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Fire lapping

9K views 16 replies 11 participants last post by  saguaro Kid 
#1 ·
Can someone explain to me the benfits if fire lapping. Is it primarily for new guns or will an old gun benefit. I have a wild west guide gun with an 18.5 in barrel in .457 ww magnum. It has had about 100 rounds or so at least, bought it used so don't know for sure.
 
#2 ·
I have never done firelapping and do not know very much about it. That said, from what little I know :rolleyes: I don't think it will do too much good for you. I think it tends to be best with potentially "super accurate" guns. But even at that there is some controversy of it's effectiveness.

I would assume that it's best used in barrels with cut rifling. Cut rifle barrels can potentially have some machining burrs, whereas button rifled barrels are "smoother." But since you figure there has been already a 100 or so rounds through it, I doubt the lapping would do anything of real value as the the 100 rounds should have smoothed it out....

I think you would be best served by spending that money on ammo or bullets to reload.
 
#3 ·
It's ideal for your rifle if it still has the factory barrel. I don't know whether Wild West make their own barrels or rechambers the originals. Marlin stamps the heck out of their barrels, and there are constrictions on every dovetail.

Anyway, it will take you all of 5 minutes to slug it and find out.

Lapping is so cheap to do as to be ridiculous compared to the benefits. Scroll down to the "Tech Notes" section of the forum; or just order a copy of Marshall's book along with the supplies. You'll need the lapping compound, and at least 20 bullets to start with.

Lapping is practically required if you want to enjoy shooting cast bullets in your gun.

Hope that helps!
 
#4 ·
The super accurate rifles usually have hand lapped custom bores, and those rarely benefit at all. It's taking a rough commercial bore and removing constrictions and rough spots that is where the process shines. The military barrel in my first Garand would accumulate copper so fast it would lose accuracy in the middle of the slow fire prone stage of the National Match course, then take all night to clean out with Sweet's. After firelapping it stopped losing accuracy in mid-match and the accumulation of copper was so slow that a handful of patches would clean it out.
 
#5 ·
I bought a Rossi 92 in 45 Colt. I brought it home cleaned it and lubed it. Went down to the reloading shed, loaded up 10 rounds with course grit, 20 or 30 rounds of medium and a like amount of fine grit. Dropped 7 or 8 grains #800 powder in the cases. Should say that the bullets were 250 grain air cooled wheel weights, sized .454.
Fired the course grit cleaned the barrel, fired the medium grit, etc.
Rifle shoots great with 20 grains of H110, 300 grain cast bullet sized .454.
When I'm not plinking the gongs I use it as a house gun down stairs.

Jim
 
#7 ·
firelapping

Concur with unclenick...I have experienced results that range from marginal improvement to dramatic. Usually this occurs in conjunction with other changes that are made to the platform, none of which by it's self is dramatic but the combination often is. I think that a very large bore weapon used for occasional shooting probably does not need this treatment. I also believe that rifles intended for precision shooting will benefit if for no other reason than the ease of cleaning. As far as advise to a new shooter:

1. Shoot carefully, paying attention to fundamentals, as much as you can afford.
2. Start hand-loading as soon as you can. You will reap immediate benefits.
3. Remember that accuracy is a combination of things, rifle, ammunition, sights, and shooter.
4. Read every part of the handloading manual that comes with your equipment then...
5. Go to a site like varmint Al for sage advise
 
#8 ·
You might read or re-read the articles on the 444 in the tech section...it has some very good information. I fire lap or hand lap most of my cut rifle barresl but not the button rifled barrels.

Everyone has there own opinions and thoughts and can come up with good explainations of the why's and why not's to do or don't just about anything...it is like Cryo-ing a barrel or which crown is the most effective....EVERYTHING concerning shooting usually has additional things going on...one thing just never does the whole job.:confused:

BUT you will never know for certain what happens if you DON'T do the lapping thing...or maybe it will take you 500-1000 rounds to "wear it in"...which is just what fire lapping OR hand lapping does....it wears down the high spots and makes things shoot a lot better.

Just one more controversial subject to conflab about...it helps some, but not others and if it doesn't seem to help then it ain't worth sh**, if it does work, then it's the best thing since sliced bread...do it or don't but don't believe ANYTHING you read or hear and only half what you see...:eek::( :D Hahahahahahah

LUCK
 
#9 ·
I've read that fire lapping tends to smooth the barrel in degrees... more at the throat, and progressively less down the barrel to the muzzle.
If I had a rifle that I was concerned about, I would hand lap it. Fire lapping is an abbreviated process, albeit somewhat easier than hand lapping.
 
#10 ·
It's not quite the same. Hand lapping requires more time, effort, and skill to do. I prefer to use guides to prevent funneling the muzzle or throat (depending on which end I work from), and it's helpful to have a stop to prevent overshooting the far end. It only works on the lands and grooves of a bore and does not address tool marks in the throat. When you are done, you should have a straight, smooth bore surface without tight or loose spots.

Firelapping does clean the throat up. I have a throat wear gauge that allowed me to measure that it moved my Garand throat forward about one thousandth of an inch. Not enough to matter to shooting, and it's not like erosion wear, which actually damages the throat. Firelapped throats look very smooth and clean in the borescope.

With the right alloy hardness and a very light load, firelapping can taper a barrel narrower from breech to muzzle by maybe half a thousandth or so. That's considered desirable for lead bullet shooting, in particular. Whether or not that happens depends on the hardness of the lapping bullet. A harder alloy tends to straighten the bore and lose the taper. A lapping bullet that's either way too hard or way too soft tends not to remove constrictions, but rather to polish the bore evenly all over. This happens because the hard bullet will spring outward elastically after passing through a constriction, while one that's too soft will bump up under pressure after passing through one.

From the above, there is a nominal range of hardness for firelapping with cast bullets. In general, it is recommended to stay within the range of BHN 10-14.
 
#11 ·
When needed, I hand lapped barrels for many years. It is quite an arduous task. A couple of years ago, I tried out Marshalls lapping kit. Since that time, I have firelapped exclusively, and the results have been outstanding in both rifles and handguns. Unless you are shooting match grade barrels where lapping is unnecessary, firelapping will definately improve accuracy, velocity, and reduce fouling.
 
#12 ·
What you say is true Uncle...that's what I was hinting at with the "sliced bread" comment without going into any details. Most shooters will buy a "firelapping Kit", follow the steps and have NO IDEA the "what's and why's" going on in the background. If it DOES work, it's great...if not...well maybe you've read some of the exceedingly hot flames produced by "failures" on many forums.

BUT, the merchandise being sold is that a smoother barrel will shoot more accurately AND be easier to clean...and as far as a factory hunting barrel, that's about all you can ask for. AND it does work fairly well even on 100 year old military barrels. Hardly anyone even knows OR cares about the nuances that are happening, they just want the illusion.

I quit doing lead lap lapping way back when, much preferring to use a fairly snug cottom mop or patches wrapped around a jag and fine valve grinding compound to get the worst of the bark nocked off, then the pleasure of shooting took care of the rest...I never thought to use grit on a bullet and actually fire it down my barrels...you know the mantra of "clean ammo"...

John Barsness did a very interesting article on barrel lapping in the Nov, 2001, #198 RIFLE magazine that might be of some help to those thinking of barrel lapping.

The thing about it is the fact of "NON-UNIFORMITY" in all aspects of firelapping...I've read to lap at low velocities at one place...higher velocities around 2000fs at another, use ANY old cast lead bullet, use ANY bullet period, and TUBBS NECO sells their kits for use with lead, jacketed AND also coated JACKETED bullets...pretty good merchandizing and a way to turn a couple thousand percent profit(or more) on silicon carbide grits and bullets, at least until everyone else jumps in and screws up the market.

I just bought 4 oz of 320 grit paste from Brownells, ~$18, for firelapping a 444S barrel and used a gob the size of a pea to do 10 - 265 gr hard cast bullets and that left enough on the steel flat bars to do at least another 25 or more.

I bought a jug of 600 grit about 30 odd years ago I've been using to POLISH many of my barrels, bolts, raceways, small parts etc and also used the stock polish Brownells sold back then...they all worked to a greater or lesser extent...at least in my mind.:D

The people who sell hand lapped barrels have their own procedures and those that use a lead lap follow well established fairly old procedures, but otherwise it's...who knows what.

Maybe the fact that firelapping within the specified parameters DOESN'T ruin many barrels and actually does some good, keeps the lawyers away.:eek:

LUCK
 
#15 ·
Try 4 to 5 grains of Bullseye or Red Dot. Start at the higher figure, you can work down if it doesn't stick bullets or goes too fast to suit you.
 
#16 · (Edited)
I see Mike beat me to it. Yes, a catsneeze load is all you need. I used 5 grains of Bullseye, but 5.5 of Unique or Hodgdon Universal will do about the same thing.
 
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