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Have you ever scoped your FX liners?

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jps2486

jps2486

Member
Apr 20, 2015
3,051
1,739
Onalaska, WI, United States
I just finished borescoping two FX 700 mm 22 cal liners just to see what they look like internally. I've done this to various powderburners which usually use either cut rifling or button rifling (yes, there are hammer forged barrels too). Unlike PB barrels which are generally smooth, I found minor scratches and tool marks inside the FX liners. When slugging them, they come out looking smooth, but I found changes is resistance as I pushed the projectiles through them, which is odd, it seems to me. I wonder if FX manufactures the tubing or buys it from a third party. It's probably extruded which may explain the tool marks.

What is your experience?
 
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I did a bore scoping on several of my liners as well, I was studying the DIY crown from inside, also the lead-in smoothness where the "lands" start forming.
I also noticed the scratches,
but longitudinal scratches that look like a micro crack on a surface, tip of a "land".
These must be a result from a stress cracking the surface when pressing through the wall thickness deforming the material.
Dimensionaly I am not worried about, I can speculate in sub microns only.
I think if I recall all of my liners had some tighter spots, I polish them all, cannot say eliminated totally but at least minimized. At one point I had an idea to fire-lap (I did that for my L2 Alpha barrels) but stepped back from that exercise ... undecided ...
 
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Variable. I scoped a never fired liner and found a bunch of pitting. The warranty replacement was smooth...

Brand new 600mm .22 FX Crown pellet liner, from the inside.

Never fired when inspected. My 500mm barrel has the same 'features'. I'm guessing they all do. Hopefully the link works. One drive link If the videos don't auto start, you may need to download to view. These weren't the only pits in there too...
www.airgunnation.com www.airgunnation.com
 
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There are virtually no barrels that do not have similar flaws as-manufactured, unless the manufacture also laps/polishes prior to delivering to the customer Do not be afraid to treat your liner to a good tapered lapping/polishing regimen.....there are many methods/videos explaining how. Assuming you do it right you will be very pleased with the results.
 
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I worked at ER Shaw barrels for long enough to be real familiar with making production grade barrels...I'm so happy that there are others who know barrels too. The price we pay for top end airgun s over 1k...I think for the price point they have should have premium barrels. My lother Wather .510 on my Texan was so bad I could see tooling marks on the rifling without a bore scope... Naked eye..it would shear pieces of lead into the action...so rough at the breach...I hand lapped the barrel for about 2 hours. Pouring about 6 lead laps. Starting at 120 grit working up to 400 grit.. My barrel know doesn't lead and looks bright shiny and uniform. Airgun s are more in need of smooth consist uniform barrels with are soft lead cast and swage slugs and pellets. I want to see more Benchmark,Kriger,Broughton,Brux,Shien barrels. Once you have a really good barrel like a benchmark or Krieger its hard to go back to rough barrels. As a side note from drilling thousands of holes in all caliber sizes making button rifled barrels on old Pratt whiney deep hole drilling lathes from WW1..holes are not drilled straight consistently until 30 caliber...reason being drill bit stiff enough to be straight.....177 barrels were so bad....22 cals not too good.either.. So when you buy a cheap barrel go.with a 30 because the chance of it being straight is way better....
 
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A little anecdote...a few weeks ago I was going to try improving a .177 FX liner for a guy by working it with a cast lap. As with any mass-produced barrel, I expected it to have loose and tight spots, and those spots become very apparent as soon as the abrasive is introduced. However the FX liner in question was so irregular that I could not move the bare lap to apply the abrasive. Ended up having to core it out to remove it from the barrel.

Happy ending, though. Ordered a LW polygonal and machined it up. The owner messaged me this morning and said he’s taken first in their last two club matches.
 
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