Bonding the Paper Patch Wraps Together

[montana_charlie]

A number of years ago, I was talking to LBT's Veral Smith about the PP slippage I was having with hi-vel PPCB.

What indicators told you that you had slippage?

CM

[CJR]

CM,

When I first started shooting hi-vel PPCB, my PPCB were not even on the target or the backstop. I saw severe leading at the muzzle. That prompted me to dry nylon-brush the rifle at the range to see if the entire length of the barrel was leaded. From the resistance I felt by dry brushing, I found that only the last third of the barrel, close to the muzzle, appeared leaded; the rest of the barrel appeared OK. I reasoned the PP was slipping(@3000fps) and not making it to the muzzle. Thereafter, dry brushing at the range became a standard procedure for me. Once I got everything right with my hi-vel PPCB, my dry brushing resistance, after every round, became consistent from chamber to muzzle. Final verification came when solvent cleaning the rifle at home and examining the cleaning patches for lead and seeing no lead, only powder residue. Granted this dry brushing technique is subjective, but it apparently worked for me. Buying an expensive borescope to examine the barrel interior was just not in my budget.

Later on I found that after shooting a tight hi-vel PPCB group, the group would slowly open up due to powder residue build-up in the barrel. When the group would start to open up, I'd dry-brush and the group would tighten back up. This is how I now shoot/test PPCB all day long at the range without solvent cleaning the barrel.

Best regards,

CJR

[montana_charlie]

CM,

When I first started shooting hi-vel PPCB, my PPCB were not even on the target or the backstop. I saw severe leading at the muzzle. That prompted me to dry nylon-brush the rifle at the range to see if the entire length of the barrel was leaded. From the resistance I felt by dry brushing, I found that only the last third of the barrel, close to the muzzle, appeared leaded; the rest of the barrel appeared OK. I reasoned the PP was slipping(@3000fps) and not making it to the muzzle. Thereafter, dry brushing at the range became a standard procedure for me. Once I got everything right with my hi-vel PPCB, my dry brushing resistance, after every round, became consistent from chamber to muzzle. Final verification came when solvent cleaning the rifle at home and examining the cleaning patches for lead and seeing no lead, only powder residue. Granted this dry brushing technique is subjective, but it apparently worked for me. Buying an expensive borescope to examine the barrel interior was just not in my budget.

Later on I found that after shooting a tight hi-vel PPCB group, the group would slowly open up due to powder residue build-up in the barrel. When the group would start to open up, I'd dry-brush and the group would tighten back up. This is how I now shoot/test PPCB all day long at the range without solvent cleaning the barrel.

Best regards,

CJR

Thanks for the explanation ...

[303Guy]

Very interesting! Thanks folks.

I had read about the egg white. I might just give it a try and see how it works (have three chickens running loose in my small yard and neighbours yards! Just need to find where they are laying!)

I reasoned that if the patches were disintegrating with cat sneeze loads then they won't work with full power loads. The first few is sent through the bore failed and I got leading near the end of the bore on the driving edge of the rifling. Now the bore has taken on a shine and the glued patches are coming through whole (mostly). Now is time to push up the velocity but that means making a trip to the range. And that is the point, to be prepared for a range trip.

[303Guy]

I learned something today - white wood glue sticks paper to to lead! The outer wrap came away in strips but the inner wrap stayed stuck to the boolit. That would not have shot straight. This was a different paper, chosen for its thickness. More significant was the amount of glue used which was quite a bit with little dilution.

[Lead Fred]

Add a bit of this to your water soak. A bonding agent

Glue? Really? Hate to clean those bores

[CJR]

303Guy,

Some questions:
1. What was your estimated PPCB velocity?
2. Did you shoot your PPCB into a sand box or fired at a target?
3. Are you trying to glue the PP to a well cleaned and degreased CB? Or are you trying to strengthen the PP with glue and only wiping off the sizing grease from the CB (as the NRA did) to act as a "release/non-stick agent" so the PP releases?

In my view, there is not a Carpenter's Glue made(polyvinyl acetate) that can stay attached to a CB when the chamber pressures are 50,000 psi , gas temperatures are high, muzzle velocity of 3000 fps, and a muzzle RPM of 200,000+ generating extremely high centrifugal forces. If there were such a "magic glue", then we'd all be sealing 50,000psi pressure vessels with Carpenter's Glue. I would suspect that once the 50,000 psi pressure builds to radially expand and lock the CB/PP in the bore, all glue bond area, between PP and CB, is effectively broken. It is very difficult for a hardened/brittle glue to stretch without breaking/tearing its bond surface.

Best regards,

CJR

[303Guy]

CJR, the loads are very light, 5gr AS30N or Universal Clays under a 206gr boolit. The primer looks about identical to one fired with no powder to give some idea of relative pressure.

There is no sizing involved. These are smooth sides that I have knurled for grip so there is plenty of keyhold for the PVA glue to bond to. These were fired into my 'test tube'. The catch medium was ground rubber and that is topped with a squeezed rag that normally takes off any patch remnants.

Using a release agent would defeat the knurling so I will just have to keep the glue away from the lead. Other tests worked just fine so it can be done. However, I would prefer a brittle type glue like what we used to use as paper glue when I was a kid. PVA wood glue is pretty flexible and that is what I think is the problem. I need a weak and brittle glue like the paper glue we used in school as kids. I also intend to try pectin.

I noticed that the first patch after cleaning was fairly clean while the second patch was pretty dark (using printer paper and a sized then knurled core).

[cold1]

Try hide glue. Comes is dry flakes and you add water and heat. Get whatever consistency you want. Water soluble for clean up too. I think there is one company that makes a premixed liquid hide glue.

[Eutectic]

Paul Mathews- "Two egg whites stirred, not beaten, in a pint of water will do a good job. When you are finished, put the medium in a sealed glass jar in the refrigerator as it will keep for months". I have not tried, everybody will have their own witches brew.

I have done this for years in many, many different smokeless powder combinations....

It is all the 'glue' you'll ever need in my opinion.

Eutectic

[CJR]

303 Guy,

A minor point. Periodically, I remove some PP with my fingernails to mike the CB to make sure the diameter has not been sized below bore diameter+0.001"/0.0015". My PP always come off without adhering to the CB. Likewise, my PP(wetted with polyvinyl acetate(PVA)+water) doesn't appear to be flexible, so perhaps we are using different water dilutions with the PVA. My hi-vel 100yd. target groups indicate, to me, that I no longer am having any PP slippage on the CB. Therefore, I would suspect the "toughening of the PP(i.e. gluing of paper layers together)", with a wetting solution of PVA+water, is preventing any shearing-off of PP layers as the PPCB makes its way to the muzzle.

The trick is to get enough chamber pressure to radially expand the CB base & CB forward section, to lock the PP to the CB in the barrel. Once that's done, we need to prevent any shearing-off of paper layers until the PPCB gets to the muzzle. After the PPCB exits the muzzle the groove-cut PP, sitting on a CB with release agent, will be easily removed by the 200,000+RPM.

Best regards,

CJR

[303Guy]

Thanks CJR, I think we are on the same page. What I aim for is a patched boolit that will only undergo patch compression on seating. Some of my rifle throats require a nose section diameter under bore so as to be able to chamber. I haven't any great success with that set up yet (i.e. no bug hole groups) but this particular rifle has a more favourable throat geometry in my opinion so I might be inclined to pursue it. I did take note on the powder residue build up you mentioned, thanks.

There are a few suggestions which I would like to try like egg white. Hide glue sounds like the stuff we used at school for wood work although I though that was hoof glue? It did require heat and water. Pectin is another.

I think I could be in for quite a bit of fun with this rifle! I bought it from a fellow that shares my first name. It must be a sign!

[303Guy]

Just some feedback. I've been putting a few patched rounds through this gun which has cleaned up the bore some. Here is the first boolit compared to the last at this time. The first had a charge of 3.6gr AS30N and the last, 4.4gr of AS30N.



The second in the photo had the seating section of the patch glued between wraps.

And the patch remnants.


The portion of patch that was glued is that below the horizontal line. The patch separated pretty early as the distance between the muzzle and the catch rag is short and the patch did not hit front first and was off from the boolit hole.

I plan on loading up a few of these and taking them to the range to see how they perform.

[Ballistics in Scotland]

As various people have suggested, the trick is getting something which will strengthen the patch in the bore, but will always detach promptly on exit. For this reason I mistrust anything that soaks into or plasticizes the patch. I don't think a glue attaching the patch to the bullet against 50,000 PSI pressure is an altogether fair view. What can cause the patch to remain as a hard tube, turned over the base of the bullet, is the adhesion of impregnated paper to impregnated paper. In extreme cases even greasing the bullet under the patch (basically a good idea) isn't likely to help.

A possibility is the use of paper to which dextrin adhesive (as used on envelopes, labels, tape or postage stamps which you have to moisten) has been pre-applied. You can buy the powder on eBay, but something ready coated is better and easier.I have had good results at 1800ft./sec. with brown paper tape, which happened to be just the width I needed. I applied it with the glued side facing away from the bullet, moistened only a tiny bit under the last edge to keep the patch in place, and briefly steamed them, well above water level, in a large pan. Friction induced heat seems to loosen it on the way down the bore.

[303Guy]

I've been thinking on the pectin adhesive. I've just glued a dry patch between layers with paper glue using a fine brush. I then wet the patch and tamped off the excess water and set in the sun to dry. Using pectin would make the process quite simple. Apply the patch dry then wet and let dry. I'll be testing this sample in a rifle for which I have record of unglued patch behaviour.

Edit;
The patch came off in long strips so I upped the charge and again glued the wraps together by brush. The fragments were smaller with inner and outer wraps still bonded. This would make a good plinking load so I think I'll load up a few and test them for accuracy. They might even make a rabbit load.