Firelapping-you either love it or hate it. Most systems advise rolling a boolet in compound.
The Puff-lon system differs, filling the case with progressively finer grits. Anybody here have experience with their system?
Respectfully,
Bill
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Firelapping-you either love it or hate it. Most systems advise rolling a boolet in compound.
The Puff-lon system differs, filling the case with progressively finer grits. Anybody here have experience with their system?
Respectfully,
Bill
If you are simply loading a grit instead of a boolit, it sounds damaging to me, and I'm a believer in fire lapping. My thought is that in traditional fire lapping, the bullet is the constant (tool) and the grit are the cutters embedded (not smeared) into the tool. The idea of fire lapping is to hit the tight spots and not hit the larger locations in the bore. I would think just using grit would keep changing as the bore changed and eventually just shot out the rifling.
For cleaning out corrosion it should be great. The idea is to remove the rust and other build up and to remove the sharp edges of the corrosion pits on the downward side so it doesn't scrape of bullet/boolit material. Been there, done that.
My trick was to fill the case with wheat bran topped off with grits and a card wad in the neck base and fill the neck with valve grinding paste with a retaining wad over that. One or two of those cleans out the bore quite well.
I've only used the Wheeler bore lapping kit. Seems like I ordered it from Brownells. I've had great results in smoothing out a couple of rough bores with it.
If you lube a cast bullet with valve grinding compound in two or three grits, one after the other in a finer progression, then use a light load of say Unique, you will get the polish you want without destroying the rifling. It is important to use just enough powder to eject the bullet, not shoot a moose. You only want to polish, not slop out the grooves or lands. I shoot 5 bullets, clean, inspect and if requires shoot 5 with a finer grit. I wipe the bullet off so the only grit is in the grooves. This has been my process for decades and I use a saw blade on a motor tool to cut grooves in 22 LR bullets to fire lap my small bore match guns when needed. You can actually remove bore chatter marks and retain accuracy, if you are careful.
Ed
First time I ever firelapped a Ruger many years ago I used unlubed 255gr K boolits, flared the case excessively and crammed J&B bore cleaner into the lube groove and crimped them over 8.0gr Unique. Fired 50 of them, the bore was NOTICEABLY smoother and groups were cut in half.
I'd agree with this. Like a steel bore brush, it sounds like emergency treatment for a bore that is close to ruined already. I've never done fire lapping, but the main reason it is done with low pressure is to avoid upsetting the bullet, and lapping most forcefully near the throat where pressure is highest, and bore erosion, held to be a bad thing, would do it anyway.Quote:
Originally Posted by huntrick64
I would feel happier with a very hard or jacketed bullet, and it is hard to see any pressure not expanding a plug of abrasive. One exception which might be well worthwhile is a moderately pitted shotgun.
I wonder if the ground glass used in the old mercuric primers had a fire lapping effect.
That might explain some of the oversized bores found on some older rifles.
IIRC the ground glass had a deleterious effect on the throat and leade increasing erosion.
It also have wondered about the ground glass in primers causing barrel wear. I do know some old publications said it did, but have never seen a test done on it. I suspect that very little bore wear came from the 0.1 grains of glass.Quote:
Originally Posted by Multigunner
The aluminum that is in primers today all becomes aluminum oxide by the time it would get into the barrel. I've never heard of that causing a problem.
Even today .22 RF uses ground glass. Does that cause a known problem?
You can polish a barrel with paper patched bullets and less chanch of harming the barrel.
The powder gases are a lot hotter than the melting point of glass. As long as it is finely divided, I would be surprised if it is hard as it passes down the barrel.Quote:
Originally Posted by perotter
I would imagine the next shot would be passing over a fine deposit of glass. Would that have any effect though? How much glass would there be deposited among the rest of the soot? There is only a tiny amount to start with.Quote:
Originally Posted by Ballistics in Scotland
All photo's of bore erosion I have seen show tiny pieces of metal flaking off - hardly the signs of abrasion.
It won't, in that case, be a deposit of sharp powdered glass. Most microphotography of bore erosion shows very fine crazing which doesn't run longitudinally, and I think the most convincing explanation is that it is thermal cracking, caused by great heat in a very thin layer of the surface, being almost instantly leached away into the cooler parts of the barrel. It is said to be aggravated by nitride hardening, like some reloading dies, as nitrogen is absorbed from the powder gases.Quote:
Originally Posted by 303Guy
This explains some things. The powder gases from smokeless powders are nitrogen-rich, and those of black powder aren't. Erosion accelerates greatly in ordinary rifle rapid fire, but it doesn't get worse in proportion to the rate of fire of machine-guns. Possibly this is because the surface just keeps on getting hotter, while there isn't any much cooler rest of the barrel any more, and only cools down once.
Modern Machinegun barrels have a stellite (Cobalt Chromium alloy) insert that reaches a inch or two into the throat and leade. from WW1 onwards they oil hardened the bore of MG barrels to reduce erosion. Before that MG barrels used with Cordite could burn out in 3K rounds, afterwards they held up for 10K or longer, when single base powder was used they held up for 18K or more before they lost long range performance, when firing over the heads of your own troops all barrels were retired after 10K rounds to be on the safe side. I have no idea how long they last these days.
Some Martenistic Stainless Steel rifle barrels are nitrided in production. Perhaps this reduces mechanical erosion.
Gas erosion occurs within the first few inches of travel, mechanical erosion occurs nearer to the muzzle because the bullet is moving faster there.
In othe words the answer is no.
My understanding was that fire lapping is to remove high spots in the barrel.
If that's true, it would seem like the compound on the front of the boolit
would be what does the work as it sluffs back when the boolit travels down the tube, and not whatever is on the sides.
Years ago, I was gifted a bit of diamond dust polishing compound that I watered out with grease
and fired a few soft/pure lead rounds through a pair of .45ACP Colt Gold Cups.
I put a little dab around the front end of a loaded SW round, and it was so weak,
from behind, you could see the boolit in flight as it came out.
The barrels look like mirrors, and they can shoot to one big hole at 75 feet with cast.
Interesting I have several grits of diamond dust I use for sharpening plane irons and wood chisels on a lapping plate. I have a 45 colt with some thread choke and have heard mixed opinions on weather it is a good or bad thing to fire lap. I need to make up my mind.Quote:
Originally Posted by Winger Ed.
I did it in the late 80's or so when fire lapping was all the rage.Quote:
Originally Posted by onelight
I think it was just before moly coating was in fashion, and maybe when you were supposed to cryogenically treat your barrel.
I used the diamond dust because I had it, and there was a novelty factor of using it.
But any of the abrasives will get ya to the same place if used properly.
Answer: sort of... To explain, years back we were shooting .30WCF's at a very short (in a barn) "winter" range, and powder-position in the case -- so little in a big volume -- was the "cause" for adding a filler to take up the space. History has it that the British regiments were instructed to ALWAYS raise their muzzle straight up, to guarantee powder adjacent to primer flash hole, before lowering bore to target and firing, right? Cutting right to the chase, several huge white plastic jugs of plain-Jane Puff-lon filler was ordered, arrived, and used for loading. The "plus" is the stuff worked well, as advertised. The "minus" (which is, of course, subjective) might be summed up in three words: "What a mess!" Tiny flakes of Puff-Lon ended up all over the place -- from coating our hands, arms, and even the rifles. We elected to stop using the stuff solely for that reason.
I've added to this thread re our experience -- IF I were to try a bore-smoothing -- or any product similar from them, I'd durn sure #1 Wear goggles and a tight fitting respirator mask; and #2, definitely shoot outdoors, preferably up-wind on a windy day. Note I'm NOT bad-mouthing the product -- just relating experience re my using it.
geo
I've never used the Puff-lon method but I did fire lap an old Lee Enfield barrel a long while back. It was a really bad bore so I wasn't worried about ruining it.
At the time I was reading about casting some Hot-Melt-Glue bullets for shooting indoors using just primers and nothing more. I got the bright idea of casting some Hot-Melt-Glue bullets by first applying some mold release agent in the mold cavities and then dusting the cavities with some abrasive polishing powder I had in the storage room.
Casting the Hot-Melt-Glue bullets was a snap and the abrasive powder impregnated the surface layer of my cast bullets well. Since it was a rifle length bullet just one large rifle primer wasn't quite enough to get it to blow out the muzzle end so I used a magnum primer. That pushed my abrasive bullet pretty close to the muzzle but I still got no fully exiting Hot-Melt-Bullets though.
I figured that a few (very few) grains of blue dot or 2400 would make those bore-lapping abrasive bullets make it all the way out the muzzle end and I was right. It worked like a charm getting those DIY Hot-Melt-Glue bullets to travel the length of the bore and exit without alot of fanfare or muzzle blast. Unfortunately for me, the abrasive I used was a bit to fine to get down into the nooks and crannies of such a badly pitted bore. The good thing was that my mold was casting oversized bullets so I was able to just seat them by hand into an already fired case for repeat firings.
I think if I had progressively more abrasive lapping powders I could have turned that barrel into a semi smooth-bore but I ended up re-barreling it in the end. I mention all of this to say that it may be possible do so a light bore polishing by this method. It may take more time than it would with more solid bullets because with those Cast Hot-Melt-Glue bullets it really doesn't take to much to get them to spit out of the muzzle end so, time may be a factor in the method you choose to go with. I wanted to take it slow even on my already messed up barrel. I could see some improvement but not until I'd fired about 12 or 13 Hot-Melt-Bullets through that bore using that fine powder.
HollowPoint