Going Smallish Not Smellish

[Zeek]

This weekend, I hope to test two variants of the NEI 89 grain 25-20 in PPCBoo format. That CBoo works VERY well in my Marlin Cowboy 25-20 as a GCCBoo, so I hope that the PPatchin' tests work out at least as well.

The CBoo used casts 0.258" in diameter. The first PPCBoo is a 3X Tracing Paper (0.001" thick kind) on a CBoo core sized down to 0.251", so the final PPCBoo comes out with a 0.257" O.D. The second one is a 2X Tracing Paper patch on that same CBoo core, but sized to 0.254", so the finished PPCBoo comes out at 0.258".

Here is a picture of the 2X-patched PPCBoo:

It is, essentially, a one-diameter rifle-type CBoo. I got the PPatch to lay down on the smallish point by pulling the PPCBoo away from my light grip on its point, while turning it. This causes the excess material to lay down in successive folds arrayed in helical format up the side of the point. Once dry, they are strong. Using my all-manual PPatching method, these were no more difficult to patch-up than are larger-diameter PPCBoos.

I figure the 3X patch will have the least likelihood of giving trouble, so I will try it first. Then, I'll take the load that worked best on it, substitute the 2X PPCBoo, and begin firing a longish string. If the accuracy becomes worse, over time, then I'll know that this 0.004" total-diameter-added PPatch is too thin for the 0.007" (groove diam minus bore diam) rifling. Of course, that assumes that the 3X-patched PPCBoo will shoot worth sour owl sweat. Like the gambler said, "Nothing ventured, nothing gamed!"
Zeek

[longbow]

Excellent patching job! I am jealous!

The smallest boolits I have tried are 100 gr. .30 cal. They came out okay bit not near as nice as yours.

How did you get such a nice folded bottom edge? I wind up (no pun intended) twisting a tail then trimming it off. I am using somewhat thicker paper but still that is a fantastic job you have done.

I will be interested to see how these do.

I was wanting to have a lightweight high velocity load bit so far it has eluded me. Still trying though.

Longbow

[leftiye]

Summa my loads smell too.

Nice boolit! Let us know how it turns out (at the target). Maybe I'll get me one for my 25-20. (isn't that SMLE?)

[Zeek]

How to? Oh! I learned it here with y'awl, but will be glad to regurgitail it, as it were.

Cut your patch length to reach from your desired point of termination (in this case, on the CBoo's nose) to a location that is 1/3-of-a-caliber to the rear of the core CBoo's rear end. Wrap it accordianly (all puns Nintendo'd).

Now, you have a wet paper cylinder sticking to the rear of CBoo core. While it is still on the plastic-top mouse pad (really, the ONLY way to roll!!), remove your PPatch-rolling forefinger, place it on the rear of the CBoo and your left forefinger at near the PPCBoo's bas, and continue to roll that baby while enough enough downward pressure to cause the CBoo to rear up its nose a bit. This forces the finished patch on the drive band area to STAY IN PLACE, but the hung-over-the-rear-end part MUST fold to accommodate its far-more-compact inward-radial placement. Accommodating this base-edge-toward-the-base-center tamp MUST be done via folding of the excess, and it tends to do this in an even manner, given that putting lots of folds in one location causes an iterative transpuckerfication {way-bad!}, so it naturally evens out the folds thereby created. For once, nature is on OUR side!

This gives a nice even start (all around the CBoo's base) of evenly-spaced crenulations (fan-folds). Pick up the nearly-finished PPCBoo and hold its point between the thumb and index finger of the right hand (opposite for a south-paw), with its point between the thumb and index finger, at a point-upward 45 degree angle to a hard surface, and with the left forefinger pushing down lightly near the rear of the PPCBoo. Now ROLL that baby in exactly that configuration, while pushing down with the left forefinger (the left forefinger just rolls along, pushing down a bit). After completing at least one full hit-all-portions-of-the-base's-circumference roll, CONTINUE the roll as you bring the PPCBoo to a vertical position. The completed crenulations are now all ducks-in-a-row beneath the CBoo's base face.

Being careful not to let the lil' thang do a watermellon-seed-squirt-out, push down STRONGLY on the top of the PPCBoo to iron-in the crenulation folds. That finishes the base-face crenulo-fold-&-iron procedure.

Now, for the point. If your PPatch over the point is not tight, hold the PPCBoo in your left index-and-forefinger grip, with the point-part of the patch in between your right index-and-forefinger, and turn the assembly (with your left hand) as your light right-hand grip slides-and-rolls its way to the CBoo point. THAT gives a corresponding fan-fold to the excess material on the PPCBoo's point.

Now, set the finish-wrapped PPCBoo an a piece of plastic window screen material, which will allow its base to dry-and-shink-grip-the-CARP-out-of-it at the same time as its exposed upper portions. When it is dry, both of the base and point fan-folds will be like iron.
Ehhhhhhh . . . That's All, Folks!
Zeek

[longbow]

I will have to give that a go.

So far any of my well intentioned but misdirected attempts to make folded bases on small caliber boolits just downright sucked.

I have remained a tail twister and nipper but may reform now.

[Nrut]

Good stuff Zeek!
thanks..

[303Guy]

I once thought I'd paper patch for my 22 hornet - Doh! I have patched a few 25 boolits - it aint easy! I'm looking forward to your rest results.

There is a trick I learned that may be of interest, that is to use the back or edge of your thumb-nail to slowly develope a crimp on the tail as the boolit is rolled on the patching pad. It does not work with all papers. Some papers need to be dry for this trick. Just an idea.

[barrabruce]

transpuckerfication man that sounds like one of my special scrabble words thou I'm sure the wife wouldn't allow it.

Do get yer dift thou



Barra.

[longbow]

Tried the thumbnail trick but so far it hasn't worked for me.

Maybe my thumbnails are wrinkled!

[303Guy]

Tried the thumbnail trick but so far it hasn't worked for me.

It's paper dependant. I struggle with the folds when the paper won't crimp. Now I'm experimenting with no tail - well, a half millimeter overhang so as to be able to grip the edge. (So far it seems like it might work but the patch has to be wrapped real tight).

[Zeek]

Well! My Marlin 25-20 levergun does not seem to like PPCBoos much at all, but it dislikes the thin 2X tracing paper ones less than the 3X tracing paper ones. Generally speaking, it likes that same 89 NEI CBoo (in its gaschecked form) quite a bit, so I had my hopes up and now, instead, need to have my copes up. Well! Okay, BEEEEE that way!

[303Guy]

Zeek, are you using only that tracing paper? I wonder whether the tracing paper is simply too strong. Maybe a 'weaker' paper would produce better results or even a 'pulpier' paper? A boolit catcher might also be of benefit - uhmmm... that's one that you stick the muzzle into and catch the patch fragments too. (I wouldn't mind a down-range type boolit catcher. Not to mention some place to use it!)

[Zeek]

You could have a point there, 303Guy, and I don't mean on top of your head. However, that paper has worked well on other chamberings. I noted, however, that the flakes of discarded patch material were not as small as I would prefer. Perhaps I could try a 2X 16# (adds 0.010") on a CBoo sized down to 0.251, then size the 0.261" PPCBoo down to 0.259" prior to using it. That should leave enough air in the patch to help it function. The post-patching size-down would have to be done on my SAECO lubrisizer, but that action is gentle enough to work okay (the initial size-down from the 0.258 as-cast diameter is doable correctly only with a Lee-style die that I made myself).

The RL-7 charges gave pressure in the range of 25 to 40+ Kpsi, which is about right.
Zeek

[303Guy]

So patch recovery isn't a problem, just boolit recovery. How fast does the pressure rise with RL-7? Your gun, being a marlin would have micro-grooves, right? That would pose a different set of challanges, I should think.

Wouldn't the 25-20 be a candidate for Lil'Gun? If it is then a precompressed charge would set the boolit seating depth so minimal to zero neck tension could be used in the magazine. It doesn't even spill out should a boolit be pulled frpm the case. It would also put the perfance level up a few notches - but only if the case capacity just happens to be right.

[Zeek]

. . . How fast does the pressure rise with RL-7?

For example, the 13.5 grain load reaches peak pressure after 0.89" of bullet travel. Now! What on EARTH are you going to do with that information? All I can say is that most military rifle chambers give a peak pressure (with typical loads) after 1.5 to 2.0 inches of bullet travel. That, plus $50, will get you a cup of coffee almost anywhere.

Your gun, being a marlin would have micro-grooves, right? That would pose a different set of challanges, I should think.

Not so. As I indicated in my original (I believe), it is a "Cowboy" model, so has Ballard-type rifling.

Wouldn't the 25-20 be a candidate for Lil'Gun?

Perhaps so. That powder is not listed in my QuickLOAD software, so I have stuck with RL-7 which gives me a slightly-compressed load at around the right max pressure.

If it is then a precompressed charge would set the boolit seating depth so minimal to zero neck tension could be used in the magazine. It doesn't even spill out should a boolit be pulled frpm the case. It would also put the performance level up a few notches - but only if the case capacity just happens to be right.

RL-7 gives me all that. With that same 89gr NEI GCCBoo, it gives excellent MV and accuracy. I'll take a look, on-line, through, to see if there is any loading information for Lil' Gun in the 25-20.
Regards, Zeek

[303Guy]

Now! What on EARTH are you going to do with that information?

I am wondering whether the early pressure rise distorts the boolit before it is fully supported in the bore and also whether with an early pressure fall off there is enough time and distance in the bore during which the patch is being 'worked' under obturation pressure for it to fully fragment. I have a theory that the shorter the pressure peak the higher that peak needs to be to 'work' the patch to fragmentation.

[Zeek]

303 Guy:
What you are looking for, really, is the QuickLOAD readout of muzzle pressure . . . the higher the MP the more likely is the PPatch to disintegrate and in smallish fragments. Recall that, under the high-pressure-truck-tire theory, the air in the patch is under great obturation pressure and cannot escape, but then, suddenly, it emerges from the muzzle, thereby causing the PPatch to self-explode as the gas pressure causes the PPatch to expand in all locations instantly, upon emerging from the muzzle. That is the same theory as urine, only worded in a Zeekish way.
Yes, I'm going to BEEEEEE that way,
Zeek

[303Guy]

Ok, to try explain what I mean - well, firstly my idea of ideal is a pressure curve that rises slowly so that the boolit is well past the throat before the pressure is high enough to actually obturate the boolit and 'pressurize' the patch then that pressure should remain above the obturation pressure threshold till close to the muzzle when it should be falling rapidly below obturation pressure so as not to distort the boolit on exit. That would keep the patch pressurized long enough for it to 'crumble' into a paper fibre/compressed air layer on which the boolit is riding. So, with a pressure rise that is too rapid (smaller charge of fast powder) the pressure falls off too fast leaving the paper almost intact at muzzle exit even though for a short time the obturation pressure was plenty high. Meaning that the air in the paper is no longer compressed because the boolit is no longer obturating.

In the end then, a smaller charge of faster powder would require a higher peak pressure to achieve the same result. Then if that pressure rise is too fast, a 'weaker' paper might be required.

Am I making sense?

My theory might not even be correct!

Here is a boolit fired with a small charge of shotgun powder.


Not sure what it's 'saying' to me but there is something in there! There's actually more info on that same specimen if only I could interpret it. See in the first pic about a third the length from the base there is a little ridge? That is a paper wrinkle impression - that means the patch was dragged a little on firing, stretched and crinkled at that point before entering the throat taper. See the puzzle? Now the 25-20 case is smaller so a new perspective is introduced.

Anyway, I'm just trying to understand what goes on when a paper patched boolit is fired.

[Zeek]

. . . See in the first pic about a third the length from the base there is a little ridge? That is a paper wrinkle impression - that means the patch was dragged a little on firing, stretched and crinkled at that point before entering the throat taper. . . .

T'ain't necessarily so! I find that I get such patch folds on seating the PPCBoo. If such a fold carried forward directly into the throating, then it would look exactly as you show in your image.
Zeek

[303Guy]

If such a fold carried forward directly into the throating, ...

I did consider that and I have had that happening but this PPCBoo was finger twist seated into an unsized neck. It looks a lot like the boolit canted as it left the case. The crinkle impression is only on the side of the base distortion. I'm now trying a larger casting with thinner paper. Still early days. (I like thicker and pulpier paper with the idea that it holds more air but the casting is too big!)