What is the verdict on this barrel?

[Tidesloe]

Hey guy's, I dont post here often but a member for quite a few years. Im looking for some input on a chamber throat in a custom rifle.
Its a 7mm STW. Shooting 180 VLD's, 215M, 81 grains of N-570 @ 3200 fps.
I bought this rifle "new"listed on his website from a well known top custom rifle builder about 7-8 yrs ago. It shoots well, and consistent @ .5 moa avg, if I Have a good day, sometimes better, sometimes not quite as good.
I've put maybe 400 rounds through it max over the 8 years.
This past season, I drew a rare rifle tag, it only happens every 4-5 yrs, so I mostly bowhunt, and shoot archery. I got my STW out preparing for my rifle hunt and saw ejector marks on fired cases, which I had never previously seen that I was getting on each round. I ended up shooting a mule deer with it, and shot a few rounds after season with the same result. Ive never done any high volume shooting, and shoot 3 rnd groups with 20-30 min cool downs between groups.
Out of curiosity, I bought a Lyman borescope and took a look. What I saw surprised me. To my untrained eye, it looks really bad to me, and much worse than what I'd expect from a rifle with 400 max rnds through it, but what do I know? Nothing really, as I've never looked at a scoped bore. I have another custom with maybe 60 rnds through it. I havent compared them yet, but I know I should.
Wondering what you guy's with much knowledge and experience make of this throat?

 

[Mram10us]

I would give it a VERY thorough cleaning making sure to get any carbon rings and borescope again.

 

[Tidesloe]

I would give it a VERY thorough cleaning making sure to get any carbon rings and borescope again.

Thanks. Ive been trying that this weekend. Ive been soaking it in C4 carbon remover, Sea Foam, and scrubbing it. Im not getting any more carbon out of it. These pics were taken after all the scrubbing, and getting white patches. Can you see carbon rings in the pics? I dont really know what Im looking at in these pics.

 

[Tidesloe]

I would give it a VERY thorough cleaning making sure to get any carbon rings and borescope again.

The reason I got the borescope was to see if I had carbon ring buildup, causing the ejector marks on my cases. Is this carbon ring that Im seeing? After all weekend scrubbing and soaking I sure cant figure out how to get it out, if thats what Im seeing.
Thanks for your input, I appreciate it

 

[Mram10us]

The right side of the first pic looks like a carbon ring to me. Have you tried a brush spun with carbon remover in the neck area? Not trying to be captain obvious. Try spinning a 338cal brush in the neck with carbon remover

 

[Tidesloe]

The right side of the first pic looks like a carbon ring to me. Have you tried a brush spun with carbon remover in the neck area? Not trying to be captain obvious. Try spinning a 338cal brush in the neck with carbon remover

I spun a 30 cal brush in it after spraying it down with carbon remover and letting it soak for a couple of hours. Then soaked a mop in carbon remover and shoved it into the neck/throat area for a couple of hours and then respun the brush. Still getting patches coming out white.
Maybe, its possible that a 30 cal brush is too small and not getting at it. Im running it in there just to the point of getting it stuck in the bore and spinning it. Ill try a 338 brush and see what that does. Thanks

 

[DJ Fergus]

The reason I got the borescope was to see if I had carbon ring buildup, causing the ejector marks on my cases. Is this carbon ring that Im seeing? After all weekend scrubbing and soaking I sure cant figure out how to get it out, if thats what Im seeing.
Thanks for your input, I appreciate it

I have a 7mm stw burning 80.4 grains of n570 behind a 180 eld in a 28" @ aprx 3180fps. I've got around 130 rounds on it. So far, carbon hasn't been as bad as a 26" 300 Norma I have with n570. To get rid of most stubborn carbon: I take an soft foam disposable earplug, roll it up small & stick it in the muzzle. Put the muzzle in a plastic cup vertical, safe & secure place. Fill the bore up to the chamber with bore tech carbon remover. I've let it set up to 5 days in the chamber. Drain & start patching with dry patches untill they come out clean. Go back with bore tech soaked patches & see if you get any more carbon. You shouldn't get much at all. If you do push a couple more dry patches following with some wet ones, but you probably aren't going to have to do that. I can tell you that bore tech carbon remover will turn carbon into a soft mush after setting in it for 3-5 days. After a thorough cleaning like that, you may not want to run full charge loads until you get two or three rounds through. Also, it's been accepted that n570 speeds up if it's set out unsealed for several days. I also never load up much more than 15-20 rounds for a rifle at a time. That way if something changes, I don't have a bunch of loaded ammo that's not in tune with the state of my barrel. I'm guessing after 400 rounds, it's greatly possible you have some carbon build that's causing your higher pressure.

 

[Mram10us]

Have you tried a bronze brush?

 

[Tidesloe]

I have a 7mm stw burning 80.4 grains of n570 behind a 180 eld in a 28" @ aprx 3180fps. I've got around 130 rounds on it. So far, carbon hasn't been as bad as a 26" 300 Norma I have with n570. To get rid of most stubborn carbon: I take an soft foam disposable earplug, roll it up small & stick it in the muzzle. Put the muzzle in a plastic cup vertical, safe & secure place. Fill the bore up to the chamber with bore tech carbon remover. I've let it set up to 5 days in the chamber. Drain & start patching with dry patches untill they come out clean. Go back with bore tech soaked patches & see if you get any more carbon. You shouldn't get much at all. If you do push a couple more dry patches following with some wet ones, but you probably aren't going to have to do that. I can tell you that bore tech carbon remover will turn carbon into a soft mush after setting in it for 3-5 days. After a thorough cleaning like that, you may not want to run full charge loads until you get two or three rounds through. Also, it's been accepted that n570 speeds up if it's set out unsealed for several days. I also never load up much more than 15-20 rounds for a rifle at a time. That way if something changes, I don't have a bunch of loaded ammo that's not in tune with the state of my barrel. I'm guessing after 400 rounds, it's greatly possible you have some carbon build that's causing your higher pressure.

Thats a good idea on the ear plug. I'll try that and let it soak for a few days. Boretech C4 carbon remover is what Im using. That and Sea Foam

 

[Tidesloe]

Have you tried a bronze brush?

Yes, thats what Im using

 

[Tidesloe]

I have a 7mm stw burning 80.4 grains of n570 behind a 180 eld in a 28" @ aprx 3180fps. I've got around 130 rounds on it. So far, carbon hasn't been as bad as a 26" 300 Norma I have with n570. To get rid of most stubborn carbon: I take an soft foam disposable earplug, roll it up small & stick it in the muzzle. Put the muzzle in a plastic cup vertical, safe & secure place. Fill the bore up to the chamber with bore tech carbon remover. I've let it set up to 5 days in the chamber. Drain & start patching with dry patches untill they come out clean. Go back with bore tech soaked patches & see if you get any more carbon. You shouldn't get much at all. If you do push a couple more dry patches following with some wet ones, but you probably aren't going to have to do that. I can tell you that bore tech carbon remover will turn carbon into a soft mush after setting in it for 3-5 days. After a thorough cleaning like that, you may not want to run full charge loads until you get two or three rounds through. Also, it's been accepted that n570 speeds up if it's set out unsealed for several days. I also never load up much more than 15-20 rounds for a rifle at a time. That way if something changes, I don't have a bunch of loaded ammo that's not in tune with the state of my barrel. I'm guessing after 400 rounds, it's greatly possible you have some carbon build that's causing your higher pressure.

What barrels on the STW, and Norma? Some may build fouling up more than others?

 

[DJ Fergus]

Thats a good idea on the ear plug. I'll try that and let it soak for a few days. Boretech C4 carbon remover is what Im using. That and Sea Foam

Yeah, c4 is what I used. I couldn't remember that, I just now went & checked. I remembered that it was their carbon remover only. I found that the c4 worked much much better than seafoam. Just my experience. Other folks may have different opinions. When soaked for days, the c4 worked better.

 

[Tidesloe]

Yeah, c4 is what I used. I couldn't remember that, I just now went & checked. I remembered that it was their carbon remover only. I found that the c4 worked much much better than seafoam. Just my experience. Other folks may have different opinions. When soaked for days, the c4 worked better.

Alright, thanks for the advice. Ive been down to trying anything and everything I hear of. The C4 Ive used for awhile, but over the last several years, Ive gotten where I dont stress out on barrel cleaning like I used to. I just give it some wet patching, and brushing with boretech c4 and copper remover not soending a lot of time on it, and call it good. Looks like I need to pay attention to detail, with the carbon especially in the throat area.

 

[DJ Fergus]

What barrels on the STW, and Norma? Some may build fouling up more than others?

Bartlein on the Stw, Brux on the 300 Norma. I'm really starting to believe Im either going to have to go to a faster burning powder like retumbo or h1000 in the Norma or go to a 28" with n570 in the Norma to get a cleaner burn. I may be way off base on those thoughts. I'm not sure, but for now, I'm just keeping a close eye on it and using the c4.