Umarex Replacement barrel

[BBGunn]

I'm sorry. I just don't believe a steel barrel can be damaged by cleaning with a bronze brush.
I have heard it for years, never seen a single example of it, old wives tales die hard.

I had a 37yr career in steel recycling/manufacturing. The idea that you can ruin a steel barrel bore with a bronze brush is just not true. And, so long as a quality coated cleaning rod is used, there will be no damage to the bore's crown.

Much of the misinformation that starts on the internet is started from within the industry as companies try to sell people the next 'great' product.

 

[jarmstrong]

every time I clean a barrel,,, it needs to be re-seasoned by shooting some pellets, usually 20 or so, to bring back accuracy

 

[markhooper]

thanks to each of you for very helpful suggestions. Have polished center fire barrels with good luck in the past. Did not give the crown a thought most helpful. Thanks again.
DaMitch

crown is easily recrown in a lathe.. so any machine shop should be able to touch it up for you..
Mark

 

[markhooper]

every time I clean a barrel,,, it needs to be re-seasoned by shooting some pellets, usually 20 or so, to bring back accuracy

no, we just need re-seasoned for the fun time shooting at least it a good excuse.. my airguns only get cleaned with a lube cleaner on a cotton patch if they look dirty.. I hadn't cleaned one in 8 years so I took the time to go through each one.. now I suppose one must be too clean and needs shot.. or maybe some of each
Mark

 

[Gerry52]

Gee I hope you are right. Bore scope will tell all. Thanks for your input it’s appreciated

Please keep us updated on what you find out. I, for one, am curious if your dilemma is easily fixed & if it was just a re-seasoning issue. Thanks!

 

[DaMitch]

Please keep us updated on what you find out. I, for one, am curious if your dilemma is easily fixed & if it was just a re-seasoning issue. Thanks!

Will do. Recrown will be done this week as well as bore scope again after polish.

 

[markhooper]

was tempted to buy one but now I don't know.. did it have any damage to the crown?? you just said that it was getting recrown but did you find any damage or are you just recrowning?? I don't see any reason to recrown if you don't have any damage..
also you said that it was getting borescoped after polishing.. but you didn't say if you saw anything wrong with the bore..
normally we don't fix something that is not broken..
so just wondering if you are just doing all this to see if it works better.. or did you actually see anything wrong??
the suspense is killing me
Mark

 

[EncoreUneFois]

You can’t bugger up a steel barrel with a brass brush any more than you can scratch a diamond with a shard of glass - a bore brush for an air gun is however not a useful cleaning method. You are not trying to remove powder residue ‘cos there isn’t any.

I’m a huge fan of polishing barrels though.

What you are doing is removing micro burrs from the rifling. Not one of my polished barrels has ever been pellet fussy, none have needed regular cleaning and none need ‘leading in’ to shoot well.

If you think about it on a microscopic scale it makes sense. A rough edge on a land will affect the projectile. Leading in is just smoothing out that rough edge by filling it with lead scraped off pellets to make it smooth. Smooth out the steel then there is no need - also smooth steel doesn’t pick up lead in the first place. Just basic mechanical engineering. Tribological wear will mean that some lead is deposited, but orders of magnitude less than if (under a microscope) your barrel looks like a saw blade.

I have tested this by mounting a pellet in a drill bit and running it against a smooth knife blade - essentially zero lead transfer.

Soft material against hard and smooth material- it is blindingly obvious.

 

[JDGriz]

@EncoreUneFois This is most likely 100% correct, but...

 

[JDGriz]

The other thing that leading does is to create a smoother step from freebore to the lands. Sharp 90 deg. lands beginnings shave off parts of the pellet as opposed to compress the lead. Shouldn't the end of freebore be chamfered at 45 deg. or more? - it isn't on cheap barrels, I don't known about the expensive ones.

 

[DaMitch]

Have minor damage to crown Hence going to clean up. I caused the issue on crown. Gauntlets are great guns so any issue with barrel is on me.

 

[EncoreUneFois]

@EncoreUneFois This is most likely 100% correct, but...

View attachment 406138

I had my first Margarita in a restaurant called the Mangy Moose on the shoulder of that canyon aged around twelve!
Water erosion is a different beast. These were water cut:

Although to be fair, that is a water jet loaded with sand. Which is harder then steel.

 

[EncoreUneFois]

I can’t find my old microscopy photos but this is lead rubbed on rough mild steel;

 

[EncoreUneFois]

And this is lead rubbed against smooth steel;

 

[nervoustrig]

Shouldn't the end of freebore be chamfered at 45 deg. or more?

Yes, a barrel with a sharp step into the rifling will tend to cut the pellet and/or snag it in a way that causes it to enter the bore canted. Neither is good for accuracy.

 

[Firewalker]

Lots of interesting opinions here. Many are being published as truth and the term "old wives tails" being offered as evidence.

Simply put, I gunsmithed for my mentor for a few decades after being an armorer in the military and the answer is not as simple as it seems.

Bronze-phosphor compounds used in powder burning barrels are considered "safe" for bores BUT a brush with a steel crimp shoulder will scrape the crown and lands.

Brass and aluminum are softer but they too offer erosion in the form of displaced metal either of the host barrel or fouling from the shoulder.

The issue is of friction and foreign materials, "dirt" in the form of silicon etc. will remove material or displace the sharp edges of the rifling.

Yes, barrels are harder but since we are throwing out comparatives, imaging using your mothers fabric scissors on paper. Why does high quality paper with NO foreign material dull them so quickly?

Displacement

So... If you want to keep your POI, use materials that can't scrape or displace edges or barrel materials. Cloth patches on a pull through are more than enough to clean a properly lapped/polished barrel.

 

[nervoustrig]

Agreed, microscopic abrasive particles are abundant in our environment and can easily become embedded into the bristles of a brush or the shaft of a coated cleaning rod. In the amounts likely to be encountered in normal use, I don’t think one needs to be concerned about the bore itself. However, carelessly dragging a rod across a sharply-defined feature like the crown has the potential to blunt the edge because of how even a small amount of force translates into massive pressure (pounds per square inch) when it is focused on an infinitesimal point of contact. As Firewalker describes, the damage can be either due to material lost to abrasion or due to material displaced by a burnishing action.

By the way, scissors dulling on paper is the result of substances added to paper like titanium oxide (Mohs hardness of 6-7).

 

[EncoreUneFois]

Lots of interesting opinions here. Many are being published as truth and the term "old wives tails" being offered as evidence.

Simply put, I gunsmithed for my mentor for a few decades after being an armorer in the military and the answer is not as simple as it seems.

Bronze-phosphor compounds used in powder burning barrels are considered "safe" for bores BUT a brush with a steel crimp shoulder will scrape the crown and lands.

Brass and aluminum are softer but they too offer erosion in the form of displaced metal either of the host barrel or fouling from the shoulder.

The issue is of friction and foreign materials, "dirt" in the form of silicon etc. will remove material or displace the sharp edges of the rifling.

Yes, barrels are harder but since we are throwing out comparatives, imaging using your mothers fabric scissors on paper. Why does high quality paper with NO foreign material dull them so quickly?

Displacement

So... If you want to keep your POI, use materials that can't scrape or displace edges or barrel materials. Cloth patches on a pull through are more than enough to clean a properly lapped/polished barrel.

Paper (and more severely cardboard) has a lot of sand in it. Ship a painted part in cardboard and expect anything touching the box to be sanded shiny by arrival.

(I learned that the hard way when shipping prototype parts to Ferrari in the 90’s)

 

[EncoreUneFois]

Agreed, microscopic abrasive particles are abundant in our environment and can easily become embedded into the bristles of a brush or the shaft of a coated cleaning rod. In the amounts likely to be encountered in normal use, I don’t think one needs to be concerned about the bore itself. However, carelessly dragging a rod across a sharply-defined feature like the crown has the potential to blunt the edge because of how even a small amount of force translates into massive pressure (pounds per square inch) when it is focused on an infinitesimal point of contact. As Firewalker describes, the damage can be either due to material lost to abrasion or due to material displaced by a burnishing action.

By the way, scissors dulling on paper is the result of substances added to paper like titanium oxide (Mohs hardness of 6-7).

Absolutely correct.

 

[Firewalker]

Paper (and more severely cardboard) has a lot of sand in it. Ship a painted part in cardboard and expect anything touching the box to be sanded shiny by arrival.

(I learned that the hard way when shipping prototype parts to Ferrari in the 90’s)

No, fine papers do not have sand in it, the fibers are about as pure as they can be, the paper displaces/moves the burr. The same happens with any hard material against a fine edge.

ANY movement or displacement reveals itself in a POI shift.