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Discussion Starter #1 (Edited)
JS44
Posted - 05/30/2007 : 7:09:44 PM
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There's some spare Ljungman parts at Gunbroker.com. They show and refer to "gaskets" being part of the spares. I didn't know these rifles had gaskets.
Mine seems to need something like that, though, since it leaks gas. I know because I found some black soot stains on the inside of the handguard where the gas tube goes into the front of the receiver AND the energy of the empties being ejected has declined in the 4 years that I've had it.
If such a thing as gaskets were ever made for these as repair or overhaul parts then I need to get some.



Dutchman
Posted - 05/30/2007 : 7:39:57 PM
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Interesting. I'm going to speculate. I'd say they're legitmate and probably a depot level maintainence item so it wouldn't nessessarily show up on parts take down schematics. I just checked the schematic down further in the forum and it doesn't show these gaskets but then it shows the gas block attached to the barrel.

The other parts are legitimate. The new replacement handguards come with little pieces of wood across the bottom to keep them from being pushed apart and cracking. I've had a couple like that.

I think maybe we're all going to learn something new today and that's a good thing.



Dutchman
Posted - 05/30/2007 : 7:54:10 PM
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Ok, I put out an email to someone in Sweden that should yield facts instead of speculation. Olle Janson of the Gothia Arms Historical Society. He and I have had email and he is quite willing to answer questions for us. He will prove to be a valuable resource for us all.

Once again, its an auction link that's going to serve as an educational pivot point for everyone. Thank you for bringing that to our attention.

Dutchman



Dutchman
Posted - 06/03/2007 : 3:30:02 PM
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From Sweden:

"There is not ANY gasket at all in the Ljungman construction! The
gas tube is tightly screwed to the rifle. This is one of the drawbacks because it has a serious negative influence to the movement of the impact of each bullet when the gun gets warm!

The Bolt carrier has no gasket and this is positive! It is clearly noticeable when you shoot – fell the gas coming backwards over your head."

http://old.gunboards.com/uploaded/Dutchman/200763152836_ag42_detaljeradlista.jpg
Download Attachment:
194.83 KB



jim in Oregon
Posted - 06/03/2007 : 6:31:41 PM
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There are NO gaskets or rubber-like 'O 'rings in the AGm/42B rifle... nor are any needed..

I've taken the gas tube apart from the gas block and gas block off the barrel and gas tube off the receiver on more than one rifle. The tube is a simple screw in fitting at both ends and if installed properly doesn't 'leak'.. unless one fills the gas tube with gun oil perhaps..:)(don't do that) The gas tube should be kept clean and free.

Neither is there any requirement for any gasketing between gas block-barrel..nor could you get a gasket between them as the fit-tolerences are far too snug. Have no idea what those gaskets advertised wre for or from, but they are not a part of any original Swedish AGm/42B rifle.



JS44
Posted - 06/04/2007 : 6:42:29 PM
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It doesn't surprise me too much that they are bogus because they don't look like they fit in anywhere. I had to ask, though.

It appears that I need to take my gas system apart and fix a leak. Does that gas tube bushing (that's what Numrich GPC calls it) have to be un-threaded from the breech side of the receiver first? I can't tell much by looking at that schematic. Not even if the "Gas Tube Bushing" is even threaded. There are no flats to accomodate a wrench on it but something has to hold it in place.

Is it hard to get the gas collar off of the barrel after the crosspin is knokced out? It doesn't look to complicated but I just want to know if there's anything I need to know before I start into it. I don't want to apply too much force thinking that these parts are just stiff from being on for decades and end up bending, twisting, galling, or breaking something.



jim in Oregon
Posted - 06/08/2007 : 2:01:09 PM
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JS44,
Before you 'fix' anything, clean the gas tube-block well with carb cleaner. Describe the leak-location again??

FWIW, the 'discovery' of the leak and resultant oily stuff is an indication the gas system may be fouled.

Also, the direct impingement gas system( not adjustable) has MORE than enough access for gasses to operate the bolt carrier-action,( more than enough) so even a pinhole leak won't harm the action..if that's what it is.

The gas block is threaded onto the tube..Removing the gas block entirely requires driving the retaining-locating pin and also the muzzle plug sight assembly. The end of the tube on the breech is also threaded..



JS44Posted - 06/10/2007 : 12:17:11 AM
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Jim, Thanks for replying.
This is an on-going problem with this rifle. We kicked this around a while back at the thread below.

http://old.gunboards.com/topic.asp?TOPIC_ID=207859&SearchTerms=AG42 (This very thread I have appended below, as the second "posting", so that the referral will be easy. Carcano)

I tried the carb cleaner method you suggested back then then AND I have always sprayed a good long dose of brake cleaner down the gas tube when I clean the rifle after each use.
I put 20 more rounds of FNM ball though it after the carb cleaner and ejection was *maybe* a little better but still weaker than it should be.

What I found was a blackening of the INSIDE of the handguard at the rear end near where the gas tube goes into the receiver. It was on the metal, too. Enough of it to indicate a leak. I rarely have ever taken the handguard off so I don't know how long it took to accumualte that fouling. I used the word "soot" before for lack of a better term. Powder fouling is probably a more accurate term.

I don't want to shoot it with the handguard off and my hand wrapped around the leak area to feel for how much is venting. That sounds potentially dangerous.
I don't want to remove the gas collar entirely off the barrel. Just foward enough to unthread the tube from the collar and receiver and gas tube bushing. The idea being to asses the condition of the gas channeling components and go from there. Either re-tightening with lock-tite on the threads or replace the gas tube and/or bushing if the threads are damaged.
It could also be a chunk of something solid somewhere in there that won't come out by solvent alone and is causing just enough of an obstruction to prevent enough gas from getting through. Like you said, the gas leak istelf might not be bad enough by istelf to cause a problem. Also, nothing feels loose and there are no dents in the tube where it's exposed. I won't know anyting more until I take it apart and look.

I bought this rifle off of an individual. For all I know he took it apart, for whatever reason (just to see what's in there?), and didn't put it back together tight enough. This seems to have gotten worse little by little over time. That and finding the powder fouling under the handguard has lead me to the gas leak hypothesis.
I could once again try lubing the cases like I tried a while back but that didn't seem to affect the briskness of the ejection cycle then.

In the past year I replaced the recoil springs with new (un-issued) ones from Springfield Sporters and the added tension of new springs made things a little worse. I think I forgot to mention that before.
The rifle is not a beater. Based on the Ljungman's I've seen in person and pics of them on line it's in the top 20 percent.
The idea is just to get it operating in it's nominal range of functioning. Now that I've started loading for my more recently aquired M96 I'll at least give it a try for the Ljungman with loads tailered to it per your suggested load info posted elsewhere.



Dutchman
Posted - 06/10/2007 : 12:39:29 AM
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Originally posted by JS44
I don't want to shoot it with the handguard off and my hand wrapped around the leak area to feel for how much is venting.
Take the handguard off and lay a folded piece of paper over the gas tube junction at each end of the gas tube. The paper will react accordingly if there's a minor or significant leak.



JS44
Posted - 06/10/2007 : 10:23:02 AM
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"Take the handguard off and lay a folded piece of paper over the gas tube junction at each end of the gas tube. The paper will react accordingly if there's a minor or significant leak."

There's definitely a leak there on account of the powder fouling I found. It's just a matter of how much of a leak and wether that's what's causing the problem.
Thanks, JS



jim in Oregon
Posted - 06/10/2007 : 6:48:43 PM
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JS44,
I doubt any previous awner since import took the rifle apart that far.

You might try and remove the handguard, clean all exposed areas of tube and junctions with receiver and gas block well.Then get a tiny amount of Red Loktite thread sealant and with rifle butt downward, apply just a dap around the place where the gas tube enters the receiver. Allow to set and wipe off any visible excess.

Ensure that the gas tube is clear best you can.A can orf that computer store compressed air applied from the breech should show ir escaping from the bore IF you stuff a few patches in the chamber.

Then try shooting the rifle with handguard removed and a piece of thin paper like a used dryer fabric softened used atop the area hed in place with tape to see IF there's anny appreciable leaking still.

Usually the Ljungman has problems with too violent gas action; can't say I've ever heard-seen one where the gas action was weak when all the springs were in good condition and rifle was clean.Assume your extractor is in good condition and chamber is clean? any signs of hard extraction on the brass?



JS44
Posted - 06/10/2007 : 9:34:11 PM
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Jim,
Why not just take it apart and see what's what?? If everything is threaded together I can't see why I shouldn't just do that and be done with it. Is it really that dificult to take the gas system apart and put it back together? Not only could I find and fix the leak, and it does leak, but I could give the gas tube and related components a good internal scrubbing and remove anything hard that might be causing an obstruction. Things I that I can't do just by using spray cleaners alone.

The extractor works fine. It never has failed to extract one. I keep the chamber clean, too. No signs of hard extracion either like bent or torn case rims.

As far as the previous owner taking the gas system apart I can't think of a *good* reason to either unless it was giving him problems at one time. I've had gun shop owners tell me of guys brining in guns in peices, far more than just field stripped, to have them put back together. Curiousity, boredom, repairs, or whatever the reason it happens.
I mentioned this only in exploring all the possibilities for why mine is having issues.



jim in Oregon
Posted - 06/11/2007 : 08:57:11 AM
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JS44,
There are a couple more things you might do before taking the gas tube system down.
Remove the small metric screw which fills the hole atop the gas block.It's mildly staked but with a proper screwdriver comes out.
This gives you access down thru the block and into the barrel-bore to insure that opening is open-unobstructed.A pipe cleaner and solvent with a bore light will help.

You can also get three of the 10" large craft pipe cleaners and twist them SECURELY together and insert from the breech end with solvent to insure no hard obstruction is in the tube.
When you replace the small metric screw in the top of the gas block, add a tiny toothpick end sized bit of red loktite and it'll stay put.

Good luck whatever you do end up doing.

One thing I have noticed about the FNM ammo is the greenish waxy gunk they put on the primer for water resistance has a tendency to gum things up after shooting.



JS44
Posted - 06/11/2007 : 10:58:29 PM
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Jim,
I almost started on taking that screw out just now but I don't quite have a bit that fits the slot as it should. I need to find one that fits better since this is probably gonna be a bear to break loose. I'll do that and have a look and clean from there.

I have a feeling that before all is said and done that It's still going to boil down to laking the gas tube and bushing out for the leak.

You're not kidding about that green primer sealant . I don't know why they don't use something better.



jim in Oregon
Posted - 06/12/2007 : 09:10:40 AM
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JS44,
Dose up the small blanking screw atop the gas block with a good penetrating oil and let set.
Have someone help hold the rifle plumb abd firm or use a gun vise.
It doesn't take much to break that tiny screw loos providing you have a screwdriver blade that fits and apply good downward pressure to it.
***Be curious what you find and what the outcome is.

Good luck.Low gas pressure and weak extraction-shell throw is sort of an anomaly as I indicated earlier..usually it's the opposite problem..:) You do have the rubber buffer intact I assume?



AWO425
Posted - 06/16/2007 : 04:54:14 AM
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Something else:
I don't know, were the thing with the gas tube interference with the barrel when hot comes from!!!!!!!!!!
The gas tube is screwed into the gas block, but NOT screwed into the receiver, it should be floating in the gastube screw(part #8)!!!!!!!!

How do I know that? Simple!
On my Ag42 the gastube was stuck in the screw because of lots of powder fouling baked on and the gun stringes verticaly real bad, starting at 12 o'clock with the fist shot and ending at 6 o'clock with the last of the mag. I nearly got gaga, shimming the barrel, changing my grip of the gun, NOTHING worked.

Than I did take out he gastube screw and found all the dirt, cleaned it and from that day on, there was NO stringing anymore!!!!!!!!!!!

And yet another thing to be corrected:
Has anyone ever found a Ag42 barrel with more than 4 grooves?????
I did not.



JS44
Posted - 06/16/2007 : 8:22:04 PM
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I couldn't get that machinist access screw on top of the gas collar (gas block) out. Couldn't find a bit that would get a good enough purchase in that narrow screw slot so to hell with it.
It was then that I noticed that the gas tube DOES NOT screw into the receiver itself but into the gas tube bushing. The bushing is slotted at the front where the gas tube enters it for some kind of special little spanner wrench that probably has never existed outside of Sweden. It was NOT loose so that means that it couldn't "leak" like I had thought. The fouling I found under the handguard and around the gas tube near the receiver is apparenty from gas being blown back through the hole where the gas tube busing passes through the receiver. That seems highly probably and even nominal now that I know the tube does not thread into the reciever. I tried to turn the bushing slightly and the gas tube twists a little in response so there is some clearance between the bushing and the receiver hole. Just enough, anyway, to allow a little bit of gas back through. It must have accumulated over time and I don't take the handguard off but very rarely. I sprayed A BUNCH of brake cleaner down the gas tube while observing down the bore from the chamber end and there seems to be no obstruction of the flow into the barrel from the gas tube and barrel collar (gas block). That pretty much blows away my two possible theories on the gas system obstruction and/or leaking.

Next outing with this rifle I'm going to try lubing the cases again and pay closer attention to the results.
See if that helps.

AWO425, how did you ever manage to get that gas bushing (screw) off of the gas tube in the receiver??? Mine is very tight and there's no good way to wrench it off without damaging it. I'd kind of like to get it out so I can scrub the crud buildup off.

Anyhow, Thanks again to those of you who have helped me with this.



AWO425
Posted - 06/17/2007 : 02:13:53 AM
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On my AG42 I use a piece of leather wrapped around the bushing and pliers to get it out.
Better would be a special made vise, in that way, that you take a piece of bar steel, drill a hole (ID of hole= OD of bushing) saw a slot and d&t a small cross screw besides that hole to clamp it on the bushing.

Next best thing is to find a tube (aluminium prefered) that fits over that bushing, take a piece of it and slot it, put it on the bushing and thatn use the pliers on the tube.

Getting the tiny screw in the gasblock out:
Trimm a screwdriver bit so it EXACTLY matches the slot, chuck in in the lathe, but the gasblock with the screw on the bit and press against the underside of the barrel with the pinole of the lathe.
Have someone turn the lahte chuck to get the screw started out.

Chris: Use of penetrating oil doe not hurt.



rwwje
Posted - 06/30/2007 : 7:39:10 PM
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The gas block screw can be easily removed using a "hand impact" tool found at modest cost at auto parts stores (in conjunction with the appropriate hollow ground screwdriver bit). You, in this case, lightly strike the hand impact with a hammer; it's the only easy way to remove the staked screw to inspect/clean the gas port. The hand impact tool is normally used with a heavy hammer to break "big" frozen nuts/bolts, not little screws.



JS44
Posted - 07/02/2007 : 11:06:10 PM
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rwwje,
I've used a hand impact wrench before. I didn't have one when I tried to get my gas block screw out. I tried hittting the screwdriver with a rubber mallet as i tried to turn it. Problem was that I didn't have and couldn't find a bit that would fit that screw slot close enough. I didn't mess with it too much because I didn't want to hose up the screw head. As much brake cleaner and carb cleaner that I ran through it after I tried the screw I'm pretty much convinced that it's as clean as it's going to get. Also, by looking down the bore from the chamber end and monitoring the flow rate as I hosed copious amounts of the above mentioned cleaners down the gas tube it's pretty much evident that there are no obstructions in the gas block. With that observation I don't see a need to take that screw out (I hope).

When I do shoot it, probably this weekend, I'll come back here and post the results. Good or bad. I'll try lightly lubing the rounds again and see if that helps. I don't remember it having any affect when I tried it not long after I got it back in 2003. We'll see.



JS44
Posted - 07/08/2007 : 10:54:10 PM
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I shot 40 rounds of FNM through it today. It throws most of them about 20 feet to about the 2 or 3 o-clock position but some, for whatever reason, go forward of me only a few feet. Still it seems to be better than what it was before. It was either all carb cleaner and brake cleaner I hosed down the gas tube or that I lightly lubed the rounds this time.
I don't think it'll get any better than this and I can live with it.

Thanks to all that helped on this,
JS
 

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Discussion Starter #2
GUNSMITHING: Is the gas collar on an AG42 soldered?

JS44
Posted - 01/28/2007 : 1:54:46 PM
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I noticed in some detailed pics of someone elses AG42 posted here that there appears to be a fillet of solder between the gas collar and barrel. By looking at the gas collar on mine with a magnifier I don't see it on mine. This is a point of concern for me since mine seems to have a degenerative problem cycling ammo reliably, stove-piping and not throwing the empties very far and I've tried several brands of ammo.

The rifle is thoroughly cleaned, including spray-cleaing of the gas tube, after every time to the range.
Should the collar be soldered to the barrel, in addition to being pinned, to make it air-tight?



jim in Oregon
Posted - 01/31/2007 : 11:29:23 AM
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I've removed several gas blocks from AG /42B rifles and the pin and the tube are all that hold them in place.
The gas tube-block can be cleaned well using carb cleaner, inserted down the gas tube from the action end.Place a cleaning rod witth patch in the bore beneath the gas block and allow the solvent to sit for about ten minutes, then removes the patch( plug) in the bore and blow the gas tube-block out well.

Your problems with stove piping etc are most probably related to useing ammo which doesn't have the proper poweder burn rate for cycling-timing the direct impingement gas op system.

Are you a reloader?

What ammo have you been using?

What signs of difficult extraction are you seeing on your brass?

Have you tried lightly lubricating the cartridge case before loading up?



JS44
Posted - 01/31/2007 : 11:33:46 PM
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Thanks Jim,
How do you get a tight enough patch in the bore by the gas port to hold the carb cleaner in for that long without it all seeping out? I'll give that a try. What I've been doing for cleaning the gas tube is using brake cleaner and sticking that extended spray tube in the breech end hole and squirting it through till it runs out the muzzle.

Also, I wanted to take out that screw-in plug on top of the gas collar to see what I can see and clean out any hard crud or debris. It was too tight and I didn't want to tear the screw head up. It doesn't appear to be staked in place. Just very TIGHT.

For ammo I've been using FNM the past year. It worked with that but the ejection in this rifle was never as brisk as others report from theirs. It's flung them maybe 20 feet, give or take, with an un-obstructed path. The last time some would only go about 3 feet some times. Other times a little further. Some stovepiped. The problem seems to be degenerative. It has worked with M/41, PMC, and S&B in the past as well as FNM. With Igman it stovepiped at least once every 10 rounds.

I do reload but not for 6.5X55 yet. Since I got my second Swede, an M96, I'll be startring to sooner or later. I've read what you've posted ain the past bout reloading for the AG42 and I'll probably go that route and have ammo compatible for both my 6.5's.

I have never seen any signs of hard extraction like bent or torn off rims. A case has never stuck in the chamber and I've never had it break an extractor.

Back when I got this rifle in 2003 I did try lubing the rounds with a little bit of oil like the manual suggests but I didn't see what good it did for this particular rifle.

Thank you again for your reply and help,
JS



jim in Oregon
Posted - 02/01/2007 : 09:22:31 AM
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JS44,
Double up oiled patches if necessary to provide a fair seal in the bore beneath the gas block while you allow the cleaner to work in the gas tube-gas block.

The small screw atop the block is staked, but the screw is VERY short.You must use a proper fitting gunsmith-type screwdriver and rigid holding of the rifle which will enable you to remove it. A light tap with a small gunsmith's hammer as you apply turning torque should break it loose.So much for that..

Unless you want to upfit that screw with a new screw and tapped hole for an adjustable gas block I don't think that's necessary to properly clean the gas block area.

The FNM ammo is about as good as we have readily available these days, but it is not 'perfect' for the Ljungman.
Even the M94/41 Swede ball ammo has problems when the rifle heats up which is why the Swedes in their later instructions had the soldiers lube the ammo cases..:(...:(...Poweder burn rate and resultant timing -obturation of the action-cartridge cases just wasn't quite right.

I suggest you disassemble and clean the action, bolt, springs etc completely and then relube-lightly grease the rails, bolt interior etc.That after cleaning the block and gas tube as directed.

Reloading your own ammo( different recipe than what works best for the Swede Mauser bolt guns) will all but eliminate the problems you are experiencing.

Ambient temp and the type of firing you do( timed-repid fire produce much heat) will effect the place and distance the spent cases fly to...but not alot when proper ammo is fed the Ljungman.

Springfield Sporters still sells the gas block.You can get one for the next owner so he can return the rifle to original if you wish.

Tapping the existing gas block and installing an adjustible screw in it will help, but attention to ammo used still will be needed.
I think there's a 'sticky' here for that process.I can help answer questions beyond that if you decide to do that.

You haven't indicated what sort of shooting you want to do with the Ljungman.

Slow fire?, rapid fire?, timed fire?
Blowing thru the 10 round mag and reloading fast with stripper clips for another hot session?.. :)


JS44
Posted - 02/01/2007 : 7:26:36 PM
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Jim,
I'll try the carb cleaner thing. If the patch leaks I'll just keep putting carb cleaner back in the tube. No problemo. After I shoot it I clean and lube it like you indicate above. Always have. I've read your posts about the gas regulator mod but I haven't decided wether to actually do it or not.

The type of shooting I do with it is pretty much slow fire. Sometimes I don't even load the mag all the way full. I've never have and don't intend to "machinegun" it. I have an AR-15 for that :)

Again, this is something that's gotten worse with time lately and led me to beleive it had a leak somewhere that was worsening. Like you sugested, though, crud buildup in the gas tube and collar would have a degenerative affect as well.

I don't think I'll be going shooting this weekend but next weekend I very likely will. I'll will have cleaned the gas tube like you said before that and we'll see how that works.
I'll report the results here then.
Thanks again for your time and guidance on this. I do appreciate it.



JS44
Posted - 02/11/2007 : 10:15:59 PM
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Yesterday I cleaned the gas tube with carb cleaner as described above and shot it today with 20 rounds of FNM ball. No stovepipes but the ejection still seems weak.
I noticed when I had the handguard off that there was some soot on the right rear indide of the handguard where the rear sight base is. There was more soot there on the metal where the tube goes into the front of the receiver. It looks like there's a gas leak there that's probably causing the problems I've been having with it. I'm wondering if replacing the gas tube and gas tube bushing would help. How hard is it to remove the front sight base and gas collar without tearing up the finish on the barrel? On one hand I can live with how it worked today (not stovepiping) but ideally it would at least be nice to have it working like it should.
 
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