This barrel was cleaned prior to scoping, Shooters Choice patches until they went in white and came out white.









For comparisons sake, here is a representative picture of another barrel of mine:

Lead area


I'm just looking for opinions based purely on the images before I describe the problems I'm having with the top barrel, because I'm curious if I'm seeing them the same way others do, since this is my first use of a borescope.

Upper barrel looks used.  Cracking, no major fissures but chunks may be breaking off and skinning jackets, minor coppering, perhaps a little neglect (spotty rusting).  If the order is muzzle at top to bottom it's time for a new barrel.  What's the throat look like?

Second barrel looks good and broken-in (the edge of the leade is smoothed, still has tool marks from chatter in the depth of the grooves).

OST so I can read everyone else's oppinion.

Sorry, I should have identified the area of the barrel.  These images are all from the first 3-4" of the barrel after the throat.  The rest of the barrel to the muzzle looks quite similar to the bottom reference photos.  The top barrel has 250 rounds through it and is less than 1 year old.

Looks like you need to use a good brush? Patches alone aren't sufficient in most cases. Looks like fouling and possibly that the barrel got extremely hot cracking the chrome lining??

It's a stainless barrel, no chrome lining.

I will brush it and take after pictures to see if there's any change.  But jaq is correct, no chrome.

Please explain to us what we're looking at -- is it different barrels; is it the same barrel but different places down the bore?

The top set of pictures is the area immediately after the chamber on one barrel.

 

The bottom set of photos is from a different barrel that shoots better OP was using for comparison.

The first 7 photos are of the same barrel, taken in multiple points radially, from 1/4" to 4" from the breech.

The second 2 photos are from a different barrel simply as an example of what I think a premium barrel should look like.


I've been cleaning the trouble barrel now, again, on SOMT's advice.  The cleaning cycle I've done is: Soak the brush in solvent, make 6 strokes through the bore, switch to a wet patch and jag, then dry patches until they come out clean.  I've done this 3 times now and it still takes multiple patches to come clean after every brushing but I wasn't sure if the brush might be depositing more than it's breaking free, so after the third go around I got the borecam out and looked, and I don't see much difference compared to the pictures in the OP.

I'm going to do another 3 passes at brush/patch cleaning then I will take more images and post them.

ETA: Part of the reason for this post is I have issues with the first barrel I would like to resolve, the other part is to get input on what we're actually seeing in the borecam, as it's really quite hard to know.  At this point I see it as a great comparison tool, but whether those dark spots are pits, or copper, or xxx, I don't know.  I was hoping someone would.

Shooters Choice and a jag like this sized so that pushing a wet patch takes some effort:  

Ok, here it is after quite a bit of brushing, with some pauses to allow the solvent to work.  If Tinyeye kept the order I uploaded correctly, then this series of pictures is starting at the throat, at 12 o'clock and each subsequent image is further towards the muzzle, all at 12 o'clock, all the way to the muzzle and crown.  Breech to the right, muzzle to the left, each picture is moving further left.














At this point I begin advancing further for each picture because there is little change and it looks how I would expect/hope.









And now we reach the gas port, where I see similar color/patterning downstream, making me think that maybe that area near the breech just really is stubbornly fouled.







Back to normal.

And the muzzle

Send member JohnBurns an IM asking if he has any thoughts. He has a lot of experience with building excellent shooters and I believe he has used a bore scopde quite a bit.

I am hardly an expert but it looks like you're early into stainless barrel alligator skinning.  I used to read my friends benchrest magazines and they had articles on barrel wear and such.   Stainless barrel throats will erode like yours into what looks like cracked mud puddle and moly steel will just wear away smooth.

I am not an expert at all so I suggest you keep digging.   Just tossing out my remote two cents.

It looks like a terrible barrel shitting the bed early.  Lots of throat fire cracking and alligator scaling.

Eeeyup.





Noveske?





 

Shooters Choice turns blue, it's the reason I use it.  But I've ordered some KG12 and Parker style jags, so I will give that a try.  For what it's worth, I don't have any other premium barrels, many with much higher round counts, that look like this inside.  Stainless or carbon.


Ultimately I don't believe that my cleaning methods are what's caused this barrel to have this appearance, and there are not a lot of (easily found) borescope images on the net that I can find that look similar, which is why I posted here hoping someone knew what we were looking at.

This barrel has never shot up to my expectations, initially I believed it was because all of my precision shooting experience has been with bolt actions, and an AR is simply harder to shoot to the same level as a bolt gun given how easy it is to manipulate, it takes some practice to manage trigger and grip control through the trigger break to keep from influencing the gun.  Then I thought I just had not found the right load, since it's shown streaks of precision in some 3 round groups.  It will shoot 1.5" 5 shot groups, which isn't terrible, just not what I was hoping for.  It's also been a copper fouling pig since day one.  Every trip to the range resulted in many many blue patches, regardless of how many or few rounds I shot, which lead me to believe that it was simply not lapped as well as it should have been, which led me to buying the borecam, and here we are.

I think this will turn into a barrel lapping thread shortly, because at this point I don't feel like I have anything to lose.  I'm already unhappy with the barrel.  Going back to the manufacturer after 10 months and 250 rounds isn't something I really want to do.  I've already replaced it with another precision barrel that meets my expectations for accuracy and have reinstalled this one in another upper with an ACOG, so being a 1.5" gun isn't an issue, and probably better than a good number.

The worst that will happen is I make it worse, which I'm more than willing to do if I learn something in the process.  So I've already spent some time on the various benchrest forums reading up on bore lapping.  I've got everything I need to do it, lead, pot, 1 pc steel rod, silicon carbide lapping compound in 180, 240, and 320 grit.  I think I will cast some laps and give it a shot.  Now that I have the borecam I can at least inspect what changes are made.  I have a feeling however that even if I'm able to restore the surface finish and appearance of the bore, it's likely not going to shoot any better, and I'm not sure how to get any measurements on bore/land diameter other than where I can reach with a small hole gage.  So I will likely cast a number of laps, some to use as laps, others to use as slugs, in an attempt to feel any diameter inconsistencies.

And I'll post pics as I go.

That's a very generous offer, I appreciate it.  I'm compelled to learn how to do these things myself.  If you were closer to me and I could participate I would accept immediately.

I cast 5 laps tonight.  First thing I noticed when slugging was that the last 2" of the barrel (muzzle end) is significantly tighter than the rest of the barrel.  I don't know if it's truly tapered, or if there's just a small dimensional change.  I'm not sure if I should try to work this out or not, the 22LR guys seem to want a tight muzzle, but I was under the impression in centerfire cartridges it was more desirable to be relatively straight.

I made an initial pass with 220 grit, paying more attention to the scaled area.  When it began to loosen up, I applied a bit more compound and worked it again until it loosened up a second time.  Each of these were 5-6 strokes.  I think that lap is shot now and will move on to the next.

I cleaned the bore with patches and lots of solvent, and I noticed an immediate difference when I got to running dry patches through.  Prior to this bit of lapping, even wet patches would stick in the bore, dry ones were impossible to run through slow and steady, you had to force them and they would hitch, then get them going again.  But now, patches glide with consistency through from breech to muzzle.

Then I stuck the bore cam in.  I can notice some improvement in the surface finish, mostly in the grooves at this point, but some on the lands.  I'm going to do 1 more pass with a new lap, then I will take some screen shots and test fire before going any further.

Here's the lap.  I cast it around a set screw, clipped off the flash from the muzzle, then filed a taper on the end to make sure the largest diameters were from the cast features.



And here is the bore after my second lap at 220.  Noticeable difference between this and the before.  Same parameters for the images, first is the lead, each moves progressively down the barrel towards the muzzle, all oriented from 12 o'clock.





























Word to the wise, if you ever decide to try this, take your handguard off before you start casting laps.  So you don't end up picking lead splatter out of every keymod slot and nook and cranny


I'll try to get to the range and see what it'll do this week.

Jim did you walk away mid post?

Looks better, great thread

Now that I'm thinking about it, what bore scope is that and ball pal price ?

Lyman borecam, 200 to 250.

Still haven't gotten to the range, however, sitting at home tonight I got thinking about the stainless Rock Creek barrel I have.  When Franklin Armory came out with their binary trigger, I bought a cheap DSG upper on sale to build a rifle for the trigger.  This is the barrel that came in that upper.  It saw roughly 1400 rounds of .223 and 5.56 as I worked through some of the issues with the trigger.  A good amount of this shooting should be considered like one might consider full auto given the rate of fire achieved with the trigger.  It also saw a couple bricks of .22 LR through a kit.  I never cleaned the barrel during this entire period of time.

Tonight I thought I took photos of the uncleaned bore, the cleaned bore, and the lapped bore, as I lightly lapped this barrel with a lead lap and 320 grit.  Literally 2 passes through the bore, and nothing else.  However upon inspecting my SD card, I seem to only have imaged of the lapped bore.  Sorry.


Starting at the throat, working towards the muzzle.

























Held up surprisingly well compared to the other one, given the quantity of fire and type of fire.  This barrel got hot as jaqufrost could attest.  I'm going to install it into an upper and shoot it for accuracy this weekend along with the other barrel.

Very interesting thread. In for results.

Hit the range today with the following loads for testing.  Everything was same for case prep - .003 neck tension, 2.250 OAL, chamfered case mouth, no crimp.  
69 SMK, 23.8 grains 8208 XBR, BR4
77 Nosler CC, 23.0 grains 8208 XBR, BR4
Black Hills Mk262
69 SMK, 25 grains RL15, CCI 400.

All uppers were fired from the same lower with a Larue MBT and A1 stock.  I also used the same optic and swapped for each run, so ignore the sighter and #1 groups as they were used to get a relative zero with a load I know not to be very accurate.

Walther barrel:


The problem barrel after being lapped:


Rock Creek barrel which has seen full auto like fire prior to lapping:


I think the only thing conclusive is that I fucking suck at trying to shoot ARs from the bench.  I can squeak out some tiny little groups with a number of bolt actions.  Some of them I built myself.  I know my reloading practices support at least .6 MOA in those rifles.  But I'm pretty much done trying to do anything precise with an AR.  Fuck it.  At least I didn't make it worse?  Christ this is frustrating.  I still plan to build a rifle machine rest, for load development.  Maybe I'll revisit this then.

I even let the damn things rest between groups and entertained myself with the Appleseed 10/22 while the barrels cooled:


Shot this group at 25 meters from sitting/sling with Federal Bulk Pack


Then shot this AQT between loads



what a waste of time and energy.

The inconsistent NPoA with the 10/22 is bugging me.





How is the AR supported? Bipod or rest?



How does the reticle behave when you dryfire?

OP...do not worry about your bench shooting.  You are not alone.  I am fighting to learn how to incorporate all of my gear into some kind of synthesis.



I mean....I can shoot bolt guns from the bench no problem.....but get me behind an AR-10 and....LORD it takes some work.



You don't know how many rounds it has taken me to get this far at 100 yards...with a damn rifle rest.







100 yards

winds gusting from 5 to 25 mph

178 Grain Hornady AMAX

40 grains of IMR 4064



Mega recivers

Geissele SSA-E Trigger

JP 22 inch barrel w/ matched bolt.

Leupold Mk IV 6 X 20, 30mm tube

Haha, I have to hold left because I must have a bit of cant in the front sight and run out of windage.  Makes it tough to estimate the hold off on the varying sized targets.

Anyway, supported by the bull bag in the first picture.  I've tried a rest and rear bag, bipod and rear bag, and now this bull bag.  I'm pretty certain that my problem is a consistent follow through.  Any AR seems to recoil differently each shot.  I'm never able to get any consistency.

When I shoot a bolt gun, it's easy for me to support it in a way that it always recoils the same, shot to shot.  That is, rises off target slightly as it pushes back into my shoulder.  The ARs, sometimes jump up, sometimes straight back, sometimes pull left or right.  I think that's why I seem to have my best results from a bipod - a solid bipod keeps the rifle from rotating and allows it to recoil freely in a more consistent manner than any other bag/rest setup I've tried.

To cap off this wonderful waste of an afternoon I left that 10/22 in that stupid rack at the range  At least it was still there when I went back.

I stumbled into this thread . Just for point of refrence I has a standard M1A with Hornady off the shelf 308 that would shoot groups better than that at 100 yards off the bench and thats with the windage maxed out with a canted scope mount.  There is something wrong here and I dont think you are at fault.  I would let someone else shoot your lods and rifle and also try off the shelf ammo to see the results. I wish you luck    

I would like someone else to shoot but I don't have anyone in my circle of friends that I trust to shoot groups better than I do.  I'm not saying that because I'm some super benchrester, I'm not, but I live in a world of "pie plate at 100 kills deer"





I've pretty much given up on the idea of a .5 MOA AR.  I've spent too much time and money chasing it at this point and have moved on.  I can buy a list of parts for a bolt gun, thread and chamber myself, true the action myself, and within 3-4 development loads be in that .5 MOA range every time I've done it, so that's what I'll keep doing.



However, if you're offering, I'll send you one of these uppers to test if you'd be willing to try.

Thats a very nice offer.  I do not have the time right now with a litte girl coming in the next 30 days.  I used to shoot NRA shoots here and Smallbore SECNAV shoots.  The fundamentals are the same . Check in the hometown forums and see if a member will meet you out there before we ship down here.  If that fails we can attempt in march if thats what your down for. A Marine Buddy of mine hust recently got his FFL and would be able to help go over most of the rifle.  What type of crown and FH or muzzle break are you running? And the twist rate please.  From your post earlier I know you  know this but it seems like a small step was missed.   Also try locking the rifle down into a led sled and drill the feet into the table if possible . eliminate you as the problem.  

Im thinking this too. Thats a little too much movement even from the bench.  Give a full look over the rings or try a different optic set up. Hell even irons.  Thats an easy test.  A moving reticle can do this.  I had the same problem with a PSL . Even a slight optic "wiggle" will be multiplied at 100 yards

I'm not a gunsmith or a machinist...but the pics posted look exactly like machining chatter to me.  It makes sense that lapping would remove it.

Is this button cut rifling?  Cause then my idea at least has merit.  If it is hammer forged rifling then I'm just dumb!  

http://www.midwayusa.com/product/152946/tubb-final-finish-tms-throat-maintenance-system-224-caliber

shoot 2 -3 every 300 rounds......