Help interpreting Borescope

[Allthewatts]

I have a prefit Barrel on my Tikka that I installed, I've been struggling with accuracy since I got it, Maybe me, maybe something else. My goals are to get out to long ranges with this rig, and my hope was to get into the ELR game a bit, but my shooting must improve before that happens.

I'm shooting some slow loads right now, and I'm right at about .9MOA at 300 yards, with ES~15ft/s, Hornady 147 ELD-Ms at 2550 ft/s.
130 ELD-Ms in Hornady brass do okay, but around the same accuracy at 2995ft/s.

Anyway, after taking a step back and re-assembling everything, I figured a good barrel inspection was inorder, and this looks a tad rougher than what I was expecting. I'd love thoughts on other more experienced folks that can tell me this looks fine, or looks to be an issue. (I so wish I looked before I started shooting to better calibrate myself.) These photos are after alot of patches of CR-10 and Hopes. It still looks like a bit of Carbon and copper in here, so My thought is maybe CLR is an answer. It cleans my muzzle brake super well.

When inspecting this barrel, I keep noticing alot of copper fowling, even at 300 rounds down the tube.

The barrel is a 26in 6.5mm, 5R, 1:8.

Lands look okay, some fairly early fire cracking maybe?

This is a regular view, chatter marks, with what appears to be pockets.

There's a point 18 inches from the chamber in the barrel where its fowled with copper all the way around. almost like a very minor change in diameter at this point.

I'm curious for any thoughts. Thanks!

 

[celltech]

That actually looks pretty good to me other than the carbon fouling...you should see a Savage barrel. If you use CLR don't let it get on the barrel bluing, it will eat it right off.

 

[SupressYourself]

If that was an expensive custom barrel, I'd be pretty disappointed in its roughness. However, I had a factory Savage barrel that made yours look pristine, and it hammered. I finally swapped it out due to velocity loss and the fact that I had a new one sitting there.
It does appear to still be quite fowled considering how much you cleaned it. CLR is pretty aggressive. I would get some Boretech Eliminator and try that out with a nylon brush.

 

[Ravenworks]

Quit over thinking things and put the bore scope down.
I think what will help you the most is finding a good load for your rifle and stop over analyzing your bore scope.


Do a search here for bore scope threads to see what I am saying

 

[Allthewatts]

Yea, I'm

Quit over thinking things and put the bore scope down.
I think what will help you the most is finding a good load for your rifle and stop over analyzing your bore scope.


Do a search here for bore scope threads to see what I am saying

Agree with finding a load. I have done a fair amount of development on the 130gr eld-m., Trying to get enough berger 144 lrht to make it worth it!

It's more of a check on the bore, I was quick to learn that I have not been cleaning thoroughly enough.

 

[Evintos]

You'll get varying opinions on barrel cleanliness. The amount of cracking you have is minor. I'd leave the copper in there based on the amount of chatter, even in the heavily fouled area since the edges of the land/grooves are still well defined. If the build up is bad enough in the corners that it starts looking like a smoothbore, clean it out. KG Industries KG-12, Boretech CU2, Boretech Eliminator, etc. will do a good job in removing copper.

 

[Allthewatts]

Well hit the range again today, and ran a bullet seating test with some 147 ELD-Ms over H100V. After cleaning with BoreTech CU2 following instruction on the bottle, and then running some Kroil down the tube and letting that sit over night, followed by a dry patch in the morning before testing.

Groups shrank to a repeatable 0.55MOA, with very stable velocities.

Its like a new gun to me!

 

[spamassassin]

A borescope is basically just senseless heartache with a USB connector. If you don't KNOW what you're looking at then everything you see will only cause you unnecessary concern and not provide any information. A barrel that's as rough as 5 miles of dirt road can be easily as accurate as one that's slick as glass. It's a single component in a complicated system. In OP's case all he needed to do by all appearances was change seating depth.

 

[Allthewatts]

Same seating depth that I had been firing before hunting for the cause of issues ended up being best performing seating depth.

The usual 20 thou jump for the Hornady eldms.

 

[Snek123]

A borescope is basically just senseless heartache with a USB connector. If you don't KNOW what you're looking at then everything you see will only cause you unnecessary concern and not provide any information. A barrel that's as rough as 5 miles of dirt road can be easily as accurate as one that's slick as glass. It's a single component in a complicated system. In OP's case all he needed to do by all appearances was change seating depth.

Hi man, sorry for OT, but could you please give me your opinion about my barrel's scope? It's a 308 WIN Sako TRG 22, apparently has ran about 400 rds through! Thanks a lot! Merry xmas!

 

[Rider47]

While I agree that load development is likley the path to improved precision with this barrel, a borescope IS a useful tool if you know how to interpret what you see, and not psych yourself out. The images do not show "chatter marks", they are reamer marks (normal marks made when the bore is reamed, after drilling, to bring it to the proper internal dimension). These are largely removed by pre- and post rifling lapping in high quality barrels, which this isn't. You are correct, the "pockets" appear to be areas where the button (this appears to be a button-rifled barrel as there are button streak marks in both the lands and grooves) has encountered a wider spot in the bore and has not flattened the reamer marks as much. This appears to be a not particularly well made, sub-match grade, button rifled barrel, but this does NOT mean it can't be made to shoot better. However, for improved precision, a higher quality, properly lapped SS match grade barrel would be advised.

Sweets 7.62 and/or use of a patch with 600 grit lapping compound (Brownell's) will usually remove stubborn copper deposits.
(No - you will NOT damage this barrel with 600 grit silicon carbide lapping compound used with a cotton patch.)

If this was my barrel and I was attempting ELR shooting, I'd plant tomatoes with it - before I'd spent too much time, and money on powder, primers and high quality bullets. Alternately you could try "fire lapping" (look it up). While I wouldn't, continuing to work up loads varying primers, powder, charge wt., seating depth, neck tension etc. to extract the best from this barrel is not a bad idea either, as the learning will be invaluable. Edit: assuming 6.5 = 6.5CM? - better brass (Lapua etc.), Berger Hybrids, H4350, neck sizing.

Just a note - I just waited one year for a pre-chambered match grade SS barrel from Krieger. Through the borescope, it is a beautiful thing, and it shoots! (When I ordered it they said lead time was a year, and they beat this by ONE DAY.)

 

[wade2big]

Whose barrel @Allthewatts?

 

[Allthewatts]

Preferred barrel blanks

 

[wade2big]

Preferred barrel blanks

Looks like it shoots well for you now. Good to here.

 

[Allthewatts]

Preferred barrel blanks

Though you should see my 338

Looks like it shoots well for you now. Good to here.

Yep! I think it I was to buy another from them, I'd have it lapped, a service they now provide.

 

[wade2big]

Though you should see my 338

Yep! I think it I was to buy another from them, I'd have it lapped, a service they now provide.

What is the additional cost to do that?

Is your 338 from them? Which cartridge? Does it have a rough bore? Does it shoot well?

 

[Allthewatts]

I have a 26in 6.5 creedmoor 1:8 twist from them.

My 338 is a savage barrel, soon to be a 33xc once I pony up to find a barrel for it. That barrel shoots well, but looks insane, so chattered.

I have a tikka factory barrel, and that one looks perfectly smooth.