StainLess Steel MediaBallisti-CastMidSouth Shooters SupplyRotoMetals2
Graf & SonsTitan ReloadingLee PrecisionInline Fabrication
Page 1 of 2 12 LastLast
Results 1 to 20 of 36

Thread: How do PP bullets achieve accuracy?

  1. #1
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131

    How do PP bullets achieve accuracy?

    If the purpose of the paper is to act as a "jacket" that keeps the lead from touching the rifling and causing lead fouling, how is spin applied to the bullet? Does the paper have sufficient purchase to spin the lead? I know it must work, or no one would have done it then or still be doing it now. I have read about some who create a bullet that when patched is bore diameter, and most make it groove diameter (or somewhere between the two). I guess I can accept the groove-sized PPB, but how does the bore-sized PPB work if nothing is large enough to engage the rifling?
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  2. #2
    Boolit Master in Heavens Range
    felix's Avatar
    Join Date
    Mar 2005
    Location
    fort smith ar
    Posts
    11,631
    Soft lead; obturation. ... felix
    felix

  3. #3
    Boolit Master

    Join Date
    Apr 2008
    Posts
    5,046
    Let me assure you, unless you, it does work.
    I have not found anything but confetti after a shot.

  4. #4
    Boolit Master

    Join Date
    Apr 2009
    Location
    milton fl
    Posts
    1,120
    Seth, welcome to the forum. The bpcr shooters use the powder charge to upset the boolit into the thoat & riflings. Check the bpcr threads, I know they explain it much better than I can.
    With smokeless, if your sizing your boolits to say .002 over groove, you can either start with a casting enough undersized to take up what you need, or just wrap over the boolit & size back to what you need. The paper will compress the lead down without tearing. I do alot of this. Give it a try, you might be suprized at the results.
    Docone is right about the confette, if the wind is blowing toward you, you'll get covered if you shoot enough lol.
    Gun control 1ST ROUND ON TARGET.

  5. #5
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    Quote Originally Posted by docone31 View Post
    Let me assure you, unless you, it does work.
    I have not found anything but confetti after a shot.
    I don't understand what you're saying. "unless you"... what?
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  6. #6
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    Quote Originally Posted by felix View Post
    Soft lead; obturation. ... felix
    So... if the lead expands to engage the rifling (that is what "obturation" is, right?), what's the point of paper patching? I thought the purpose, or at least part of the purpose, of the paper "jacket" is to prevent leading the barrel.
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  7. #7
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    Is the paper strong enough to withstand the friction applied to it when going down the barrel between the bullet and rifling - after the bullet has "obturated"?
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  8. #8
    Boolit Master

    Join Date
    Apr 2008
    Posts
    5,046
    Sorry about that. I have too many distractions going on.
    If the paper is carefully wrapped, I prefer wet, it is amazingly strong! The paper becomes a strong barrier. It shrinks down to the casting to the point where the lube lands show through the paper.
    I remember the first paper patched boolitt I made. It must have been the most exciting thing I had done in a while! When It dried, it was real hard.
    I loaded them, shot them, and have done so ever since.

  9. #9
    Boolit Master
    Join Date
    Mar 2005
    Posts
    321
    6.5 mike, are you're sizing .002" over groove before or after patching? I like my cores a thou over bore. Sizing the patched core to groove works for me.

    Seth, the paper is strong enough, the boolit spins and leading is avoided at higher velocities than you'd usually expect from a cast boolit. Feel free to try it yourself to see if we're kidding.
    Just because change doesn't make a difference doesn't mean that change is bad.

  10. #10
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    What kind of paper are you using, and where do you get it? I've been Googling "cotton rag paper" in my search for some. From what I've read so far, I need to know what paper I plan to use and it's thickness, as well as the bore and groove dia.'s of my barrel, before I can spec out a die. I just bought a used Corbin press and need dies.
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  11. #11
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    Quote Originally Posted by oso View Post
    Seth, the paper is strong enough, the boolit spins and leading is avoided at higher velocities that you'd expect from a cast boolit. Feel free to try it yourself to see if we're kidding.
    I believe you. Honest! If it didn't work, it wouldn't have survived this long. I'm just trying to get a better understanding of the physics of how it all works. The cotton rag paper must be very different from regular old paper.
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  12. #12
    Boolit Master
    Join Date
    Mar 2005
    Posts
    321
    The paper I use is watermarked Strathmore Bond 25% Cotton. I found it among some old typewriter papers I had about.
    Just because change doesn't make a difference doesn't mean that change is bad.

  13. #13
    Boolit Master

    Join Date
    Apr 2008
    Posts
    5,046
    I use lined notebook paper, or cheap computer printer paper.
    They both work well.

  14. #14
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    So, you're saying that you don't need any special "cotton rag" paper? Any paper, like regular notebook paper, will work fine?

    If you're using paper of varying thicknesses, how are you achieving a consistent or desired final bullet diameter?

    How did you decide on a diameter for the lead?
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  15. #15
    Boolit Master
    Join Date
    Apr 2005
    Location
    Magnolia, Arkansas
    Posts
    589
    Buffalo Arms has Paper Patch Paper forsale if you want to try what Dave Gullo recommends. Or like Docone31 says try the computer paper or notebook, I have used that kind with good results also.
    My mother always said I was the Flower of the Family, The Blooming Idiot

  16. #16
    I'm A Honcho! montana_charlie's Avatar
    Join Date
    Feb 2006
    Location
    West of Great Falls, Montana
    Posts
    15,403
    Seth,
    What kind of application are you contemplating.

    Will it be a modern caliber and smokeless powder...or a black powder cartridge with a big bruiser to throw out of the muzzle?

    There is a little bit of difference in technique between the two 'religions', even though the basic theology is the same.

    So, tell us what you need to get done, and we can let the right 'bunch of missionaries' give you advice on how to get to heaven.

    CM
    Retired...TWICE. Now just raisin' cows and livin' on borrowed time.

  17. #17
    Boolit Man
    Seth Hawkins's Avatar
    Join Date
    May 2005
    Location
    Jacksonville, NC
    Posts
    131
    Sharps rifle, .45-70, strictly BP, shooting at paper & steel. I've owned the gun for a number of years, but haven't shot it yet. I've got everything I need to load for it, except the bullet. The swaging press gets me closer. I just need to order dies for the swaging press. This will allow me to adjust the weight. But I need to determine the diameter.
    Political Correctness: A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

    Semper Fi -

  18. #18
    Boolit Master

    Join Date
    Apr 2008
    Posts
    5,046
    An example,
    I cast for my .30cal. I size the casting to .308, then two wraps of paper. This gives me .318. From there, I size to .309. They grow to .310.
    That is just an example of what works for me.
    You might have to modify for your sharps. I believe, the .45, gets wrapped wet, let dry. If you are useing 16lb computer paper, or lined notebook paper, you will have your finished diameter.
    That is what I have read.
    Montana Charlie, and others have all kinds of neat rolling boards, techniques. They are great folks, and they can really help. I load for smokeless, they load for the real thing.
    If you get a chance, click on some of their long range shots.
    I am so far out of their league, I might never catch up.
    T

  19. #19
    I'm A Honcho! montana_charlie's Avatar
    Join Date
    Feb 2006
    Location
    West of Great Falls, Montana
    Posts
    15,403
    Ok, you need to decide if you want to shoot bullets that are patched-to-bore diameter, or bullets that are patched-to-groove diameter.

    If you were shooting smokeless, you would choose patched to groove, but with BP you have the choice.

    Most of the guys shooting PP with BP are using patched to bore bullets. They run about .451" in diameter after the paper has been wrapped on, so they start out at around .444 to .446" while naked.

    The actual size depends on the thickness of your paper...if you find the paper first.
    If you start off with a bullet, then you go searching for paper that works with it.

    The 25% rag, 9-pound, onionskin paper sold by BACO will add 7 thousandths to your naked diameter.
    If your bore is .450" and you want a patched-to diameter of .451" then BACO's paper would work real well with a .444" bullet.

    I have some 25% rag, 9-pound, onionskin paper that is a different brand from what BACO sells. My paper adds (only) 5 thousandths to the bullet, so I would look for a .446" bullet.

    Get the picture on patching to bore diameter?

    There are some factors to look at when deciding whether to patch to bore or groove diameter.
    First is the type of chamber in your rifle.
    The modern SAMMI 45/70 chamber is not real PP-friendly. A lot of guys will patch to bore with tthat kind of chamber, but they have to overcome some of it's unfriendliness.
    First thing is to use brass with extra thickness in the neck wall.

    Norma basic brass, trimmed back to 45/70 length will have a wall of about .013 to .014".
    This helps get the bullet out of the chamber and into the throat with minimal problems from the 45 degree step at the end of the chamber.
    It's real important that your cases be fully as long as the depth of your chamber to help with a smooth transition past that chamber step.
    And, finally, having the thicker neck wall also means you won't need quite so much crimp to grip the 'smallish' bullet so it doesn't fall out of the case.
    That grip is important when you consider that only about two tenths of the bullet will be held by the brass.
    The rest will be shoved up into the bore when you load the cartridge...and that is why the bullet is patched to bore diameter.

    The old original chambers were shaped differently than today's SAMMI types. They were tighter, for one thing. The brass case, after it was fired, was just big enough to take the bore diameter patched bullet when being reloaded.
    Also, that 45 degree step didn't exist. It was a much gentler transition that was less likely to 'damage' the bullet as it passed into the throat.

    I started playing with PP about 18 months ago. Because I have a SAMMI-type chamber, I decided to patch to groove.
    That allows me to use standard wall thickness in my cases, and the bullets fit well in the fired case mouth without crimping.
    They also seat deeper in the case...almost the same depth as a grease grooved bullet.

    If you decide to use groove diameter, you have the same kind of numbers to play with...they're just bigger.
    My paper, which adds 5 thousandths to a bullet, makes a real nice fit in a fireformed case if I start with a .454" naked bullet.
    I get the same kind of snug fit if I use BACO paper on a .452" bullet.

    Here's a picture of some recently fired patched-to-groove bullets.
    These are actually .452" bullets that were wrapped with my (thin) paper. Even though they were a loose-ish fit in the case mouth, they still bumped up nicely, and left the muzzle in perfect condition.



    You can easily answer your original question about how they achieve accuracy by seeing how the rifling engraves them through the paper...while never actually allowing contact between lead and steel.

    Now, you know the basic parameters available for you to choose from.
    Ask your questions...

    CM
    Last edited by montana_charlie; 02-09-2010 at 12:25 AM.
    Retired...TWICE. Now just raisin' cows and livin' on borrowed time.

  20. #20
    Boolit Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    6,905
    On the choice of paper, you get lined note-pad paper and lined note-pad paper. Some stick together when wet wrapped better than others. Then there is printer paper. The cheaper ones adheres to itself rather well when wet wrapped. Then there is dry wrapping. Printer paper works pretty well for this. The advantage to me is the ability to twist tighten the wrap and to re-align if I get it wrong. 'Crimping' the til is nice and easy with dry wrapping - no tearing of the soft, wet paper. ('Crimping' the tail can still be done with wet wrapping - just let the patch before 'crimping').

    You asked about the paper being able to withstand the trip through the bore. Well, the trick is to get the patch to come off quickly on exiting the bore, not to get is to stay on in the bore - have a look at this pic.



    This is not good. The patch must come off at the muzzle and this one survived as a single wrap! Not enough obtuation and boolit to bore pressure.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check