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View Full Version : Are PP'd boolits hard on barrels?



Marlin Junky
01-31-2009, 06:45 PM
I was wondering how long the life of a typical factory barrel is that has had mostly PP'd rounds fired down it at 2500+ fps.

MJ

felix
01-31-2009, 07:00 PM
As usual, you prolly will get tired of it before the accuracy completely goes. ... felix

docone31
01-31-2009, 07:11 PM
When I was in the paper industry, I noticed wear on metals from moving paper. However, it was on the same spot of metal, not the same piece of paper moving over different areas. Of course, there was no obturation, nor substantial push on it either.
That said,
I have a feeling, if there was any wear other than reasonable, it would be the same for the duration. If the bore opened up in time, paper thickness could also increase, extending the life of the barrel.
With the lessor pressure than jacketed loads, and the slower speeds of the projectile, I suspect any grand wear on the bore/groove would equal itself out.
I noticed, my rifleing got more defined. I suspect, the paper eliminated machine imperfections, feathers, and drift. Definately, the hammer marks are gone.
There will be wear, however most of my barrels have suffered from heat/wear, more than slower firing. I do not know about anyone else but, I am a slow shooter anyway, patching, I go a tad slower. Rarely do I experience heat. Heat accelerates wear.

bcp477
01-31-2009, 09:03 PM
Just as docone says, there will be wear. Just as with jacketed bullet loads, much of the barrel life issue will have to do with the LOADS you use, not just PP bullets vs. plain cast or jacketed, etc. Hotter loads = more heat and gas cutting....and faster barrel wear....period (regardless of bullet used). There is absolutely NO evidence that a barrel used to shoot predominately (or only) PP loads will wear out any faster than any other barrel. As I only shoot PP loads now, relatively mild ones at that, I expect that my "new" M48 barrel will be good for at least 10,000 rounds, perhaps a lot more. I'll get back to you with a definitive answer when I wear out this barrel - but I expect that it will be many years from now.

Digital Dan
02-01-2009, 09:32 AM
Don't know that lubed patched bullets have significantly different wear rates than any of the others or not. I do know that unlubed paper patch will wear a bore with alacrity. I've used the process to take the "gray" out of old bores with as little as a half dozen mild loads so constructed. I also know that paper containing kaolin, which is common to glossy paper will wear bores quickly. It is a very common additive in paper manufacturing and is highly abrasive.

leftiye
02-01-2009, 06:35 PM
DD has the answer - I think. It's probly not the wood fibers that will wear a barrel, but whatever other crap is added to the paper for whatever reason. We all could benefit from finding a non-abrasive, strong paper to patch with.

Bullshop
02-01-2009, 09:38 PM
Has anyone else tried wax paper? Kinda like a pre lubed patch paper. I got a big roll of a kina semi clear translucent wax paper from a yard sale. This was a big roll a paper at about 50 lbs..
It mic's at about the same thickness as my meager supply of 9 lb. onion skin. I tried it this past week and it worked pretty good. It does'nt have quite to toughness as the onion skin but its not all that fragile either.
I guess it would be pretty much water proof too. So the big question is does anyone know of anything that may be in this type of paper that could be harmfull to a barrel?
BIC/BS

docone31
02-01-2009, 09:47 PM
We used that wax when I was in corrugating for some specialty corrugated.
It was some slippery stuff.
From what I figuire, it is pretty much Alox. I doubt very much it will have an effect on a barrel other than depositing. That cleans up fairly easily.

JeffinNZ
02-01-2009, 10:23 PM
I suspect the burning charge is doing more towards wearing out your barrel than the paper patch is. Throat erosion and all that. Thank goodness Cordite is no more.

docone31
02-01-2009, 10:56 PM
Jeff, I am highly inclined to agree.
With the lessor pressure of the patched boolitt, I wonder, if the flame front erosion is not actually lessoned.
I have noticed a significant reduction of recoil between jacketed, and patched loads with the identical powder charge. POI is different also. My jacketed loads are wilder than the paper loads. I am an easy 1" @100yds with paper, vs. 2"+ @100yds with jacketeds.
Same weight projectile, same powder charge, same case brand, same primer, same rifle. The jacketed .303 British is .312, the paper is .314. Both 180gns. Charge is 40gns Surplus 4895. Neither load is crimped, both neck sized.
With the primer observatin, the jacketed is flatter, the patched resembles milsurp fired primers. The only lube I have on the patches is some auto wax to size. Not much remains on the patch. It is just shiney from the sizing.
From my primitive observations, in other words I have no way to measure anything except targeting, I am guessing there is less pressure with paper. The biggest difference is felt recoil.
Erosion from the expanding gasses would be less from the less pressure. I have not been able to recover a fired boolitt, they either fragment, or go so deep into the berm I cannot find them. Jacketeds do seem to be visible after firing though. The jacketeds are bent and deformed. The patcheds make holes in the berm. I have not been able to determine if the rifleing marks are deeper on the patched projectiles. The paper acting to magnify the rifleing upon engraveing.
I am going to bet my barrel on it, that, paper patching is less wearing on a barrel than jacketed.

montana_charlie
02-01-2009, 11:28 PM
HowWe all could benefit from finding a non-abrasive, strong paper to patch with.
Sounds like you've come back around to the lens cleaning tissue we talked about in the Paper 101 thread.
It's strong, is not much weakened by water, and you can bet they don't put anything in it that will 'modify' your lenses...
CM

Red River Rick
02-02-2009, 12:02 AM
and you can bet they don't put anything in it that will 'modify' your lenses...
CM

Huh! And here I thought I was getting "cataracts". Now I realize the "tissue" paper I've been using to clean my glasses has been scratching the heck out of the lenses.

Thanks MC, now I don't need surgery, just new glasses.

RRR

pdawg_shooter
02-02-2009, 09:14 AM
My 1895g has a little over 1900 rounds through it, all paper patched. I can see no damage ore wear in it. A little flame damage in the throat but that is all. Dont think I will live long enough to wear it out!

Digital Dan
02-02-2009, 08:20 PM
Well, there is more here from a paper expert.

http://castboolits.gunloads.com/showthread.php?t=34782

PP and pressure.............Matthews says PP generates less. I don't know that flies with BP but suspect it's true with smokeless powder. As I understand it quickness is a variable with smokeless and with less resistance, such as with less engraving force or barrel friction you might get less pressure for a given charge. Resulting in a modification of the pressure curve? Dunno about that either..........all speculation.

Where you won't find kaolin as I understand it: Onionskin, tracing paper, dress pattern paper etc. Gloss, or great opaqueness or stiffness are indicators of kaolin in my opinion. I note from close and detailed inspection of the bore of a picket rifle (unbreached) there are still tool marks on the lands....133 years old. Otherwise I see no indication of any form of wear, either from patch material or erosion.

RMulhern
02-07-2009, 02:14 AM
Extremely!

After about 80,000 rounds....ya won't be able to hit ya outhouse wall!!:castmine::drinks:

Naphtali
03-01-2009, 01:12 PM
Among the most abrasive jobs in industry is use of slitter blades on paper. Having written that, the paper to which I refer is cardboard boxing paper with a high wood fiber content. A friend owns a hard surfacing company. A substantial portion of their business is hard facing slitter blades -- and resurfacing them as needed.

I've just become interested in paper patching. In Matthews' book he recommends no more than 25 percent cotton content. Were I going to shoot enough to be concerned about excessive wear on a barrel's interior, I would strongly consider a much higher cotton content, cotton being less abrasive than wood fibers.

Hope this helps.

docone31
03-01-2009, 11:43 PM
I ran a B-Flute corrugator years ago. Slitter/Slotter, and ultimately became a die maker for the die press.
There is a big difference between Kraft type paper and what I use for patching.
That said, and it was years ago, we got a real polish on steel with the paper running over it. Our Slitter blades were mostly self sharpening as the back sides ran against each other.
Now, we also did waxed corrugated.
It was stinky miserable stuff. It slipped everywhere. I believe it was a type of what is not Alox today. That stuff was miserable to handle! In the die press when we cut each board, the individual pieces would pop out and go everywhere, slippin and slidin. That was in the days when we hand tied each bundle. Miserable!
To cut to the chase, the waxed board seemed to be more passive to the blades, and dies than unwaxed board. When I ran the corrugator to make the waxed board, after the flutes and bounds were starched together, each run went through a tray of wax. It did not seem to affect the starch bond as only the outer bounds were waxed. It would seep through the total board after being cut into lays.
I wonder, if paper patching reduces the abrasive qualities of the paper. The calcium bicarbonate is perhaps smoothed in wrapping, and sizing, and the slight lube during sizing adds to the slick effect.
In other words, perhaps in a patch there is a different quality of the paper after wrapping the diminishes the abrasive quality of paper after wrapping.
The die presses would actually wear grooves in the die plate. We would have to put masking tape on the plate to increase the pressure of the dies. Both the blades and plate would wear.
When I worked in magazine printing, the sheet stock from the roll would wear definate shallows in the metal guages. Not only the edges, but, from the constant movement of virgin paper stock over flat pieces. The dust from the machines would abrade the shafts, gears, and bearings. Dust from paper was a constant issue. When paper dust would get into the lube in the bearings, they did not last long at all. I am referring to corrugated dust rather than magazine stock. The teeth on the baler got real rounded, and shiney fast. The scoreing machines however got a real polish on them. They lasted a long time. They never had paper movement over them. The reels kept pace with the stock.
From what I have seen in my barrels, they are getting more shiney, and the rifleing appears sharper.
I think paper is more passive than jacketeds on the bore. Especially if it fits well.
On the corrugating note, my largest concern was spliceing the rolls. I worked every phase of the machines except for operating/feeding the corrugator. It intimidated me. Once I did it, it was simple. Slice the roll with the putty knife, slap on some starch, stick it under the feed stock to be spliced, and off it goes. Split the upper roll feed stock, remove the double paper at the end, and run the machine. I got quite used to it. Hand feeding the die press was harder, stripping the die sheets took some getting used to. Feeding the slitter/scorer was actually boring.
I did that for many years. I enjoyed it. Worked nights. It would be below 0 outside, I would work the corrugator all night. Step outside, MAN! it was cold!
Single faceing corrugated was a pain. Those end rolls filled up quickly!
It was fun though. I got to play with paper forklifts, load up trucks, stack huge rolls of paper, play with huge expensive machines! I got good at it. Got to make die boards.
I had fun back then. Made some good money for the times. None of the fancy machines they have today.
I do believe though, paper is easier on the bore overall.