Bore Analysis

[AZgeek]

So I got my first bore scope. Used it today for the first time on a factory Remington 24" 7mm Mag barrel pulled to harvest the action. Couple of questions for those with experience:

1. How would you rate the rifling on a scale of 1-5 with 5 being like new?
2. Is the barrel copper fouled? Cleaned the shit out of it with MC-7 but the closer to the muzzle, the more residual copper I see.

Three pics from chamber to muzzle:

 

[canezach]

I would say the rifling is a 4. Those are some sharp edges on the lands. That doesn't mean you necessarily have a lot of life left, since there are a ton of factors at play, but at the moment, the rifling looks really nice

I've seen worse copper fouling, so I wouldn't even be concerned with it. If you had those copper streaks for the entirety of the rifling, I'd be concerned. You could try to eliminate more copper, but you're probably close to the point of diminishing returns in the time and effort vs cleanliness ratio

 

[Steel head]

I’d concur
4
Copper towards the muzzle is common.

 

[AllenOne1]

That copper should come right out with something like BoreTech Eliminator. Barrel and rifling look really good low round count.

 

[canezach]

For reference, here's a Lothar Walther DT barrel in 6.5 Creedmoor that I shot out. While it's not the best image, you can see where the lands used to be but have been so eroded to be almost invisible now

 

[AllenOne1]

For reference, here's a Lothar Walther DT barrel in 6.5 Creedmoor that I shot out. While it's not the best image, you can see where the lands used to be but have been so eroded to be almost invisible now

View attachment 7640947

How many rounds are on that barrel?

 

[AZgeek]

Thanks gents!

Maybe one last question. Is the heavier fouling closer to the muzzle simply caused by the increased friction on the jacket making it softer due to the heat?

 

[AZgeek]

For reference, here's a Lothar Walther DT barrel in 6.5 Creedmoor that I shot out. While it's not the best image, you can see where the lands used to be but have been so eroded to be almost invisible now

View attachment 7640947

OMG. My rating is a -1 on this one!

 

[canezach]

How many rounds are on that barrel?

That had just over 2500. Steady diet of 140 ELDMs and 140 BTHP at 2840ish. The lands were eroded for the first third or so of the barrel length. Towards the muzzle it still had rifling, but obviously still pretty worn.

 

[Newbie2020]

@canezach did you see a loss of mv over time?

 

[canezach]

@canezach did you see a loss of mv over time?

I did, but I don't recall it being over time, like it wasn't a gradual loss of a few FPS. It was like 2840, then suddenly 2820 for a little while, then 2790, and so on. It was certainly a noticeable loss of MV. I don't shoot for groups that often, so I couldn't tell you if the groups were getting larger, but in the middle of a local match it literally went from hitting everything to suddenly throwing about 50% of the shots I took on one string. The next string it went back to hitting everything, then back to throwing shots

 

[AZgeek]

FYI. I tried some of the Bore Tech C2 copper remover. It removed about 2/3 of all the copper fouling in 4 patches without soaking! Appears to be good stuff.

 

[theLBC]

For reference, here's a Lothar Walther DT barrel in 6.5 Creedmoor that I shot out. While it's not the best image, you can see where the lands used to be but have been so eroded to be almost invisible now

wow, how was it shooting at that point, or just before?

 

[canezach]

wow, how was it shooting at that point, or just before?

It officially "died" during a local match. First string of 10 rounds, it shot incredibly well, impacts on 9 or 10 out of 10. Second string, complete shit, like I couldn't hit the broadside of a barn. Third string it was back to shooting really well. I don't remember any of the other strings of fire. I knew it was on its very last legs, so I wasn't surprised it was dead, but what surprised me was seeing it go from hammer to shotgun back to hammer