Patch to bore + .001 or cast to bore + .001?

[303Guy]

(Or size to bore plus). There seems to be two ways of doing it. Final patched size to bore plus or cast/size to bore plus then patch.

I have been patching fit the throat and that means the casting is going to be under bore size for part of the boolit length. My results seem to indicate that this is OK. Accuracy has been better than expected for the bore condition and patch disintegration seems complete. In fact, even in the 'test tube' I only find a few small fragments (and I know the fragments are not accumulating in the suppressor 'cause I just fired a gun that doesn't have one!) I'm getting zero leading so the patch must surely be doing its job in the bore.

Obviously there is more than one right answer here. I'm trying to get an understanding of what is required and what actually goes on within the bore.

Any input will be appreciated. :drinks:

[nanuk]

I have been patching fit the throat and that means the casting is going to be under bore size for part of the boolit length.

303Guy: I'm not following this statement. Why does patching to fit the throat, mean it is going to be under bore size for part?

I assume you are using your smooth 2 diameter GC homemade heavy?

[onesonek]

I believe the only right answer is,,,,, each barrel has it's own set of wants or rules.
I may be missing something in your wording 303, but there is bore dia and there is groove dia.. I'm new to paper patching, but after all my reading and research, I think I will follow P-Dawgs general "rule of thumb". That is to cast or size to .001" over bore, and then patch and size to .001- .0015" over groove. Then comes into play the throat dia.. If it tends to be on the roomy side, I would maybe patch up to it, or .0005" under throat. From what I gather , smokeless don't obturate at the start like BP does, (totally different pressure curves), so a good fit is more critical in that throat/leade area with smokeless.
In my case with the one I am going to start patching, I can cast .001" over bore, and patch to .0015" over groove, and that happens to put me .0002-3" under throat dia.. I have accumulated 4-5 different types of paper to experiment with, and still need bucksot to make me a sizer.
I just got sidetracked with .375-444 first.

[303Guy]

I may be missing something in your wording ...

Why does patching to fit the throat, mean it is going to be under bore size for part?Oops! I was very unclear there! :oops:

The casting will be under bore size for part of its length if the patched boolit fits the throat. (The front section of the patched boolit is bore riding so the core is a little under bore). So part of the casting is under bore size.

This applies to a tapered casting as well as the sized, two diameter casting.

Well, I have no choice but to use a core with the front half under bore diameter with my pig gun but today I shot it and the accuracy was astounding. I'm not actually sure what the bore diameter at the muzzle is as it has a non removable suppressor.

The boolit casting that shot real well in my BSA&M cavalry carbine is definately loose in the muzzle for about half its length but the patched boolit is snug in the throat and the patched nose will only just enter the bore at the muzzle.

onesonek, you have highlighted the essence of my question. My casting nose is under-bore while the patched nose is interference bore-ride and the rear is over groove as patched and snug in the throat.

[pdawg_shooter]

I believe the only right answer is,,,,, each barrel has it's own set of wants or rules.
I may be missing something in your wording 303, but there is bore dia and there is groove dia.. I'm new to paper patching, but after all my reading and research, I think I will follow P-Dawgs general "rule of thumb". That is to cast or size to .001" over bore, and then patch and size to .001- .0015" over groove. Then comes into play the throat dia.. If it tends to be on the roomy side, I would maybe patch up to it, or .0005" under throat. From what I gather , smokeless don't obturate at the start like BP does, (totally different pressure curves), so a good fit is more critical in that throat/leade area with smokeless.
In my case with the one I am going to start patching, I can cast .001" over bore, and patch to .0015" over groove, and that happens to put me .0002-3" under throat dia.. I have accumulated 4-5 different types of paper to experiment with, and still need bucksot to make me a sizer.
I just got sidetracked with .375-444 first.

That "rule of thumb" is just a starting point. It works for me, but results may vary. I have 1 rifle I have to patch to .004 over groove to get accuracy. It has a very generous throat. One time I took some 311446 that had been sized .304 and patched to .314 and run them through a .309 die, loaded them up in my 06 and they shot great. My .458 had to have the rifling leade cut to 11º to get it to shoot PPs at all. Keep trying, its fun!

[303Guy]

Keep trying, its fun! That it is!:drinks:
Challenging too! But fun.

[barrabruce]

I thought you would have trouble 303 guy with the patched nose to bore + a bit.

Seems I can't see how the riflings gunna cut the paper all through and pull it off the core the same each shot.

Sure could stuff them in further down the bore thou for better aliagnment.

I just lube the nose with alox now and hope for the best.
The paper on mine starts with the rifling.
When I eject a round it has dirty marks of fouling and rifling to around a 1/4" back from seating depth on the nose body taper where the patch starts

I seat mine out so they have to just push the bullet in the case a tad on lock up.
Firm hand seated bullet

I may go back and try full patch again soon thou.

Barra.

[zippidydoodah]

I am new to paper patching and wondered if the teflon tape used by plumbers could be used in place of paper. Would it work?

[docone31]

No.
The simplest and easiest is lined notebook paper.
Many have tried the plumbers tape.
Paper works very well.
Just plain paper.

[pdawg_shooter]

I am new to paper patching and wondered if the teflon tape used by plumbers could be used in place of paper. Would it work?

Tried that stuff one time. Once was enough. Leading, NO accuracy and strings of teflon over everything. I used 16# green bar printer paper on almost everything now.

[303Guy]

... teflon tape used by plumbers could be used in place of paper. Would it work?I think we have all felt compelled to try it! Paper works by acting as a cussion between boolit and bore and some think the air trapped within the fibres of the paper give it a pneumatic effect which also helps disintegrate the paper at the muzzle. As you can see, teflon tape does not meet that criteria. It can also can smear in the bore.

I asked the question about a patched to bore nose section of boolit because that's what I am doing and even that bit of patch dissapears at the muzzle and I have just found the boolit in question to be very accurate in a very poor bore. Something is disintegrating that patch. It could be the impact of the boolit into still air in front of the muzzle that blows it up. I don't know. The forces involved are quite intense and paper is quite weak - the paper I use anyway.

[MBTcustom]

Given the forces that are being applied to the paper, it is not hard for me to see how the paper would not just plain vaporize on its trip down the barrel. If your barrel is in bad shape this would be compounded by the gasses trying to get around the boolit. I think that paper is so fiberous that when confronted with pressures like those in the chamber of a rifle, the fibers feel free to come loose from their matrix and just float around.
One experiment that I unknowingly did was on my .358 Malcolm wildcat. I cut the chamber of the rifle to the depth of the parent cartridge, but after fire forming, the neck retreated backward about .050inches, leaving a gap between the neck of the case and the start of the throat like so.
http://www.castboolits.gunloads.com/picture.php?albumid=534&pictureid=3927
"That's a mock chamber that I cut in half."
This made it so that even though the boolit was lodged securely in the throat and the neck of the cartridge, the base of the boolit had to pass through a "ring of fire" before It could make it into the throat of the barrel. I didn't know this at the time but resulting effects on the patch gave an interesting look at what can happen to the patch when gasses are allowed to have their way with it:
First, I kept getting a ring of paper left in the chamber of the rifle "actualy ironed on to the neck portion of the chamber, right where that gap is seen. I would try to chamber the next round and the boolit would get stuck in the throat with that ring of paper around the nose. Closer examination showed that the ring of paper came from the diameter of the boolit just above the base. It was cut clean with very little fraying.
Second, Upon examination of the chamber with a light, I saw a deposit of white dust all over the neck area of the chamber. Careful extraction showed that this white powder was vaporized paper.
The only reason I was able to see this was because the chamber of the rifle was cut wrong, but I would wager dollars to doughnuts that your patches are doing the same thing as they travel down that rough barrel. Seems to me that the trick is to use enough paper to get the boolit on its way, and you have just enough to get the job done.
I believe that my experiments with faster powders show similar results in that accuracy goes to pot and I see a lot of white smoke and smell burning paper very strongly after every shot ie. the powder vaporized the paper before the boolit made it out the barrel. However, I think that it is this vaporizing action that is critical to PP success because it is necessary to use a paper that is easily frayed in order to get good results. I think that the paper is vaporized, and acts kind of like cream of wheat to fill the holes that are letting gas go by. All of the papers that I have used that were of very strong, highly compressed, composition (100% cotton vellum, grocery store reciept paper, etc) didn't work very well compared to the relatively weak green bar paper.
So, the boolit to bore fit is kind of a secondary goal in my mind. It seems to me that the trick is to compress the fibers hard enough between the boolit and the barrel that the powder can't destroy the paper fast enough to get around the boolit on its way out the barrel, but not so stiff a paper that the gasses cant make it seal the bore. I think that one of the big problems with finding the perfect PP load is the lack of variety in paper thicknesses and densities. The best you can do is find one that is close and smoosh it down to what you want with sizer dies, but this changes the density of the fibers so its kind of like fishing in the dark. I think that boolit fit to the bore and patch fit to the groove diameter is not as important as getting the right tension of paper between the two.
If you found the magic combination that shoots well out of that old gun I would hold on to it like grim death.
That's my theory anyway, sorry I drug on so long.

[303Guy]

... boolit fit to the bore and patch fit to the groove diameter is not as important as getting the right tension of paper between the two.That's a good point.

I too think the patch crumbles and forms a 'air/paper fibre slurry' between the boolit and bore. But not always.

I don't know whether there is any leading in the bore but if there is it is being wiped away by the filler. The shotgun powder loads I tried did not have any filler and there did not seem to be any change to the bore condition but accuracy was not there. Nor was velocity although I did try to match the pressures by judging primer appearances. Patch disintegration seemed to be about the same.

[MBTcustom]

The shotgun powder loads I tried did not have any filler and there did not seem to be any change to the bore condition but accuracy was not there. Nor was velocity although I did try to match the pressures by judging primer appearances. Patch disintegration seemed to be about the same.
I noticed the same thing when I had the .303 barrel on my rifle, for some reason those PP boolits did not like any sort of a fast powder. The best results I got, were when I used the slowest powder that I could find data for "IMR4831". the rifle choked on Green Dot, Unique, SR4756, and H335.

[n.h.schmidt]

Hi Guys
Interesting ideas about patch reading. For my attempts in the last few months,I have had different results. To make it short, the time I had good results was when I got confetti. Lots of strips on the ground. You could see where the lands had cut the paper. The more the paper became a white vapor cloud the poorer the target results. My conclusion to date has been ,it's in the barrel condition. My nice smooth .30 cals ( a couple of .308s) and one 8X57 with a new condition barrel get confetti with ease. Good accuracy too.
My MAS7.5F has sometimes worked with PP. Its getting smoother and is comming around to more reliable results. It's my 303s that have got me pulling hair out. I have one with a fair bore that works well with PP ,always has. A P14 that will only shoot PP if I pre-condition the bore with some Lyman Super Moly lubed cast bullets first. Without the moly conditioning ,I get white vapor cloud upon fireing and can hardly hit the target. With the moly ,I get the strips and bigger parts of the patch and good accuracy.
I have a No4 with whqat looks like a perfect bore. It has yet to shoot a PP load with accuracy.
I don't know what it is but the patch simply atomizes . No paper can be found. The moly conditioning has no effect.Cast bullets work good with ths rifle. Could the infamous cordite effects on the bore be the problem? I an trying to improve things by using JB bore paste to smooth things up.
n.h.schmidt

[DIRT Farmer]

Intersting comments. My experience is limited to qulified sucess in the 303 and to me unbeliveable results in the muzzle loading .451 Gibbs. I would guess there has to be some simularities in the mechanics of the sucessful package exiting the muzzle and hitting where you want it. I understand the "launch' is very different, but finding shards of baper at least 1/2 the diamiter of the slug in the muzzleloader and full width of origonal started me to wondering, what is different. Playing with the 303 which I load with the Lyman 311-291 as cast, per 303 Guy's sugestion and using IMR 4350, 20 lb coperier paper wraped dry amd lubed with a very light touch of 45% BW 45% cisco and 10% olive oil just to seat the package in the case neck, I tried wheat bran filler. Sudden sucess, the paper patch survived the ride and I found bigger pieces od patching.
As my main interest is shooting a lot, as ecominicly as I can, I started playing with IMR 4227 Starting very low and working up to the book load. With wheat bran it shoots well, with out the bore leads. My guess is a less perfict fit needs a wad to start, as the throat is generous and not very smooth. The filler allows the package to pass the leede and throat area with less blow by. The serviving patch pieces are larger, and are not as stained as without the filler.
Any thoughts?

[longbow]

I have wondered about all this myself and still have no good conclusions yet.

I started paper patching for .44 mag Marlin with microgroove barrel. I wound up getting good results with a 0.421" boolit patched to 0.432" for my 0.4315" groove diameter.

Now with microgroove the rifling is very shallow and my bore diameter is about 0.425" so my cast boolit was well under bore size yet it worked well.

I tried 0.424" boolits and thinner paper with very poor results.

Next was my .308" and I started based on Lyman's old PP boolit designs in my Lyman Cast Bullet Handbook. They recommended 0.301" boolit for standard .30 cal so I made a mould to cast 0.301" then patched to groove diameter. Worked well,

So I figure for my .303 I will just use thicker paper. Well, that was a no go! I got very poor accuracy. I decided to knurl the boolits to increase diameter to 0.304" then patched to groove diameter and that improved things a lot. I wasn't sure if the larger boolit or the knurling made the difference as some prefer a grooved boolit to smooth for paper patching. In any case that worked pretty well.

I have not recovered paper patch pieces from either the .308 or .303 but used to find lots of confetti from the .44. Generally I would find strips and small pieces when using the 0.421" boolit but all I got was very small fragments when I tried the 0.424" boolits with thinner paper.

So, the .44 Marlin defied the cast to bore and patch to groove idea yet made nice confetti. The .303 is what I am working on now and so far not bad results but not great and I have tried the 0.301" boolit (so about 0.003" under bore size) boolit with poor success and 0.304" knurled boolit with moderate success.

My thought of what to try next is to ream out the base of the mould to 0.304" or maybe a bit bigger and leave the nose at 0.301" then patch up to just past the transition.

The BP buys generally use parallel cylindrical smooth boolits patched to a little over bore size to allow easy chambering then let the BP bump the boolit to groove diameter. The undersize patched boolit is to allow for fouling. However, most who shoot matches seem to wipe between shots or use a blow tube.

It seems to me that if you are going to wipe between shots then it really shouldn't matter which method is used as there is no fouling. However, if patched to bore diameter then there is some "uncontrolled" bumping up going on. I certainly can't argue with the results many get with this method but it does make me wonder why the boolit bumps up so evenly. Consistency in loading I suppose.

Nonetheless, it makes more sense to me to cast to bore and patch to groove to ensure that the boolit fits the throat and groove diameter. The solution ~ a two diameter boolit with nose patched to bore or a little better and base patched to groove.

There were original BP moulds made like this. The boolit inside the cartridge was bore diameter patched to groove and the boolit outside the cartridge was under bore diameter patched to bore. This eliminates the need for the base to bump up but still gives the easy chambering of the patched to bore feature.

At first I was thinking like barrabruce in that if the rifling didn't cut the patch then how would it shred to release cleanly but think back to my .44 Marlin with 0.421" boolits ~ not a problem. Also, looking at recovered BP boolits from patched to bore shooters it is obvious that the base of the boolit bumps up more than the nose so rifling is not likely going to cut paper wrapped far up the ogive.

That would also apply to cast to bore/patch to groove because again, depending on how far up the ogive you patch the rifling may not cut through the patch completely.

Also, along the lines of clean patch release, I originally read that the paper patch should be moistened with a mix of glue and water to make sure the patch layers don't slip. I tried that method and found it worked in my .308 with no problems. It wasn't until after I had success that I read that it shouldn't work!

Recently I have read that using glue to make a tough paper jacket is a good way to go.

There is also a huge difference in what acceptable accuracy is. For me, with my No. 5 Lee Enfield I would be quite happy with 3" groups at 100 yards but that certainly isn't match grade accuracy.

Yesterday I got scattered large groups of 6" or so at 50 yards using the knurled 0.304" boolit patched and sized to just under throat diameter of 0.315". Gas checked plain cast boolits did much better ~ also sized to 0.315".

Who is right? Maybe everybody... depending on boolit fit to throat and bore, paper thickness, alloy hardness, and paper qualtiy.

I have more questions than answers (obviously) and still have lots to learn but I guess that is all part of the experience.

Sorry to ramble on here, just kind of thinking out loud.

These threads are always a good place to learn, share and discuss.

Longbow

[303Guy]

Could the infamous cordite effects on the bore be the problem?I consider the effects of cordite to be a blessing for paper patching because it opens up the throat and gives the bore a taper toward the muzzle - a condition that can be reversed by the use of pull-through's! That reversal would be in the last few inches of bore which can be cut off or counter-bored. Corrosion toward the muzzle might also be responsible the the end bit opening up.

My near mint bored rifle has a distinctly tapered bore after 500 rounds of cordite machinegun ammo but the throat is still close to original shape - just all the sharp edges are gone.

Anyway, my best two rifle throats are grossly oversize, the one from rust and the other from cordite. Those are my two shooters! The patched boolit starts to engage the rifling for half their total length and are so large that they seat tight without any neck sizing. The nose section of the boolits are patched to bore as tested at the muzzle - they can be pushed in with a slight resistance - yet I find no confetti. Only the patch base ring gets recovered. That follows the boolit right to a halt in the catch medium (test tube). They castings taper from the point of seating to the ogive and are parallel for the seating bit.

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

Notice the absence of obvious rifling impressions on the boolit? They're there, just not obvious in the pic.