The Wonderful World of High Velocity PPCB

[Zeek]

. . . It seemed like I was shooting undersized CBs and they were everywhere but in a group. These .308CB, right after casting, were sized to 0.3015" D. diameter, wrapped twice with 100% rag Vellum, spray lubed with lithium/teflon spray and sized to 0.308"D (NRA recommendation). After getting home, I took the patch off a couple PPCB and miked the CB. They measured about 0.299"D- not good. So it seems I was final sizing them down too much and most likely this was the cause of the wild shooting.

First, please avoid the spray-on lubes . . . they will put on WAAAAY too much goopy. The scant trace of paste floor wax is all you need. Yes, I have tried no-lube-at-all PPCBoos, and have found that the PPatch tends to friction-catch in the caseneck and bunch-up just outside the casemouth, as a result. So, I favor the very-light-lube-via-wax approach, because it DOES lube the seating PPCBoo yet it does not fill up the paper's pores with non-gaseous material.

What Happened: Your PPatch sized-down to the point where it was "harder than lead alloys" and then the last three thousandths of size-down was via core size-down-and-lengthening. Upon emerging from the die, the core sprang back up a half thousandth.

I have been trying to get that point across, here, for some time. The PPatch will work better if it is NOT sized down that far. The PPatch gets that hard when it is squished down around half of its added thickness. So:

1. For a PPCBoo using a pre-sized-down CBoo core: CHECK FOR CORE SIZE-DOWN on every batch, using a test-PPCBoo dried with a hair-drier-then-sized-down. If you get ANY core size-down, then you need to switch to a thinner paper. or
2. For a PPCBoo where you are doing the size-down only after doing the PPatch, then you WILL be COUNTING on this hard-patch-sized-down-the-core thingy. In that case: if the post-sizing core diameter is less than your barrel's land-to-land diameter, then switch to a thinner paper.

The third way, of course, is to size-down the CBoo core then patch up to the desired diameter and let the PPCBoo's entry into the rifling, combined with the core's obturation, compress the PPatch. I like that option best, as it traps the most air in the patch, for that hyper-succulent pneumatic-ride-&-sealing effect.

I've got another batch final sized to 0.3095"D with some lightly lubed with the NRA formula and some lightly lubed with LBT Blue. We'll see how these fly next week. The loads shot at the 100 yd. range were 41 gr. H4895 and 43 gr. WW748 behind an LBT 150 CB and the Lyman 311291.

Hope springs eternal!
Best regards,
CJR

LBT Blue is awesome for groove-&-GC CBoos, but it will tend to fill up the paper pores and is non-gaseous. Try the VERY LIGHT paste-wax application . . . . barely enough to notice at all. It lubes the patch but does not fill its interstices with goopy-nongaseous-material. That is a pretty difficult thing to beat, especially with way-hard-to-smear high-viscosity blue-goopy.


The adventure goads ever-onward-and-oops-ward!
Zeek

P.S., CJR, my version of your kindly parting salutation goes, "Hope springs infernal in the humans unabreast!"

[CJR]

Zeek,

Thanks for your comments. After my latest batch of PPCB goes downrange, I'll try a very light coat of JPW on the next batch and and see what it does.

Best regards,

CJR

[barrabruce]

I agree with all the above....But I reckon and correct me if I 'm wrong here.

When I size down and patch up..or just wrapp and then size down.

I found that if the core is compressed ..yeah the paper done it....but I get a bit of un even core diameter also. Can't be good for accuracy.

I am trying a harder core and cutting tests show after sizing down and cutting the patch off to be positively more concentric and even with less size done of core..which seems logical.

Now I ain't no scholla but with a home made'ee whack'em through sizer and a good decent wack with a hammer after the initial alignment taps like seating into the chamber bore. that this is to be true.

It is not a good a whack as what the powder going off would be I presume and maybe the push rod would be different to a column of gas on its bum...but it has showed me that if my offerings can't servive this than they aint gunna in my barrel.

Of course the pressure will most likely compress the paper and core to a equal..ibium some where.

Just offering a wrapped package that doesn't have to be squished or compressed too much to do it is the trick I thunk.

Hey would happen if I wrapped then in a thin sheet of copper or something I wonder???
Probably too hard and rip the rifling out the bore .
Barra

[windrider919]

There are a few 'items of interest' that might help your search for accuracy. First of all, do you know what the actual throat and rifling lead really ARE? You should do a chamber cast. I found in several rifles that I developed an accurate PP load that fitting the wrapped bullet to the chamber was critical. The PPCB has a couple of characteristics that make it different than the jacketed or GGCB/CheckedGGCB. First of all, the paper has LESS friction than copper or even lead so less pressure builds up in firing. Second, the properly wrapped cast bullet is more COMPRESSIBLE then the other types. Additionally, because the PP bullet is usually a SOFTER alloy than required for a bore contact cast bullet, it will be more damaged/distorted if fired while cocked in the chamber. Using these propertys - I found that centering the bullet was critical for that one hole accuracy. A lot of throats are larger than you would like but with PPCB you can just use a slightly larger bullet OR thicker paper. Example - I mentioned that 458s often do not have a 459/460 throat but instead have a .464 throat. (Note: a factory .308 Win of mine has a throat of .315) I center and align my bullets by loading the bullet fairly shallow in the case neck, with the nose just touching the rifling. I also had to use a .454 bullet instead of a .450 or even smaller (BP uses a wrapped bullet of .450, un-wrapped size around .443, but that DID NOT work in multiple rifles using smokeless). The .454 bullet is then wrapped with standard paper to achieve .008 with 2 wraps. The "oversize" bullet centers itself, is less prone to leaving paper rings in the chamber and dropped my groups from 1 3/4" down to less than 3/4" at 100 yards. Because the paper, unsized you understand, can compress quite a bit and has less friction, even loads that would be max for a jacketed bullet of the same weight are 'low pressure' and do not flatten the primers as much. I know some guys are getting good accuracy with sized PPCB and so did I but fitting the bullet to the chamber and NOT sizing gave me even better accuracy with multiple rifles. Try it both ways to see what works with you. FYI: I developed a PP load for a M1 Garand that when single loaded shoots 1 3/8" at 300yds using the same chamber matching technique. And finally, as said before, no 'lubed' patches although I am using a water soluable wax in quarter strength that is barely noticable on the paper when dried. It helped accuracy in ALMOST every case but there have been a few exceptions. I use it mainly as a 'glue' to help the patched bullet stay tightly rolled, like some guys use Elmers white glue or egg white in the patch wetting water. But the patch is still 'soft' and full of air between the fibers when dry, that is important! The wax mostly just helps hold the wrap together a little better.

Note2: Check your expansion plug on your reloading dies. Jacketed bullets need aprox .003 tension on the case neck to properly grip. If you load a PPCB into a case neck .003 smaller, it will swage down the shank of the bullet inside the case and accuracy will suffer. I have found that when I switched my expander ball for a larger one so the tension was .001 max the bullet was not damaged in seatiing and accuracy soared! ( this is true in lots of cartridges, I find that lots of lead bullets [nom. OD of .452] loaded in 45ACP have been crushed undersize [to as much as .446 sometimes] inside the brass either in loading or crimping, especiallly taper crimping.) I frequently amaze pistol owners who swear that their guns will not fire lead bullets when I use my loads and get better accuracy than they have ever gotten with ANYTHING!

Note 3: Recently I have been PP jacketed .451 pistol bullets to .460 with a slightly thicker paper and shooting them as a light bullet load. Accuracy is only 2 1/2" at 100 yards with the velocity I am loading for of 1800 to 2000 FPS. Of course, there is nothing to hunt with them as they are nothing but explosive expansion bombs at that velocity but it has been an interesting way to get rid of a box of 500.

Note4: All PP nubees want to wrap something other than paper. FYI - its been tried hundreds of times, just search through past threads right here and it is mentioned and tried and tried and tried and tried........ad nausium.
Please, Please, Please: read some of the old threads before you start a new one on Teflon tape, copper foil
, sandwich wrap, etc,
In fact, its been discussed so many times that I am flabbergasted SOMEONE has not made one of the stock discussions into a STICKY !!!!!!!!!!

[barrabruce]

Thank-you wind rider
Will put your theories/findings to test and see if it happens for me.
I hope it does
Bruce

[CJR]

Windrider,

Good post! Your comments on neck tension is very interesting and something benchrest shooters do. As a result, there are neck sizing dies available that come with different neck bushings to vary the neck tension. At present, I resize my cases without the expander button installed. Then the necks are flared with a "M-style"neck die ( two-step diameter button) which opens the neck ID slightly before flaring. My full-length resizing die is adjusted so that when checked with a Sinclair Bump Gage the case shoulder is 0.002" less than/back from the chamber shoulder. This gives some centering of the cartridge when it is chambered. However, I still believe that different neck tensions need to be tried to improve group sizes. I intend to do that after I get some consistent hi-vel PPCB small groups.

Best regards,

CJR

[barthmonster]

windrider... Thanks for the post. Full of great information for a newbie or maybe anyone else too...

[CJR]

My hi-vel PPCB adventure continues. After discovering and correcting a scope base/ring problem I decided to really check my chamber. Sure enough, my relatively new 308 Win had a throat that was 3-4X longer than what SAAMI drawings showed. This dictated a longer OAL and that gave some smaller reproducible groups, still not sub-MOA. Likewise, I discovered that as long as I let the barrel cool down sufficiently, my 100 yd group size was repeatable. Then I got some small groups @ max. velocity with WW748 ball powder. Very encouraging considering I had not sorted my PPCB into 1 grain lots to improve accuracy. Likewise, some loads were 100% load density and some slightly compressed. These loads were moving at hi-vel! If a deer would have been standing @ 100 yards, it would be dead.

The other fact I discovered is that some WW748 loads are 10,000 psi to 12,000 psi LOWER in pressure than the Hodgdon and IMR powder. Likewise, some of the WW748 loads have some of the highest/max. velocities. So it appears I'm evolving towards the Win ball powders because they are touted as having low flame temperatures (qualitative statement). Sooooo, I was interested in a quantitative assessment and did a rough calculation to determine what the reduction in propellant gas temperature should be using the Ideal Gas Law. equation. I assumed the PPCB was at 750F temperature at 50,000 psi (w/H4895)and the pressure was reduced to 38,000psi (WW748) and calculated what the gas temperature would be for this pressure reduction. Using WW748 reduced the propellant gas temperature by almost HALF! Granted this is a rough guesstimate but better than nothing. So though we really don't care that much about propellant gas temperature for jacketed bullets, maybe this is what we need to consider to get consistent/small hi-vel PPCB groups. As a matter of fact, I now recall the NRA used Win ball powders to achieve their 3000+ fps/tight groups in the 300 Win Mag but they never stated any reasons for using it. Prior to that , the NRA had touted 4895 for their 308W PPCB loads. What could be better than getting max. velocities with 12, 000 psi less pressure?

My hi-vel PPCB shooting and testing continues! One day, I'll get consistent small groups with hi-vel PPCB. Hope springs eternal!

Best regards,

CJR

[303Guy]

I have found that the tiniest smattering of lube on the patched boolit works best for me. The patch survives the trip down the bore with more powder behind it that way and the bore stays clean. Without the lube, the bore seems dirty. My lube? STP. I use STP on my case lube pad and roll the patched boolits on it. The difference the lube makes is quite evident when pushing the patched boolit through the sizer. I do believe one should not be filling the air voids in the patch with any kind of liquid. STP flows along the paper fibre surfaces slowly but surely, leaving the patch appearing to be dry. I would imagine that auto wax polish would have a similar effect but perhaps be a better water proofer and lubricant.

Things might work differently for me because of bore condition. Some of my rifles have rust damaged bores and most have cordite induced tapered bores.

[CJR]

I sent more hi-vel PPCB downrange today. My groups are getting smaller and staying on paper. The first 3-shot group had two shots @100 yds.spaced 0.4", with the third shot horizontally to the right 2". The second target 3-shot group was about 0.75"x 2", again with horizontal stringing.

The load specifics were:
1. Unweighed 311291, PP just to front driving band with the bore-riding nose unpatched.
2. CB sized to 0.301"D right after casting.
3. BHN was 13 (checked with LBT BHN tester).
4. PP was Vellum (100% rag), 0.0025" thick, water-wetted with some Elmer's glue, dried, lubed with LBT Blue (match-head amount), sized to 0.3095"D.
5. Bullet seated to an OAL of 2.75"( I have a long throat/freebore).
6. Powder was 43 gr. IMR 4064.
7. Cases were IMI, trimmed, no weight sorting, no neck turning.
8. Primers were Federal Standard LR.

Barrel was allowed to cooldown after each round fired. After about 10 rounds, I started dry brushing after each fired round with the final group opening to 4" x 4".

After getting home, I pulled past targets and saw horizontal stringing as well. Checked my Caldwell Lead Sled and found rotational play in front rest bracket attachment to large 1" elevation screw. Took it apart, cleaned, and epoxied the i" elevation screw to front rest bracket..

It was a good day! Future plans include bullet weighing and sorting, outside neck turning, W760 loads, and maybe some neck bushing dies to try different neck tensions.

Hope springs eternal!

Best regards,

CJR

[Doc Highwall]

My .02, I have the books where in the NRA tests, they found that the bullet needed small grooves to keep the patch from slipping in the bore and this was incorporated in the two Lyman moulds. Also in the black powder paper patch section it is mentioned about using distilled water and Kenny W. mentioned about putting alcohol in the water to help the patch to shrink tight on the bullet after it dries.

[docone31]

I use conventional castings in the caliber desired. They have lube lands. I then size them to .308 after casting. From here I wrap wet two times with notebook paper, or computer paper. I use a cigarette roller. This squeegees the water out, making the wrap really tight. It then dries. As it dries, it shrinks. From there, I apply a little Auto Wax. Just enough to lubricate the patch to size it. In the .30 cal, I size it to .309. In my .303 I size it to .314.
I did have to bed my patched barrels. The extra heat from the patch going down the bore, made my barrels act like spaghetti! POA went all over the place untill I bedded it.
Jacketeds, and lead loads did not do the heat thing like Patched loads did. 20rds reasonably fast, and the barrel was HOT!
At 100yds, I do not try to get MOA, but I get good groups, with no keyholing. It did take a while to get the bore clean useing the patched loads after sizeing. Now, they shine!
My wife likes the loads. She can put them where she wants them to go.

[CJR]

Doc Highwall,

Could you elaborate on the distilled water, alcohol for the PP. Some have advocated using baking soda to break down the sizing in the paper. But what does distilled water or alcohol do? Only improve shrinkage or does it glue the paper together tighter?

I use Docone31's cigarette roller trick on my 30 cal. bullets and they get real tight. I hand roll my 375 bullets and they appear to be tight as well. Veral Smith suggested I use glue in water for the PP.

Best regards,

CJR

[Doc Highwall]

CJR, the distilled water is for people that have hard water where they live and the alcohol is to help in the shrinkage and drying.

[Doc Highwall]

CJR, the distilled water is because where some people live they have hard water with a high mineral content like where I live. The alcohol is to help the paper shrink and dry tighter on the bullet.

[CJR]

I had a good day at the range testing lots of hi-vel PPCB rounds. My testing philosophy now is to first follow the NRA approach/guidelines until I get decent hi-vel PPCB loads and then try all suggestions offered to me on this thread to fine-tune my final loads. No chrono'g of velocities was done at this time as I intend to do that next spring after all testing is completed. All other interesting info I discovered will be posted on the other thread I started; "Sharing Info -----". I achieved max. accuracy of these loads at a " guesstimated" velocity of 2700 to 2800 fps. Here's my test results:

RIFLE USED

A standard Charles Daly Mauser in 308Win with a long factory free-bored chamber. Not a benchrest rifle. Scope was Nikon Monarch 3.3x10x44 w/ Farrell steel Picatinny rail & steel Tactical Performance System rings.

RANGE

100 yds.

BULLET

Lyman 311291 (4-cavity mould), 175 gr (1 gr. variance)., BHN ~13, NO GAS CHECKS, sized after casting to 0.3015"D, two wraps in Vellum (100% rag, 0.0025" thick) wetted w/ a 50/50 mixture of water & wood glue (Veral Smith's suggestion to me) sprayed with dry film Teflon & dried, coated w/small amount of Alox or LBT lube, sized to 0.3095"D, loaded to O.A.L of 2.765" w/ slight pressure felt when chambering the round.

CASES

Unweighed IMI (Israel) brass, trimmed & prepped.

POWDER

46, 47, 48, 49, 50 grs. of WW760 ball powder(progressive burning propellant)

ACCURACY

Best group was 1 1/16"x 1 13/16" for four (4) shots, 1 7/8" x 2" for five (5) shots with 50 gr. WW760 (NRA recommended load for 160 gr. PPCB ). I guesstimate my velocity to be 2700 to 2800 fps. Barrel was allowed to cooldown between shots. I dry brushed after each round to determine where in the barrel I was getting powder residue build-up. Residue build-up was minimal and after a few brush strokes, the felt barrel resistance was constant from chamber to muzzle. My guess(from manual info) is that pressure ranged from about 44,000psi to about 50,000psi.

Next spring I'll try to achieve 3000 fps with my LBT 150 gr. bullet PPCB which according to my manuals is doable. I'm aware the NRA used a little more lube on their 3000+ fps PPCB in the 300 Win, Mag to tighten up groups. So I'll be playing with all types/amounts of lubes to get an accurate, "shoot all day hi-vel PPCB load" that is accurate.

Hope this helps anyone interested in developing hi-vel PPCB loads. I personally went from decent groups, then "minute of berm/bank" groups to these results. I'm slowing closing in on the solution by shooting lots of PPCB. To say this is a fun, would be an understatement!
Best regards,

CJR

[windrider919]

Excellent research.

Interesting and a good illustration on how different rifles act differently. When I tried white glue in my patch water I did not get good accuracy at all. I tried it at 50/50, 30/70 and even down to 10% which gave the best accuracy on the white glue trials.

I had better luck with egg white which gave some quite impressive groups under 2" at 100 yards [the rifle in question is a 458 Win Mag] but the problem was, in the Texas Gulf Coast, my patches with egg rotted/mildewed within a couple of weeks.

Still. never beat the results with water soluble wax (at 10 - 25%) in my rifles.

Have you tried Reloader7 powder? Worked well in my fairly fast .308 Paper Patch loads. 2700FPS with a PP 166gr round nose, 50% bore riding but patched over both major dia. and nose. This gave consistent 1 1/4 five shot groups.

[nanuk]

CJR wrote:
Next spring I'll try to achieve 3000 fps with my LBT 150 gr. bullet PPCB which according to my manuals is doable.


150gr boolit at 3000fps is a formidable hunting tool!

With the right alloy, it should act like a premium, and penetrate very well???

[1874Sharps]

A friend of mine recently used a 168 grain PP gas checked 30 caliber boolit at max load out of a 30-06 bolt gun to take a 900+ pound bull moose at a laser ranged 270 yards with two shots through the chest. I have used the same boolit on a deer with great and devastating results. The boolit in question is cast at 0.301" and has a standard gas check shank. The paper patch is placed just in front of the gas check and the check holds the patch in place so that it does not slip and also shields the patch from the hot gases of the burning powder. My 30-06 rifles will shoot these boolits at over 2800 fps and it seems the higher the velocity the better the accuracy. What is not to love?!!!

[waksupi]

CJR wrote:
Next spring I'll try to achieve 3000 fps with my LBT 150 gr. bullet PPCB which according to my manuals is doable.


150gr boolit at 3000fps is a formidable hunting tool!

With the right alloy, it should act like a premium, and penetrate very well???

Actually, at that velocity, the boolit would not perform well. That is far beyond where you want a lead boolit to be. Veral says, and I agree, you do not want the striking speed at over 2200 fps for anything you want to eat. There is a great possibility of the boolit coming apart, and not getting the necessary penetration.