6.5x55 PPCBoos CAN Work

[Zeek]

In the 308 Copper Bullets in 318 Mauser thread, I ended up fiddling around with paper-patched JBoos and paper-patched Copper-Boos in my Model 1896 Swedish Mauser (6.5x55). I got them to work okay, and learned some interesting lessons. This thread is a PPCBoo follow-up to what I learned and shared in that thread.

I polished out the mouth of my 0.259" diameter Lee push-thru die a bit further and found that it would size down the long 160 grain NEI 6.5mm CBoo after all (it had given me trouble, initially), but that CBoo is right on the very edge of having its butt expand too quickly to get through the die ~~~> use good lube, add on a GC, and process through with a very fast stroke and it WILL got through fine, but still just barely. There are so very many things, I'm finding, that put the 6.5 CBoo and PPCBoo work into that real = a VERY narrow window where you can get it to work. This issue is not as heavily manifested in most chamberins, but these wide-shoulder/narrow-neck things magnify this problem. I need to find a better bulk filler.

Here is the CBoo (unsized) and the finished PPCBoo, after adding a GC, sizing to 0.259, giving them a way-hard oven HT, and patching up to 0.269" with a 2X16# patch.


I shot these without sizing-down the as-wrapped PPatch, as my rifle's groove diameter is 0.269", or perhaps a bit larger (it is a military barrel and I last checked its groove diameter perhaps a decade ago, but this is what I recall). I tried 40-to-50 Kpsi loads with AA-4350 and got mostly the abusual (for 6.5x55) large-patterns-not-groups.

I then moved down to what would be a ~29 Kpsi load (w/o corn meal), added corn meal, and got the first group of the day. At 1.8" at 50 yards 2200 fps MV), it was not a belch-ringer, but far better than I expectorated.

I went up to what would be a 38 Kpsi load (w/o corn meal), added the corn meal, and maxed out on the pressure (Russian Wolf primer just barely started to crater), so the corn meal was really boosting the pressure in this fat-body/small-diameter-neck case ~~~> be CAREFUL in this chanbering when using bulky fillers! It gave 2360 fps, and 7 of 8 shots went into 1.0". A second group of the same load gave 1.5", but that is still doing okay, under my own rather different-from-others' PPCBoo experience.

I tried backing off the powder quite a bit further and using the corn meal. It still gave slight cratering of the primer. Therefore, the corn meal, although it does seal against gas leakage, takes up LOTS of room even when compressed. So, the less powder you use (therefore, you add more corn meal), the smaller is your effective case capacity. This makes it VERY difficult to adjust the maximum pressure!

This stiff pressure was causing the cases to expand more than in my usual loads, so I had to quit using the Lee Collet Neck Sizer die and run the brass through a full length sizer. This caused the light grip that I had used on the PPCBoos to be replaced by the normal JBoo way-death-grip. I reshot the "good" load with the FL sized cases, and got a 2.15" group, but the cartridges DID go in and out of the rifle easier.

Conclusions

1. The hard CBoo seemed to help, but this one was so hard that I could barely get a load hot enough to obturate the CBoo core. So, I need to try a slightly softer CBoo core.
2. Without the corn meal, gas leakage eats your lunch. If the CBoo is hard enough to take the fast twist, then it is almost too hard to obturate, so you need a bulk filler to give gas sealing. This may be the main reaon we have had so much trouble with the 6.5: the performance window width is so very narrow as to be extremely difficult to find!
3. If I want to stick with the AA-4350, rather than buy a special-use-only slower powder, I will need to find a fluffier bulk filler, so will try 303Guy's idea of using bran. A fluffier filler will not make such a profound decrease in the effective case capacity, so should allow one to adjust the max pressure by lowering the powder charge.
4. PPCBoos like a rather light grip by the neck.
5. I need to order a 270Win Lee full length sizer ejector/neck-expander assembly, then grind the expander button down to ~0.268", so that I can USE my FL sizer die without having to put up with a way-death-grip on the poor long-suffering little PPCBoo.

So, I'll try this same CBoo core again and with this same PPatch, but using an alloy hardness of around 20 Bh (i.e., I'll soak the Boos at ~430 F, prior to quenching, rather than the 450F that I used on this batch). I'll get back to you all on how the results come out.

The 6.5x55 is tricky! This load used a way-long CBoo core, which helps get the rear end of the Boo to obturate and seal. A lighter CBoo core would be even more difficult, in this regard!
Regards, Zeek

[madsenshooter]

I know the boolits already long, but you should see it on my widescreen monitor! The one laying down looks 1.5x the one standing up!

[Zeek]

Today, I cast up some more of those waaaay-long NEI 160gr 6.5mm CBoos and sized them down to 0.259" in my Lee push-thru for the second phase of my 6.5 experiment (see below). I noticed that the size-down was FAR easier this time than last. It seems that the Lee push-thru die needs a bit of time to "break in," even after having been smoothed-out and given an easy-in-low-angle entry cone.

I'll do an oven HT this time at 430F (was 450F last time), so the CBoo core of the PPCBoo will be softer (20 Bh?), so they will begin obturating at a lower pressure. This should allow me to get reasonable accuracy at a lower pressure (the harder PPCBoo cores of the last batch required a load that was too hot for this old Model 1896 rifle). In order to GET a milder load, I'll stick the the AA-4350 powder, but switch to a lower-bulk-density filler ~~~ bran ~~~ so that the effective case capacity does not go down as fast as the powder level. This big-shoulder/narrow-exit case is way-touchy, that way, to high-bulk-density fillers, with the result that a lower charge (with more filler) gives the same too-much-pressure reading (slight cratering of even the tough Wolf primer!!) as with the greater charge, meaning that this baby has no "throttle control"!! THAT is NOT okay! 303Guy, I sure do hope that bran stuff will flow well through my small-exit-hole feeder container. Corn meal and COW work through that hole fine. We'll see.

I don't know when I'll get at the shooting, as there are lots of things coming up for us in the near term, but I will get back with the results.
Regards, Zeek

[303Guy]

Great work, Zeek. That 160 looks soooo cool! And you got 6 into 1"! Holy cow! You're onto something there. Looking forward to the bran trials. Yes, I found the pressures much lower with bran. I have a theory that it flows much easier through a bottle neck than corn meal. Corn meal does something else for softer cores and that is to imbed itself into the base (which forms a cup) and travels down-range with the boolit. Wheat bran doesn't do this. In fact, I had to keep the charge up to get enough pressure to stay out of the supposed SEE zone. Your milage will differ as you have an extreme shoulder funnel as compared to a 303 Brit.

I'd tend to trickle the bran into the case using a funnel and fill 'er up to the brim. Bran does not flow well! That's the downside of it. It can't be metered accurately either. On the upside, by trickling it into the case until full to the brim, the variance is quite small weight wise.

Good luck with those trials. I hope they happen soon - now that I'm all fired up eager!

[StrawHat]

Great work, Zeek... Corn meal does something else for softer cores and that is to imbed itself into the base (which forms a cup) and travels down-range with the boolit...

I do not PP fo rthe 6.5 Swede, yet, so maybe this is already been tried but would a card wad at the base of the PP boolit prevent the corn meal from anchoring itself to the base? Yes, an extra step but one that might help accuracy.

[303Guy]

... would a card wad at the base of the PP boolit prevent the corn meal from anchoring itself to the base?

Good question! I havn't tried it but now that you've asked I shall do so. The thought did cross my mind and I do have a little card wad punch I made. I think I may have not tried it because I have had card wads adhereing to the bases and I do get patch base ring adhering to the base. So, I'll give it a trial and post the results.

[Zeek]

. . . Corn meal does something else for softer cores and that is to imbed itself into the base (which forms a cup) and travels down-range with the boolit. Wheat bran doesn't do this. In fact, I had to keep the charge up to get enough pressure to stay out of the supposed SEE zone. Your mileage will differ as you have an extreme shoulder funnel as compared to a 303 Brit.

I'd tend to trickle the bran into the case using a funnel and fill 'er up to the brim. Bran does not flow well! That's the downside of it. It can't be metered accurately either. On the upside, by trickling it into the case until full to the brim, the variance is quite small weight wise.

My "plan" was going to be to do just as you suggest. This makes it a certainty. I noticed that the bran would not pour well from my flip-top mustard container (pour/squirt hole is ~0.2" in diameter), so I thought I'd just "make a funnel" by encircling the casemouth with finger/thumb, remove the container's top, and then pour away until it tops off. I should, then, be able to raise and pinch/catch the excess bran with my finger/thumb combo and return it to the container.

The main benefit of the bran, from my viewpoint, is its low bulk density (weight per unit volume). Filling the case completely and then seating the PPCBoo into it will hold the powder in place, but, when the charge is ignited, the powder will compress the bran mass into perhaps 1/3 of the volume that it would with corn meal and perhaps 1/5 of what I'd get with COW. Nevertheless, it looks like it will be a nice dense littie pill jammed onto the PPCBoo's tail feathers all the way up the bore, thereby providing a gas check of a sort. THAT effect is very important, given that this AA-4350, although rather slow in burning rate, was blowing the PPCBoos all over the target at 50 yard, but the same charge worked far better, accuracy-wise, with the corn meal added . . . . it just upped the pressure too much because it would not compact enough at blastoff. So, what I need is the same effect as corn meal, but greater compressibility . . . . bran may be the answer!

At any rate, 303Guy, thanks for the good tip. The fact that we are both thinking in the same direction is encouraging . . . the darn experiment might just work. It sure would be neat to be able to shoot these-here javelin-PPCBoos in that lovely old Swedish Mauser.
Regards, Zeek

[Zeek]

Well, I took those slightly softer long-ass 160gr PPCBoos to the range yesterday, and came up with some darn good news, and a real luck-out. The luck-out was that I changed two major factors at once, yet the accuracy improved and the pressure situation abated. Lovely! Now for the details

As before, after casting, I applied a GC and sized them down to 0.259 in a modified Lee push-thru sizer. The alloy was softer (Oven HT at 430F rather than the 450F of the first son-of-a-batch), so the CBoo core was 20 Bh. That was my estimate, but I just went out, sawed a PPCBoo in half (as-cast, it is way too long for my LBT Bh tester), sanded both ends flat and measured it ~~~> 20 Bh on the button. Mah!! I HAD to change this factor because last weekend's ~26 Bh PPCBoo's were so hard that I could only just barely tag the lower end of the envelope without exceeding the rifle's max working pressure. I used the same 2x16# nearly-full-length PPatch, for a jammed-into-the-leade LOA of 3.0"

The second factor I changed was to switch from corn meal to wheat bran as the bulk filler. This change, too, was mandatory: 1) at least this 6.5x55 test series would not function AT ALL without a filler; yet 2) COW and corn meal fillers take up so much room (when compressed by the powder burn's jamming the filler forward) that I was getting the same more-than-optimal-pressure reading (slightly cratered Wolf large rifle primer) even with considerably reduced charges of AA-4350. With bran, it was so fluffy that it would not even pour from the small mouth-diameter of my COW dispenser, so I unscrewed the lid and just poured-and-tamped it in using the point of the PPCBoo that case was going to fire.

I started out using the same charge range that did best with the too-hard cruise missile PPCBoo the prior weekend. After getting used to the bulk-pour-and-tamp-down approach needed to get the case full of bran filler, I shot a group of just 1.32" (for seven shots @ 50 yards). No fliers this time . . . they all went into the group. Load: 38 grains of AA-4350; 2324 fps MV. Better yet, NO adverse pressure signs.

Therefore, I tried a grain more and it started to open up, but that COULD have been because the long PPCBoo was sticking waaay down below the neck and, at that charge level, its base nearly touched the powder. When a round goes off, a center column of powder shears off and follows the bullet, leaving the portion of powder below the shoulder portion of the case behind . . . . so says Mic McPherson, who knows far more about this sort of stuff than anyone else I know. If that is true, then this load would have had nearly zero filler under the PPCBoo, so would tend to act more like there were no filler at all (the 6.5x55 shoots PPCBoos very poorly without a filler, in my experience). I'll test that idea further using shorter PPCBoos that don't stick even come close to touching the powder.

I then tried to see how far down I could go (below the prior mininum-charge-for-decent-accuracy) and still do okay, given the CBoo core's lower hardness. It did just fine at 37 grains [2193 fps / 21 SD, 1.35" group], but started to open up (and show non-round holes) at 36 grains (always filling with bran right to the casemouth). So, with this PPCBoo at 20 Bh and this rifle, the sweet spot, given a full-of-bran filler, is 37-to-38 grains of my lot of AA-4350. LOTS of variables, here, so, if you try this CBoo core in your Swede, work up carefully! I provide these charge levels just for your reference, not use.

QuickLOAD shows these charges as yielding in the range of 33-36 Kpsi, but that bran filler, even though it compresses FAR more than COW or corn meal, must still up the pressure some. The primers showed ZERO cratering, so I'll just guess at ~40 Kpsi. That points to an ideal Kpsi/Bh ratio of 40/20 = 2.0, which is easy to remember. This ratio is a bit higher than the 1.5 used for GCCBoos. I suspect that less-tricky chamberings would give more of a range of Kpsi/Bh ratios, rather than this narrow band, but at least we now have at least one combo that will work in the WAAAY-PITA 6.5x55!

As indicated above, the top charge allowable may have been limited more by the minimum allowable CBoo-base-to-powder distance than by max allowable pressure. In that case, work with shorter-CBoo-core PPCBoos will broaden this "sweet spot" range considerably, given that the PPCBoo's rear end will be much further from the top of the powder, leaving room for bran in the "column" (assuming that Mic's column-shear theory is true).

If I were to use this for hunting, I would soften the point and nose, after sizing then oven heat treating, by sticking it in a water bath up to the top of the bands, dabbing on a bit of Tempilaq 450F heat-indicating paint (from Brownells) on the point, then playing a propane flame at the water/nose junction of each CBoo just until the Tempilaq melted, then moving on to the next CBoo (no need to quench). That makes the nose/point dead soft, but leaves the bands hardened. I'd then patch, load, and hunt. This works. Otherwise, our rather brittle hard-alloy PPCBoos would be good only for plinking, varmint, and target work ~~> a most unsatisfactory eventuality!

I'll try working with some lighter 6.5mm CBoo cores next. Moron that later!
Regards, Zeek

[Zeek]

Well, that way-long-thaaang 160 grainer was fun, but here's another one that should be interesting.

It is the NEI "264-125--GC-DD" (cherry #24). Mine casts 0.271" on the bands and 0.255 on the nose, with a DD-band diameter of 0.262" (by memory) . . . and I sized it through a 0.259" Lee (modified) push-thru sizer die adding a GC, did an oven HT @ 430F (20 Bh), and gave it a 2X16# patch which brings the band diameter to 0.269" and the nose diameter to 0.265". So, no post-patching size-down required.

Its LOA in my rifle is 2.92" by hand, but I may be able to use it at 3.0". Either way, the base of the PPCBoo is at-or-just-forward-of the base of the neck. A 36 Kpsi load of 42 grains of AA-4350 should give an MV of around 2700 flips ~~~> that is an 85% loading density. However, I may have to use a hotter load to get this shorter CBoo core to obturate. A nominal 44 Kpsi charge of 45 grains (89% loading density) would give 2800+ fps. Of course, these pressure guesses are low because the added bran filler, although fluffy, will add something, but I will try loads in this range. For RPM, (720 x 2700)/7 = 277,700 RPM. Whoa!

With this PPCBoo, the DD-band on the nose is getting a hard bore-ride (bore is ~.257" & DD-band is 0.259"). However, other than the DD-band, all portions of the CBoo core are covered and doing gripping/centering/torque-up service. It will be interesting to see "what gives" using this little pill.
Regards, Zeek

[DIRT Farmer]

Zeek, 303 Guy, some learning requires screwing up. As the 2 grove 303 has me frustrated at this point, I was playing with the YUGO 8x57and wheat bran 20.5 of IMR 4227, and "the" Lee bullet. Things were going nicely, then I pulled the trigger, no pop, no boom. Dang bad primer? when back to the shop, I put the offending load in the press and used my good old (as in old) vice grips and removed the casting. The wheat bran was packed like a rock. I used a drill bit to remove it and the last to come out was scorched, DUH, no powder. As the filler was packed hard I loaded 2 more intentily with out powder. I did not hear a pop at all from the primer, no bullet movement no nuthing. Without powder or filler or crimp, I would have expected a casting to be stuck in the throat. I will try that to find out. My question then as I have had the neck go down range with corn meal, in the 303 before I swore off that for filler, now I think I will load some with a primer and corn meal just to find the consistency of the material in the case. Hope this is not a thread hijack but we don't have a filler section. Any ideas or comments? And I am going to make a load stick for the 8mm.

[Zeek]

Zeek, 303 Guy, some learning requires screwing up. As the 2 grove 303 has me frustrated at this point, I was playing with the YUGO 8x57and wheat bran. . . I pulled the trigger, no pop, no boom. . . . I . . . removed the casting. The wheat bran was packed like a rock. I used a drill bit to remove it and the last to come out was scorched, DUH, no powder. ....

Yes. Packed like a "gas-checking rock," to be specific. It would have done the same with a powder charge behind it, but would have left no evidence, given that it would have been carried out the muzzle and dispersed in the wind. The reason that I like bran over COW or corn meal is that it compacts so much more, on blastoff, so ends up taking up less case capacity. This minimizes the filler-induced pressure increase yet provides the superb gas-check-for-about-nothing that we should all love and cherish.

Like 303 Guy and Mah-Seff, you are on the riot path, DIRT Farmer. Either that or we are all three getting a really realistic false-ride.
Zeek

[Zeek]

Well, it is not all that I could have asked for, but the results are one heck of a lot better than I had feared, so I'll accept it as damn good news. Earlier (not surlier) in this thread, you saw the 20 Bh PPCBoo in question. Today, I ran it with a bran filler and AA-4350, but tried AA-2495 too, at Mic's suggestion.

My "starting load" of 43.5 grains, when combined with the bran filler, raised the pressure to the point where I got light primer cratering (on V.-hard/thick Wolf LRPs!) and a 2.9" 50-yards group. Mah!!! It behaved much better once I backed off to 41 grains (plus the bran), giving ~2600 flips and groups of 1.15" to 1.4". For a CBoo, that is scootin' so fast that it would blow up on game even if the nose were annealed. However, it will be handy for blasting rocks and varmints.

AA-2495 is "faster" but yields its max pressure after ~3" of bullet travel, just like AA-4350, when both are used in this pressure range. Using 34 grains plus the bran, I got ~2600 flips and a compact 1.3" group (for 8 of the 9 shots, with one out there ~4.5" = an obvious cull that I missed rejecting).

These best loads both shot at an LOA 2.95, which is with the PPCBoo seated out 0.030" longer than I can jam the PPCBoo into the leade cone by hand (from behind with a rod). So, a stiff-jam-fit seems to help.

Although this CBoo's DD-band gives a very stiff jammed-across-the-land-tops fit (lead alloy against barrel), it worked just fine, thankyou ~~~> no problem of the alloy-touching-barrel variety. The RPM is ~267,000, which is really turnin'!

So, if sized to 0.259", toasted for an hour a 430F, then quenched, and patched 2X16# right to the back of the DD-band (no post-wrapping sizing needed), we can now shoot this this NEI DD-band pill in this way-kinky chambering with two loads that give ~2600 flips and good field-accuracy. Neat. I never thought that I would see the day when anything over 1800 flips would hit the chosen hippo-cheek from more than spittin' distance with this chambering. The long 160grainer did well too, albeit at slower MV, but still WAAAAY above 1800 flips. This just goes tah show yah how very useful the PPCBoo approach can be, even with a nearly-impossible-to-master fast-twist chambering like 6.5x55.
Regards, Zeek

[303Guy]

Zeek, that's great work you have done with the Swede. And pretty swifly too! Interesting discovery there DIRT Farmer. So just the primer compacted the wheat bran? But the boolit did not move! Could the WB be assisting in initial pressure build up during early ignitian stages? Mmmm.... maybe it's time to pull out my 303/25 and load up some of those PPCBoos I made a while back. It did show some initial promise, killing a turkey. It has a much slower 1 in 10 twist so will not have the challenges the Swede presents (the cores are a bit small for my fingers to wrap). It has the added advanvantage of having a very sexy looking cartridge!

P.S. That DD boolit is real interesting. A riding band up front. Clever! That would solve a mutitude of bore-ride fit problems.

[45 2.1]

Zeek-
Different fillers behave differently. Most of the bran fillers raise pressure faster and are a detriment to long storage due to absorbing moisture from the powder. Inert fillers, depending on compression used are more lenient in that regard. Try some other fillers, but don't try ground corn cob..... enough of it will take the front of the case with it.

[goofyoldfart]

45 2.1 : When you say don't try ground corn cob--is that due to the corn cob being to coarsely ground or what? would a very fine grind (almost powder like) work or do you believe that it could/would take the front of the case with it? Just really curious and you do seem to have more experience with that stuff than I. thank you and God Bless.


P.S. : today is 30 years SOBER!! YEEEEEHAAAWW. Think I'll have a drinkie and celebrate :P

[nanuk]

zeek: you wrote: I shot these without sizing-down the as-wrapped PPatch, as my rifle's groove diameter is 0.269", or perhaps a bit larger (it is a military barrel and I last checked its groove diameter perhaps a decade ago, but this is what I recall).

so, patched to .269 could be slightly undersized.

have you tried a slightly thicker PP to bring the Patched size up to .270-.271?

I've not done any PP shooting, but a heck of a lot of reading, and there is some suggestion that with Smokeless, a hair OVER groove can work.

I'd be interested in your experience if you tried that.

[Nrut]

Hello Zeek,
Where have you been?
I hope you have been out hunting or doing some more PP experiments and that you will post more here in the future as I enjoy and have learned a lot from your threads..
I have had some great PP groups with my 9.3X74R only to have some stinker groups from the same loads next range trip.. Lots of work ahead next summer but boy is if ever fun!
Later,
Mic

[45 2.1]

45 2.1 : When you say don't try ground corn cob--is that due to the corn cob being to coarsely ground or what? would a very fine grind (almost powder like) work or do you believe that it could/would take the front of the case with it? Just really curious and you do seem to have more experience with that stuff than I. thank you and God Bless.

I've used several grinds of corncob........ too much in the case and a case will expand against the case and pull/stretch the brass when fired (just seems to be a property of the material). That amount changes from OK to too much fairly fast. Small amounts seem OK. Work up to it and don't assume its OK until you've done it.

Zeek, your on the path and doing well. Normal boolits will do the same when you get the powder and filler right. Keep going.

[Old Coot]

A couple of years ago there appeared an article in the Fouling SHot where a gentleman was fireforming cases in a 450?577 Martini Henry. He used COW on top of a light load with a paper wad to hold it in the case. .After firing at a piecd of 3/4 " plywood across his 12' wide basement a 1/2" appeared. The filler was acting as a solid projectile following ignition. Since this obviously occurs within the case as well I personally refrain from using granular fillers in anything but straight walled cases. Especially because I do not have the pressure measuring equipment.

Frank Barnsness did an article in the Handloader Magazine where he measured pressures with a piezoelectric setup that was attatched to the barrell of the rifle, and hooked to a computer with the appropiate software. Barnsness found that pressures were dangerously high long before customary pressure signs appeared (cratered and flattened primeers, hard extraction, case head expansion, etc.)..

I am not trying to tell you all what to do, I'm just passing on information, but be aware that pressures are probably a LOT HIGHER than you think they are.

By the way I have immensly enjoyed this discussion. At the moment the only gun I patch for is my Whitworth copy. I use a .446 cast pure lead slug and patch with two wraps of Morilla tracing paper. Accuracy over 75 to 80 grains of Triple Seven Is quite acceptable. I started because I was trying to get away from lubed bullets and those cursedly expensive felt wads. Patching also makes reloading in the field much easier and neater.

[danyboy]

Zeek,
Question: Why did you do a left hand wrap ? Just curious.