The Basement Articles: The Paper Jacket

Discussion in 'Tips, Tricks and Techniques' started by Ian, Jan 9, 2016.

  1. Ian

    Ian Well-Known Member

    High performance with paper jackets


    When I first started re-experimenting with smokeless powder and paper-patched cast bullets a few years ago, I spend many hours researching information on various websites as well as buying and reading Paul Matthew's book The Paper Jacket. I tried lots of things in several calibers, experimenting with paper, fit, bullet design, alloy, powder types, and after all the things that worked and didn't, Pdawg Shooter from Cast Boolits summed it all up in one short paragraph. I tried it and it just plain works. I'll expound on his technique here.


    >Core needs to be sized .001-2" larger than BORE diameter. I have some custom moulds that cast exactly the size I need, but for those that don't, standard caliber bullets can be used if they are sized down to the proper dimensions. A push-through die, like Lee Precision makes, is the best way I've found to do this. You can modify an existing die size to the right sizer for your cores, or have a custom die made. To size down bullets up to ten thousanths, I roll them first on a case lube pad and shove them through the sizer nose first. Sometimes, even though I have some custom moulds that require no sizing, I run the bullets through the sizer for quality control and cull the ones that get squeezed. Grease-grooves are a must, micro-bands like Lee or Ranch Dog "tumble lube" bands are a very good design for this. "slicks", like traditional black powder, pure lead patched bullets, do not work very well at high velocity with smokeless powder, I've tried it several times and it's a bust. The paper needs to be wrapped wet with some stretch so it can shrink into the grooves and grip the bullet tightly.


    >Patch to .001-2" over groove, larger if throat permits. The preferable thing is size the patch to the throat freebore diameter, and size your necks to have an ID of .001" smaller than freebore diameter to hold the boolit just well enough.


    >Paper Jackets shoot best for me when firmly engraving the patch into the lands or the taper/ball seat of the rifle's throat upon closing the breech. Seating long and letting the gun do the final seat per Pdawg's method gives me the most consistent and best accuracy.


    >You need to select a paper that will make a finished jacket that is throat diameter or a little smaller. If the rifle doesn't have a sharp transition from chamber to throat, the jacket can be thick enough to seat and hold by itself in a fired case. I prefer about .001" neck tension on my patches, so be careful to not size your brass too much or expand it too little. Depending on the rifle, sometimes I have to slightly resize my brass to grip the bullet with .001" tension, sometimes it's ok just using unsized cases, like I said it all depends on the throat entrance diameter. Most modern, smokeless, bottlenecked cartridges have chambers designed with large chamber necks and small throat entrances, so it is necessary to size down the necks to below throat entrance diameter and patch to the same size as throat entrance diameter in order to hold the bullet adequately yet not shave paper off on the sharp edge of the chamber-throat transition.


    >Green Bar printer paper, of the 16 lb variety, is absolutely wonderful stuff for smokeless paper jackets. Wet patch, two wraps and a twist, cut the ends of the patch anywhere from 30/45 degrees, whatever you prefer. I like to make a template and cut them out on a guillotine paper cutter, five layers thick. I mark a stack of five sheets of paper with segments anywhere from 3/4" to 1-1/2" wide depending on length of bullet, mark all the way across with a pencil and ruler, and staple one edge between each line to keep the strips together as I cut them out. Once I have my strips cut, I clamp a guide to the cutter table at the appropriate angle to the blade, mark the patch length on the top strip on the stack, line them up, and cut the ends. This gets me five finished patches per whack. You will have to experiment to get the length of the patches exact, especially with wet-wrapping, because you want no overlap of the patch ends, but as little gap as possible. Remember, wet paper stretches when you roll it on tightly, so your dry patches will be considerably short of meeting on the ends when wrapped around a sized bullet. I use a varnished board with a slot cut across one end, about 1/4" from the edge, for a patching board. Put the wet patch on the board so the pointy end hangs over a little, make sure it's perpendicular to the groove in the board, wipe the excess water off with your fingers and smooth the patch to "stick" it to the board, position the bullet in the groove on top of the patch, flip the point up with your thumb to stick it to the side of the bullet, and start rolling. Make sure the point tucks nicely on the back side and doesn't get wadded up.


    >I make two full wraps and twist the tail. It will come untwisted slightly, but don't worry about it. When dry, the tail will be like aluminum foil and you can re-twist it tightly and it will stay put. Clip it off so there's a little stump left. When base-first final sizing, bottom the bullet on the ejector stop and it will crush the nub on the base into a nice base "wad". Another method is to clip the tail wet or just make the patch so it barely overlaps the base of the bullet and fold it over, then gently twist the bullet's base against the patching board to "form" the paper tightly against the bottom like papier mache. Leave the bullet standing on it's base to dry to keep the base part formed nice and flat.


    >You will need to lube your patches after they are dry. Any lube works, but you need something for the patch, even straight Johnson's Paste Wax or beeswax. I prefer a really soft mix of beeswax and Vaseline. Don't be afraid to base-first size/lube like a conventional boolit, just heat the sizer up a bunch so the lube flows well.

    >Begin with starting charges of the slowest ball powder for which you can find data for your gun and the equivalent weight of copper-jacketed bullet.


    >Experiment with compacting, inert, granular fillers once you work out the case prep, core size, and patch.


    >Alloy: Pure lead, 50:1, soft range scrap, stick-on wheel weights, roofing lead, shower pan lead, or clay pipe joint lead is good to 2000 fps in most guns, 2200 fps in some others. Air-cooled wheel weights to 25-2700 fps, depending on caliber. Water-quenched and aged 50/50 clippy wheel weights and pure lead will go to 3K. Water-quenched clippy weights will go faster than that. High-antimony, brittle alloys like linotype or even Teracorp Magnum (92-6-2) are too brittle for best results, very hard on paper during engraving. The alloy needs to be malleable. Lead/tin binaries are excellent for smokeless paper patching.


    >This exact technique has worked for me with smokeless powder from .270 Winchester at over 2700 FPS to .45/90 at over 2,000 fps, and at similar, copper-jacketed velocities in a bunch of calibers in between. Accuracy has been as good or better than copper-jacketed bullets with the appropriate tweaks.


    Ian


    Pay special attention to throat fit with the patched bullet. Just as with grease-groove bullets, FIT IS KING, and minimizing tolerances is key to accuracy. The paper jacket should be wrapped to just cover the break in the ogive of the bullet, or just forward of the part of the bullet's nose that is exactly bore diameter so the patch doesn't snag and get peeled back or wadded up like the wrapper on a soda straw when it's fired.


    Another thing, paper-jacketed bullets don't like any kind of jump to the rifling. The harder you can engrave them and tighter they fit in the throat when chambered, the better. Keep a cleaning rod handy if you have them quite tight, as the cartridges will de-bullet when extracted without firing.


    Ian
     
    Reed, kenneth and Doug like this.

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