Barrels really do make a difference

[Smokinyotes]

I’ve got a Tikka T1X and a 10/22 with a Volquartsen barrel on it. I had never looked in either barrel with a borescope until tonight.
Between the 2 guns they have been fed a diet of SK rifle match. Closing in on 10,000 rounds between the 2 of them (significantly more through the 10/22). I figured it was time to clean them. After looking into the Tikka the barrel was heavily powder and carbon fouled. It looked like the barrel had been painted black on the inside with the odd spot of grey. Took almost an hour to get it clean with iOSSO paste and iosso brush.
Onto the volquartsen barrel, to my surprise the barrel was bright and shiny the entire length with the exception of about an inch right at the throat. What was in the throat cleaned up in a couple minutes.

 

[.22LRGUY]

I would be interested in knowing what factors resulted in that difference between the two? Bore polished on the VQ/smoother finish? VQ barrel carbon steel like the Tikka T1x?

 

[Smokinyotes]

I would be interested in knowing what factors resulted in that difference between the two? Bore polished on the VQ/smoother finish? VQ barrel carbon steel like the Tikka T1x?

Looking with the borescope the VQ does look very smooth with no imperfections. I’m not sure what steel is in it but it is a carbon wrapped barrel.

 

[RRCo.]

I was cleaning one the other night which I'm sure was neglected in the past and after lots of brushing and wiping decided to give it the old kettle full of boiling water down the bore; easy since I have the right funnel.

Made a remarkable difference and I put that down to the thermal expansion and contraction freeing off a lot of the congealed or hardened fouling. Had a lot of roughness and apparently worn rifling up to about a foot ahead of the chamber. The difference afterwards was striking and I put that down to thermal expansion and contraction breaking loose a lot of the hardened deposits.

 

[grauhanen]

The characteristics of the surface of the bore will have a considerable effect on how it accumulates fouling and detritus and how readily it can shed them. A 20 inch barrel will have around 12 square inches of bore surface area, a 16 inch barrel near 10 square inches. The rougher the surface the more it will have fouling stick to it and the more stubbornly it will retain it.

 

[Sun_and_Steel_77]

Make a difference for what exactly? Aesthetics through a bore scope? Pride of ownership?

My unmodified T1X is hands down the most consistently accurate rimfire rifle I have ever owned...period.
I have owned and shot extensively heavily modified 10/22's with barrels manufactured by Kidd, VQ, Green Mountain, WhistlePig, and others I've probably forgotten. Only the Kidd barrel would give my T1X a run for its money.

The same rules apply here for centerfire barrels...I have seen some barrels that look hideous through the borescope but shoot lights out. It is nice to have a well finished centerfire barrel that resists fouling and reduces time between cleaning but it isn't nearly as important with a rimfire barrel.

I clean my rimfire barrels once a year if I'm feeling ambitious and most shoot like dog crap until they are well "fouled" again.

 

[AikiNut]

does anyone cast a lead lap in their barrel and run valve lapping compound through the bore before starting to use a new rifle?

 

[adamg]

does anyone cast a lead lap in their barrel and run valve lapping compound through the bore before starting to use a new rifle?

That's the barrel manufacturer's job. They are supposed to do that before they ship it out. All quality barrel manufacturers do that.

 

[_Shorty]

Lapping a finished barrel is likely to ruin shooting precision. The lapping process results in bell-ending the bore at the ends due to the difficulty of keeping the lapping rod straight, so you have to cut the ends of the barrel off during the fitting process. That kind of material removal on a finished barrel, where the bore gets enlarged at the ends, is going to ruin how the bullet exits. It is very important that the bore be uniform up to the muzzle, and even better to have a slight choke with the muzzle/crown actually being the tightest point in the bore. This is one of the big reasons for wanting a custom barrel, the lapping process. Factory barrels usually do not get that kind of treatment, making it a desirable feature of a custom barrel. But it is something that needs to be done before you cut the chamber and cut to length so that the enlarged ends are either cut off to make the muzzle end or enlarged even further by cutting the chamber. That way the remainder of the bore is as uniform as possible.

 

[eco]

Oh no. You just poked the tikka nuts nest. Watch em all come out to give you their piece of mind on their holy tikkas

 

[Leuchtkafer]

Lapping a finished barrel is likely to ruin shooting precision. The lapping process results in bell-ending the bore at the ends due to the difficulty of keeping the lapping rod straight, so you have to cut the ends of the barrel off during the fitting process. That kind of material removal on a finished barrel, where the bore gets enlarged at the ends, is going to ruin how the bullet exits. It is very important that the bore be uniform up to the muzzle, and even better to have a slight choke with the muzzle/crown actually being the tightest point in the bore. This is one of the big reasons for wanting a custom barrel, the lapping process. Factory barrels usually do not get that kind of treatment, making it a desirable feature of a custom barrel. But it is something that needs to be done before you cut the chamber and cut to length so that the enlarged ends are either cut off to make the muzzle end or enlarged even further by cutting the chamber. That way the remainder of the bore is as uniform as possible.

Close, but what actually happens is that both ends of the bore get restricted. The lap is not pushed completely through the muzzle end or withdrawn completely from the breech end, so these areas see less cutting action compared to the rest of the bore that has the full length of the lap passing it. All good for the muzzle end, but restrictions ahead of the chamber kill barrels. A minor amount of lapping can be done to a finished barrel, gunsmiths that focus on benchrest builds consider it essential to help season the leade of a freshly cut chamber and get the barrel competitive sooner. How much lapping can be done to a finished barrel before killing it remains a dark art, even experienced lappers push their luck and mess it up sometimes. There shouldn't be an issue keeping the lapping rod straight as a jig should be used or one is liable to run the rod across the top of the lands and really do some damage.

does anyone cast a lead lap in their barrel and run valve lapping compound through the bore before starting to use a new rifle?

Not a great substance to use, some random products I looked up are 120 grit and that's too coarse. I got some 280 and 400 grit powder from Lee Valley and all you have to do is suspend it in oil. It's a risky operation as detailed above but done right would benefit many factory rifles. If you've got a barrel that only shoots 1" groups at 50 yards you've got nothing to lose by trying it as the barrel is a tomato stake anyway.

 

[_Shorty]

I'm not close. I'm correct. "The lap is not pushed completely through" means a portion of it is still in the bore so you can easily push it back the other way again without having to reinsert it. Some of it is sticking out and lateral forces can then be involved. (Even on the muzzle end opposite of where you're working the rod.) This is literally what causes the bell-ending/bell-mouthing, and is why you normally do not do this job on a finished barrel. As I said, it is difficult to control the rod at the ends in order to avoid those lateral forces. When the lap is in the middle of the length it is controlled by the bore and more or less cannot do anything you do not want it to do. It is the partially inserted and partially sticking out state at the ends where the problems come up because lateral force is then possible. Again, you usually do not do this job on a finished barrel for this reason. If one chooses to undertake the task with a finished barrel then you've got to be careful not to work the muzzle end at all so it does not get bell-mouthed at all. You'd then try to avoid having the lap exit at all on that end. But you're still much better off doing this on the blank before you do the machining work so that you're getting rid of the ends anyway. It is indeed unusual to undertake this job on a finished barrel because of the risk of ruining it that is involved. Might as well fire-lap it like David Tubb if you want to do that work on a finished barrel. Lapping without partially exiting either end is going to leave a restriction, as you mention, but that restriction is only going to be desirable on the muzzle end. Slightly choked muzzles tend to shoot better. But having that kind of restriction on the chamber end is not desirable at all, and you would not want that. You want it to be as uniform as possible for the entire length, save for some choke at the muzzle if you want some choke at the muzzle, which you probably do.

 

[Leuchtkafer]

How are lateral forces applied if the rod cannot move laterally?

 

[_Shorty]

How are lateral forces applied if the rod cannot move laterally?

While the guide will certainly reduce the chances of the rod flexing, the rod is not perfectly rigid, and the chances of the lap being perfectly formed in aligned fashion on the rod are low, too. The guide will reduce the chance and amount of flexing, not eliminate. And it is kind of difficult to ensure the lap is formed in alignment unless you've got some way of guiding both ends and still being able to pour molten lead in. That misalignment, even if small, means when a portion of it is protruding it is possible for there to be unwanted lateral forces, even when taking measures to reduce the possibility as much as possible. If you're happy performing this operation on finished barrels, be my guest. Personally, I'm only comfortable with it being done where the portions that are likely to be bell-mouthed are being cut off before the barrel is finished. The ability to achieve a more uniform bore, and some choke if desired, where desired, is much more likely in that case. The extremes where the bore starts and finishes is where unwanted characteristics are possible, and they are much less likely everywhere else. So when you intend to cut that portion off and discard it anyway, it isn't a concern. Is it a big enough concern to be worth worrying about? That could be said of all operations involved in building a gun, and everybody has different expectations and acceptable allowances. How much precision is one chasing?

 

[jparent]

Oh no. You just poked the tikka nuts nest. Watch em all come out to give you their piece of mind on their holy tikkas

I'm no Tikka nut, in fact I've often remarked on this forum how I have sold several Tikka's over the years to buy "lesser" rifles I preferred more. However I agree with Sun_and_Steel_77 the T1x is the most consistently accurate rifle I have owned. My fiancé has one as well and it is the same. Really hard to beat in it's class.

 

[Leuchtkafer]

While the guide will certainly reduce the chances of the rod flexing, the rod is not perfectly rigid, and the chances of the lap being perfectly formed in aligned fashion on the rod are low, too. The guide will reduce the chance and amount of flexing, not eliminate. And it is kind of difficult to ensure the lap is formed in alignment unless you've got some way of guiding both ends and still being able to pour molten lead in. That misalignment, even if small, means when a portion of it is protruding it is possible for there to be unwanted lateral forces, even when taking measures to reduce the possibility as much as possible. If you're happy performing this operation on finished barrels, be my guest. Personally, I'm only comfortable with it being done where the portions that are likely to be bell-mouthed are being cut off before the barrel is finished. The ability to achieve a more uniform bore, and some choke if desired, where desired, is much more likely in that case. The extremes where the bore starts and finishes is where unwanted characteristics are possible, and they are much less likely everywhere else. So when you intend to cut that portion off and discard it anyway, it isn't a concern. Is it a big enough concern to be worth worrying about? That could be said of all operations involved in building a gun, and everybody has different expectations and acceptable allowances. How much precision is one chasing?

OK, there seems to be some conflicting views on what happens to the ends of the barrel from lapping. I don't care about being "right", I'm just interested in what the truth is. Are you aware of any concrete published data of bore measurements before/after lapping? Have you lapped barrels yourself and taken measurements, if so, could you share your data? I've done some lapping myself but didn't do any measuring, so I don't have any data on this. I can say that from slugging after, none of them have felt like the muzzle opened up, still gave me the choke effect.

Some basic principles of lapping are that any major profiling work like taper lapping or removal of a flaw like a mid-bore restriction should of course be done on an unfinished blank before chambering or crowning. There are few reasons to lap a finished barrel, one being to help a freshly cut chamber smooth out and the other to remove a phenomenon referred to as "glazing" that can occur in stainless barrels. The thought of lapping a finished barrel gives me the butterflies but if I never roll up my sleeves and do it, perhaps screw it up a few times too, I'll never learn the art of it.

I need another project like I need a hole in my head, I'm just swamped with work for several months. I do have a couple scrap barrels lying around that could be used for a lapping experiment to take measurements before and after, actually gather some empirical evidence on this subject. I just can't prioritize such a side quest while I've got things to do that are important to me for the short shooting season we are now in. Add it to the list, lol.

 

[_Shorty]

OK, there seems to be some conflicting views on what happens to the ends of the barrel from lapping. I don't care about being "right", I'm just interested in what the truth is. Are you aware of any concrete published data of bore measurements before/after lapping? Have you lapped barrels yourself and taken measurements, if so, could you share your data? I've done some lapping myself but didn't do any measuring, so I don't have any data on this. I can say that from slugging after, none of them have felt like the muzzle opened up, still gave me the choke effect.

Some basic principles of lapping are that any major profiling work like taper lapping or removal of a flaw like a mid-bore restriction should of course be done on an unfinished blank before chambering or crowning. There are few reasons to lap a finished barrel, one being to help a freshly cut chamber smooth out and the other to remove a phenomenon referred to as "glazing" that can occur in stainless barrels. The thought of lapping a finished barrel gives me the butterflies but if I never roll up my sleeves and do it, perhaps screw it up a few times too, I'll never learn the art of it.

I need another project like I need a hole in my head, I'm just swamped with work for several months. I do have a couple scrap barrels lying around that could be used for a lapping experiment to take measurements before and after, actually gather some empirical evidence on this subject. I just can't prioritize such a side quest while I've got things to do that are important to me for the short shooting season we are now in. Add it to the list, lol.

Conflicting views in the firearms world?! That's unpossible! hehe. No, I have not lapped any myself. Not even firelapped, though I did contemplate trying that with at least two barrels/guns that I wasn't happy with, hah. I am only going off of what I have read over the years in some articles on the subject and discussions on forums with people that do that kind of work, and what makes sense to me from a physical standpoint. I might be able to, but I'm not sure I could even find the sources I've read again after all this time, but I'm sure some googling would reveal people on both sides of the fence, as it typically does.

I'm sure if you were careful about how you worked the muzzle end you'd be more than capable of not ruining/removing any choke that's already there. Removing less/no material is as simple as not lapping in that location, after all. Which would simply involve not allowing the lap to go far enough to do so, and that would definitely avoid having it protrude and potentially do something you don't want it to do. But that would also not clean up that region, so you'd have to decide and/or experiment to find out how much material you're willing to work in that region. On the other end, it might be less risky around the chamber to try to maintain uniformity with the middle section of the bore. But I'm not sure I'd want to do that on a finished barrel, as was already mentioned. Experimenting and attempting to learn on a throwaway barrel is one thing, but trying to actually attain a very precise rifle is another. I'd want to avoid as many shortcuts as possible in the case of the latter and just ensure as much was done as ideally as possible. And as far as barrels go, that would entail leaving lapping up to the custom barrel maker, for me.

 

[grauhanen]

I have no stake in the question of to lap or not to lap.

I'm not sure I could even find the sources I've read again after all this time,

Shorty, one of the sources you may have read is what Dan Lilja (of Lilja barrels) has written on the subject of hand lapping a barrel. Like you, Lilja recommends against lapping production or factory barrels -- that is, those that are already cut to length and crowned and chambered. In "The Making of a Rifle Barrel" (posted online in 2015) he says the following:

For those who think that lapping a production barrel or a factory barrel could improve its performance, I’ll offer a little advice: don’t do it. Lapping will wear both ends of a barrel oversize. If the barrel has already been cut to length and crowned as well as chambered, this would most likely cause more harm than good. The barrel would become oversized in both the critical muzzle and throat areas. Accuracy would probably suffer.

See https://riflebarrels.com/the-making-of-a-rifle-barrel/

___________________________________

For the lapping curious, Lilja explains that hand lapping is performed on custom barrel blanks only before they are cut to length and chambered.

Since some readers may not be familiar with the term lapping, I’ll describe it briefly. A lap is cast inside of the barrel and is attached to a rod similar to a cleaning rod. An abrasive is “charged” into the lap, and it is then pushed and pulled through the barrel. The object is to improve the surface finish and make the size uniform from end to end. In practice, lapping is performed by hand and is a time consuming process, requiring a good deal of experience and feel if the results are to be successful. Another advantage to lapping is that the surface finish will be parallel with the rifling. Only the best quality match grade barrels are hand lapped. No production grade barrels are.

Readers looking for more information on barrel making and the processes involved, including hand lapping, see the excellent summary by Geoffrey Kolbe http://www.geoffrey-kolbe.com/articles/bmart.htm

 

[_Shorty]

Thanks for those links. I'll save them this time. haha. I've definitely read both of those in the past. After work I'll have a look to see if I can still find the others, as I seem to recall more reading material than just those two.