EXTENDING COMPETITION BARREL ACCURACY THROUGH BORE HONING MAINTENANCE

[pgcpty]

A colleague ISSF Competition shooting friend of mine just renewed his 6BR barrel after 4000 fired rounds. This fellow is our top performer and in his youth performed at Olympic level so he’s no slouch.

He told me that 6BR competition barrel life is typically around 2800 rounds after which accuracy falls off, so he extends barrel accuracy life by honing the first 8 to 10 inches of the barrel with valve grinding paste to dull/smooth the sharp edges from the pitting caused by powder erosion. He then finishes with JB Bore paste and uses a bore scope to monitor the process throughout.

His method is to wind a patch around a 6mm bristle brush applying the paste in oil around the patch. 20 strokes to the 1st 8 inches of the barrel using a cleaning rod and essential bore guide. Wash, clean and inspect both barrel and brush before repeating with JB Bore Paste, wash, clean and inspect before shooting.

I have read extensively about shooters full length honing barrels to reduce fouling but this exercise is a quantum level above that.

When we discussed this my friend said he tried it because he had nothing to loose, the barrel was close to its accuracy limit with groups opening up with too many shots being 10’s rather than 10X’s

The process restored accuracy and was repeated twice more before retiring the barrel.

My question is how many of our gunsmiths have experience with this technique and care to comment on it?

 

[simplerider]

sounds very close to what the Tubb throat maintenance system (TMS) is supposed to accomplish. Sounds like your friend is a bit more precisie though.

 

[338 Mollett]

I buy into it .For the last week I have talked to barrel makers about cleaning hence getting the old ,hard carbon out.When you shoot big overbore cartridges Like I do carbon is always an issue.So my question was in using the bore paste products how much harm is there?The worst build up is the first third of the barrel in my experience so I theorized what honing the bore paste will do the slight choke should take care of.This fellow seems to confirm that.

 

[afrench]

while, not the exact same procedure, some may find this interesting.

http://www.7mm.com.au/death-barrel/

 

[nhm16]

I use JB bore paste every now and then, using VFG felt pellets, and I can definitely feel more resistance in the first few inches of barrel.

 

[clowdis]

while, not the exact same procedure, some may find this interesting.

http://www.7mm.com.au/death-barrel/

This guy destroyed his barrel using brush only with paste in about 800 strokes in 800 rounds. He also didn't allow the brush/rod to rotate. I know a couple of shooters that have extended barrel life by using diamond lapping compound on a patched brush every 500 rounds or so and just lapping the throat area. Apparently this smooths the cracking in the throat and helps to give a few extra shots before the barrel becomes trash. I, myself, just use JB in the throat of my 7RSAUM but I can't quantify extra rounds yet. 1369 rounds and still shooting fine.

 

[butchlambert]

A colleague ISSF Competition shooting friend of mine just renewed his 6BR barrel after 4000 fired rounds. This fellow is our top performer and in his youth performed at Olympic level so he’s no slouch.

He told me that 6BR competition barrel life is typically around 2800 rounds after which accuracy falls off, so he extends barrel accuracy life by honing the first 8 to 10 inches of the barrel with valve grinding paste to dull/smooth the sharp edges from the pitting caused by powder erosion. He then finishes with JB Bore paste and uses a bore scope to monitor the process throughout.

His method is to wind a patch around a 6mm bristle brush applying the paste in oil around the patch. 20 strokes to the 1st 8 inches of the barrel using a cleaning rod and essential bore guide. Wash, clean and inspect both barrel and brush before repeating with JB Bore Paste, wash, clean and inspect before shooting.

I have read extensively about shooters full length honing barrels to reduce fouling but this exercise is a quantum level above that.

When we discussed this my friend said he tried it because he had nothing to loose, the barrel was close to its accuracy limit with groups opening up with too many shots being 10’s rather than 10X’s

The process restored accuracy and was repeated twice more before retiring the barrel.

My question is how many of our gunsmiths have experience with this technique and care to comment on it?

You're kidding?

 

[CatShooter]

A colleague ISSF Competition shooting friend of mine just renewed his 6BR barrel after 4000 fired rounds. This fellow is our top performer and in his youth performed at Olympic level so he’s no slouch.

He told me that 6BR competition barrel life is typically around 2800 rounds after which accuracy falls off, so he extends barrel accuracy life by honing the first 8 to 10 inches of the barrel with valve grinding paste to dull/smooth the sharp edges from the pitting caused by powder erosion. He then finishes with JB Bore paste and uses a bore scope to monitor the process throughout.

His method is to wind a patch around a 6mm bristle brush applying the paste in oil around the patch. 20 strokes to the 1st 8 inches of the barrel using a cleaning rod and essential bore guide. Wash, clean and inspect both barrel and brush before repeating with JB Bore Paste, wash, clean and inspect before shooting.

I have read extensively about shooters full length honing barrels to reduce fouling but this exercise is a quantum level above that.

When we discussed this my friend said he tried it because he had nothing to loose, the barrel was close to its accuracy limit with groups opening up with too many shots being 10’s rather than 10X’s

The process restored accuracy and was repeated twice more before retiring the barrel.

My question is how many of our gunsmiths have experience with this technique and care to comment on it?

You're kidding?

What Butch said!!!

 

[jden]

A colleague ISSF Competition shooting friend of mine just renewed his 6BR barrel after 4000 fired rounds. This fellow is our top performer and in his youth performed at Olympic level so he’s no slouch.

He told me that 6BR competition barrel life is typically around 2800 rounds after which accuracy falls off, so he extends barrel accuracy life by honing the first 8 to 10 inches of the barrel with valve grinding paste to dull/smooth the sharp edges from the pitting caused by powder erosion. He then finishes with JB Bore paste and uses a bore scope to monitor the process throughout.

His method is to wind a patch around a 6mm bristle brush applying the paste in oil around the patch. 20 strokes to the 1st 8 inches of the barrel using a cleaning rod and essential bore guide. Wash, clean and inspect both barrel and brush before repeating with JB Bore Paste, wash, clean and inspect before shooting.

I have read extensively about shooters full length honing barrels to reduce fouling but this exercise is a quantum level above that.

When we discussed this my friend said he tried it because he had nothing to loose, the barrel was close to its accuracy limit with groups opening up with too many shots being 10’s rather than 10X’s

The process restored accuracy and was repeated twice more before retiring the barrel.

My question is how many of our gunsmiths have experience with this technique and care to comment on it?

You're kidding?

My thoughts exactly Butch, So much wrong with this I don't know where to start so I wont.

 

[johara1]

He may be a good shooter,but he doesn't have a clue when it comes to barrels………. jim

 

[normmatzen]

Interesting smart a** comments to a serious question.

Let's see, how does the Australian team typically do against the USA teams in international competition?

 

[Keith Glasscock]

Seems like a bit of a presumption the all Australians treat their barrels to such lapping.

If they do, maybe we should compare competetive barrel life between lapped barrels and not. Of course, that's not something we can do over the internet.

I think that the Australian team does so well because they are not afraid to spend time, money, and effort to obtain their goals. Everything else is secondary.

 

[clowdis]

A colleague ISSF Competition shooting friend of mine just renewed his 6BR barrel after 4000 fired rounds. This fellow is our top performer and in his youth performed at Olympic level so he’s no slouch.

He told me that 6BR competition barrel life is typically around 2800 rounds after which accuracy falls off, so he extends barrel accuracy life by honing the first 8 to 10 inches of the barrel with valve grinding paste to dull/smooth the sharp edges from the pitting caused by powder erosion. He then finishes with JB Bore paste and uses a bore scope to monitor the process throughout.

His method is to wind a patch around a 6mm bristle brush applying the paste in oil around the patch. 20 strokes to the 1st 8 inches of the barrel using a cleaning rod and essential bore guide. Wash, clean and inspect both barrel and brush before repeating with JB Bore Paste, wash, clean and inspect before shooting.

I have read extensively about shooters full length honing barrels to reduce fouling but this exercise is a quantum level above that.

When we discussed this my friend said he tried it because he had nothing to loose, the barrel was close to its accuracy limit with groups opening up with too many shots being 10’s rather than 10X’s

The process restored accuracy and was repeated twice more before retiring the barrel.

My question is how many of our gunsmiths have experience with this technique and care to comment on it?

You're kidding?

My thoughts exactly Butch, So much wrong with this I don't know where to start so I wont.

OK guys, exactly what's wrong with this? How many of you shoot lapped bores? The only difference between what happens at the barrelmakers and what this guy is doing is that he's using a patch on a borebrush and lapping the throat about 20 strokes every 500 shots or so whereas barrelmakers use a lead lap. It ain't rocket science. You do need to be careful what lapping compound you choose as some of the valve grinding compounds will remove all the rifling in about 20 strokes.

 

[johara1]

We don't use valve grinding compound as he stated……… If you want to try that in your barrel go to it , I guess that will be another smart a$$ answer. I remember when Hart about bit his pipe off when you mention JB's ……… jim

 

[BoydAllen]

A friend of mine gave me a PPC barrel that I only had to slightly modify the tenon pitch diameter of to use on my primary benchrest rifle. It shows the start of some alligatoring, but the edges of the fissures are not as sharp as I would expect. It shoots lights out....seriously. When I asked my friend about the way that the back of the bore appears, he mentioned about one of the old benchrest/toolmaker greats telling him about using diamond paste. Barrels that are starting to show the kind of pattern that this one does, become tighter in the areas where the alligatoring is starting. I believe that there are two issues here, knowing what the appropriate material is, and how to use it, and having excellent control of the process. Beyond that there is the matter of people commenting on something that they have no experience with. Another friend, with exceptional mechanical skills and background, has managed to improve the accuracy of both factory and match grade chambered barrels. It is not for the clueless, clumsy, or feint of heart, but it has been done, the one requirement is a usable groove diameter at the muzzle. If that is too large, there is little that can be done with standard sized bullets. He uses cast laps.

 

[Jay Christopherson]

My sense is that something like this could work. But, like so many things, 99% of shooters don't have the knowledge, skills, or experience to pull it off or even attempt doing this and when they do the first time, it comes out badly. So, rather than work it out by trial and error, it's easier to just buy a new barrel and replace it and tell people it's impossible... :-\ (not pointing a finger at any posters on this thread because I have no clue if anyone other than the OP's friend has actually tried it, just a sweeping generalization)

This guy might have destroy 99 barrels working out a process that produces the result he wanted. I've seen too many absolutes disproven to dismiss the possibility out of hand.

 

[BoydAllen]

My talented friend learned his basics, for centerfire, after starting on RF, on one problem 7mm barrel, which he had rebored to .30 by a shop that I sent him to. When he got it back, he slugged it and looked at it with his borescope and pronounced it perfect. The reason that it was worth the trouble was that it was match grade stainless, and had been ordered fluted. This is not to say that he did not learn more on subsequent barrels, but none of them were rendered unusable in the process.

 

[pgcpty]

Re BoydAllen

EXTENDING COMPETITION BARREL ACCURACY THROUGH BORE HONING MAINTENANCE
« Reply #14 on: Today at 12:04 AM »

A friend of mine gave me a PPC barrel that I only had to slightly modify the tenon pitch diameter of to use on my primary benchrest rifle. It shows the start of some alligatoring, but the edges of the fissures are not as sharp as I would expect. It shoots lights out....seriously. When I asked my friend about the way that the back of the bore appears, he mentioned about one of the old benchrest/toolmaker greats telling him about using diamond paste. Barrels that are starting to show the kind of pattern that this one does, become tighter in the areas where the alligatoring is starting. I believe that there are two issues here, knowing what the appropriate material is, and how to use it, and having excellent control of the process. Beyond that there is the matter of people commenting on something that they have no experience with. Another friend, with exceptional mechanical skills and background, has managed to improve the accuracy of both factory and match grade chambered barrels. It is not for the clueless, clumsy, or feint of heart, but it has been done, the one requirement is a usable groove diameter at the muzzle. If that is too large, there is little that can be done with standard sized bullets. He uses cast laps.

Very interesting Boyd. My friend first picked up on this technique years back on a benchrest forum, by the way he only does this when the conventional end of barrel accuracy is becoming evident and uses his bore scope to closely monitor the process as honing progresses

Very surprised that Butch Lambert thinks this is all a joke!

 

[jden]

My talented friend learned his basics, for centerfire, after starting on RF, on one problem 7mm barrel, which he had rebored to .30 by a shop that I sent him to. When he got it back, he slugged it and looked at it with his borescope and pronounced it perfect. The reason that it was worth the trouble was that it was match grade stainless, and had been ordered fluted. This is not to say that he did not learn more on subsequent barrels, but none of them were rendered unusable in the process.

Boyd,
What you posted is old technology that was used sparingly back in the 70's and 80's. Now we just buy a new barrel or jump the chamber .050 or so if its a real good one. Same goes for honing process mentioned, Why bother with a barrel that has a few thousand rounds on it?

One other thing...In my 25 years of competition I have never heard or seen anyone using this method on a BR barrel for competition win anything.

 

[BoydAllen]

My friend that has done some lapping has not done it to extend the life of barrels, but rather to improve their performance, which he had done. The fellow that gave me the barrel did exactly as you said, after setting it back and the diamond paste work that I mentioned. As to the reason that anyone would bother, normally, I would agree with you, but this barrel has made me question that. It is extremely accurate. Only time will tell how long that will last, and it may be a while until I find that out, since I have set it aside. It was not the only barrel that he gave me, and I plan on using one or more of them to learn how to properly cast a lap, and use it to evaluate the interior dimensions, just as my friend does for every barrel he chambers, and every rifle that comes to him with accuracy problems that cannot be otherwise explained. From what I have seen, it is a great tool.