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Can a barrel just go bad?

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Dr. Kralenstein

Dr. Kralenstein

Member
Apr 14, 2022
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The Laboratory, United States
OK, struggling in this one. I have my beeman 2028 that I made into a carbine, have a thread in the air pistol section. Anyhow, I'm having an odd issue.

Gun started off with decent accuracy, and it started to go south and get hard to load. Lost the barrel o-ring. Replaced the o-ring, and still accuracy has diminished further.

I checked to make sure everything is tight and clean the bore. Getting worse. I swap scope to a known good one. Still shotgunning what used to be its favorite pellets.

I lapped the crown and polished the barrel. It's just as bad if not worse now. It'll probably settle a little after another round of seasoning, but it's giving me 3" wandering groups at only 5 yards!

So my question is, can a barrel just 'go bad'?bad?

Also, if I swap my 1358 barrel onto the gun, it gives me dimes at 35 yards. It's definitely something related to the pistol barrel.
 
Those are Chinese barrels, so I imagine anything can happen. All my China guns wear good barrels now but I have tried to fix them. But while checking the runout internally on my lathe I noticed that the bores on some of their barrels aren’t even centered, I was done. They are also made from the softest steel known to man.
 
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JimD said:
Seems really odd. I've certainly never experienced anything like that. Is it possible there is an issue with the mounting of the barrel? Could it be touching were it shouldn't or not properly clamped in place at the breach?
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Nope. It's rock solid. The threads for the set screws are good. It holds the longer, heavier barrel without issue. Loads smoothish, better than my old Prod.

I may sleeve up my 22 kral 12" barrel and see if it will work with the mags/bolt. Or I might order a barra 1100z barrel for $25 and cut it to whatever length I want. They'll fit this breech.
 
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Vetmx said:
Those are Chinese barrels, so I imagine anything can happen. All my China guns wear good barrels now but I have tried to fix them. But while checking the runout internally on my lathe I noticed that the bores on some of their barrels aren’t even centered, I was done. They are also made from the softest steel known to man.
Click to expand...

I'm with you on the barrel tolerance. The rifling looks good, not very deep though. No tool/machine marks that I can see BUT the bore does look off center now that I've gotten to know the barrel better.
 
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AlanMcD said:
Are the pellets literally from the same tin? I ran into a similar situation years ago, and it turned out that the problem was a new order of pellets were not as good as the prior batch of tins I had ordered. Of course the results were not as bad, but it was still a huge fall off in accuracy . . .
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Same pellets as before. It shot well with AA16s, and HN terminators. Now, I can't even shoot it at 20 feet. Missed my pellet trap and smacked the concrete wall. It didn't like cphp before this, but would still give me 1" at 20 feet, now they're all over. What's odd, is a couple pellets will land on each other in a row, then it's all willy nilly again.
 
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The good news is the gun only had decent accuracy to begin with. Decent accuracy is closer to horrible accuracy than it is to great accuracy. Anything you did to that barrel pushed it in a direction. Unfortunately that direction was worse. If the barrel has an internal oring for the probe and it ate it, that might be the first clue to where the banana peel was located that your accuracy was going to eventually slip on.
 
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If you have done that much work on the barrel, I'd look to other factors such as pellet clipping or even switching out the scope to test it. It seems really odd that the accuracy is getting worse and worse. I've had both clipping and a scope do both, and I thought I had messed up the barrel somehow. That's a big group at that range.

Alternatively, I have cleaned a barrel that shot well and it needed reseasoned with lead for some thirty or more shots.
 
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Airgun-hobbyist said:
If you have done that much work on the barrel, I'd look to other factors such as pellet clipping or even switching out the scope to test it. It seems really odd that the accuracy is getting worse and worse. I've had both clipping and a scope do both, and I thought I had messed up the barrel somehow. That's a big group at that range.

Alternatively, I have cleaned a barrel that shot well and it needed reseasoned with lead for some thirty or more shots.
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I've completely removed the moderator and adapter to eliminate clipping. I've swapped scopes twice with known good ones. I've even pushed a pellet down the barrel to see if any damage happens. Nope, the rifling marks aren't deep though. Made sure pellet seating depth is past transfer port so to rule out skirt deformation.

I think I just go a bad Chinese barrel.im going to scrub with a brush next. Can't hurt it.
 
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Dr. Kralenstein said:
I've completely removed the moderator and adapter to eliminate clipping. I've swapped scopes twice with known good ones. I've even pushed a pellet down the barrel to see if any damage happens. Nope, the rifling marks aren't deep though. Made sure pellet seating depth is past transfer port so to rule out skirt deformation.

I think I just go a bad Chinese barrel.im going to scrub with a brush next. Can't hurt it.
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Sounds like you've gone about investing pretty thoroughly. If there's very little witness marks on the pellets, I would try a bigger pellet head size. It does sound like the big groups are the results of being too small for the bore. I polished a bore out too big for the ammo once. It did the same thing with regard to group size.
 
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A couple years ago after owning my Akela for a while ,I pulled the barrel to polish it and check the crown and the leade.
Touched up the crown lightly and smoothed the leade.
I reinstalled the barrel and suddenly It was getting somewhat of a shotgun pattern. Before this the gun was shooting pretty well.

I pulled the barrel to recheck and reinstalled. All looked fine but the accuracy was not returned.
I backed off the barrel screws and just snugged them down. I had not been cranking them down hard but now the screws were certainly less tight.

After that my old barrel accuracy was back. I haven't touched it since except to clean with a patchworm, but preasantly the gun is a 30 yd one holer and 1/2" to 5/8" at 50 yds.

Might want to try backing both set screws out and resetting to just snug. I had mine too tight.

Good luck
 
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OK, so I scrubbed the barrel out til clean patches came through. Here is a 5 shot group with cphp at only 15 feet. This is with the rifle sitting in a caldwell steady rest.
20231231_200302.jpg
 
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Vetmx said:
If the barrel has an internal oring for the probe and it ate it, that might be the first clue to where the banana peel was located that your accuracy was going to eventually slip on.
Click to expand...


Buried in the most mundane forums and topics are some literary gems like this one.

Makes for more enjoyable reading.
I appreciate it. 😊
 
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Tried some FTTs in 5.53mm and they group the best so far. Not good enough for a 20 yard test though. I wonder if the bore is oversized, especially after scrubbing/polishing?

I might order some 5.54mm and 5.55mm to try, but for the price of a couple tins, I could get another barrel and chop it... and be rolling the dice again.
 
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