Crosman barrels - inspecting for piloted crowning tool damage



Author Topic: Crosman barrels - inspecting for piloted crowning tool damage  (Read 10130 times - 1 votes) 
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Offline nervoustrigger

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I have noticed a few reports recently of finding rifling damage on Crosman barrels at the muzzle, believed to be from the use of a non-floating pilot on a crowning tool.  So for users who are struggling to get decent groups, I wanted to briefly explain a way to inspect for this potential damage.
 
Firstly, let me say I am not an expert on this and there may be a better way to do this inspection, and I invite the more experienced gunsmiths to comment.
 
So with that said, here we go.  This is a fairly straightforward visual inspection.  Start by cleaning the barrel.  You don't want lead and graphite covering things up.
 
Then the trick is getting both a light source and your line of sight going down the end of the barrel at the same time.  If you have the barrel off and can shine a flashlight through from the breech end, that works best.  Otherwise you might be able to do it entirely from the muzzle end by playing around with lighting and angles.  My big noggin kept getting in the way :)  Anyway, as you look down the bore, what you're looking for is a change in the sheen of the rifling about 1/4" - 1/2" down.  Basically what happens is the crowning pilot burnishes the rifling and gives it a different appearance from the rifling further down.  If your barrel has this damage, it will be quite obvious because there will be a distinct ring all the way around the circumference.
 
GTA member deerfarm sent me a .22 Marauder barrel that he had given up on and replaced with an aftermarket barrel.  On this barrel it was pretty easy to spot the damage.  It is worth mentioning that the cotton swab test will not detect this type of damage.  Also, it was not apparent from pushing pellets through.  That may be due to the choke.  I think if it weren't choked, it would have been possible to feel a change in resistance just before the pellets emerged from the muzzle.

Here are some examples provided by GTA members:

K.O. was the first I am aware of to present a photograph of a barrel from 2014:
https://www.gatewaytoairguns.org/GTA/index.php?topic=80859.msg771681#msg771681


Oldnoob had the same type of damage on a Discovery purchased in March 2014:
https://www.gatewaytoairguns.org/GTA/index.php?topic=64067.msg612685#msg612685


ACZan just got one around October 2017:


There are even examples of this damage on the newer Maximus, which Crosman confirmed they are manufacturing with their newly re-engineered process.  Here's one from starlingassassin from May 2017:  https://www.gatewaytoairguns.org/GTA/index.php?topic=126375


Lastly, here's another example of damage that looks different but has a similarly detrimental effect on accuracy.  It is from a Discovery barrel that Ozarkairgunner sent me in November 2016.  Shown here is the section I chopped off to get back to good rifling:


Pushing a pellet through met with a lot of resistance once it reached the damaged section.  The pellet emerged with the entire circumference of both the head and skirt smeared.  After removing the bad section and deburring the bore, pellets look much improved:
« Last Edit: October 20, 2017, 03:14:57 PM by nervoustrigger »
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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #1 on: June 06, 2016, 11:54:41 AM »
Seen it on quite a few as well ... Sadly most with modest to heavy pilot damage never shoot very well even after extensive lapping and prep to "Try" and correct it.

Tho that said ... even with all the Bad Rap Crosman gets on there .22 & some .177 barrels, have seen / have some of these OEM barrels shoot good as the renowned LW barrels do !!
 
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Offline moorepower

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #2 on: June 06, 2016, 02:48:03 PM »
Out of the 4 Crosman barrels I looked at, 2240, 1377, Disco and P-Rod, all had the rifling wiped off the map. I recrowned 3 of them, as I don't plan on using the 2240 barrel, and shot 2 of the 3, the 1377 barrel and the P-Rod barrel. Both barrels shot lights out after the rework. 3 of the 4 there was no rifling left. 1 was harder to see, but with a ground pin gauge it was easy to tell. Look down the barrel with a flashlight and you can see it fairly easily.
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Offline K.O.

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #3 on: June 06, 2016, 04:11:01 PM »
I have been lucky only  one of my barrels had  the problem, a 2260 barrel which I had planned on shortening to 18" anyways...

it was pretty bad though...
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Offline Matt15

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #4 on: June 06, 2016, 04:17:10 PM »
I bought a 24" disco barrel to use on my 1377. I did not notice any thing made by the crowning Pilot but I do have a line running the full length of the barrel.  ???
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Offline bmoney

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #5 on: June 06, 2016, 04:21:40 PM »
Interesting.  I will have to check my 2260.  I thought it was odd that the only pellet the 2260 will shoot is JSB 18.1 and I mean others are thrown all around.  It doesn't even like 14.5grn crosman premiers in dome or hollowpoint.  H&N Barracuda 21grn and Beeman Kodiak 21grns are thrown like curveballs at 15 yards.  I will check my barrel later.  Thanks for the heads up.

EDIT- my barrel looks fine, still weird to me that it won't shoot crossman, H&N, Beeman and RWS pellets.  JSB's only for this one.  May have to order an 18" from Baker airguns, I like the look better with the TKO on there.
« Last Edit: June 06, 2016, 04:32:45 PM by bmoney »
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Offline Geoff

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #6 on: June 06, 2016, 04:25:19 PM »
i have several crosman barrels i will check them.  just tagging this thread for ease of locating again.
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Offline Ribbonstone

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #7 on: June 06, 2016, 04:30:54 PM »
I usually stuff a bit of fluffy white cotton down the bore (from the muzzle) about 1" and shine the light over my shoulder.  The white tends to diffuse/reflect the light and allow a decent look at the actual surface of the bore.
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Offline K.O.

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #8 on: June 06, 2016, 04:44:17 PM »
Interesting.  I will have to check my 2260.  I thought it was odd that the only pellet the 2260 will shoot is JSB 18.1 and I mean others are thrown all around.  It doesn't even like 14.5grn crosman premiers in dome or hollowpoint.  H&N Barracuda 21grn and Beeman Kodiak 21grns are thrown like curveballs at 15 yards.  I will check my barrel later.  Thanks for the heads up.

EDIT- my barrel looks fine, still weird to me that it won't shoot crossman, H&N, Beeman and RWS pellets.  JSB's only for this one.  May have to order an 18" from Baker airguns, I like the look better with the TKO on there.

you also need to check the leade (for a smooth transition to rifling rather than a sharp edge)...also about half my barrels had a burr at the transfer port that needed knocked down...

Jason has a thread on how he does his barrels but I lost my bookmarks...
  • The Great Northwest, United States, Washington
PC77 steel breech 18.7" barrel,  700 fps @ 15 & 755 @ 20 pumps with 7.4g Crosman points

1322 steel breech 14.5" barrel, 640-650 fps @ 22 pumps w/14.3g CPHP

1322 MLT steel breech 19" barrel, 682 fps @ 22 pumps w/14.3g CPHP,  13xx/66 hybrid

1322XLT 22" barrel, 700 fps  @ 11 pumps & 750 @ 16 w/14.3g CPHP,   13xx/2100 hybrid

MK-1322 steel breech 22" barrel, 750 fps @ 17 pumps & 805 @ 22 w/14.3g CPHP,   Mk-177/2240/13xx hybrid

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Offline bmoney

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #9 on: June 06, 2016, 05:14:48 PM »
Interesting.  I will have to check my 2260.  I thought it was odd that the only pellet the 2260 will shoot is JSB 18.1 and I mean others are thrown all around.  It doesn't even like 14.5grn crosman premiers in dome or hollowpoint.  H&N Barracuda 21grn and Beeman Kodiak 21grns are thrown like curveballs at 15 yards.  I will check my barrel later.  Thanks for the heads up.

EDIT- my barrel looks fine, still weird to me that it won't shoot crossman, H&N, Beeman and RWS pellets.  JSB's only for this one.  May have to order an 18" from Baker airguns, I like the look better with the TKO on there.

you also need to check the leade (for a smooth transition to rifling rather than a sharp edge)...also about half my barrels had a burr at the transfer port that needed knocked down...

Jason has a thread on how he does his barrels but I lost my bookmarks...

Right about the time you posted this I did the Q tip test.  It has a bur that is catching the cotton fibers.  If anyone has the fix to this I would appreciate it if you could post it. 
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Offline nervoustrigger

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #10 on: June 06, 2016, 06:36:48 PM »
Here is a link to my little barrel accurizing writeup:
http://www.gatewaytoairguns.org/GTA/index.php?topic=98836.msg925609#msg925609

Offline nervoustrigger

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #11 on: June 06, 2016, 06:43:33 PM »
Matt, for what it's worth, I have one of the barrels with a line running down the bore and it shoots great :)   It was a big surprise.  I did recrown it and polished the leade but I did not polish the bore.  I thought I would need to but it was printing 3/8" groups at 25 yards and that exceeded my expectations for a pumper so I never took it apart for that step.

Offline Matt15

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #12 on: June 07, 2016, 03:41:17 PM »
Matt, for what it's worth, I have one of the barrels with a line running down the bore and it shoots great :)   It was a big surprise.  I did recrown it and polished the leade but I did not polish the bore.  I thought I would need to but it was printing 3/8" groups at 25 yards and that exceeded my expectations for a pumper so I never took it apart for that step.

That is great news! What pellets does yours like? I have only tried the 7.9 gr crosman pointed and it did not like those (no surprise).  :D
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Offline nervoustrigger

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #13 on: June 07, 2016, 04:15:56 PM »
My particular barrel shoots the Air Arms 10.3gr best, followed closely by both JSB- and AA-branded 8.4gr.  But let me qualify that by saying when it comes to finding the very best shooting pellets, the difference between pretty good and excellent seems to come down to the particular batch.

Also, the RWS Meisters group about 1/2" at 25 yards which makes a very effective house sparrow wrecking ball.

All this is at around 10fpe on a 24" barrel.  I know it defies logic...a barrel that long and slender ought to be a harmonic vibration nightmare but the fact it shoots various pellets (i.e. different weights and velocities) well tells me it is pretty well behaved.  FWIW, I did firm up the barrel band by shimming where it attaches to the end of the pump tube and there is a grub screw on each side coming up at an angle to bite into the barrel.  Just carefully tapped the plastic and took care not to over torque them.  POI has been rock solid from day to day, month to month. 

Offline birdmove

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #14 on: June 07, 2016, 05:11:01 PM »
   You can use a bore light, which is basically an angled flashlight, that uses a bent clear plastic rod to conduct the light. You can get one pretty cheap. Use the bore light at the breech and look down the muzzle.
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Offline Matt15

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #15 on: June 07, 2016, 07:24:32 PM »
My particular barrel shoots the Air Arms 10.3gr best, followed closely by both JSB- and AA-branded 8.4gr.  But let me qualify that by saying when it comes to finding the very best shooting pellets, the difference between pretty good and excellent seems to come down to the particular batch.

Also, the RWS Meisters group about 1/2" at 25 yards which makes a very effective house sparrow wrecking ball.

All this is at around 10fpe on a 24" barrel.  I know it defies logic...a barrel that long and slender ought to be a harmonic vibration nightmare but the fact it shoots various pellets (i.e. different weights and velocities) well tells me it is pretty well behaved.  FWIW, I did firm up the barrel band by shimming where it attaches to the end of the pump tube and there is a grub screw on each side coming up at an angle to bite into the barrel.  Just carefully tapped the plastic and took care not to over torque them.  POI has been rock solid from day to day, month to month.

Thanks! Mine is cut down to 16".
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Offline bmoney

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #16 on: June 08, 2016, 06:55:06 PM »
Well a couple days ago I took a .22 cal nylon brush and made about 15 passes through my bore with Mpro7 cleaner.  Then ran about 6 patches through until clean.  Today I just shot the best five 5 shot group on a card that I have ever shot at 15 yards.  Four out of five groups were a ragged hole with one going just over 1/4 inch.  I think I need to credit a lot of it to the pellet packaging from Airgun depot, I really like the foam cut outs they package the pellets in.  Unlike Amazon with their rather sloppy packaging, I could not find one damaged pellet skirt in the 500 tin of JSB exact 18.1grn.  I also did not shoot as quickly today.  I should recheck how it shoots Crosman premier domes but if it will consistently shoot the JSB's this good then I will be quite happy. 
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Offline nervoustrigger

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #17 on: June 09, 2016, 03:49:43 AM »
I said I would report back when the .177 Disco barrel arrived and it did today.  I was pleased to see no evidence of a crowning pilot having been used, however it does have the line running down the bore very much like one I got over 2-1/2 years ago.  I went ahead and gave it a full manicure and pedicure and swapped it onto the 2240 HPA.  It was almost 1am by the time I got finished and sighted in with the aid of a flashlight so it wasn't under the best of conditions.  Nonetheless it was hitting the smaller spoons (1") at 25 yards every single time using the cheap RWS Basics wadcutters (830fps / 10.7fpe).  I tried two other types of pellets and they had a similar POI which is usually a good sign.  So far so good with this one!

Offline nervoustrigger

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #18 on: June 09, 2016, 11:45:52 AM »
Hey guys, I'm curious.  Does anyone know why the .177 barrels have the line down the bore?
 
I assume it is a seam from the manufacturing process of the raw tubing.  My understanding is that DOM (drawn over mandrel) tubing is commonly used and therefore some speculation on the forum that is likely what Crosman uses.  Prior to today, I thought it was a seamless process but it turns out it isn't.  Apparently it's just that the seam is "almost invisible" according to this article:
https://www.metalsupermarkets.com/difference-between-erw-dom-and-seamless-tube/
 
In a nutshell, it explains that the manufacturing of DOM tubing starts just like ERW (electric resistance welded) tubing, it's just that it gets finished up differently which yields better dimensional tolerances and conceals the seam.  So I guess the degree to which the seam is "almost invisible" can vary.
 
I've never seen this type of seam on any other barrels except from Crosman.  But even more curious is that it's only on the .177 barrels, not the .22.  At least from the handful of each that I have seen.

Offline rayandkerry

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Re: Crosman barrels - inspecting for piloted crowning tool damage
« Reply #19 on: June 09, 2016, 11:04:08 PM »
I have a brand new Marauder and it kinds blows LOL.

I tried doing a recrown and it did improve things a little bit, but still there are a still a number of flyers and the groups are large compared to my disco, which is like a scalpel.

I did see something in my marauder barrel that looks like the pic in this thread.  Should I just send Crosman a pic if those marks and ask them to replace it?  I suppose I shouldn't have done the recrown before talking to them.  So what is the solution if they don't replace it?  Chop the barrel and recrown?
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