View Full Version : paper patching and sizing questions
sven556
04-23-2013, 09:14 AM
I've noticed there are several ways people are sizing and patching bullets. I tried patching as cast and then sizing once to .308, lubing with a dab of lee lube. That resulted in tearing the patch as it went through the sizer.
The other ways I've read about are to size the bullet to bore diameter then patch to groove diameter or size to groove patch and size back to groove diameter. My question, how do these fit into the chamber after that? the forward portion of the bullet would be over bore diameter. I don't think I'm picturing everything right in my head. I'm thinking the front of the bullet should be bore diameter and the rear part should be groove diameter.
Dan Cash
04-23-2013, 01:15 PM
I think that those who are sizing a patched bullet are using a push though sizing die. I tried that but as geragnasher (I think) pointed out, doing so created an excentric bullet and buggered the pase. I find it best with my technique to size to bore diameter or a thousandth over then patch to groove diameter or a thousandth over, lube and load. Have had no luck reducing a bullet far enough in a Lyman type sizer. The machine is not strong enough; your loading press with a push through die is.
Green Lizzard
04-23-2013, 04:17 PM
if you are using a bore riding style it could be tough.but with thin paper it will just slighty engrave the paper on the nose
wmitty
04-25-2013, 01:52 AM
sven556
I have seen it suggested both ways as you described it. I have had success by sizing the boolet to bore diameter ( in my case, .367") using a lapped Lee push thru die; patching the sized boolet to slightly over groove diameter and then sizing to groove diameter or .001/.002" over groove dia. using a second Lee push thru die. I lubed the patch sparingly with 45/45/10 lube before sizing. You are correct in saying the nose should be bore diameter. In my situation, the nose is several thousandths under bore dia.; but accuracy has been quite satisfactory.
pdawg_shooter
04-25-2013, 07:47 AM
I always lap the nose section of my bore riders large enough it will be the same diameter as the sized bullet. This allows me to patch full length and eliminate any chance of the nose sagging or distorting under acceleration. A bullet with a distorted nose section just about insures flyers.
That is where I was going with on other thread. If there is a kind of works the best bore diameter dimension/ratio to body length. Most of the PP molds I have seen seem to be 80% plus bore. The boolit I was asking about would be bore+ tail .5" of .931" body. Do not have mold to open up. I guess I will try a couple and see, if not-ingots we go. Gtek
pdawg_shooter
04-26-2013, 07:44 AM
IMHO, ANY unsupported lead in front of the patch is at risk of distorting under acceleration. That is unless you are using low pressure, low velocity. But if you are doing that why patch. The reason I patch is to equal or surpass jacketed performance. Past experience points to the Loverin style bullet to the the best for sizing down and patching, simply because you can patch to the start of the ogive or a bit past. Any "bore riding nose" I have ever tried has needed the nose lapped out to give best accuracy without flyers. After lapping the nose of a 311289 out to .303 the accuracy went from 4+MOA to just under 1MOA. This was in a 300RUM at just over 3000fps.
pdawg,
After many PPCB rounds downrange, I am slowly coming to the conclusion that a full-patched CB up to and slightly over the ogive is best for hi-vel and accuracy. My LBT 150 LFN load is fully patched to ogive and is sub-MOA at 3000+ fps. The testing so far on my new 180 PP design (modified NRA PPCB design), at about 2600 to 2700 fps, is showing the best groups with full patching to start of the ogive with the base slightly below the case neck. I've found that the old NRA recommendation of "partial PP", i.e. forward edge of patch back from the ogive and against forcing cone, does not group as accurately at 100 yds. in my 308 Win. I suspect the bare bore-riding section of the CB is allowing some small amount of bore-yaw before bullet muzzle exit which then opens up the group. Also, I notice that my dry bore brushing after five rounds of full-patched bullets has more consistent resistance per barrel length than the partial-patched bullets with the same powder charges. Bullet weights vary no more than 1 gr. and round concentricity TIR is 0.0015".
Best regards,
CJR
Thanks pdawg for straight up loud and clear Loverin designs a general rule for success. I will never know how much time and aggravation you "Meisters" have saved me with your been there and done that's- BIG THANKS. Gtek
pdawg_shooter
04-27-2013, 01:39 PM
Thanks pdawg for straight up loud and clear Loverin designs a general rule for success. I will never know how much time and aggravation you "Meisters" have saved me with your been there and done that's- BIG THANKS. Gtek
And a big you are welcome. I have maed every mistake that can be made in the last 40+ years of PPing. Maybe I can save someone some headachs.
bigted
04-27-2013, 03:00 PM
I have had good results by patching to the diameter of the shot and fire formed case with just a slight flair on the mouth...take my latest example for instance...the 43 Spanish roller...[military rifle].
first I drove a lead slug thru the barrel to find the first diameter to fire form the cases to the chamber.
I fire formed the brass to the chamber with some .439 inch patched boolits ...I fire form with black powder as it gives a nice bump at the firing to expand into all the area in the chamber.
next I measured the case mouth that had a slight flair to determine the throat diameter...being .454 inch.
next I determine what diameter of a slick boolit I needed to patch up with my onion skin to arrive at a diameter that is such to be able to finger seat into the unsized case.
so taking a .444 inch diameter slick of 400 grain weight and patching with my paper to .450 inch I felt pretty sure that I would be close to the correct size to begin my experiments for accuracy.
now I took 22 grain of 5744 and after depositing it into the case I then filled the rest with corn meal to provide a slightly compressed load that would hold the powder charge next to the primer for good ignition.
next I seated the patched boolit in the case and pushed it down to a point that it would chamber in the rifle.
now I take my size die and run the loaded rounds into it till the neck gets sized such that there is no flair left and there is slight drag on the patched boolit.
finally I lube the exposed boolit patch with Redding case lube paste for a fine patch lube for smokeless powder paper patched loads.
I should stop here and mention that my patched boolit is patched such that the paper being patched over the o-give to a point that it [ the patched portion] begins to go into the muzzle of the rifle so ensuring that the paper does not strip upon ignition and its journey into the rifling of the barrel in the throat section.
this method ensures that the boolit is not required to bump up or that the case has to fill the throat before anything of substance happens. upon ignition the boolits just begin their journey without the fire cutting or any other nonsense that could happen with a smokeless load that does little in the bumping dept.
another very nice by-product is that the expensive brass does not get worked very much at all.
at my short 35 yds. range in the front yard I can put these into the same hole with the vintage military sights for as long as I care to shoot. while this is not long range tests I feel certain that this will do good with my shooting ability at hunting ranges.
so this is my method...learned here from several fellers that covered the ground before me... has worked in all smokeless patched loads I've tried it in so far. just ensure that the patch extends over the o-give to a point that it will begin to go in the bore of your rifles muzzle and all should be well...
as a beside... I will mention my greeser loads as well... I do the same method but with a boolit from 'accurate molds' ordered to cast a boolit of .452 inch diameter that also finger slips into the unsized case. same load and all except with the 409 grain greese groove boolit of the .452 inch diameter. these do very well in the shooting dept. as well.
just fill the throat and set back and smile.
303Guy
04-27-2013, 04:24 PM
Well stated, bigted. :drinks:
I seem to be having boolit buckling in the bore. It could be misaligned launch too. This from a boolit that is touching the rifling firmly for about a third of its length up front! Of course, the boolit could have been bent to start with but it was a swaged boolit.
sven556
05-08-2013, 09:01 AM
Thanks for all the advice. Sounds like I should start by sizing to bore and then patch up to groove. Looks like I need to get a new sizing die!
303Guy
05-10-2013, 02:38 PM
Re-read pdawgs posts. He's covered just about every angle.
ANY unsupported lead in front of the patch is at risk of distorting under acceleration. - check. I have evidence of that. It's always uneven (on my recovered samples).
... and eliminate any chance of the nose sagging or distorting under acceleration. - check. This latter can be seen on recovered boolits by the uneven rifling impressions toward the nose. Casting flaws can also cause that as the void collapses under the force of acceleration.
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