BPI Shot Buffer and old barrels

[FromTheWoods]

I was comfortable using BPI Shot Buffer in '73 and '94 Winchesters: .32-20, .32-40, and .38-55. Then I began reading about plastic fillers melting and ringing barrels.

Now I'm asking you folks.:
--Will BPI Buffer in these cartridges harm old Winchesters?
--Can I safely use this buffer in the necked calibers: .25-20, .25-35, 30WCF, 32WS?

[geargnasher]

Why do you need the compacting filler? How about Dacron if you're using a powder that needs to be positively located against the primer?

I'm interested reading any articles that discuss barrel ringing with granular PSB used as filler, I use a lot of the stuff myself and have had nothing but good luck so far, but I have a formula that I stick with for using it, and many cartridges are unsuited for it.

The only problem I could forsee is excessive case stretching with those thin cases. IME, the granular fillers can put additional stress on the shoulder of the case and cause the brass to flow toward the muzzle, shortening case life. This is really only at high pressures with modern cartridges, though. I use PSB in my .30-30 for some midrange loads with plain-based boolits (1830 fps) and have zero problems.

Gear

[btroj]

I have never heard of a filler melting in the barrel and then causing ringing of the barrel.
I have never used a granular filler vut have used Dacron some. I prefer to think of Dacron in the way Gear put it once, not a filler as much as a powder locator. It works to keep powder toward the primer.
Where did you hear these "reports"? We're they reliable sources? I don't consider many web sources as at all reliable, too many rumors are repeated over and over yet nobody seems to know someone who actually had the problem.

[Char-Gar]

Where have you read about shotgun buffer melting and ringing a barrel/chamber? That is a new one on me.

There have been stories out there for years about dacron tufts ringing a barrel/chamber which is mostly BS.

I have loaded many rounds with Precision Shotshell Buffer, and it doesn't melt, it just comes out the end of the barrel in a little white cloud.

[Maven]

FTW, How much BPI are you thinking of using? I generally use 1.0cc or less in my .30cals. (including metric .30's and 8mm Mau.), and sometimes as little as 0.3cc (8mm Mau.).

[Char-Gar]

I use .5 to 1.0 cc in my 30-06 depending on the weight/length of the bullets. I just use enough to get compression on 50/WC872. This will produce 1.9 to 2k fps, again depending on bullet, and this is all I want.

[FromTheWoods]

The following is what began to spook me:
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From-- http://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/52510046?r=83510046#83510046
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Some food for thought.
Chamber Rings and Natural Fibers

This article, written by John Campbell, is reprinted here by special permission of American Single Shot Rifle News.
emember the abomination of double-knit fabrics and "leisure suits" that befell men's fashion in the 1970s? I do. And I also remember the happy day when someone once again discovered that natural fibers were best. The world returned to cotton, wool and sanity.

Now it appears that the same philosophy offers us a solution to this over-powder wad/chamber ringing problem. Some of you may remember a few years back when I ruined the chamber of a perfectly good .38/55 Winchester Single-Shot by blowing out 30-30 brass with "squib" loads. I was using 12 grs. of Bullseye, a Dacron fiber wad to hold the powder in place, and a Lyman 311227 cast bullet in the case mouth just to plug the end of the "tube." In less than half a dozen rounds, I had a magnificent chamber ring. It was so bad that I had to pound the cases out of the rifle with a rod.

I reported this incident in the ASSRA News and the piece spurred quite a bit of response and speculation. Charlie Dell was among those who chipped in some commentary. He declared that he'd never had any problem with kapok wads in smokeless powder cast bullet loads, and that he'd never ringed a chamber. I had no reason to question Charlie's contention, but I did give him my recipe for chamber rings nonetheless. Intrigued, Charlie and a learned associate proceeded to see if they could reproduce the chamber ringing effect under controlled conditions.

They used an old "junk" Winchester barrel, chambered it to 38-55, and followed my loading formula. Sure enough, they got rings. And they kept getting rings under the right conditions. Charlie even cut the chambers out of these ringed barrels and cross-sectioned them to examine the swollen rings. Charlie showed me a few of these chambers. After more tests, Charlie reported his findings in this journal some issues back.

The bottom line to Charlie's investigation was that Dacron was the absolute WORST thing you can use for an over-powder wad. Contrary to what some gun writers had suggested in the 1960s and 70s, Dacron is not consumed in the process of ignition. It is merely melted. And under certain conditions, this plastic glob does ugly things to a nice rifle. Here's my analysis.

In a worst case scenario, this goo is thrust ahead of the powder gases and against the base of the bullet. There it encounters an object of resistance (the bullet) and acts much like hydraulic fluid (which is incompressible). If the bullet is breech seated in the barrel, or loaded out in fixed ammunition to engage the rifling, resistance is enhanced and things are exacerbated. As the Dacron goo strikes the base of the bullet, it is momentarily trapped between the bullet and the massive pressure of the powder gas building up behind it. For a microsecond, it has no where to go... except to exert a radial, lateral stress on the barrel steel. If that steel is of a modern alloy with high hoop strength, it can sometimes resist this lateral force and everything seems normal. The bullet begins to move, the pressure at its base is relieved, and the gun fires it projectile downrange. When the bullet exits the muzzle, the melted Dacron evidence is blown to the winds.

However, if the steel of your gun barrel is of a less sophisticated 19th century alloy, like that found in an original Winchester Single-Shot, bad things can happen. The lateral force exerted by the melted Dacron goo is often enough to defeat this steel's strength. In that situation, the Dacron is melted by the burning gunpowder as it is driven forward to whack against the base of the bullet. There it is momentarily stopped, and it "hydraulically" impresses its wafer-like form into the case and chamber. At first, you don't notice that anything strange is happening because the rifle sounds normal and the bullet hits the target where it is supposed to. At first, the ring impression is very light -- almost invisible. But this insidious "Dacron effect" is cumulative. Fire about 50 shots or so and... surprise, you've got a nasty ring! The first time you are aware of such a problem is when extraction becomes a little too sticky. You look at the fired case carefully. Then you see it. Right there around the case neck where the base of the bullet was seated is an obvious ring. By then it's too late. The damage is done.

The only way out of this predicament is to gauge the depth of the ring and then get a neck or neck/throat reamer specially made to clean out the depression. This will increase bullet/case/chamber neck clearance and degrade the bullet-aligning qualities of the chamber. Bullets sized to a larger diameter may help to obviate this drawback, but the results are unpredictable. One of my Model 85s shot worse and nothing could be done to improve its performance. Another was able to handle a special Hudson bullet with its new throat and shot more accurately than it ever had before. Go figure.

But the most important thing to keep in mind with Dacron wads is that the ring-generating conditions and forces are there-- and in play -- whether they create a ring or not. If your modern Douglas barrel shows no signs of a ring with Dacron wads, it simply means that it has been able to withstand the forces that are at work. The ruinous pressure is still there!

For some reason, the Dacron chamber ring phenomenon is very scarce in rifles of .40 caliber or larger. Those who look for it in a 45-70 will look a long time. Why is this is so? Again, I can only offer my personal analysis:

When the Dacron goo hits the bullet base in a chamber the size of a 45-70's, I believe the pressure wafer it creates is markedly thinner than it would be in a 32-40. This thin edge of pressure either exerts less lateral force against the chamber wall, exerts it for a shorter moment of time, or both. The result is a greatly reduced tendency to create chamber rings. But from one perspective this doesn't make sense. If the melted Dacron's ring is narrower, shouldn't that small edge have great force? This is where my insight begins to break down. Maybe larger calibers don't melt the Dacron so completely or quickly.

But we're agreed on one thing. Dacron is bad. So what's the alternative? Actually, there are two. First, you can use no wad at all. Accurate Arms 5744 powder is reported to be fairly "position insensitive." In other words, it can end up pretty much anywhere in the cartridge case and still provide consistent ignition and pressures. My tests substantiate this. But they also hint that if 5744 was consistently back there against the flash hole, it would work even better. So would a lot of other powders that aren't as "Schuetzen-friendly" as 5744.

For them we still need a harmless wad -- like Charlie Dell's kapok. But just try to find some kapok these days. I eventually gave up looking for old life preservers and wracked my mind for a substitute. Then ASSRA member Mike Brennan suggested the obvious: cotton. That's right, cotton. I got my supply from the corner drug store for less than two bucks, and have been using it for years now with absolutely no ill effects. It's fluffy and it works like Dacron to hold the powder back against the flash hole. But it doesn't give you chamber rings. Not in a range of cast bullet loads that I've used it in from 25-20 to 45-70. And let me emphasize that my experience with cotton wads has spanned several years and several thousand rounds. I don't use much. Just enough to hold the powder in place. That amount varies from one caliber/case to another. In process, I push the cotton down against the powder with a section of old 22 caliber jointed cleaning rod. I don't tamp it down.

So far, accuracy with cotton wads is outstanding and the chronograph reveals extreme spreads and standard deviations that are about half those of identical loads without cotton wads. When the round is fired, you can just notice a thin fan of white from the muzzle. This tells me that the cotton fiber is not burning to charcoal -- or melting like Dacron. The cotton is merely riding behind the bullet and dissipating into the atmosphere as the projectile exits the muzzle. And since natural fiber cotton does not enter into a hydraulic, "plastic goo" state under ignition, I don't believe any lateral pressure at the base of the bullet is enough to force a ring into the chamber... even with old Single-Shot barrels. The impedance and ring force conditions may still exist, however.

On the upside, cotton wads may even serve to enhance accuracy by protecting the base of the bullet from distortion and impingement by powder granules. Cotton's insulating qualities may also help to keep more lubricant working for you for a longer time. So at this point, I'm confident enough about cotton to let you in on the secret. It just goes to prove a gentleman's adage, "In clothes or shooting, natural fibers are best."

[white eagle]

If a shot buffer is in a shot cup
how can it hurt ?

[Chicken Thief]

So in essense you use a case that is way to big for your load/shooting, why?
Slower powder and larger filling?

And as the author says the problem occurs with one loading in one case with one boolit.

If this was a "general problem" dont you think this site would be pasted with warnings against dacron filler?

[Cap'n Morgan]

I'm pretty sure John Campbells chambers would still have developed a ring, had he used a cardboard disk over the powder instead of Dacron. Ringing is most likely caused by rapidly compressed air between filler and bullet, not by melted Dracon. The filler is just acting as a piston - and the 38-55 case is pretty long for its caliber giving this "piston" a large volume of air to compress into a fairly small area - This is probably why Campbell didn't notice problems in regards to the larger 45-70 case.

[geargnasher]

I'm pretty sure John Campbells chambers would still have developed a ring, had he used a cardboard disk over the powder instead of Dacron. Ringing is most likely caused by rapidly compressed air between filler and bullet, not by melted Dracon. The filler is just acting as a piston - and the 38-55 case is pretty long for its caliber giving this "piston" a large volume of air to compress into a fairly small area - This is probably why Campbell didn't notice problems in regards to the larger 45-70 case.

I agree.

It's very, very simple. If you use an over-powder WAD, any kind of wad at all, and leave open air space between powder and boolit, YOU WILL RING YOUR CHAMBER. Any sort of tight wad over the powder that leaves airspace is creating a situation where the boolit that's crimped in the front of the case becomes a bore obstruction. We all know what a bore obstruction does to guns. That is why we so often caution when using Dacron or any other filler that you must not ever tamp it down hard against the powder, or you will create a pressure spike when the pressure smacks the boolit base.

A card wad can do this, Kapok can do this, dryer lint can do this, and TP can do this if any of them are installed incorrectly.

Don't blame the filler, blame the improper use of these fillers.

The correct use of Dacron, in applications that genuinely call for it, is to use only enough so that WHEN FLUFFED NATURALLY it will fill the space between the boolit base and powder plus maybe 25%. Dacron is springy, and will put slight pressure on the powder column to keep it in place, key word SLIGHT. Dacron also compacts gradually when the burner is lit, creating a gentle transition of space all the way to the boolit base. Dacron doesn't melt when used with slower powders, especially ball-type rifle powders. If used properly, even if it does melt under light charges of super-fast pistol powders (which my results with a few hundred fireforming rounds completely contradicts), it shouldn't cause problems, it just has to be loaded to the correct density.

As far as the compacting fillers, they all have issues of their own if you don't have a very good and clear idea of what you're doing. The cereal fillers (Puff-Lon is one too, don't be fooled!) can and do absorb moisture and solidify if stored too long, and this can cause restrictions in the case that can increase pressures to unsafe levels. Any compacting filler in a bottleneck case has inherent pressure-raising effects, and there are limits to both the sane and effective use of them. Inert fillers like poly shot buffer store well and work predictably, but they can still be very dangerous.

As for old, "weak" barrels with cast boolits, if you're concerned about damaging them with fillers, use Trailboss and forget the filler.

Gear

[FromTheWoods]

I use the BPI to aid in accuracy. Some of our bores are ugly.

So:
--Do not leave an air space between the powder and the filler.
--Do not compact the filler (too much).

--Do snug the filler between the base of the bullet and the powder charge.

Would you folks mind offering more "Do's and Don'ts" for the use of BPI in old Winchester calibers?

I have been filling the .32-40 cases to where the bullet slightly compresses the buffer--to 3/8 or so of an inch below the mouth.
170 gr. .322 RNFP Oregon Trail Laser-Cast (Lead)
21.5 gr. H4895
5.8 gr. approx. Original Shot Buffer
CCI 200 Large Rifle primer

It seems to be a necessary component for my youngest son's .32-20--worn bore, key-holing without buffer. We are testing new loads in it, so I'll not include the one we were using.

[geargnasher]

I think you covered it pretty well, and don't see any danger in what you're doing as long as you don't get too much below the shoulder-body junction in the cases. The narrower the shoulder, the higher percentage of filler you can use. I gernerally have the best results with a slight compaction of the BPI filler, and with powder charges that allow only filling the area to the shoulder-body or slightly below with powder. This compacts the filler "just" the right amount when fired, and it makes a really dense plug behind the boolit that protects the base from gas leakage with soft boolits, plain-based boolits, and bores that make good dynamic fit and seal a challenge, like rusty bores or bores with restrictions from things like roll lettering.

You might also find that each individual cartridge has it's ideal "density" level and proportion with the filler, and it might be a very narrow ideal window. The amount of compaction needs to be just right for best results. Once you get a load dialed in pretty well, try adjusting the amount of filler in very slight increments until you find the sweet spot, just like you would with the powder charge.

Gear

[btroj]

I find it interesting that I saw a cloud of white Dacron goo upon firing each shot duringmy Dacron filler test. Sure looked like normal old Dacron to me, not melted goo.
I must just be imagining things.

[Char-Gar]

1. That article has been around a while.

2. You will note it is about dacron and not shotshell buffer. There is a big difference you know, not the same thing at all.

3. Gear is 100% correct about wads and how many things use as a filler can become wads if not used correctly. You can take his post to the bank.

[303Guy]

I don't think Dacron melts too easily in the bore. I suspect that the chamber ringing with the use of Dacron type fillers is caused by a wad of powder striking the boolit 'obstruction' and the boolit base expanding outward. The wad itself could also expand outward against the boolit base.

[runfiverun]

my take on it is that the filler/card is slamming into the boolits/bullets base.
take a look at what cartridges are ringing and where the ring is.
using filler is
A. like adding more powder. making the case smaller.
B. used to protect the boolits base.
C. as a powder positioner.
D. must be in contact with both the powder and the boolit slight compression will provide the best results.
E a good filler is inert and not affected by moisture [humidity] in any way.
F and finally no matter what filler you use someone will tell how it's the worst thing you can possibly come up with and the best filler "ain't made no more".
or is sumthin you can only get in south st.petersberg in march, but only in the rainy years.
G. and most importantly.... you must work the load up with the filler as part of the recipe.

[FromTheWoods]

Thank you all for your comments and help with this.