Barrel lapping

[Stimey]

I have been looking into lapping my new barrel, is there any home brewed ways of doing this?  I have posed this question else wheres without any results, how good are you guys here.  LOL Thanks for any responses.

[wncchester]

Wellll...for any of us to give you an intelligent answer we really need to know more.

What's the barrel, is it factory or custom, new or old, how does it shoot now, why do you want to lap it and what would you wish to accomplish?

And, how good are you with hand tools and home machine work?

[Stimey]

Sorry if I sounded as if I were questioning your intellagents, but anyway I have been a sheet metal mechanic/machinest/jack of all trades for 32 years, dont know if that qualifys me or not.  I am working on a Savage 17HMR Stainless, I am wanting to do this to help reduce fouling, as well as increase accuracy, I know I have been reading to much, but isnt that what all of us gun/fishing nuts do?  I am also doing a 223, both of these rifle are unfired and new.

[Keith L]

You might want to shoot it first.  My stainless Savage shot dime sized groups (5 shots at 100 yards on a calm day) as soon as I put a good trigger in it with the factory barrel, no lapping.  And I have never had a bit of fouling from it.  I have no reason to believe it can get any better than that.  Clean it good before shooting, though.  I dragged lots of chips and junk out of the bore with a patch, so I scrubbed it good with a brush prior to shooting it.

I think the new ones have an improved trigger.  Mine was junk, so I put in a Rifle Basics trigger, and epoxied in some washers to the synthetic stock so the barrel returns to the same place in the stock each time it is removed.  I also added a pad to the cheekpiece so my face fit the stock with the scope I put on it.  Other than that it is as it came from the factory.

[iiranger]

The Rifleman did an article... you take a rod in the barrel, brass welding rod works o.k. for larger bores, mil. surplus .30/ 8mm/ etc.. Cleaning rod with a brass brush you are willing to sacrifice...  Not sure i would trust it with .17. You put a collar around the rod. Tight patch. Like that. Go in from chamber is easier. Then you pour lead into the muzzle to make a plug. When it is cooled, solid, you push it out front. Wouldn't hurt to WD 40 the barrel inside first... Coat with your choice of "grit." "Valve Grinding compound" for auto valves is available at auto supply stores in varying grits. Jewlelers have "jewelers rouge" a very, very fine abrasive... Bon Ami. Toothpaste. Tooth Powder...  Pull back and forth until the barrel is smooth to your satisfaction or the plug is "worn" and loose. If you aren't through, smooth barrel or tired, do it again...

This was for smoothing military surplus barrels that had not been cared for welllllll... "NRA moon scape" surface... And barrels were probably "cut rifled" with tool marks ...

This was before the kits to shoot barrels with grit impregnated bullets.

POINT... Today most barrels are button rifled which much smoothes things. Rifling is "ironed" into the steel. Custom barrels are often lapped before rifling. Maybe after...

As suggested, since shooting is a lapping process, shoot it first. The target system, --shoot 1, clean for 5 shots; shoot 2 (or 3) and clean for 10 or 15 shots; shoot 5 and clean; And if the barrel is grouping... stop...

My bottom line, this is all BARREL WEAR! Each stroke uses up a part of the barrel's life. Your barrel, your call, but I would rather be sending bullets down the barrel than pulling a rod back and forth... ENJOY, happy trails...

[Stimey]

Thanks folks for the imput, I havnt got it to 100 yard yet, but it make one tiny ragged hole at 52 yards with 10 shots.  I hope 100 yard has as good of results as 52.  Thanks again for your help, I am still debating this in my head so further info is welcome.

[Cknerr]

The guys here are correct in that most barrels today do not need lapping. If it doesn't shoot, there is usually another reason.

However, if you think it really needs to be done.. then here are a few pointers.

I use a rod close to the diameter of the bore. Then using a patch to "align" it in the center of the bore, I pour lead down a heated barrel. Not real hot barrel, just enough so it will pour at least an inch down into the barrel without setting up first. You want about 1/2" of just lead in front of the rod. When you remove the plug & rod assembly, drill a small hole as close to center of the plug as you can. Screw in a wood screw, this is how you keep the plug from getting loose as it wears out. An 1/8 of a turn makes a big a difference. Make sure the edges of the screw DO NOT rub the bore!

I have a small handle I made about 18" long with a bearing in the middle. I stick the rod through the bearing and tighten a nut on each side. I think i forgot to mention the threading part earlier....Pulling and pushing with both hands on that handle makes life a whole lot easier.

Take about 5-10 strokes, ALWAYS the same number whatever number you decide on. Remove the plug, swipe on fresh polish and then clock the plug to the next rifling groove. You will have to figure out some way of keeping track. After being bored out of your gourd from all this, mistakes happen easily and then you have a problems. Make sure you go all the way/completely  around the clock  before you stop. IE. each groove gets the identical amount of work. This keeps the wear even. After a total of 400 strokes, you are probably done. Some barrels are worse then others and 400 wasn't even a close start.

BTW, this is how you also freshen a muzzle loader barrel. Just start with a lot rough grit and work your way up. I usually make a new plug for each grit.

It sounds like your rifle is doing pretty well, I doubt lapping is going to do much good. Lapping cmodern barrels helps more if you have a tight spot in the barrel. Rough barrels just shave the bullet a little until the "pot holes"  get filled in (paved over) with copper, then they are smooth and will surprise you at how well they shoot.

Good luck,
Chris

[quickdtoo]

Stimey, I would just use JB Bore non-embedding compound, Bore Bright, USP paste, Flitz, Mass, Simichrome or any fine metal polish on a patched jag and give it 50-100 strokes, changing patches every few strokes, and be sure to use a bore guide. I've done all 4 of my 17Hmrs and a 17MachII with this method, it cuts down the break-in time until you get the best groups, no need for the shoot-n-clean-shoot-n-clean ritual.

Works for me,

Tim

[Stimey]

Hey great info guys, I just wanted to thank everyone for the advice.  I might give it a while, and see how good this little rifle becomes, the groups just keep tightening up.  Can a rifle keep getting tighter groups untill the hole in the target is actualy smaller then the bullet itself?  Just kidding, thanks folks

[Rogue Ram]

I just asked Wayne at Oregunsmithing this very question as I have an issue with fouling that popped up on a gun that never exhibited these problems before.

As the guys here have pretty much said, its a rare bird that needs true lapping. Wayne detailed doing it about the exact way Chris just did. The plug is a necessity, if you just use a patch, you won't consistently lap all the surfaces in the barrel, especially the grooves. That said, I do what Tim does in conjunction with breaking in a new barrel and watched it work wonders on a Krieger barrel (but this was an already lapped barrel mind you).

Shoot it, if it groups, I wouldn't lap it.........in my case, uh, well, I found I have machine marks in the barrel  (don't ask me.....). I have one brand of ammo that shoots beyond good, and better than any handloads so I'm done with the rifle and won't lap it.

Good luck..

RR

[gunnut69]

Lead lapping a barrel is a fairly drastic step. I would go with the J-B to polish the bore first.. Also lapping a 17 is tough. It is very eaasy for the rod to damage the crown/chamber/or the bore. I would agree with the lap procedure except taking the lap from the bore. Move the lap out to the point where most of it is out of the barrel to charge with grit. I you take it out you should never rotate it to the next groove.. I have seen laps tightened with screws but they almost always tighten differencially causing problems. If the lap becomes loose run it out a bit and tap it on the end or better yet recast.. You cannot recut or freshen a bore with a lap but can use a lap with a groove for a cutter to recut a bad bore in a muzzle loader. Lapping is NOT a cure all. Firelapping or applying abrasives to cullets which are then fired thru the bore is very distructive. The throat is where the first impact of the abrasive laaced but is applied and where it cuts the most.. I've seen the throat lengthened to a point the barrel was junk by firelapping.  A bit of J-B is one thing, lapping is another. The valve grinding compound is a very poor idea also. It way too coarse. Abrasive powders are available from Brownells and 600 grit is for only very bad bores indeed... The last little thing is a caution I always try to point out, never try to fix what ain't broke. If the rifle shoots well why on earth would you consider the most potentialy distructive process a smith can use on the bore..