I've got a couple of rifles that just plain will not shoot worth a damn -- never have. One is a cheap gun with, let's say, less than precise tolerances. But the other is a 1960's vintage Safari-grade Browning FN .375 H&H. It was unfired when I got it. It will shoot a couple of bullets 2-2.5 inches, but most of the time it's a 3-inch gun. We've tried bedding the action, then bedding barrel and action, recrowning and trigger job, but it still won't shoot. I'm running out of options short of rebarreling, which I hate to do on a vingage gun like this if I don't have to.

So I thought I'd try fire-lapping. Does this work? Does it hurt the barrel? Which system is best?

I've read claims that fire-lapping will improve accuracy on just about any factory-barrelled rifle, but I want second opinions from you guys before I try it.

The cheap gun I don't care about. If it ruins the barrel, so be it. But the FN is something I don't want to screw up -- at least worse than it already is.

I don’t know you, so don’t take offense at this...but how much experience do you have with shooting heavy calibers like .375 H&H’s?

I very seldom shoot anything above 06’s and I’m a pretty fair shot...but hand me a .375 H&H and I doubt that my groups would stay the same size.

If you don’t have allot of time behind this rifle perhaps it would be helpful to have someone that shoots them allot try it out for you and see how he does with it...or have it fired from a mechanical rest that takes the human element out of the equation.

As for fire lapping, it isn’t going to hurt a bore with rough rifling and about the only problem that might crop up is if the barrel already has a worn throat area. Fire lapping can aggravate that a bit sometimes.

My take -- firelapping (or for that matter, hand lapping) definitely smooths imperfect factory barrels. They will look smoother and shinier, and less scrubbing will be required to clean them.

On the downside, I've never seen an accuracy improvement. Never. Never seen accuracy suffer either. It just didn't affect accuracy.

Firelapping can also erode the throat noticeably. Many factory rifles already have oversize throats, and firelapping will only worsen the situation.

McPherson (in his book, Accurizing the Factory Rifle) claims that fire lapping with cast bullets will erode the throat more than fire lapping with jacketed bullets. I don't know if that is true.

Saeed did an experiment,
http://www.accuratereloading.com/fire.html
and the results were kind of all over the place..

generally, the larger the bore, the better the improvement in groups.

I have been told this can also give you a couple more FPS...

the AR rounds will have the bores firelapped, after I can publish "real - to be expected" loads, and then will work on firelapping...

jeffe

I view fire lapping as a last resort type of thing to be tried only when ALL other approaches have failed.

The .375 H&H cartridge is known for being quite accurate, and the barrels used on the early Browning FN's were notorious for their accuracy capabilities. I don't know how many different loads you have assembled and tried, but before I attempted anything that could produce irreversible results like fire lapping, I would revisit the bedding, the crown and try a few more different loads.

Just out of curiosity, which specific bullets are you shooting? There are bullets out there where the quality (dimensions & consistency of production) simply aren't good enough to produce groups of 2" or smaller every time, on demand.

The number of those bullet brands/configurations seems to be getting smaller every year, thank goodness, but they do still exist.


N.B: I agree with Malm, again. I HAVE found fire-lapping to GREATLY omprove accuracy in some really bad barrrels, but I wouldn't even dream of using it in a good barrel unless absolutely every other option had been tried two or three times and had failed.

Let's see now, I've shot 270 grain Hornadys, 300-grain Hornadys, 270-grain A-Frames, 300-grain A-Frames, 260-grain Partitions and 260-grain Ballistic Tips. I've also shot Barns and Woodleigh solids (300 grain). Not to mention four or five boxes of different factory loads, with plain old Core-Lokts shooting the best.

I've tried Winchester brass, Federal brass, Remington brass and Norma brass. I've shot varying loads with IMR 4350, H 4350, IMR 4064 and Reloader 15. I've loaded bullets deep (to the cannelure) and out to the rifling.

I have considerable big bore experience, including owning another .375 H&H (Mark X) that shoots MOA with several different loads, as well as a 404 Jeffery (another MOA rifle), a .416 Rigby, and a .458 Lott. These go along with 20 or so other calibers I own with varying degrees of obtainable accuracy in all of them. I will add that I am rarely satisfied with accuracy results in most of my rifles. But 3 inches? Comon!

As it stands right now, I would not hesitate to use the rifle on dangerous game, but to be a one gun safari rifle (especially if leopard is in the mix), it has to do better than that.

quote:

Originally posted by GAHUNTER:
As it stands right now, I would not hesitate to use the rifle on dangerous game, but to be a one gun safari rifle (especially if leopard is in the mix), it has to do better than that.

With that rifle I would hold off pulling the trigger until I seen the whites of their eye's.

I noticed you didn't mention trying different primers. A primer alone can be responsible for a 3" group. Re-check the bedding. Tighten the guard screws, and then while holding the barrel and forearm with your left hand, loosen the front guard screw. IF you feel ANY movement, re-bed until you can't. Look the crown over real good under good lighting. Make sure that the ends of each individual land and groove is sharp and clean. Make sure that there is enough clearance between the barrel and the forend so that you cannot "force" the barrel to touch the stock at any point.

Check the scope and mounts. Before I would fire lap the barrel, I would even swap scopes one time to verify that that isn't the problem.

If all of this checks out and you are still convinced you need to fire lap your barrel to improve the groups, then follow the instructions and good luck.

Second malm's suggestion on primers. If you're using Magnum primers, try standard Large Rifle. It doesn't change the velocity much (if at all), but it tends to lower the peak pressure and probably changes the barrel's vibration nodes quite a bit. JJHACK changed his 375's groups from 1.5" at 100 meters to all-holes-touching, just by changing to LR primers.

Jaywalker

leon - with all you've done either rebarrel or trade the thing off. fire lapping even if it does any good, isn't going to improve a bad barrel that much

If anything, firelapping might help you if your barrel fouls, but it is highly unlikely that you'll see an accuracy improvement from this process... Firelapping also tends to stretch your freebore a bit, so you have to figure this as a possible drawback...

- mike

I have only firelapped one barrel. This was on a Winchester M70 push feed in 7x57. The barrel fouled so badly with just one box of ammo that accuracy which was already somewhat bad went even further down the crapper. Cleaning the barrel was a two day job, 8 hours the first day and at least 4 more the next, hence the firelapping.
Well, that helped the bore fouling problem but accuracy was sgtill crappy as hell witht he bullets doing 3 to 5" on an erratic basis. All screws were checked and found to be tight. The gun was glass bedded and a trigger job done, with no improvement. I was ready to dump the rifle off at the next gun show. While sitting in my shop thinking about what I had tried so far, I decided to replace the scope. The scope on the rifle was a brand new Leupold 4X. Well, when I tried the rifle out after the scope switch, the first group after sighting in was .375". Since then, no load has been larger than one inch and most much les that that.
Just my thought on you problem, try another scope you're positive works.
Firelap only as a last resort, and then, only if the barrel is a bad fouler.
Paul B.

With a rockem-sockem caliber like 375, I would suspect the scope, or the scope mounts first. I have heard of normal 6-48 scope mount screws sheared off from recoil---8-40s are better.

quote:

Originally posted by xs headspace:
With a rockem-sockem caliber like 375, I would suspect the scope, or the scope mounts first. I have heard of normal 6-48 scope mount screws sheared off from recoil---8-40s are better.

A good quality 6x48 screw, properly tightened will withstand the recoil from a .375 H&H. If they shear, it is probably because of a loose mount. But I agree, the 8x40 provides more strength.

I have firelapped one rifle and that was a levergun. My guidegun had three bulges in the bore and varied in measurements, so I had found out by "slugging" the bore.
Had another rifle that had "fliers" and I changed from the WLRP's to a FED 215 and what a tight shooter!
just my .02

good shootin

Hi GAHUNTER I had been working really hard to get a Model 70 to shoot untill I tried Barnes TSX ( I saw you tried Barnes but my guess is it was the solid) I tried the TSX as the last thing I had left to try before lapping and then maybe a barrel replacement. I could not be more pleased with the guns accuracy now !!

quote:

Originally posted by malm:



Check the scope and mounts. Before I would fire lap the barrel, I would even swap scopes one time to verify that that isn't the problem.

About two years ago, my deer rifle went nuts on me. Free floated the barrel, fire lapped the bore, and did every thing BUT check the scope. Was all set to trade it in on a nice Tika T3, when an old guy at the gun shop asked "Did you try the scope?"

After months of aggrivation, and much embarrasment, it was the scope. Funny thing is the fire lapping appeared to help some what, (the rifle shot better than before) but the new scope might have had an effect also.

This response is not so much toward the original question but more toward firelapping in general.
I have a Ruger 77 7mag that would shoot sub 1", then 1.5" then 2.5" groups. This happened every time and took hours to get the copper out. After extensive firelapping with jacketed bullets the rifle will shoot sub 1" for up to 10 groups with no cleaning.
I also had a 10" Encore barrel in 7BR that fouled badly. Again I firelapped a lot with jacketed bullets. Cleaned up the surface and eased cleaning but moved the throat out .180 in the process. The lesson there was to never get the lapping compound on the ogive, keep it on the parallel.
I also firelapped a heavy fouling 25-06, finally got it to clean a lot easier and now it shoots sub 1". That one, I think there was an accuracy improvement but I may have just found a better load along the way.
In general, I think firelapping is a good idea for bad fouling rifles, keep the compound off the ogive and I think it can be a real help in reducing the fouling. As far as accuracy, maybe? in the case of my 7 mag it certainly extended the accuracy to more than the first three shots. Improved it, I can't say.
Just my 2 cents.
Joe

I firelapped a .300 WM and a 6mm, both stock Remingtons. Both cleaned up a lot easier, and both have shot groups under .5 moa afterward.

Those are the facts I have. Hope it helps.

Fast Ed

Maine Woods beat me to it. You really need to try a few recipes with Barnes TSXs. Every gun I've tried them in REALLY liked them, especially the .375 Taylor. I'll suggest RE-15 but those other powders listed should be tried too. I'm going to have to try that Large Rifle instead of Magnum Primer thing myself....

MKane160