closed cell foam

[1874Sharps]

Beekeeper,

You certainly will not go wrong with a cork filler (or something that is firm) or a full case of BP. The US Calvary 45-70 load, as I recall, used 55 grains of BP with a cork wad over it to fill the airspace. I do agree with BigTed about letting somebody else do the airspace experiments. I am a firm believer in using a full case in most cases. Having a gun get ruined or blown up (and maybe wearing a "steel mustache") just does not sound like a good time. Everyone agrees that a full case of BP is safe. If recoil is an issue, there are ways to deal with it other than reducing the load.

Longwood is right about charred cornstarch being added to BP when it is being made. I do this when I make BP, as it helps the kernels bind together and not crumble.

[Longwood]

Longwood is right about charred cornstarch being added to BP when it is being made. I do this when I make BP, as it helps the kernels bind together and not crumble.

I learned about it here.
I do not recognize the name.
have you been on any of the threads about making black powder?
There has been a few discussions on this site. Unfortunately they seem to have no home and are in the cloud or fog bank, or,,,,.

If you ever come across a powder manufacturing thread, please join in.

[1874Sharps]

Also, Nobade does bring up a good point about the 1863 Sharps and airspace. For those who are unfamiliar, the 1859/1863 Sharps rifles are caplock rifles that are breech loaded with a boolet and loose powder, or a special brass case containing the boolit and powder, or a nitrated paper cartridge containing boolit and powder. Of the different ways to do it, the nitrated paper cartridge admitedly has some "looseness" in the powder column. In my '59 Sharps the chamber is equipped with a floating gas sleeve just forward of the chamber where the powder stops and the boolit begins. As far as I can tell, the chamber is full of powder when the rifle is fired. As the boolit begins its travel down the barrel the hot gas of combustion expands into the small void at the muzzle end of the gas sleeve and exerts pressure on it so as to seal the back end of the sleeve to the block face. I say all this to illustrate Nobade's point that there is a type of airspace in this process. I am not sure of the proper conclusion this evidence points to.

Longwood,

Yes, I have in past months or years joined in the discussion on making BP and have been on both sides of the debate questioning the safety and perhaps the wisdom of making one's own BP. I just had to do it, though! It seems my powder was leaving a little more fouling than factory made stuff, but I used it extensively in my 12 gauge CAS loads where fouling was not a concern.

[Chill Wills]

I think we need to clarify what airspace we are talking about loose powder is one thing, an OPwad with a space between it and the boolit is completely another. (is it NOT?)

Bingo!

Nanuk, I would agree.
Floral foam is much used with the Schuetzen crowd. Dacron - Poly fiber is great stuff and very inexpensive.

Ted, I would stick with what you are comfortable with as should we all. Many (millions) of military 45-70 have been arsenal loaded with reduced charges.

I have No idea how many (millions) of part full target and gallery loads have been produced by the factories back in the day. It is in the literature- history. Also, the father of the 1874, the percussion Sharps used loose powder.

My personal best load for one of my favorite rifles, 45-2-4/10 Hepburn does not completely fill the case. But, it is deadly accurate. Ah, deadly does not = safe some think. OK. They can think what they want. Works for me. The load is fine. It just happens that the accuracy load is about 98% density.

I don't normally get into these forum things but I started this one What came over me?

[waksupi]

For those who don't want to buy a full bag of dacron, this is a fine time of year to hit a yard sale, and buy an old pillow for 10 cents.

[nanuk]

I would say that is true.

The difference between straight and bottleneck cases also has me wondering ...

CM

Hey, CM, can you refresh our memories as to the concerns regarding the differences?

is it the idea that in a BN case, the boolit base is not exposed to the initial blast from the primer, even if there is airspace, as the shoulder would bear the wave and redirect it, BUT in a straight case, the boolit indeed can be exposed to the primer blast if the powder is settled flat in the case?

Please excuse my ignorance, as I'm trying to understand the differences

[montana_charlie]

Hey, CM, can you refresh our memories as to the concerns regarding the differences?

No, I can't.
1874Sharps brought up that subject, and it is an issue that I have never had reason to contemplate. Therefore, it makes me 'wonder' if airspace in a bottleneck cartridge is any more, or less, dangerous than one in a straight case.

Since I have no means to look at possible differences myself, I am as ignorant on the subject as you are ... with small hope of curing that ignorance unless someone else has some wisdom to share.

CM

[375RUGER]

The biodegradable cornstarch peanuts do work. I used some recently to fill space in a midrange .44 mag load, just spearamintin' with pushing the powder up against the primer.
The cornstarch smells like burnt marshmallows when set on fire. I didn't smell anything but gunpowder at the range though.
One thing I like about the cornstarch is that the peanuts are straight with a consistant diameter so you can just cut to length with a razor.

[bigted]

Bingo!

Nanuk, I would agree.
Floral foam is much used with the Schuetzen crowd. Dacron - Poly fiber is great stuff and very inexpensive.

Ted, I would stick with what you are comfortable with as should we all. Many (millions) of military 45-70 have been arsenal loaded with reduced charges.

I have No idea how many (millions) of part full target and gallery loads have been produced by the factories back in the day. It is in the literature- history. Also, the father of the 1874, the percussion Sharps used loose powder.

My personal best load for one of my favorite rifles, 45-2-4/10 Hepburn does not completely fill the case. But, it is deadly accurate. Ah, deadly does not = safe some think. OK. They can think what they want. Works for me. The load is fine. It just happens that the accuracy load is about 98% density.

I don't normally get into these forum things but I started this one What came over me?

i definetly am intrigued by the airspace thing. this is the reasson i asked the question and while the thought that blackpowder burns/explodes differently then smokless and therefor causes more of a shockwave then smokless is something that sounds reasonable but even with that im no engineer and i am taking others word for what happens so this' new ' to me idea that an airspace does no harm is a new thought and thusly i would like to know more about the thought/fact.

im only a few years into this cartridge / blackpowder process and still in the juvanile portion of my learning so any news is good news...as for me now...im going to leave no airspace in my loads till it makes sence that the most preached excercise in loading bp is bunked.......

i as well would love to see mythbusters tackle this one and come to a conclussion.

[windrider919]

Heres the way I was taught. And articles in the early 70's in the American rifleman bore the theory out.

In either BP or smokeless, a partially full case will have the powder along the bottom and air in the top of the case. Upon ignition by the primer, the powder may be thrown forward against he shoulder or bullet base. So the primer may not evenly/consistently ignite that powder charge because it works best when every grain of powder is surrounded by the primer 'flash' and ignites at the same instant. ( Note - it does NOT hurt BP powder to be flung forward against the bullet base. )

Testing [BP & Smokeless} showed that if the powder charge was all the way back against the primer, better accuracy resulted. So shooters, an example being offhand in NRA HP Rifle or in Silhouette started raising the muzzle up, then back down level in competition after loading each new round so the powder was in the same position from shot to shot. This is true in EITHER BP or smokeless. Additional testing and examining old Army testing results showed that FULL cases of BP ignited more consistently and gave better accuracy than ones with any air space. BUT the only danger in BP shooting reduced charges is if a over-powder wad was used to hold the powder back...then the force of the wad hitting the base of the bullet caused pressure to rise as if there was a bore obstruction. No wad or a wad with no airspace between wad and bullet base, no problem.

Also, does anyone remember the rash of 'chamber ringing' and rifles blowing up with REDUCED loads back around the same time (smokeless only, NOT BP ). Finally, it was theorized that a small, reduced charge with lots of airspace MIGHT be experiencing reflecting pressure waves in the micro-second before the bullet had even started to move. And that these pressure waves impacting each other as they reflected off the bullet base and the case base was causing pressure spikes at multiples of what the firearms were built to handle. THATS when the 'no air' thing really got started. The other competing theory was that the pressure spikes were causing the progressive burning powder to burn so fast { five to seven times regular burn rate was theorized} it was in effect detonating instead of the regular burn. Or maybe BOTH were occurring. So most people started using slower burning powders for redced charges and started trying to get as full a case volume as possible. And then seem to have forgotten WHY!

BUT, repeat BUT...when powder charge is 70% or greater than total volume, the detonation problem goes away...hence the newer loading manuals starting there as the lowest load point for most powders, Lyman and cast bullets being the exception, leaving it to the loader to take the chance.

Also, Dacron fiber, never used as a wad but instead used as a 'fluff' to hold the powder back in the rear of the case...DOES count as air space. Used like this it completely burns and leaves no residue. If you are getting any residue with Dacron fiber, you are using many times too much. Here is an example where the powder is held back by the primer , the fluff counts as airspace, BUT the Dacron does not count as a wad so is safe to load, (with medium or slower powders).

And the same would be true of any of the foams ( or fiber wads or lube cookies )...if there is EMPTY air space between the foam and the bullet base it is BAD. And of course, the foam should be completely back against the powder too, even if it is not compressed. But some air space between the powder and foam IS not that harmful to anything except accuracy. REPEAT - just NO air between any material in the case and the bullet base!!! Also note, the WEIGHT of the foam COUNTS as added to the projectile weight! So those using a QUICK, low volume powder (pistol powder in a rifle case) at max pressure might go over pressure if they don't add the filler weight to the projectile weight. An EX: a MAX load of Unique for a 400gr 45-70 load without filler might have the pressure go +P using 10gr of COW, raising the 'projectile weight' to 410gr without a reduction in charge.

Another thing to note, using COW or other organic cereal filler works great, for rounds loaded and shot fairly soon. But multiple incident reports bear out that using COW or grits, etc in bottleneck cases that were loaded than sat on the shelf for months or a year could cause the shooter to experience an exploding firearm. What happens is that there may just be enough moisture in the COW/Grits/Farnia/etc to cause it to CAKE...then when fired this solid cake is forced into the shoulder of the bottleneck case, causing a PLUG/bore obstruction!!!! BIG BOOM! So for LONG TERM STORAGE - use an inorganic filler such as Dacron or Polyethylene buffer powder like in shot-shells or DRIED cotton fiber.

[bigted]

windrider...thanks for sharing that. it sheds some light on the subject at hand nicely.

[montana_charlie]

The fact that it sounds historical gives it som credence. But, it sounds so logical ... appeals so strongly to common sense ... I think I am going to adopt that explanation as "my belief" on the subject from now on.

In the future, you may even hear me state some of that as 'fact'. If you disagree ... that's tough.

CM

[1874Sharps]

Windrider's post states some interesting theories, indeed. As far as I know, the theories set forth have not been proven but are speculative, only. If anyone has a reference to the contrary, I would like to read it, as this is an interesting subject. It has been years since I took physics in college but I will try my best to talk a little about pressure waves. Waves may interact constructively (the waves combine to form a wave of larger magnitude) or destructively (they cancel out each other's magnitude). A pressure wave's propagation is also different if the propellent burns (smokeless) or detonates (BP). I buy the idea that if there is a "plug" such as an over-the-powder wad and an airspace in either a smokeless or BP load it will create a "jackhammer effect" on the base of the boolit (especially with BP, which detonates). The old 45-70 cavalry reduced loads used a column of cork over the BP and not just an airspace. They saw the need to do so and I doubt it was for the sake of better accuracy, as the accuracy standards for the trapdoor Springfield were not rigorous by any means. It is true that Dacron or foam is largely air. So would there then be a difference between such a BP load and a load that had a BP "pellet" at the base and a big airspace between it and the boolit? It appears the answer is "yes". Back in the day there were gallery type BP loads that used a greatly reduced load (a cherry bomb in a boxcar), but that really is not what we are talking about here. At the other end of the spectrum, a BP load with 98% load density (a little airspace in the load with no wad) is pretty close to 100% load density. One thing is for sure and something we may all agree on: Using a full case of BP in a given load is safe.

[bigted]

i am fasinated with the way this thread has progressed and the ideas are very thought provoking. i know from personal experience that a lod...either blackpowder or smokless...is , [in my experience], more accurate at ranges ive shot at with a full case rather then a partial case full...either with the aid of a more solid filler or the whole case below the boolit with powder. it has always been my findings with either rifle or handguns that this is the case for me.

id like to feel free tho to experiment with squib loads in blackpowder but till i find definitive facts ...i for one will continue with the 100 % load density at least with the bp. i dont really load sp with fast pistol or shotgun powders so that is no unpleasant change for me.

as i said above tho...i am very interested in this theory/thought about air space NOT being destructive to my firearms...am anxious to read more about this subject.