PDA

View Full Version : Paper and bore wear?



jh45gun
03-21-2009, 06:43 PM
I have heard that paper patched bullets wear the bore more then Cast bullets do but less than condom bullets what is the truth on this?

docone31
03-21-2009, 06:51 PM
There is wear.
I have fired a bunch of paper patched boolitts through my barrels. Once I figuired it out, I went to town.
I am genuinely wondering, if I will live long enough for it to show up.
Once the patch clears the residual leading, and polishes the bore. unless there is grit introduced, I wonder how much wear actually takes place.

Alasgun
03-21-2009, 08:09 PM
I guess I'm wondering if anyone has ever gone back? It would seem that all this bore polishing that I here is taking place would be a wonderful way to "break in" a new barrel. Will my jacketed bullets foul less and /or maybe shoot better once the thing is "worn out" by the patched bullets?
Mike

docone31
03-21-2009, 08:32 PM
I do fire jacketeds from my rifles. Mostly to stay current with how they perform.
I have to aim higher with jacketeds with the same load.
In terms of breaking in a new barrel.
I believe it is a good system for breaking in a new barrel.
A few threads back, I wrote on how my MilSurp barrel had distinct hammer marks in the bore. I fired undersized patched loads with some Clover spread extremely lightly on them.
I fired 18 undersized patches with Clover through the bore, then fired sized patches from then on. The barrel has no indication of hammer marks I saw in the bore, the rifleing is sharp.
I wish I even had a way to take a picture of what the barrel looked like. It looked like a step ladder over the rifleing going the opposite way. Mind you, it was not that large in comparison, but, it was quite visible. Looking through the barrel now, it just plain looks like a rifled barrel.
I suspect, firing 200 sized patches through the new barrel would be a real good way to break it in.
After I fired the Clover and then fired the sized patches, accuracy got progressively better. One day, I did some heavy firing with my rifle, and the heat from firing made the barrel act like spaghetti. I went home and bedded it the next day. Now, it is point and shoot. If I miss, it is me, not the load or rifle.
In this rifle, my patched load is .314. I fire .312 jacketeds rather than spec .311. My rifle is notorious for large bores.
With the jacketed loads, same charge as patched loads, POI is lower than patched. My scope has three dots below horizontal. The paper is dead horizontal, jacketed is the next dot lower.
Again, same bullet weight as patched, same charge for both.
I have some jacketed set aside for when I am lazy, but in reality I do not like jacketed loads in my rifles. I do better with patched loads.

bcp477
03-22-2009, 04:36 PM
Why shoot jacketed bullets ? ("go back", as Alasgun put it). I began with PP bullets because of the obscene prices of jacketed, in the first place. Since I am getting everything I need from PP.....why would I ever again want to buy another jacketed bullet (and voluntarily be raped) ? As far as I'm concerned, the makers of jacketed bullets can well and truly go F themselves.

montana_charlie
03-22-2009, 07:41 PM
As far as I'm concerned, the makers of jacketed bullets can well and truly go F themselves.
While you're welcome to think anything you want, that seems like a pretty harsh sentiment to state publicly. Considering the many things that jacketed bullets do well, I think if we could only have one or the other we would have to go with the copper skin.

For one thing, I don't think the military would last long on a straight diet of paper patched cast bullets...
CM

jh45gun
03-22-2009, 07:58 PM
Still waiting to hear how much barrel wear you get if it is measurable or what?

Digital Dan
03-22-2009, 08:39 PM
JH, it's a good question but I cannot answer is concisely due to the variables involved, nor can anyone else aside from yourself. Best way of evaluation I think would be the judicious use of a Stony Point OAL gauge...or the pragmatic 'shoot until it don't" approach.

You see, with paper patch the variables involve the type paper and lube, if any. Many shoot patched bullets dry and I can tell you flatly that doing so, even with proper paper will polish a bore quickly. 6 shots through an ancient gray .405 Winchester bore turned it bright and eliminated 80% of the problem of copper fouling with that one. That was with onion skin and I shudder to think what might occur with improper papers. I think it important to differentiate between "polish" and "wear" in this discussion. I'm thinking without scientific basis that polishing isn't a bad thing if you keep shooting paper patched bullets. OTOH, if you've polished a bore with paper, maybe it will lose some edge with jacketed bullets? I don't know, it's just a suspicion. I've been told that GG bullets don't work well thru a barrel that has tasted copper but cannot attest to that. I can say that for hunting grade rifles, paper patched loads will follow copper without a burp.

This issue of wear is largely circumvented by lubed bullets I think and I say that for a couple of reasons. The bore of my .44 Mag rifle had digested over 1,000 rounds of this diet and I use 50/50 Vaseline/Beeswax. If it was wearing the bore I doubt it would have that lovely soft amber tone it carries. It it was wearing the bore I also would imagine the accuracy would fall off until such time that I adjusted OAL in the load. I haven't needed to do that and the load shoots as well today as it did at the 100 round point. I do need to put on sunglasses to look down the bore after I clean it though......(Dan's joking a little there...).

So, in very broad terms I would state that PP loads will polish the bore in some circumstances and probably cause accelerated wear in others if one is not attentive to proper paper quality and lube. In contrast, I think it just as likely that GG bullets will pick up the odd piece of grit and leave its mark on a barrel too. I call it a wash, all things being equal. I also don't think you'll live long enough to wear out a barrel with PP loads that are properly constructed.

What you get out of the practice is the option of higher velocity for a given alloy, and saying farewell to leading in the trade. It's fun to "roll your own" and they shoot well once the particulars of your gun and load are worked out. Lastly, if you use pure lead, or at least very soft alloy, you will see terminal performance like you would not believe. Patched bullets do not make the meat blood shot in my experience, but they do make a mess of the boiler room.

An odd stray thought: Patched bullet have "impressions", not engraving after traveling down bore. Bee DNA is likely to confound a lot of CSI types, adding a whole new meaning to the term "African Killer Bee". You should after all, wear latex gloves when patching bullets, and something other than your tongue to wet the patches. We have made some advances since Jim Bridger passed thru the Tetons. [smilie=1:

docone31
03-22-2009, 09:04 PM
Dan, you explained pretty well what I was trying to say.
I have over 1000 .303 rds through my Smelly now. The rifleing looks pretty sharp. No rounding, no enlargeing. Inside, shine like no tomorrow.
Well put.

n.h.schmidt
03-23-2009, 10:01 PM
Hi
No doubt there is some barrel wear with paper patches. Also with plain GC bullets too. Either is almost nothing compaired to jacketed slugs. Something I haven't seen covered yet is the the effects of primer residue in the bore. I have used some primer pocket cleaner tools in the past . One is like a very stiff wire brush and another type had something like a screwdriver blade that rotates. Both showed rather rapid wear from the abraisive primer residue. This also is shot on and down the barrel. We know this is present because of the barrel rust you get when fireing Corrisive primers and not cleaning. There is nothing to be done about this ,I suppose. With all the indignities the barrel has to put up with ,it's a wonder they las as long as they do.
n.h.schmidt

windrider919
03-24-2009, 03:26 PM
I have a theory. (NO NO don't hang me yet!!!) What I look at is pressure and compare it to bore wear. If a load shoots with less pressure than another otherwise identical load I would assume (ass {of?} u me) there is less wear going on. Based on that premise, I loaded and shot a J-bullet (.458), GCGG(.459) and a PP (.454 unsized + .008 PP = .462) bullet using identical powder, primer and case type. All the bullets were aprox. the same weight. I did have to chuck the PP bullet up and cut 30 gr off the nose to match weight. Note I was not testing accuracy here, just pressure. The J bullet has less bearing surface than the GCGG and PP bullet.

From case expansion measured 1/2" ahead of the base and primer flattening the J bullet develloped the most pressure, then the GCGG and finally with the least pressure, the PP even though it was .004 overbore!

So, Any agreement or dissagreement on the pressure vs friction / wear in the bore theory?

docone31
03-24-2009, 08:26 PM
Windrider, I have experienced the same thing, with better accuracy over jacketeds.
My .30s, and .303, POI is higher, lighter primer signs, recoil is lighter, report is slightly different. Same rifle, same weight bullet, charge, same primers, same brass.
I have a feeling, paper acts as a bearing surface down the bore. Anything sticking up on its travel gets worn down, feathers, in my case hammer marks, burrs.
Under compression, paper gets rather hard.
On my rifles, I have the same scope. It has three dots, with one at the cross hairs.
Jacketeds hit on the dot under the cross hair, patched hit on the cross hair.

Digital Dan
03-26-2009, 03:29 PM
I have a theory. (NO NO don't hang me yet!!!) What I look at is pressure and compare it to bore wear. If a load shoots with less pressure than another otherwise identical load I would assume (ass {of?} u me) there is less wear going on. Based on that premise, I loaded and shot a J-bullet (.458), GCGG(.459) and a PP (.454 unsized + .008 PP = .462) bullet using identical powder, primer and case type. All the bullets were aprox. the same weight. I did have to chuck the PP bullet up and cut 30 gr off the nose to match weight. Note I was not testing accuracy here, just pressure. The J bullet has less bearing surface than the GCGG and PP bullet.

From case expansion measured 1/2" ahead of the base and primer flattening the J bullet develloped the most pressure, then the GCGG and finally with the least pressure, the PP even though it was .004 overbore!

So, Any agreement or dissagreement on the pressure vs friction / wear in the bore theory?


I agree there is a correlation between pressure and degradation of the bore but don't think friction has anything to do with it. It that were so the worst "wear" would be at the muzzle where the velocity is highest. It's not.....most always found in the first few inches where pressure is highest.

Maximilian225
03-26-2009, 05:49 PM
Hey Dan,
Does this ring any bells?

If yuro'e corseseyd and dsyelixc can you siltl raed oaky?

:mrgreen:

Lead pot
03-26-2009, 06:18 PM
I get by average 30 fps lower velocity using a PP bullet compared a GG bullet of the same weight and powder charge.
I think what wears a bore is heat and gas blow by plus velocity.
I have one rifle I use with just a PP bullet and during the last primer shortage I lost count because I use nothing but pistol primers in that rifle and I number the box with a consecutive number so I know how many rounds went through that rifle and I lost count with the 11 th brick since the last primer shortage because I used them in other rifles too.
The bore still looks like it did when the rifle was new but I shoot just black powder and never a copper jacket in my powder rifles.
Most of you will never shoot 11,000 PP rounds through your rifles so I wouldn't worry.
Shoot them and have fun.

rhead
03-26-2009, 08:52 PM
I agree there is a correlation between pressure and degradation of the bore but don't think friction has anything to do with it. It that were so the worst "wear" would be at the muzzle where the velocity is highest. It's not.....most always found in the first few inches where pressure is highest.

Increased friction will cause an increase in pressure due to the resistance to acceleration. The increase in friction at the muzzle due to the increased velocity is somewhat offset by the fact that the bullet has been engraved to accomadate itself to the shape of the barrel, reducing the coefficient of friction. The gasses behind it are also cooler and lower pressure.

Digital Dan
03-26-2009, 10:26 PM
Hey Dan,
Does this ring any bells?

If yuro'e corseseyd and dsyelixc can you siltl raed oaky?

:mrgreen:

It do!:drinks:

legend
03-27-2009, 02:40 AM
while i have never fired a paper patched boolit in my life,i have made many for friends.

i hope to live long enough to say"I wore out a bbl shooting ANY bullet"
oh yeah i did destroy one throat in my salad days(220 swift)

Digital Dan
03-27-2009, 01:03 PM
Increased friction will cause an increase in pressure due to the resistance to acceleration. The increase in friction at the muzzle due to the increased velocity is somewhat offset by the fact that the bullet has been engraved to accomadate itself to the shape of the barrel, reducing the coefficient of friction. The gasses behind it are also cooler and lower pressure.

I would rephrase my previous. Friction has little if anything to do with any aspect of interior ballistics beyond those effects attendant to neck tension and uniformity of powder burn. The energy required to impart spin on a bullet via the rifling accounts for less than 1/2 of 1% of utilized energy. Overcoming friction requires less than that. Yes, it will affect pressure but the amount is very small.

Baron von Trollwhack
03-27-2009, 04:31 PM
My own view is that some papers have damaging elements within their making, such as silicone, and other surface coatings and unusual enhancements. Don't think so? Talk to people in the paper industry about the stuff in their paper stock or scope/lens people like Zeiss tech, Leupold, etc. about what to cleans lenses with.

Like in that Sharpe info, I always used 100% cotton rag bond of a premium quality and saw what I believed to be a burnishing effect in a brand new miroku b-78. Yet I know some here might be using very common paper and it is slam full of grit. But also it is probable thay you have to have a premium barrel to sustain damage affecting the bore and accuracy. Mosins don't need worrying about. Badgers on Sharps, yes.

BvT

pdawg_shooter
03-31-2009, 08:11 AM
I have used green bar printer paper for years. Over 3000 through my 45-70 and the rifling is fine. I dont think I will live long enough to damage a barrel with paper.

windrider919
03-31-2009, 04:32 PM
Because I was shooting the same load and using the same weight bullet I think bullet inertia was equal in all three different loads. The engraving force as the bullet moved into the rifling was different and is partially based on friction too. The 'softer' bullet would engrave with less force, moving ahead of the pressure of the gas easier. But as I discovered with a 30" barreled 22LR, barrel friction will slow down a bullet in a barrel and does have an effect. Just look at it this way, the PP bullet is under-size and only the compressible paper is engaged with the rifling. I too use 100% cotton rag paper because I have worked in multiple paper mills as a millwright and know all kind of microscopic trash is left in the cheaper paper. So don't shoot brown paper grocery bag. Yes, paper IS slightly abrasive. However, it is less abrasive than cupro-jacketed bullets that cause rifling wear ahead of the chamber {and slower powders still burning in contact with the barrel}. The NRA proved many years ago that muzzle wear was not from bullets but from cleaning rods. In general, paper is more polishing on a microscopic level than abrasive. The secret to this argument is that although paper might have some effect it is so slight as to be negligible. I would think that no shooter will 'wear out' his barrel shooting PP or cast bullets or even jacketed. Every barrel I have ever seen that lost accuracy was not "shot out' with any type of ammunition but had been damaged by bad cleaning methods or dubious 'improvements / treatments' done to increase velocity, etc. Even the old campfire urban legend of barrels only lasting 10K rounds is just that, a legend. I have picked up many rifles for a song that were supposedly shot-out and either cut off 1/4 inch at the action end and re-thread/ re-chambered or just cut off 1/2 inch and re-crown the muzzle. 90% of the time the re-crown was what was needed and then I would have another great shooting rifle to sell at a profit. Their ignorance was my benefit.
in conclusion, I think worrying about 'abrasive paper' is making a mountain out of a mole hill. It's effect is so slight that we should not wast time on it.

docone31
03-31-2009, 04:54 PM
That is what I thought.
Add sizing, with wax as a buffer and you reduce the immediate wear. Once the lands are engraved, they slide affecting micro polishing.
I like the cheaper papers though. I get better results down range with them. I believe, the extra particles add to keeping the layers "bonded" in the wrap.
It was more edge on wear that I saw when I was in the paper industry, than flat sheet wear.
If a weight was added, that was another story however.

yarro
03-31-2009, 10:29 PM
Properly cleaned barrels lose their accuracy due to throat erosion or crown damage. More barrels are damaged due to improper cleaning technique. I put 25k of surplus .223 down a none chrome lined bore in an M16 and the bore was fine. The throat on the other hand had eroded and a bullet had to go almost an inch farther down the barrel to engage the rifling than when it was new. The point I replaced it was when velocity had dropped over 200fps over the velocity when new as it could still hit the 320yard 20" gong at the range when it wasn't too windy, which is OK for a short barreled MG. A buddy at worked washed out the throat in a .300Rem Ultra Mag in less than 1000 rounds. Unless you are sending projos that are seriously erosive down the bore or cleaning it wrong, I expect that the barrel throat will go long before your rifling wears out.

-yarro