BCG binding in upper

[guitarist1993]

Search failed me, I found a few similar topics but none that matched the problem I'm having. Sorry if this has already been addressed.

I just got back from sighting in my new build, and I had a strange problem. The upper is a VLTOR MUR, BCG is from Rainier Arms, bolt and barrel are from Compass Lake Engineering, lower is Noveske gen 1 chainsaw with A5 spring & 7 position tube with the standard A5 buffer.

Twice, when I went to charge the rifle, the BCG would get about 95% of the way forward before locking up while still out of battery. It binds so hard that I cannot just pull the charging handle to free it, I have to "mortar" it to free the live round. It never happened while firing, only when I went to load the rifle. Once it happened when I inserted the mag (20 PMAG gen 3 with 5 rounds of my reloaded Sierra HPBT 69g) on a closed bolt and slingshotted the CH, the other time when I inserted the same mag into the gun while the bolt was locked back and I hit the bolt release. Both the upper and BCG were clean and very well lubricated.

When I got home, as I was cleaning, I took these pictures:

Never seen wear like this on the bottom/rear of the BCG before
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_132556_zps0c6782af.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_132556_zps0c6782af.jpg.html)


Here, you can see some wear around the cam pin
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_132621_zps9f4a32a9.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_132621_zps9f4a32a9.jpg.html)
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_132714_zps70ff936e.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_132714_zps70ff936e.jpg.html)

A little wear inside of the upper around the cam pin slot and just underneath the CH slot
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_133506_zps51704f71.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_133506_zps51704f71.jpg.html)

After I thoroughly cleaned and lubed it, I checked a 30 round PMAG that I keep loaded with 68g Winchester Power-point rounds, and the same thing happened, it bound up without full going into battery:

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_140120_zpsb7a57b2e.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_140120_zpsb7a57b2e.jpg.html)

I tried my PSA BCG in this upper, same thing happened. Tried a different lower, thinking maybe the A5 system was the culprit, but nope, it still locked up. Tried the Rainier BCG with the bolt that it came with, same thing. No matter which bolt, carrier, and lower combination that I used, no change although both BCGs and all 3 bolts worked perfectly in my PSA upper, on both my Noveske and PSA lowers.

It would cycle 3 or fewer rounds before binding, sometimes doing so on the first one. Neither did it matter whether I pulled the charging handle with my support hand, the "21st century gunfighter" way, or the older, traditional way with my strong hand. It seems to work fine when I pull the CH and let it go without a magazine in though.

Any suggestions?

[NeoNeanderthal]

Might be a stupid question, as it wouldn't really explain the wear patterns, or other bolts working...but is your gas tube straight? If it is out of wack it can put some torque on the BCG and keep it from going into battery. Otherwise your upper receiver might be out of spec, considering other bcg's have worked.

[SpankMonkey]

Did you assemble the upper? Did you use a insert inside the upper before screwing the barrel on?

It sounds like the upper is out of spec or the upper was squeezed to much when the barrel was installed. Always use a insert when installing barrels.

[guitarist1993]

Might be a stupid question, as it wouldn't really explain the wear patterns, or other bolts working...but is your gas tube straight? If it is out of wack it can put some torque on the BCG and keep it from going into battery. Otherwise your upper receiver might be out of spec, considering other bcg's have worked.

Gas tube is straight.


Did you assemble the upper? Did you use a insert inside the upper before screwing the barrel on?

It sounds like the upper is out of spec or the upper was squeezed to much when the barrel was installed. Always use a insert when installing barrels.

A friend of mine who has more experience building uppers helped me. We used a clamshell type clamp to hold the upper and an insert that simulated the placement of a gas tube, but I don't think it offered much support. That said, I find it hard to believe an MUR would be that easy to torque this badly. The barrel nut is at 50lbs.

So am I shit out of luck if that is the problem?

[Kokopelli]

What do the folks at Rainier and Vltor say? I see the marks on the BCG, but not the corresponding marks on the upper...

[gashooter]

remove all oily residue from gas tube inside upper receiver, and inside/outside of the gas key. Apply ink from Sharpie marker outside and inside the port of the gas key as well as the exposed end of the gas tube. Then cycle the bcg several times and field strip the upper and inspect for removal of ink. this technique will help identify what parts are making contact with others. post up pics of the results so I can see what you see.

[guitarist1993]

I'm about to call VLTOR now.


remove all oily residue from gas tube inside upper receiver, and inside/outside of the gas key. Apply ink from Sharpie marker outside and inside the port of the gas key as well as the exposed end of the gas tube. Then cycle the bcg several times and field strip the upper and inspect for removal of ink. this technique will help identify what parts are making contact with others. post up pics of the results so I can see what you see.

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_165415_zpsc7545aab.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_165415_zpsc7545aab.jpg.html)

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_165439_zpsdba65e49.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_165439_zpsdba65e49.jpg.html)
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_165453_zpsfd996949.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_165453_zpsfd996949.jpg.html)
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_165505_zps6c973baa.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_165505_zps6c973baa.jpg.html)

Upon closer inspection, there also appears to be some pre-mature wear on the charging handle. This was brand new until today.

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_171231_zps5cc57235.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_171231_zps5cc57235.jpg.html)
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_171257_zps8f8305cc.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_171257_zps8f8305cc.jpg.html)
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_171311_zps31df9c96.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_171311_zps31df9c96.jpg.html)

[Slippers]

A friend of mine who has more experience building uppers helped me. We used a clamshell type clamp to hold the upper and an insert that simulated the placement of a gas tube, but I don't think it offered much support. That said, I find it hard to believe an MUR would be that easy to torque this badly. The barrel nut is at 50lbs.

So am I shit out of luck if that is the problem?

Does a MUR upper even fit in any of the standard clamshells? I thought the shape was completely different than a forged upper. I know that other CNC uppers don't fit the brownell's blocks, which is why I use a reaction rod instead now.

It certainly sounds like your upper might have been squished a bit.

[VIP3R 237]

Does a MUR upper even fit in any of the standard clamshells? I thought the shape was completely different than a forged upper. I know that other CNC uppers don't fit the brownell's blocks, which is why I use a reaction rod instead now.

It certainly sounds like your upper might have been squished a bit.

You have to do some mods, and even then its iffy. OP call Vltor.

[Eric D.]

It most certainly does not. I've never handled an MUR upper but it looks like you would have to hog away quite a bit of plastic to get it to fit - enough that the clamshell would then be useless for a standard upper.


Does a MUR upper even fit in any of the standard clamshells? I thought the shape was completely different than a forged upper. I know that other CNC uppers don't fit the brownell's blocks, which is why I use a reaction rod instead now.

It certainly sounds like your upper might have been squished a bit.

The wear on the BCG rails is normal but it may be premature in your case, wear around the cam pin pocket in the upper is also normal. The wear on your charging handle does look a little extreme, especially for a low round count. The wear in this picture, in the charging handle track, is what concerns me:



A little wear inside of the upper around the cam pin slot and just underneath the CH slot
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_133506_zps51704f71.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_133506_zps51704f71.jpg.html)

[gashooter]

I concurr after the ink test that the upper is tweaked along the center axis from torque.

Maybe the MFG will help you out with another stripped upper.

[Iraqgunz]

To properly check the BCG fit, you need to disassemble the BCG and insert the carrier only. I would check to see if the tube is too high or low rather than left or right.

In addition the clamshell is not correct for a MUR and it may have gotten tweaked somehow.

[Robb Jensen]

Have you tried the carrier alone it the upper receiver? (No bolt, FP OR CAM pin) to see if the binding is between the carrier key and gas tube?

If it moves freely then the binding is between the bolt and bbl extension.

[guitarist1993]

So I pulled the gas block to put Sharpie all around it and check the alignment. Here are the results, using a stripped carrier, like IG suggested:

Top
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_185652_zpsb8be1295.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_185652_zpsb8be1295.jpg.html)

Left side
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_185701_zpsd6ee72df.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_185701_zpsd6ee72df.jpg.html)

Right side
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_185710_zpsb7d16a10.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_185710_zpsb7d16a10.jpg.html)

Moving it back and forth, I did notice that it is a bit smoother when it's just the carrier. I can feel when the carrier key come into contact with the gas tube, although it's so faint that I can't imagine it would be what's stopping the carrier when pushed forward by the buffer. I recorded 2 videos, with and without the bolt installed, but I don't know if they'll be at all useful. They're uploading now.

After re-installing it, I did my cycle-test again. It made it further before locking up, this time it seized up on round #14.

[guitarist1993]

http://i546.photobucket.com/albums/hh440/scottydoe13579/th_20130915_193117_zps086cc126.jpg (http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_193117_zps086cc126.mp4)


http://i546.photobucket.com/albums/hh440/scottydoe13579/th_20130915_192945_zps355172b7.jpg (http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_192945_zps355172b7.mp4)

[Dead Man]

How many rounds total in this setup?

Without any additional issues, the wear alone wouldn't be a concern. Some rub more than others and show what looks like heavy wear early on. The MUR receivers are made to tighter tolerance than regular M4 receivers... it's common for them to fit barrel extensions, takedown pins, and even carriers much more snugly (downright stiffly sometimes). I suspect you've simply got a combination of parts that are fitting a bit too tight. Since this is a home-build and your options are pretty limited, I would shoot it for another 200 rounds and see if it "breaks in." I bet it will. I would suggest adding an XP spring, but I don't know enough about the A5 system to know if that's even an option.

ARs should be fully drop-in functional from round one, but just because one hiccups a bit when it's brand new doesn't mean it won't be a perfectly reliable gun.

[guitarist1993]

70 rounds. This was my first time firing it, so I went to the range to sight in my scope and follow Compass Lake Engineering's recommended break-in procedure.

[SpankMonkey]

Your not SOL. Go shoot the gun, get 200 rds through the upper and see how it is doing. If it's still tight you can heat up the lower rail below the dust cover with a heat gun. Not a torch but a heat gun.

Then run the carrier back and forth as it cools. Heat it up to 350 to 400 degrees. It will not damage the upper at those temps. Make sure and run the carrier as it cools. That section of the rail will move out and away from the carrier giving the carrier space to move in the future.

Make sure and use a insert in the future.

[guitarist1993]

Have you tried the carrier alone it the upper receiver? (No bolt, FP OR CAM pin) to see if the binding is between the carrier key and gas tube?

If it moves freely then the binding is between the bolt and bbl extension.

If that's the case, could it be a result of receiver torque or something similar? There's no way in hell we managed to break the barrel extension loose putting the muzzle device on.

[guitarist1993]

I got ahold of Vltor support today, and the representative I spoke with recommended that I send it in. I'll take it apart this weekend to send it off and see about putting the barrel in a different upper to find out if the extension is off.

[guitarist1993]

UPDATE:

I don't think the upper is the problem. The carrier moves freely when stripped, and when the bolt binds up, the carrier is still able to move.

Upon closer inspection, I can see a few burs on the lugs of the barrel extension. The lugs on the bolt show corresponding wear patterns. I've contacted CLE to request an exchange. I'll update when again when I hear back.

[K.L. Davis]

ETA: Just read your update - seems you are on the right track.


the BCG would get about 95% of the way forward before locking up while still out of battery.
If it is closing that far... the carrier is probably not the problem, I would suspect the bolt is binding in the barrel extension.


A little wear inside of the upper around the cam pin slot and just underneath the CH slot
http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_133506_zps51704f71.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130915_133506_zps51704f71.jpg.html)

Checking out the wear marks here... further indicates your issue is in the bolt to barrel extension lock up.


There's no way in hell we managed to break the barrel extension loose putting the muzzle device on.
I've seen lots of guys do it... not as rare as you might think.

[guitarist1993]

If it is closing that far... the carrier is probably not the problem, I would suspect the bolt is binding in the barrel extension.


Checking out the wear marks here... further indicates your issue is in the bolt to barrel extension lock up.

Yep. I imagine the wear I'm seeing on the charging handle and inside the upper is just a result of the MUR's tighter tolerances, combined with me cycling the handle so much during troubleshooting. Having to mortar it to free the bolt is likely exacerbating the wear as well.

So I guess this is good news, since that means the upper wasn't out of spec or somehow torqued.

[Hookuleez]

Gas tube is straight.



A friend of mine who has more experience building uppers helped me. We used a clamshell type clamp to hold the upper and an insert that simulated the placement of a gas tube, but I don't think it offered much support. That said, I find it hard to believe an MUR would be that easy to torque this badly. The barrel nut is at 50lbs.

So am I shit out of luck if that is the problem?

What clamshell vise block did you use on a MUR? I was under the impression that MURs are not compatible with clamshell vise blocks. If you used a standard clamshell vise block, it is likely that you crushed the receiver a little.

[guitarist1993]

What clamshell vise block did you use on a MUR? I was under the impression that MURs are not compatible with clamshell vise blocks. If you used a standard clamshell vise block, it is likely that you crushed the receiver a little.

After the recent updates, I'm pretty sure it's not the upper. The burs on the barrel extension and wear on the bolt all point to it binding in the extension. When it locks up, the carrier is still able to move slightly when I pull on the CH.

I spoke with Compass Lake today and they said it's a rare but known issue that they've had before. I'll send it in this week.

[WS6]

ETA: Just read your update - seems you are on the right track.


If it is closing that far... the carrier is probably not the problem, I would suspect the bolt is binding in the barrel extension.


Checking out the wear marks here... further indicates your issue is in the bolt to barrel extension lock up.


I've seen lots of guys do it... not as rare as you might think.

Then they were either being ridiculous, or the gun was not build correctly, IMO. However, my statement is assuming a Geissele reaction rod vs. clam-shell which transmits all of the pressure to the upper vs. containing it "within" the barrel extension like the Reaction Rod.

Have you seen otherwise?

[The_Hammer_Man]

I've purchased and installed several (around 18-19) AR barrels from CL. Never had an issue EVER.

With that said, I always get properly headspaced bolts at the same time.

Do you have another bolt around the house? Would be interesting to see if a different bolt gave you better/worse results.

Good luck.

[guitarist1993]

Tried a PSA and a Rainier bolt in addition to the properly headspaced one from CL. Same thing. Compass Lake said it's a rare issue they've run into before since they don't make the extensions in house.

[gashooter]

My sons Bull Barrel rifle had a binding bolt issue that was caused by stack tollerances in the timing of the bolt to extension. I swapped out a different CARRIER and the concern went away. The root cause of that issue was the cam pin slot was at the minimum spec and the extension was just enough to prevent lock-up. I put a Spike's carrier in it and the bolt would clear the lugs and lock up.

Do you have a different carrier to try?

[guitarist1993]

I did try my PSA carrier, I don't remember if I tried it with the CL or Rainier bolt though. The barrel's back at CL now, so I'll have to wait till next week to see if that fixes the problem.

[guitarist1993]

UPDATE:

Compass Lake called today and said they assembled an upper with my barrel and it functioned fine. They'll be sending it back, I'll assemble it again, and if it's still seizing up, I'll send it back to them. Frank told me he'd really like to take a look at it for himself. So even though it looks like the problem hasn't been fixed yet, kudos to CLE for their great customer service so far.

If it's still doing it, I'll consider whether to send it to Vltor or CLE

[The_Hammer_Man]

There's nothing like a "what the hell?" situation like this to get a gunsmith's interest :)

Had an intermittent FTE issue with a build that after basically disassembling/reassembling it twice turned out to be a crack, of all things, in the gas tube.

I'll bet it turns out to be something simple like that.



UPDATE:

Compass Lake called today and said they assembled an upper with my barrel and it functioned fine. They'll be sending it back, I'll assemble it again, and if it's still seizing up, I'll send it back to them. Frank told me he'd really like to take a look at it for himself. So even though it looks like the problem hasn't been fixed yet, kudos to CLE for their great customer service so far.

If it's still doing it, I'll consider whether to send it to Vltor or CLE

[guitarist1993]

Well boys, I'm officially stumped. Got a new MUR in today while the other one is away at Vltor for warranty consideration, and when I put the upper together (only hand tight, I don't have a vice to torque the barrel nut), it's still binding. Could it be that low torque on the barrel nut is keeping the extension from seating fully? If I had just assembled it to hand tight both times, I would think this is problem. But while I wasn't able to check the torque the first time, it sure felt like 50 ft lbs.

If that's not it, I don't know what it could be. At this point, the only parts I haven't been able to isolate are the gas tube and block, and the barrel. I'll call Compass Lake tomorrow and talk to them about sending the whole thing to them to check out.

[Iraqgunz]

I have a sneaky suspicion that you lower is possibly out of spec. Have you tried this upper on another fully assembled lower?

Have you actually fired this upper with live rounds? I'm just thinking you have the perfect storm in regards to some tolerance issues and once you shoot it, it will work itself out.

At the same time, I would install the barrel again into the new upper and then I would try it on another lower receiver first. I would also get some dummy rounds and cycle them through the weapon. By cycling I mean pull the bolt to the rear, and allow it to fly forward into battery. And then pull it to the rear and let it fly again.

[guitarist1993]

I have a sneaky suspicion that you lower is possibly out of spec. Have you tried this upper on another fully assembled lower?

Have you actually fired this upper with live rounds? I'm just thinking you have the perfect storm in regards to some tolerance issues and once you shoot it, it will work itself out.

At the same time, I would install the barrel again into the new upper and then I would try it on another lower receiver first. I would also get some dummy rounds and cycle them through the weapon. By cycling I mean pull the bolt to the rear, and allow it to fly forward into battery. And then pull it to the rear and let it fly again.

Yep. Tried on both my Noveske chainsaw Gen 1 and my trusty PSA. Both function fine with my PSA upper. I've even had it lock up when moving the BCG by hand during testing, without the lower attached.

Yeah, I originally noticed the problem the very first time I cycled the gun. I loaded a mag up with snap caps and it bound up going into battery when I hit the bolt release. I thought that was odd, but I'd heard of people having issues with snap caps, so I thought nothing of it. It did it twice the next day at the range in 70 rounds. That said, it hasn't been a problem when firing the gun, only cycling it manually. But after seeing the marks on the lugs of the bbl extension, I'm hesitant to keep shooting it without hearing what the manufacturer says first.

Here's a better pic of the wear marks on the extension:

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130925_144804_zps12bbcd27.jpg (http://s546.photobucket.com/user/scottydoe13579/media/20130925_144804_zps12bbcd27.jpg.html)

Little hard to see because of the flash, but the lug a 7 o'clock shows some significant wear. I imagine this where the binding is happening.

[Iraqgunz]

I can't really offer much more. This is one of the follies you have to deal with when trying to build your own. So either something is truly wrong, or your perception of this issue is off.

What doesn't make sense is that you said you tried other bolts and carriers which almost has to rule them out.

[guitarist1993]

I even tried a different cam pin thinking that might be it. I am 100% out of ideas.

[constructor]

There is a batch of extensions going around that are out of spec. it's causing some tight headspace.
The depth from the face to the front of lugs should be .907" some are .903. The bolt lugs should be .278+-.002. The shank on the barrel .620 so there should be apx .009" clearance between the front of the bolt and breech. Sometimes there is no room, the bolt will not turn with nothing in the chamber.
Stick the bolt by itself in the extension and turn it. If that is ok then check the headspace the same way while the barrel is out of the receiver. At least that will rule out those 2 possibilities before you start a build.

Vltor and Mega receivers are usually tight, that keeps the extension square with the receiver bore. Some receivers are loose and the front at the barrel nut threads is out of square. If it is it can make the extension sit cocked in the receiver. That can make the bolt bind when passing through the lugs. It's not a bad idea to square the front of the receiver for that reason.

[guitarist1993]

Just got off the phone with Frank from CLE, he said to go put some more rounds through it to see if it's just a break in issue. If it's still doing it, I'll send the whole upper off to them to fix. I am so done with trouble shooting, I really hope it's just a tight fit. At this point, the only parts I haven't been able to test individually are the gas tube, gas block, barrel nut, and barrel, although CLE said the barrel worked fine in a different upper.

[sinister]

with 5 rounds of my reloaded Sierra HPBT 69g)

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_140120_zpsb7a57b2e.jpg

Do you size fired cases with a small base die?

Does this happen with factory ammo?

Did Frank use a .223 Match chamber or a 5.56? Was the brass first-fired in this barrel (or was it shot in a 5.56 chamber)?

Did you check gas tube alignment when you tightened the barrel/rail nut (it looks like it has a Noveske rail nut and not a standard nut)? Is the gas tube still straight?

It looks like you have minor gas tube binding, especially if, as you say, there's no problem with the bolt and carrier sliding freely in the upper without the gas tube mounted.

Just a point, Noveske "Chainsaw" components are blems -- they should be functionally perfect, just with a cosmetic (finish) flaw.

While Frankenguns usually fit together you have a blem lower, a non-standard billet upper, a non-standard barrel nut, and a grab-bag of pieces-parts fed hand loads.

[guitarist1993]

http://i546.photobucket.com/albums/hh440/scottydoe13579/20130915_140120_zpsb7a57b2e.jpg

Do you size fired cases with a small base die?

Does this happen with factory ammo?

Did Frank use a .223 Match chamber or a 5.56?

Was the brass first-fired in this barrel?

Did you check gas tube alignment when you tightened the barrel/rail nut (it looks like it has a Noveske rail but and bot a standard nut)? Is the gas tube still straight?

Just a point, Noveske "Chainsaw" components are blems -- they should be functionally prefect, but with a cosmetic flaw.

RCBS dies, not sure about small base. I use a friend's press and equipment. It did it with some reloaded Mk 262 as well. I don't remember if I shot any PMC bronze when I first took it out, so I actually don't know if I've run factory new ammo through it. Both reloads function fine in my PSA.

I believe it is a true 5.56 chamber. I specifically asked for it, although the invoice said Wylde, but I think the barrel says 5.56 (don't have it in front of me now).

I've checked to make sure the gas tube is straight. It's an NSR and the included barrel nut on a Vltor MUR

[Iraqgunz]

Just curious. Did you ever strip the carrier down as I recommended and insert the carrier only into the upper to check for gas tube alignment or binding?

[guitarist1993]

Just curious. Did you ever strip the carrier down as I recommended and insert the carrier only into the upper to check for gas tube alignment or binding?

Yep. Carrier moves smoothly with no binding.

[constructor]

Reloads? Check the case size compared to a "go" gauge with a RCBS case mic. If the reloads are longer than the "go" I'll bet that is the problem. When reloading try to push the shoulder back .004 from the fired case size (out of the same rifle) if loading the same ammo for 2 or more then you'll need to size it .004 smaller than the shortest chamber.

[guitarist1993]

When I've been doing these tests, I've been checking it with Winchester Ranger 68g soft point. Factory new, cycled manually. Haven't fired it.

ETA: Made my final decision. I give up. The whole thing will be going to CLE for them to un**** it for me. At this point, it's out of my very limited realm of expertise.

[eodinert]

Just out of curiosity, did you try it with another charging handle?

[guitarist1993]

Just out of curiosity, did you try it with another charging handle?

Yep. Tried my BCM GFH mod 4 and a standard one that came with my PSA upper. Like everything else, the both work fine in that upper.

[guitarist1993]

Yep. Tried both my BCM GFH mod 4 and a standard charging handle that came with my PSA upper. Both work fine in that one.

[Mall_Ninja]

ETA: Made my final decision. I give up. The whole thing will be going to CLE for them to un**** it for me. At this point, it's out of my very limited realm of expertise.

When you re-assembled the upper after getting the barrel back from the manufacturer. What method did you use to mount the barrel to the upper?

[guitarist1993]

When you re-assembled the upper after getting the barrel back from the manufacturer. What method did you use to mount the barrel to the upper?

I just tightened the barrel nut by hand, just to hold it in place while I tested it. I asked Frank if that would make a difference, he said it shouldn't.

[Mall_Ninja]

I asked Frank if that would make a difference, he said it shouldn't.

Agreed...

Keep us posted on the outcome!

[guitarist1993]

Will do gentlemen. Hopefully this story has a happy ending.

[m4fun]

Had a similar issue on a build. Like GASHOOTER narrowed it down to the CAM. Found the combination of a particular CAM in a PSA upper. Different CAMs would work fine and the CAM in particular would work in other uppers.

[guitarist1993]

I'd love for that to be the problem. Unfortunately, I've only got the 2. I did try the PSA cam in the Rainier carrier with no luck

[guitarist1993]

Had a similar issue on a build. Like GASHOOTER narrowed it down to the CAM. Found the combination of a particular CAM in a PSA upper. Different CAMs would work fine and the CAM in particular would work in other uppers.

I'd love for it to be something simple like that. Unfortunately, I only have the two that I tried.

[guitarist1993]

Compass Lake called today, said they assembled the upper and couldn't find anything wrong with it. So it was either something I installed incorrectly (not sure what it could have been) or it's an ammo problem, although the fact that it did it with 4 different types including factory new ammo leads me to believe otherwise. Again, it never malfunctioned during live fire, only when I tried cycle the bolt manually to eject an unfired round. Hopefully I'll get it back this week and be able to run a few hundred rounds through it this weekend before my next 3 gun match next Sunday.

ETA: You can shoot 5.56 out of a Wylde chamber, right? I was unsure what chamber CL used until today

[Mall_Ninja]

ETA: You can shoot 5.56 out of a Wylde chamber, right? I was unsure what chamber CL used until today

Yep, the main idea behind the design, an accurized 556 chamber...

[guitarist1993]

Got the upper in today. I cycled 1 mag of Winchester Ranger 68g through it. It bound twice, but neither time hard enough to require me to mortar it to free the round. I'll be going to the range in the next week or so to run some rounds through it. So I'm thinking it was just a combination of tight parts that caused the issue.

[Mall_Ninja]

Got the upper in today. I cycled 1 mag of Winchester Ranger 68g through it. It bound twice, but neither time hard enough to require me to mortar it to free the round. I'll be going to the range in the next week or so to run some rounds through it. So I'm thinking it was just a combination of tight parts that caused the issue.

What exactly transpired in relation to it failing twice?

[guitarist1993]

Pulled the charging handle back, round ejected, let it slingshot forward, bolt locked into battery, pull on the charging handle again, bolt starts to rotate but does not unlock fully, forcing me to hit the FA and try again. Like I said, I was able to free it without having to hit the stock against something while pulling on the CH, so I'm not worried. I'm just glad to have it back and ready to shoot!

[Mall_Ninja]

Pulled the charging handle back, round ejected, let it slingshot forward, bolt locked into battery, pull on the charging handle again, bolt starts to rotate but does not unlock fully, forcing me to hit the FA and try again. Like I said, I was able to free it without having to hit the stock against something while pulling on the CH, so I'm not worried. I'm just glad to have it back and ready to shoot!

Was there any abnormal marks on the cartridge? Especially the projectile?

[constructor]

If you look at the SAAMI published specs the ammo can be larger than the chamber which does not work. The chamber can be in spec and work with the go and nogo gauges. The ammo can be in spec according to the SAAMI drawings but if the chamber is the minimum allowable spec the ammo can be larger than the chamber and cause it to bind. Notice below the min chamber headspace dimension is 1.4636" and the max ammo headspace is 1.4665 which is .003" larger than the chamber. And why do we have SAAMI???

http://i143.photobucket.com/albums/r125/bastardsquad_photos/223Rem.jpg

[Iraqgunz]

Help me understand something. Why are you cycling live rounds through your weapon? Get some dummy rounds. Better yet, lube it up and go out and shoot it.


Got the upper in today. I cycled 1 mag of Winchester Ranger 68g through it. It bound twice, but neither time hard enough to require me to mortar it to free the round. I'll be going to the range in the next week or so to run some rounds through it. So I'm thinking it was just a combination of tight parts that caused the issue.