Bore Erosion and Accuracy

[woodlotowner]

Discovered this 3" from the muzzle. More than pitting, as the patched jag actually goes slack in the section of the bore. What effect will this have on accuracy. I know, shooting the rifle is the acid test, but what have been your experiences, if any, with similar conditions. No range days here in the foreseeable future.

Also, this is an expensive rifle with chatter marks from end to end in the bore.

 

[pathfinder76]

That isn’t erosion 3” from the muzzle. Clean the barrel and then have another look.

 

[iron cat]

The only way to know is to actually shoot the rifle!
I have seen some rifles with extreme erosion in the throat area ( one had over 4") that were still extremely accurate as far as hunting rifles go.
It all depends on your accuracy requirements.
Clean it and shoot it to find out .
Cat

 

[Butcherbill]

Bore scopes cause more problems than not lol, clean it and shoot it. The results are all the matter.

 

[Snider shooter]

I have a 43 Mauser with 5”’s of nasty in front of the chamber that will cloverleaf at 75 m. Shoot and find out.

 

[woodlotowner]

That isn’t erosion 3” from the muzzle. Clean the barrel and then have another look.

You are correct. It is not erosion, but rather corrosion. I don't think further cleaning will improve the situation. Tell me that's not chatter in the bore either?

 

[woodlotowner]

Yes, gents, some days I wish I had not invested in a bore scope. I will shoot it and endeavour to come back to this thread whenever the opportunity arises.

 

[woodlotowner]

I have a 43 Mauser with 5”’s of nasty in front of the chamber that will cloverleaf at 75 m. Shoot and find out.

I get that. In your case the bullet is well past the nasty and then hits the good remaining lands and spins up and stabilizes before exiting the muzzle. Glad your old classic is a good shooter. My concern is what might happen to a bullet near the muzzle after a fine whirling trip down the bore until much of the gas pressure vents around the side of the bullet (which it will) when it hits the area that is akin to a 'bulge' in the bore...just before exiting the muzzle. I was hoping for some insight into this potential accuracy killer from someone who shoots a similarly endowed barrel. I am at once concerned and intrepid as I contemplate the inevitable trip to the range.

 

[KodiakHntr]

What is the rifle and chambering? New to you?

 

[obsessed1b]

If the gun dont shoot and you have the lenght cut the barrel. Or spin on a new one...pointless to go round and round on the issue until you have shot it. I had a 303 that had 4" of muzzle corrosion that still shot 2 moa with the iron sights.. i chopped that barrel back to 18.5" and it now shoots 1.5 moa with the irons....not much gain in accuracy. No point in assuming anything until you shoot it.. i had an older marlin 30-30 that looked like it was rifled with a cheese grater...that thing shot under 1 moa with irons on a bench... shoot it then decide what might or might not be needed..

 

[woodlotowner]

What is the rifle and chambering? New to you?

Winchester Model 70 Safari Express. Can you believe Winchester let that barrel out the door? I will shoot it and go from there. A shortened, or new, barrel may be in the cards.

 

[guntech]

Discovered this 3" from the muzzle. More than pitting, as the patched jag actually goes slack in the section of the bore. What effect will this have on accuracy. I know, shooting the rifle is the acid test, but what have been your experiences, if any, with similar conditions. No range days here in the foreseeable future.

Also, this is an expensive rifle with chatter marks from end to end in the bore.

View attachment 736172

A slack patch in this area of the bore indicates you once had an obstruction and fired through it slightly bulging the barrel. Usually a detriment to accuracy depending on how close to the muzzle it is... and it is rust pitting/corrosion not erosion from shooting.

A horrible looking barrel.

 

[woodlotowner]

If the gun dont shoot and you have the lenght cut the barrel. Or spin on a new one...pointless to go round and round on the issue until you have shot it. I had a 303 that had 4" of muzzle corrosion that still shot 2 moa with the iron sights.. i chopped that barrel back to 18.5" and it now shoots 1.5 moa with the irons....not much gain in accuracy. No point in assuming anything until you shoot it.. i had an older marlin 30-30 that looked like it was rifled with a cheese grater...that thing shot under 1 moa with irons on a bench... shoot it then decide what might or might not be needed..

Agreed. Range trip required at this point...

 

[woodlotowner]

A slack patch in this area of the bore indicates you once had an obstruction and fired through it slightly bulging the barrel. Usually a detriment to accuracy depending on how close to the muzzle it is...

A horrible looking barrel.

I am the new owner (recent). A previous owner is the culprit here. I don't think it was an obstruction, as it is just on one side of the bore and the 'divot' was likely caused by significant local corrosion from improper cleaning/storage. The site is corroded to the point that it replicates a partial bulge? Anyway, I'm going to shoot it and see what the accuracy is like. Shame on Winchester for letting this barrel out of the factory.

 

[tiriaq]

The machining artifacts are quite pronounced. Could contribute to metal fouling, probably would not affect hunting accuracy.

Given that it is a M70 Safari Express, perhaps rebarreling is in order. Whether that would be cost effective would depend on how much you have invested in the rifle.

 

[pathfinder76]

Safari Express’s have 3” too much barrel anyway.

 

[woodlotowner]

Safari Express’s have 3” too much barrel anyway.

You may be on to something there. A carbine is probably the way to go. Front sight be dammed.

 

[Hitzy]

Almost every Savage barrel I have bought new looks like that train track chatter mess under a bore scope. Still tend to shoot very well, I clean the #### out of them after every range session, after 600-700 rounds they smooth out and get really dialed in. When it hits that point, I start running moly coated bullets through it, not sure why, just seems to extend that accuracy point longer.
I've posted these pics here before, one is a Remington 7mm hammer forged barrel, other is a Vanguard hammer forged barrel. Both have seen several hundred rounds, the Vanguard bore is smooth as #### and doesn't foul at all. The rem is a little chattery, but still shoots very good, just still fouling significantly due to the chatter.

 

[Buckmastr]

Nothing I’ve seen here on a borescope picture is overly concerning to me. But when I hear that a tight patch loses pressure going down the barrel, I think barrel bulge which should be visible from the exterior. That’s new barrel or chop off material. A bit of rust is common with a lot of older rifles stored dirty in southern Ontario.

 

[SHELL SHUCKER]

You are correct. It is not erosion, but rather corrosion. I don't think further cleaning will improve the situation. Tell me that's not chatter in the bore either?
View attachment 736206 View attachment 736207

That be chatter from the button rifling method used on that barrel. Looks like Savage rifling on a good day.

Don't need a borescope when looking down the tube on my Savage 212 12 bore.