this thread if you're considering lapping. It's a long address, but works with cut and pasts.
http://www.darrendong.com/tactica....ums.htm
God bless,
http://www.darrendong.com/tactica....ums.htm
God bless,
Barrel lapping by gail mcmillan
1 - 6 of 6 Posts
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Interesting thread! I can see McMillan's point on match-grade, hand lapped custom barrels. In the real world of factory barrels I think firelapping has it's place for certain applications and plenty of people have gotten good results.
As far as JB's goes, I used to participate on another forum where I got into a discussion about the abrasiveness of JB's, with my position being that it IS abrasive and I thought that excessive use would change barrel dimensions. After reading Gale's observations with a bore scope all I can say is "Nyah nyah, told ya so" to those guys! <!--emo&
--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=''><!--endemo--> ID
As far as JB's goes, I used to participate on another forum where I got into a discussion about the abrasiveness of JB's, with my position being that it IS abrasive and I thought that excessive use would change barrel dimensions. After reading Gale's observations with a bore scope all I can say is "Nyah nyah, told ya so" to those guys! <!--emo&
--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=''><!--endemo--> ID
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36 Posts
Definately some serious food for thought here.
In my extremely limited experience I have found fire lapping to be a help "fixing" barrels that are still basically sound but in need of help. I also have used "JB's" on occassion but may rethink that one.
I notice Mr. McMillan regards the "rounding" of the rifling lands as being detrimental to match grade accuracy. I have also noticed that the proponents of polygonal so called rifling use the fact that the polygonal stuff is rounded & CLAIM that this decreases friction & therefore increases velocity with less bullet defromation & therefore are supposedly a more accurate barrel.
Any thoughts on this??
[ don't get me wrong I am NOT contradicting Mr. McMillan, I respect his expertise -I use a McMillan rifle on job & have two of my own rifles using McMillan stocks. Being an old dinosaur I firmly believe that just like ALL motorcycles are ONLY American made V-Twins & are chain driven, ALL rifle barrels of any worth are cut rifled, period.]
In my extremely limited experience I have found fire lapping to be a help "fixing" barrels that are still basically sound but in need of help. I also have used "JB's" on occassion but may rethink that one.
I notice Mr. McMillan regards the "rounding" of the rifling lands as being detrimental to match grade accuracy. I have also noticed that the proponents of polygonal so called rifling use the fact that the polygonal stuff is rounded & CLAIM that this decreases friction & therefore increases velocity with less bullet defromation & therefore are supposedly a more accurate barrel.
Any thoughts on this??
[ don't get me wrong I am NOT contradicting Mr. McMillan, I respect his expertise -I use a McMillan rifle on job & have two of my own rifles using McMillan stocks. Being an old dinosaur I firmly believe that just like ALL motorcycles are ONLY American made V-Twins & are chain driven, ALL rifle barrels of any worth are cut rifled, period.]
Very interesting thread.
It made me think. I have never made a deliberate act of "breaking in" a rifle barrel.
When I first get a new, or new to me gun, I strip it down, clean it real good.
On used rifles I usually sop the bore with Hoppes and turn it muzzle down on a thick rag. All the brass fowling and yucky stuff flow out that way. This might have to be done a coulpe times, but I get them clean with no excess wear that way.
Then I just go and shoot them.
It made me think. I have never made a deliberate act of "breaking in" a rifle barrel.
When I first get a new, or new to me gun, I strip it down, clean it real good.
On used rifles I usually sop the bore with Hoppes and turn it muzzle down on a thick rag. All the brass fowling and yucky stuff flow out that way. This might have to be done a coulpe times, but I get them clean with no excess wear that way.
Then I just go and shoot them.
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39,116 Posts
This is just fascinating! Anyone who hasn't read this, it will really get the wheels turning in your head re: barrel breaking, lapping, and so on.
Here are my thoughts:
First, the obvious conclusion to me was, if barrel break-in isn't necessary, then we should at least recognized that within the first few hundred rounds of bullets (jacketed) that our barrel is undergoing some polishing and changing of dimensions, which all may affect accuracy. So.... trying to work up a load right away might not give the same results down the road. The primary advantage to the break-in process would be that we can start on our load development sooner.
Second, that discussion was obviously geared toward jacketed bullets and high velocity cartridges. We should not be quick to make blanket judgements when the scenario changes, that is, our .44 Mag Super Blackhawk w/lead bullets at 1200-1300fps is going to have different characteristics / needs than the .22-250 w/40gr. Ballistic Tips at 4,000+fps.
Something like lapping a revolver to remove the barrel choke is night and day from lapping a benchrest rifle barrel.
I have personally found that typical new factory rifle barrels, when used with jacketed bullets, will smooth up soon enough anyway. However, revolvers with lead bullets often need some help, whether they have a choke under the threads or just foul a lot with lead.
Also, the additional bore wear from lapping or any break-in process is largely meaningless if the gun will shoot a steady diet of lead bullets from then on. Lead bullets have been shown to increase barrel life significantly, this has been documented many times. Even Elmer Keith mentions it in his book Sixguns.
I do use some mild abrasives from time to time and feel that they have their place. For example... I got a .22-250 from my dad which had a rough throat. He had built this thing many years ago, before the good copper solvents that we have today were available. The throat was rough, even after using my Outers Foul Out. So I used a tight patch, wrapped around a brush, and scrubbed it out with the Remington bore cleaner which is mildly abrasive.
Throats is now smooth and fouling problems are gone. I believe that for the most part the abrasives helped clean the crud out of the throat, and did not harm the rest of the barrel.
However.... on my other rifles, which did not have rough spots in the bores, I do not use abrasives to clean. First few times it takes a while to get the copper out, after that it is easier and easier.
I have lapped a number of revolver barrels and have found significant reduction of lead fouling after lapping. I am NOT worried about wearing out any .44 mag barrels... the majority of my shooting is in the 1,000-1,100 fps range with lead bullets. The barrels ought to last forever.
Well... any other thoughts?
Here are my thoughts:
First, the obvious conclusion to me was, if barrel break-in isn't necessary, then we should at least recognized that within the first few hundred rounds of bullets (jacketed) that our barrel is undergoing some polishing and changing of dimensions, which all may affect accuracy. So.... trying to work up a load right away might not give the same results down the road. The primary advantage to the break-in process would be that we can start on our load development sooner.
Second, that discussion was obviously geared toward jacketed bullets and high velocity cartridges. We should not be quick to make blanket judgements when the scenario changes, that is, our .44 Mag Super Blackhawk w/lead bullets at 1200-1300fps is going to have different characteristics / needs than the .22-250 w/40gr. Ballistic Tips at 4,000+fps.
Something like lapping a revolver to remove the barrel choke is night and day from lapping a benchrest rifle barrel.
I have personally found that typical new factory rifle barrels, when used with jacketed bullets, will smooth up soon enough anyway. However, revolvers with lead bullets often need some help, whether they have a choke under the threads or just foul a lot with lead.
Also, the additional bore wear from lapping or any break-in process is largely meaningless if the gun will shoot a steady diet of lead bullets from then on. Lead bullets have been shown to increase barrel life significantly, this has been documented many times. Even Elmer Keith mentions it in his book Sixguns.
I do use some mild abrasives from time to time and feel that they have their place. For example... I got a .22-250 from my dad which had a rough throat. He had built this thing many years ago, before the good copper solvents that we have today were available. The throat was rough, even after using my Outers Foul Out. So I used a tight patch, wrapped around a brush, and scrubbed it out with the Remington bore cleaner which is mildly abrasive.
Throats is now smooth and fouling problems are gone. I believe that for the most part the abrasives helped clean the crud out of the throat, and did not harm the rest of the barrel.
However.... on my other rifles, which did not have rough spots in the bores, I do not use abrasives to clean. First few times it takes a while to get the copper out, after that it is easier and easier.
I have lapped a number of revolver barrels and have found significant reduction of lead fouling after lapping. I am NOT worried about wearing out any .44 mag barrels... the majority of my shooting is in the 1,000-1,100 fps range with lead bullets. The barrels ought to last forever.
Well... any other thoughts?
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5,224 Posts
If you bring home a new HUNTING gun (rifle or pistol) and clean the packing crud from it, load it and shoot with factory ammo and get 1-1.5" groups at 100 yards, leave it alone. Clean as needed, nothing harsh, no chemicals that will pit, no abrasives. Chances are, especially if you handload, you will find a load good enough to accomplish what you need it to do and shoot extremely well. Especially after "fire forming" the brass to fit your chamber. If you get more than 1.5 MOA from the factory with factory loads, other avenues should be sought out. The first of which is to try to find a load the rifle likes. If that turns out to be impossible, let the manufacturer know. Any factory rifle these days should be able to give 1.5 MOA right out of the box, if it doesn't something is wrong and it's not the consumer's responsibility to correct the manufacturer's mistake. If you are bound and determined to make the rifle shoot, try what you like, but this is the manufacturer's responsibility as far as I'm concerned.
I don't know, but maybe I've been lucky, most rifles and handguns I've purchased have shot fairly well. Some have had serious problems and the manufacturer has corrected it (except for the rude people at Remington). Granted accuracy may not have come with the first load I've tried, and sometimes I've had to cook up some interesting loads, but most of the rifles will shoot. If you demand 1/2 MOA from your rifles, you may have to a bunch of things including glass bedding the action, lapping the lugs, free floating the barrel, etc... Don't expect a factory rifle to shoot that well right out of the box, but with today's technology, AutoCAD, CNC machining, etc... 1.5 MOA with brand A ammunition is surely to be expected. Don't settle for an inferior product (whether it be a Monday or Friday rifle). Hold the manufacturer accountable for their product.
I don't know, but maybe I've been lucky, most rifles and handguns I've purchased have shot fairly well. Some have had serious problems and the manufacturer has corrected it (except for the rude people at Remington). Granted accuracy may not have come with the first load I've tried, and sometimes I've had to cook up some interesting loads, but most of the rifles will shoot. If you demand 1/2 MOA from your rifles, you may have to a bunch of things including glass bedding the action, lapping the lugs, free floating the barrel, etc... Don't expect a factory rifle to shoot that well right out of the box, but with today's technology, AutoCAD, CNC machining, etc... 1.5 MOA with brand A ammunition is surely to be expected. Don't settle for an inferior product (whether it be a Monday or Friday rifle). Hold the manufacturer accountable for their product.
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