M16 chamber brush is made up of 2 parts. The smaller diameter front section of the brush is generally made from a bronze/phosphorous material, and is made for cleaning the chamber area where the ammunition is locked into battery and fired. The back end of the brush is generally made of stainless, and is much larger in diameter for cleaning out the barrel lug recess. What can happen when using a chamber brush on a rod that is spun on a power drill, is you could ruin a barrel, I've seen this many times on problematic guns that occasionally cross our paths in the armorer courses we teach. What happens is based on the drill and the brush. The stainless bristles on the lug brush is hard, and when spun on a drill can cut grooves in the barrel. Combine this with that the drill user pushes too hard forward, and the stainless bristles on the brush get pushed forward past the barrel extension lug recess area, and are now in the chamber where the ammunition sits and expands during firing. Also take into account that the center heavy wire section of most chamber and bore brushes are made steel. So spinning a brush on a drill can create grooves in the barrel, let alone getting the stainless brush pushed in past the lug recess and into the barrel area where the ammunition sits you can get grooves in the barrel. Any deformity of the chamber can create a situation under firing conditions where the casing of the ammunition expands into a groove that the brush has made, and now you will experience fail to extract issues. I have personally seen many drill spun brush areas of barrels that now have grooves, and are now having stuck casings, and once you have grooves it is basically impossible to get them out, so now you have to throw the barrel away. To use a traditional chamber brush, simply put it on a chamber rod. Either spray solvent into the barrel/chamber area, or dip the brush in solvent. Then simply rotate the brush/cleaning rod clockwise and at the same time insert the brush so that the smaller bristle end gets into the area where the ammunition sits, and the wider stainless bristle end gets into the barrel extension lug recess. Now simply rotate the brush and rod clockwise for about 8-10 rotations, this rotating the brush with solvent combined, will generally break down most fouling, and once done all you need to do is swab out the chamber/barrel extension lug recess until things are wiped clean/dry. CY6 Greg Sullivan "Sully" WeaponsArmorer SLR15 Rifles Defensive Edge Training (763) 712-0123 |
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Probably Wylde chambers. Do ejected live rounds have a scuffed ring around the bullet about 1/16~1/8 in front of the case mouth? |
This is...a clue - Pat_Rogers
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
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My sig 553 i noticed i would have to mortar some live rds out and then I had it rip the rim off a couple of fired cases. I have never fired a factory rd in it but I took rds that passively fit in a saami spec case gauge and tested with my 550 and 551 with zero issues ejecting live rds out of the chambers but the same rds were hard to eject from the 553. I figured the chamber was really tight, rough, or both. It is an accurate rifle. Anyways I bought these: https://www.amazon.com/gp/aw/d/B00DB8E6M6?psc=1&ref=ppx_pop_mob_b_asin_image https://www.amazon.com/gp/aw/d/B00DB8E7VQ?psc=1&ref=ppx_pop_mob_b_asin_image One on 400 grit and one in 800. It actually ended up taking a few minutes of honing with each at full speed wit my drill. I did it a over a few sessions testing rds each time. Now the 553 has no issues and the accuracy was unaffected. |
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Originally Posted By Gamma762: Probably Wylde chambers. Do ejected live rounds have a scuffed ring around the bullet about 1/16~1/8 in front of the case mouth? Headspace gages are all the same. Without actually measuring his rifle's headspace, we can't tell if it's too tight. The OP needs to buy a go gage, he can layer scotch tape (.002" thick) to create a "no-go" gage. Cheap insurance and it eliminates guesswork. |
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Originally Posted By DocApocalypse: ... * All three were 100% reliable until this weekend. * With two different types of 5.56 ammo, Winchester white box and Winchester USA with crimped primers, both nitrided uppers failed to chamber live rounds intermittently, and required me to "mortar" the rifle on the ground to extract the live rounds even if they were only partially chambered. ... What say you? Winchester ammo was the least reliable for me before they took over Lake City, and they went downhill from there, this was .40sw and 9mm experience. about one round in a 100rd box was a dud. it prints groups larger than other brands during the same range session for me with 5.56. other brands I use are pmc, federal, hornady, fiocchi. of all the cheap ammo, the fiocchi seems the most consistent. I try not to buy Winchester, pretty easy these days as all the lgs carry fiocchi. best 5.56 I've ever shot was Sierra loaded ammo with tipped gamekings. back to back with the pmc green tips in the same rifle and groups shrunk by half. I keep it in pmag20 so I know what to grab for backyard coyote duty. expensive though, I think it was about $2/rd. try different ammunition, if the rifles all work perfectly, it's the shit ammo. if you still have function issues, try aggressively cleaning the chambers. |
The deuce you say.
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Originally Posted By sully: ... What can happen when using a chamber brush on a rod that is spun on a power drill... ... holy crap people actually do that to their guns?!? not being facetious, it never occurred to me to use power tools on a barrel/chamber like that. |
The deuce you say.
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Originally Posted By borderpatrol: Headspace gages are all the same. Without actually measuring his rifle's headspace, we can't tell if it's too tight. The OP needs to buy a go gage, he can layer scotch tape (.002" thick) to create a "no-go" gage. Cheap insurance and it eliminates guesswork. Originally Posted By borderpatrol: Originally Posted By Gamma762: Probably Wylde chambers. Do ejected live rounds have a scuffed ring around the bullet about 1/16~1/8 in front of the case mouth? Headspace gages are all the same. Without actually measuring his rifle's headspace, we can't tell if it's too tight. The OP needs to buy a go gage, he can layer scotch tape (.002" thick) to create a "no-go" gage. Cheap insurance and it eliminates guesswork. Headspace has nothing to do with throat design/dimensions and vice versa. |
This is...a clue - Pat_Rogers
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
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Originally Posted By racer765: Winchester ammo was the least reliable for me before they took over Lake City, and they went downhill from there, this was .40sw and 9mm experience. about one round in a 100rd box was a dud. it prints groups larger than other brands during the same range session for me with 5.56. other brands I use are pmc, federal, hornady, fiocchi. of all the cheap ammo, the fiocchi seems the most consistent. I try not to buy Winchester, pretty easy these days as all the lgs carry fiocchi. best 5.56 I've ever shot was Sierra loaded ammo with tipped gamekings. back to back with the pmc green tips in the same rifle and groups shrunk by half. I keep it in pmag20 so I know what to grab for backyard coyote duty. expensive though, I think it was about $2/rd. try different ammunition, if the rifles all work perfectly, it's the shit ammo. if you still have function issues, try aggressively cleaning the chambers. I've shot over 300 rounds of the same ammo now in a Colt, a BCM, and Del-Ton with a chrome lined barrel. Not one malfunction. I think it's the Del-Ton nitride chambers maybe not being cut for 5.56. |
_______________
"If men define situations as real, they are real in their consequences."--W.I. Thomas
_____________________
"If you ever really need a gun, you'll need it more than anything else you've ever needed in your life."
"If men define situations as real, they are real in their consequences."--W.I. Thomas
_____________________
"If you ever really need a gun, you'll need it more than anything else you've ever needed in your life."
|
Originally Posted By Gamma762: Headspace has nothing to do with throat design/dimensions and vice versa. ...and every rifle I've assembled has either been perfectly functional or slightly undergassed (300blk 16" carbine gas), no headspace issues. the chamber and barrel extension, plus the bolt, are all so tightly qc'd on any of the brands anyone would use that I never bought any gages for 5.56. I suppose tolerance stacking might bite me someday, but not yet. plus I have spare bcg and a spare bolt I pulled from the bcg I changed to 6.8 spc so even if tolerance stacking does come up I'll just mix and match until it works. if I can't, then I'll get a set of gages to verify an out of spec barrel and then get a warranty replacement barrel. the first ebr I bought was my l1a1 and I wanted to start reloading just as a hobby, so I bought the chamber oal length tool, go/no go gages, and cartridge go/no go gages for 7.62x51. turns out the aussies cut the chamber with a loooooooooond leade, I let some of the brass get long, I could load damn near .100 longer than spec case neck 7.62x51 and it would still function perfectly. group size shrunk too. |
The deuce you say.
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Originally Posted By DocApocalypse: I've shot over 300 rounds of the same ammo now in a Colt, a BCM, and Del-Ton with a chrome lined barrel. Not one malfunction. I think it's the Del-Ton nitride chambers maybe not being cut for 5.56. that is definitely a datapoint! might be worth $80 in Forster guages to settle the question. iirc the lake city 7.62x51 I put through the reloading game was on the small side of spec, I think to make sure it would chamber? been a minute. I was doing that reloading in 2001-2005. I just did neck resizing not full length and it still cycled just fine. anyone mic current Winchester Lake City? I'm not near my pile of stuff or I would do that myself. |
The deuce you say.
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UPDATE: I took one of the uppers out and put 300 rounds of Federal .223 through it without incident the other day. So, it's either the chambers are okay with .223 and not 5.56, which doesn't seem likely given the dimensions of each round are so close, OR, they were bad Winchester White Box rounds of 5.56. The amount of the "bad" cases hanging out of the rear of the chamber tells me it probably was not an incidence of the chambers being cut too tight for 5.56 but being fine with .223. It just doesn't seem likely to be a chamber issue. Further evidence: I have had Winchester White Box rounds in 45 ACP not chamber recently due to being slightly out of spec. So at this point I'm guessing it was bad ammo. The number of bad rounds is what concerns me. The fact that I had to mortar both rifles with multiple rounds suggests a really bad batch of Winchester White Box. |
_______________
"If men define situations as real, they are real in their consequences."--W.I. Thomas
_____________________
"If you ever really need a gun, you'll need it more than anything else you've ever needed in your life."
"If men define situations as real, they are real in their consequences."--W.I. Thomas
_____________________
"If you ever really need a gun, you'll need it more than anything else you've ever needed in your life."
|
Probably Wylde chambers on the short side, that's the norm. If the ejected live rounds have a scuffed ring around the bullet about 1/8 inch in front of the case mouth, the bullet is engraving into the chamber throat. Since the throat on a Wylde chamber is .224, the same diameter as the bullets, it's dependent on the exact bullet shape and exactly how the chamber is cut. The typical shape of 55gr FMJ bullets are larger at that point and are one of the "stickiest" in Wylde chambers IME. Nitride doesn't change dimensions, but there is typically an outer layer of oxide that adds a very small amount of size. It gets removed from the throat and bore within the first few rounds fired. The problem isn't nitride, it's the chamber the barrel was made with. Too many, both consumers and suppliers, go with the marketing buzzword of the Wylde chamber and it's not a good choice for general AR15 users. |
This is...a clue - Pat_Rogers
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
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Originally Posted By DocApocalypse: UPDATE: I took one of the uppers out and put 300 rounds of Federal .223 through it without incident the other day. So, it's either the chambers are okay with .223 and not 5.56, which doesn't seem likely given the dimensions of each round are so close, OR, they were bad Winchester White Box rounds of 5.56. The amount of the "bad" cases hanging out of the rear of the chamber tells me it probably was not an incidence of the chambers being cut too tight for 5.56 but being fine with .223. It just doesn't seem likely to be a chamber issue. Further evidence: I have had Winchester White Box rounds in 45 ACP not chamber recently due to being slightly out of spec. So at this point I'm guessing it was bad ammo. The number of bad rounds is what concerns me. The fact that I had to mortar both rifles with multiple rounds suggests a really bad batch of Winchester White Box. so are we concluding it was bad ammo? any additional datapoints? different factory loaded ammo? |
The deuce you say.
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