Gas cutting or Paper grain impressions

[303Guy]

I've puzzling over these strange and ominous marks on my pig gun boolit shanks.

http://i388.photobucket.com/albums/oo327/303Guy/206gr44gr2209008.jpg

In fact I've been trying to eliminate them but to little avail. Tonight I saw my patch paper in a new light. Well, a different angle light that showed up the paper grain.

http://i388.photobucket.com/albums/oo327/303Guy/Papergrain003.jpg
http://i388.photobucket.com/albums/oo327/303Guy/Papergrain005.jpg

Now the observation I've made is the the striations on the boolit are worse in the rifling impressions in the boolit. Could they be caused by the paper grain? The paper gets compressed and possibly accentuates the grain?

I tried with tracing paper which has a smoother (and harder) surface.

http://i388.photobucket.com/albums/oo327/303Guy/W748TestsPigGun021-1.jpg

I don't when these striations first appeared. Perhaps when I started using closer pictures on super macro? (Showing up defects too small to see normally).

[6.5 mike]

I've seen somewhat the same marks on a few boolits I've recovered or unwrapped. Both times it was with tracing or computer paper on soft alloy boolits, have not noticed it with 50/50 or harder.

Wonder if the papers abilty to hold ink might have something to do with it, as far as the papers finish being more "open grained", & that's a WAG on my part.

Is that your soft alloy ?

[303Guy]

Yes it is my soft alloy.

I bought some type alloy in factory ingot form. I might try toughening the alloy a bit. Those lines and boolit base edge feathering are not the only defects I'm getting.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-521F-1.jpg

There's an expansion ring at the case mouth/ chamber gap.

[pdawg_shooter]

I am guessing the line on the side is caused by lapping the patch on the second wrap. This "can" cause an unbalanced bullet and fliers. I would rather have a .020 gap on the last wrap than any lap.

[303Guy]

Yes, I think so. I normally don't allow a lap but since this was a test tube firing I didn't worry about it. I do try keeping the gap small. I twist tighten the patches until the gap has closed evenly.

[montana_charlie]

I am guessing the line on the side is caused by lapping the patch on the second wrap. This "can" cause an unbalanced bullet and fliers. I would rather have a .020 gap on the last wrap than any lap.
That 'gap' is something common to all patching, regardless of propellant.
So, I have a comment which should not cause any territorial posturing.

If the patch ends don't come together perfectly, you get a gap or an overlap.
On the assumption that one of those will exist on a given patched bullet, which would be less offensive?

If you have a gap, the alloy will bump up into the space, leaving a riased 'ridge' along the bullet.

If (on the other hand) you have an overlap, the paper will press inward ... leaving a shallow 'ditch' on the bullet.

A raised ridge results in a little bit of extra lead hanging out further from the central axis of the bullet while the ditch keeps everything closer to the axis.

In both cases, the weight is off a bit on one side, but it would have less affect ... it seems to me ... when the ditch exists due to an overlapped patch.

I'm open to argument on this ...

CM

[303Guy]

I too think the ditch is better but the raise of lap might make seating more difficult. Maybe not. Not if the lap is real small. Possibly is there is a lap then one will get both a ditch and a ridge because the start does not blend into the next layer smoothly. I guess I'll have to try it and see. I do find that the ridge always seems wider than the patch gap looked. I have one sample fired boolit that shows a line but no ridge. I wonder if that was a slight lap.

[pdawg_shooter]

I have always experienced fliers when I lap the second wrap, but haven't had any problems with a gap of .020 or so.

[303Guy]

Thanks for that tip, pdawg_shooter. Is it important to have an even gap?

[303Guy]

I just found this pic. It was of crinkled patch fragments I recovered some time ago. Printer paper I should think.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-499F.jpg

[geargnasher]

CM and Pdawg, that's a heck of a good topic and I'd love to hear more. 303Guy, you want to continue with it here, or had you rather I start a new thread?

Gear

[docone31]

I have not found the gap, or overlap to be an issue.
With my cigarette roller trick, it tends to really even things out. When dry, and waxed, it loads and leaves no mark on the casting when fired.
I also use full tilt loads.

[pdawg_shooter]

Thanks for that tip, pdawg_shooter. Is it important to have an even gap?

I dont know. I am careful to cut my patches parallel and to use straight sided bullets.

[Nrut]

I have always experienced fliers when I lap the second wrap, but haven't had any problems with a gap of .020 or so.

That is Ross Seyfrieds view also in his writings about PP.

[303Guy]

By all means, Gear, keep it here. More folks might see it and join in under a specific topic, but the question has already arisen here and it is part of bore and patch influences on the boolit.

[303Guy]

I am careful to cut my patches parallel and to use straight sided bullets.I compensate for tapered and stepped boolits with tapered patches but but the shape requires a little more tightening hear and there to get that gap to close parallel but not straight. I cut the patch leaving the ink outline so I can see where I'm at. ( know it's the hard way of doing it and one day I'm going to want to shoot more volume and I will have to switch to wet patching and straight taper boolits - it's the throats. Mind you I have one rifle that might work with cylindrical boolits).

A curious thing, this morning before heading out for work I felt compelled to try a 158gr patched boolit over a full case (14.8gr) Trail Boss and the striations weren't there. There were a few bits of what looks like rolled off paper in the bore! Makes me think the bore has gone rough again.

[windrider919]

My .02

It looks like gas cutting to me.

Question - is the base of your bullet protruding any into the case or is it totally covered by the case neck. The reason is, I was reloading a PPed 308 Win and to keep the bullets out of the rifling I seated them just deep enough that about 0.050 was inside the case. On firing the lot, got quite a few unexpected flyers and patch fragments in the barrel!

ASIDE:
You have a bullet trap that seems to do a lot of 'marking' on the captured bullets...I needed something similar but I built a water trap, a trough with plastic bag face held on by clamping boards and gasket. Bullets recover expanded more like in tissue for one and the second benefit is bullets are less damaged by the medium and easier to 'read'. Only drawback is filling the thing. Note- to make this work, you have to fire a group, drive down to the trap and use an adhesive tape (that sticks even when wet) to patch the holes before too much water runs out. I will try to remember to take some pictures next time I am out at the farm

Anyway, it would be interesting to see if the bullets which were recovered with damaged bases were also flyers. Which turned out to be true in my case.

[Old Coot]

303 Guy; Suppose that you cut your patches with a real long angle on the ends. That way the patch seam would wrap completely around the bullet in a spiral like a -barbor pole-- this would prevent any ridge or protrusion of lead from unbalancing the bullet as it would encompass the boolit.

[geargnasher]

Windrider, one thing that I learned very quickly which supports what you say when trying this PP thing in my .270 was that the boolit had to obturate (as in the true meaning of the word, which is to create a blockage or seal) the bore before the base left the case, or before powder gas started leaking significantly around the base. If significant leakage occured to allow flow of pressure around the base of the boolit during its transition into the bore, it destroyed the patch on the first and second base bands. This is why I don't like "traditional" throats for modern, high-velocity, smokeless powder loads: Any unsupported area in front of the case mouth, i.e. oversized throat, is likely to cause base riveting, accordion of the base section, and patch damage withing the first few millimeters of boolit movement. I carried this idea over from shooting HV grease-groove boolits, where the boolit absolutely must be fully supported by the case neck, throat, and leade upon firing, and the case neck/chamber neck fit had to be just right to get the boolit to start foward without getting damaged or slumped, which would of course degrade accuracy.

Patching for a tight enough fit in the throat and selecting a boolit that pressed into the leade firmly when chambered yet left a lot of boolit in the case neck seemed to take care of these issues. Before getting the patch and seating depth right, I recovered a lot of patches that looked great until the last third, from the base of the boolit forward, where they were basically blackened and burned away. The twisted bases of the patches were cut off and looked fine, little discs of compacted paper 15-20 feet in front of the muzzle on the ground, but that last third of the patch between the base and the front two-thirds was history, as was accuracy. I was able to maintain accuracy as long as I maintained patch integrity to the muzzle. I never recovered any boolits intact to see what the difference was to the boolit, but the target and patch fragments told me enough.

Since with shooting HV paper-patched boolits and grease-groove boolits the peak average pressure almost always exceeds the compressive strength of the alloy, I've always gotten the best results using extremely slow powders that move the boolit into the bore and as far as possible along it before achieving peak pressure. Once fully along it's way and up to pretty good speed, the peak pressure can go very high and not damage the boolit at all.

Gear

[303Guy]

It does look like gas cutting! But the catch medium also scratches, abrades and polishes the boolit. But, the grooves are in the rifling impression of the boolits, which is suspicious. Is the patch failing there where the pressure is greatest or is it paper grain impressions? (I suspect gas cutting but I'm trying to make sure because it doesn't quite make sense to me and I can only solve the problem if I know what it is).


Suppose that you cut your patches with a real long angle on the ends. I did try that once. The problem is the patch becomes a ribbon and is hard to apply. I contemplated a 'square' patch but that only works if the paper will bond to itself (and some papers do with a little rolling between two flexi-rulers. I also tried matching the patch angle to the rifling, thinking one more line or groove wouldn't do much but realistically, These guys are shoot 800yd gongs with paper patches that leave an angled groove opposing the rifling pitch, so I went for easiest to apply angle which is around 30° and which still holds the top edge tight.

What Gear says makes a lot of sense.

I'm, trying to get best performance and eliminate as many of the deleterious factors before moving on to alloy changes. I'm thinking of getting the boolit into the bore before the pressure exceeds the alloy strength as Gear says. I'm thinking too that some fillers might cushion the pressure by acting as a resistive plug in the case.

I will certainly need a different catch medium to allow me to see what's going on. For me. water is a bit difficult as I stick the muzzle right into the test tube straight down. That water would go everywhere! Including all over my shed floor. However, waterlogged wool furniture padding in a strong container works well and simulates flesh quit well too. But it too will destroy the boolit at those velocities I think? Maybe not. But penetration would be like flesh and that's quite deep. (It was almost exactly like flesh with j-word hornet bullets).

[MBTcustom]

I have a couple of thoughts but you might not like them.

I'm, trying to......eliminate as many of the deleterious factors before moving on
I wonder if the barrel might be one of those factors, not that it wont shoot, but in that you are trying to seal a rough surface.
I know you have played with suction cups when you were a kid, or maybe you had one of those pencil sharpeners with the lever that produces suction on a desk or counter-top? Well, I would think that your boolits performance is telling you that the seal was broken just like the pencil sharpener, gas was allowed to escape between two surfaces. Have you ever tried to stick a suction cup to a rough wood bench? That sucker wont stick no matter how many times you lick it (and honestly that just tastes nasty) however, the softer the rubber, the better and stronger the seal. With the pig gun, I would be tempted to develop a boolit with a big hollow base, like a minne-ball that will force the gasses to press the skirt (and patch) harder into the walls of the barrel, for this same reason, I would try a softer alloy rather than a harder one, it being a soft, easily obtuated projectile, it may be more likely to try to form to the bore as it rides the pipe. Seems like that when you are using a realy good quality barrel, once the boolit gets engraved and sealed by and in the rifling in the first 1/2" of its journey. It needs not change for the remainder of the trip and in fact, you need to fight change as much as possible because your seal has already been established and can only deteriorate, so therefore....harder alloy.

Another thing that would probably be a realy good idea is if you keep your eyes open for something that you could use as a water tank to fire your boolits into and give them a gentler stop. For the tests you are doing, I think it would eliminate a bunch of questions about those striations by allowing you to observe more than the very skirt of the boolit.
Just my two cents. I'm just theorizing with my keyboard.

[303Guy]

At the moment I'm working on the premise that the bore has gone rough - lead particles clinging to the rust pits maybe. Thing is, the patches used to survive the trip in the bore and now they don't, even at low velocity with light loads. I'm about to clean the bore and polish it with Autosol and if that doesn't work I'll fire-lap it. I've just prepped a fire-polishing case which has a straight has a straight inside wall. The idea is to make long wooden grooved boolits to really get the polishing compound rubbed down the bore. We'll see how it works!

[MBTcustom]

I think thats a good idea, but I wasn't trying to slam your barrel! I was making the point that softer might be better in this instance.
But I have to admit that lapping the bore is probably a really good idea because the smoother it is, the easier it will be to seal. Still I cant help thinking that it will respond well, if you can get a lot of wall pressure on a soft alloy.

[geargnasher]

How about the bran filler? I can't remember if you've tried it with this gun or not, but it ought to seal up a "dynamic" bore.

Gear

[303Guy]

Well, I fire-lapped the gun and guess what? It works - I think. I also cleaned the bore with Sweet's. There was definitely something in the bore. I took the fire-lapping a bit further and the grooves are now shining. I might just follow up with some fire-polishing. Once again, we'll see what happens on the range.

http://i388.photobucket.com/albums/oo327/303Guy/Fire-LappingPigGun025-1.jpg

The bore after firing.
http://i388.photobucket.com/albums/oo327/303Guy/PigGunBore.jpg

[windrider919]

Some thought on trapping bullets....

A light load will not effect and shape [bumping up, slipping when engaging the rifling, etc.] the bullet like a full power load..so, given that premise, we must work with full power loads to get any accurate real world data.

Now if you are catching a full power bullet anywhere near the muzzle, you have to dissipate that energy...and almost always the bullet you are trying to capture is damaged in expending the kinetic energy, defeating the purpose of examining it. Even firing point blank into a swimming pool does not work because the bulle will mushroom at that level of energy (an some yahoo will say "Not full metal jackets or AP bullets"...so YES, excepting those)

Which leaves catching the bullet DOWNRANGE after air resistance has absorbed the kinetic energy down to a level that the capture medium does not distort the lead. And that means that you have to HIT the capture medium too...made more difficult by a loads inaccuracy or the capture mediums frontal area and thickness.

Testing with sawdust and sand damaged the bullets too much, even at 100 yards. Shredded tire rubber the same. Lighter mediums such as Styrofoam shipping peanuts worked but I had to increase the thickness to 17 FEET of garbage bags to stop small caliber bullets, the big bores...forget it - they retain so much energy that they just plowed right through unless shot at ranges like 500 yards. Which left water as a 'compromise'.

Which means you have to HAVE water at the range or wherever you are shooting. And you don't want it wasted so you don't want the container to spill all the water when hit by one shot, either by the hole or by hydrostatic shock ripping it open. On the water supply, I have a creek and a 12VDC pump at one location and if I am going to be in a dry spot for testing, I have five cheap plastic 55 gal chemical drums I can haul to a waterless shooting site.

This is where your individual creativity can soar and suggestions would always be appreciated.

Garbage bags have most (+-) of this capability to make a small hole and still not rupture open, plus they are 'cheap'.

I have played with several variations of this....loose bags partially filled, adding shredded newsprint to 'densify' the water, adding gelatin to do the same (too expensive! but I did it once with store brand 'jello' on clearance sale one time). But the main thing was keeping the bags 'in-line' to be struck..so a framework was needed to support and shape the bags profile. You could build it from wood but I used two pieces of 12" corrugated tin (aluminum actually) roof, screwed together along their long edge and hung from a frame as a 'U'. I used the dimension of 24" as a HITTABLE area at 100 or more yards. Now mine, is loadable into a truck bad by one person as it only weighs about 125/30 lbs. so I can transport it to the range or other place appropriate for the testing shots.

When on location, and the trough filled with 'cells' of water, the water filled garbage bags have worked for me at 100 and 200 and 300 yards, the distance depending on the amount of kinetic energy needed to be lost, to capture bullets almost a perfect as before they were fired and showed the riling and any other imperfections without the distortions caused by a denser capture medium.

I just never came up with a better way. Any of you brainstorm anything different or beter I'd be interested.

[williamwaco]

WHAT DID YOU USE TO TAKE THOSE PHOTOS?

They are stupendous.


.

[303Guy]

Thanks. It's an 'ordinary' second hand FujiFilm FinePix S5800. With 5.8 mega-pixel resolution and a half decent lens and software it takes pretty good pictures if I do my part. The bore pic was after several attempts. Basically I put it on macro, zoomed in as much as it would allow, stuck the lens almost touching the suppressor and with the breach up against the lace curtains. The focus is not right for some reason. It goes into sharp focus then loses it as it auto brightness corrects. I've been playing with it a year now and I am still learning!

[windrider919]

And some thoughts on barrels...

303Guy, sometimes a barrel has just reached its time.

And sometimes, I have witnessed that a old 'dirty' barrel shot better as the rust pits were filled with years of a packed accumulation of rust, carbon, flakes and slivers of bullet material, dried oil, etc which covered/patched the pit and kept the bore uniform and smooth...but when cleaned lost everything. And how do you replace that 'crud' back into the pits once you have gotten it out by too much cleaning?

And I have seen lapped barrels get better....and I have seen lapped barrels get worse. Its a cr_ap shoot as far as I can tell.

I have also seen a barrel get REALLY cleaned by electrocleaning...and it actually shot quite well even though it looked like the surface of the Moon. Just Google "DIY rust removal and rifle barrel electroclean" or "electrolydic rust removal" or other variations to research the process. Course, it also has the chance to finish off the barrel and ruin it too. Ya pays your money and yah takes the chance. This method cleans EVERYTHING down to the steel and that sometimes exposes surfaces you did not want to see, so to speak.

I have used a battery charger and salt and a steel wire to do the job. Put a rubber plug in the chamber, make a electrode by cutting a straight piece of iron wire longer than the barrel and use electrical tape every inch wrapped around the wire to make a spacer so the wire stays centered and can't short out on the barrel (cover the end too?). I used 3/4" tape with 1/2" to 3/4" gaps from chamber to muzzle. Note: do not make the spacers too thick, you have to leave room for the solution to flow/move and you do not want to 'cover' any of the bore from the cleaning action. Stand the barrel vertical and fill with clean water, add a pinch of salt, 10 to 15 grains then slide the straight wire down inside the barrel, letting the excess solution overflow. Hook up the battery charger leads to the barrel and to the wire and let it sit for a few hours (check the polarity as per the DETAILED DIRECTIONS you find on your internet search, I am not going to give it to you here, I want you to do the research and find out for yourself..I've got reasons.

When you disconnect and pull out the wire electrode and drain the barrel you should find a sludge of what was in the barrel, everything but the barrel steel. Note: you may want to passivate the barrel inner surface..hint, hint, by re-connecting the charger just a little different (research electroclean again). Or by replacing the plug and filling the barrel with phosphoric acid ('Ospho' from the hardware or marine store) overnight to pickle the steel and keep it from rusting. Drain and dry and oil and shoot to test.....
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
The picture of your bore is as good as you can do with your camera, but is not in focus. But what I can see it looks like a LOT of heavy pitting. Hence my mention that sometimes it is just time to give up and not waste time, effort and expense of lapping, etc. Re-boring of the old barrel is a possibility as is replacing the barrel. I bet somebody (maybe even you) has an old barrel that was removed that is in perfect shape. Hxll, I even have a couple virgin looking 303 barrels laying on my junk shelf in my shop, surly someone in your country does too.


Rust removal

Phosphoric acid may be used as a "rust converter", by direct application to rusted iron, steel tools, or surfaces. The phosphoric acid converts reddish-brown iron(III) oxide, Fe2O3 (rust) to black ferric phosphate, FePO4.

"Rust converter" is sometimes a greenish liquid suitable for dipping (in the same sort of acid bath as is used for pickling metal), but it is more often formulated as a gel, commonly called naval jelly. It is sometimes sold under other names, such as "rust remover" or "rust killer". As a thick gel, it may be applied to sloping, vertical, or even overhead surfaces.

After treatment, the black ferric-phosphate coating can be scrubbed off, leaving a fresh metal surface. Multiple applications of phosphoric acid may be required to remove all rust. The black phosphate coating can also be left in place, where it will provide moderate further corrosion resistance (such protection is also provided by the superficially similar Parkerizing and blued electrochemical conversion coating processes).

FYI - got an old piece of equipment with a gas tank full of rust? I have used the electrolytic cleaning to clean down to shiny bare steel the inside of old tractor gas tanks and motorcycle gas tanks...so they could be sloshed/plastic coated (used first in airplanes to seal riveted tanks). I even used it to clean out the pipes in a 65 year old house..however, be aware that any pits in the tanks that are plugged with rust will be cleaned out and the tank could leak unless inside coated, and the bare steel left is so clean it rusts just from atmospheric moisture unless immediately protected with some coating like oil or paint or slosh. The house pipes were empty of all the built up crud...but several threaded joints held together and sealed with the rust leaked then and had to be repaired...but they would have started leaking in weeks or a couple of months anyway as the corrosion continued. It just identified the weak points early and let us fix them at one time.

[windrider919]

(Not) Sorry for all the posts tonight, Just lots of your posts to reply to...

On lapping barrels, the BEST method I ever found was to lightly 'fine pitch' knurl a bullet and and load the grooves with fine lapping compound, load and fire. The hard cutting/polishing grains in the compound become embedded in a matrix of lead and scrape down the barrel.

As an alternate, taking a PP bullet and forcing lapping compound into the paper is another great way to apply lots pf polishing power in just a few shots.

I have seen where people filled the grease grooves of cast bullets with lapping compound but no much lapping action takes place as the 'loose' compound is not hard forced against the barrel by a supporting matrix, only by acceleration down the barrel and centrifugal force, so it takes a lot more shots

Again as always, my .02 worth..but based on years of doing this hobby, not being a keyboard commando.

[303Guy]

Thanks windrider919. I did think of simply using phosphoric acid to passivate the bore, thinking it might have been quietly corroding. But then I got a wild idea on fire-lapping and tried that and that's what did the trick. That bore started out with a layer of scale on it. Very aggressive fire-lapping got that out but I never expected the gun to shoot more than 25yds! What made me try the fire-lapping route is a hydraulic cylinder rod I de-rusted with dry emery paper and elbow grease. The rod came out quite smooth and clean. Pity I didn't take a photo of before and after. Of course, only a custom boolit will work now but then again, the throat and bore now matches the boolits that seat tight in an unsized neck. I have another rifle with a good but oversize bore waiting to take over from pig gun MkI should it not deliver. In the meantime I'll apply that phosphoric acid tonight.

I started looking up electroclean and I see there is a bit of reading up to do. I have make myself dinner right now so I'll get to it later.

[303Guy]

I have a couple of thoughts but you might not like them. Oh but I do like them!

I wonder if the barrel might be one of those factors, not that it wont shoot, but in that you are trying to seal a rough surface.
.... your boolits performance is telling you that the seal was brokenThat's exactly what it seams to have turned out to be!

... no matter how many times you lick it (and honestly that just tastes nasty) ...
Umm [smilie=1:. I hate to tell you this but ... that's all the dried up spit from everyone else licking 'em! :mrgreen:

With the pig gun, I would be tempted to develop a boolit with a big hollow base, like a minne-ball that will force the gasses to press the skirt (and patch) harder into the walls of the barrel,
I have thought of that before but I fear that the expanding pressure within the cup might be too much. It might rivet the skirt onto the bore. I just don't know.

... for this same reason, I would try a softer
alloy rather than a harder one, it being a soft, easily obtuated projectile, it may be more likely to try to form to the bore as it rides the pipe.
My alloy is pretty soft already. I'd like it to be much harder at the case-mouth/chamber-end junction. That's not possible without some form of hard band. Brass band swaged onto the boolit maybe? Very do-able don't you think? In fact, a brass tube swaged onto the boolit would prevent that riveting effect plus provide a nose expansion limiting point like a premium paper patched boolit? Mmm.... ?!

I am still racking my grey cells for an efficient boolit stop that does not deform the boolit. I'm still drawing a blank. One thought that did come to mind is a long split pipe with hinge and locks filled with soft, oiled sawdust with a suppressor box in front of it (for urban testing). Or a heavy steel trough with clamp down lid.