Air space between bullet and powder.

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  • Last Post 20 October 2014
303PV posted this 14 May 2011

I have read that this is dangerous. Has that been proven with experiments? Breech seating bullets optimizes accuracy according to a lot of publications. But then there is a considerable air space between wad and bullet.

Piet

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delmarskid1 posted this 14 May 2011

Air space in muzzle loaders is dangerous.

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LWesthoff posted this 14 May 2011

There's even air space in some (many) commercial jacketed bullet loads. If you look at the loads used by competitors in CBA matches - printed in every Fouling Shot - you will see it's very obvious that all, or almost all the loads must have quite a bit of air space, even those using “bulky” powders like 5744. My accuracy loads in both '06 and .308W are in the area of 27 to 30 gr. of Varget or H4895, and the bullet is seated out to engrave on the lands, which creates a load with plenty of air space. Air space - by itself - does nothing to make loads dangerous. Black powder loads (and black powder substitute loads) are another matter entirely.

Wes

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Mnshooter posted this 14 May 2011

Using black powder an air space has always been considered a bad thing. I saw a muzzle loader bulge when the individual forgot to seat the ball after short starting. Most of the time they do not, but on occasion it will happen. I gather bad things can happen similarly in a cartridge gun as they do definitely do not recommend any air space. They used to recommend COW but now claim wadding si best for reducing a load. Generally, for a BPC I compress the powder anyway.

DP

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303PV posted this 15 May 2011

Thanks for your replies. I am new to loading with black powder , therefore I would like to know what's happening when short starting or leaving air space in a cartridge.

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corerf posted this 15 May 2011

Here's the deal with bp, for anyone who cares about the process. I make bp. In my youth I made other compounds that deflagrate as well in pyrotechnics, amateur.

Bp has a very consistent burn rate, just like smokeless. This is only when confined strictly. It burns like a pencil lead gets worn. It deflagrates, a fast moving flamefront that clocks below 5000 fps. If over that, its a detonation, I.e. high explosive.

Bp. Burns very slow in the explosive realm but like any deflagrant, if the flamefront can move ahead of the bulk of the propellant, it burns faster due to multiple flamefronts occuring. Its called a gas detonation, it is the hot gas moving ahead of the flame causing complete consumption of the propellant almost instantly.

To mitigate this, no airspace can be allowed iin bp work. Else the charge column will loosen, gas flows forward, causing ignition of the column nonlinearly.

Bang.

Its how salutes are made. If you were to make a salute with a tube that held 3 grams, and filled it with 3 grams and compressed it, the salute will go bang, but with a different yield. If you only use 2 grams loose, the yield is lower, the brisance is higher - shock value. A sharper bang occurs. Its less gas but pressure curve is much sharper so distructive force can be multiplied by lightening the charge depending on your intent.

So that's it. It is food for thought, the rule is the rule. I am no pro bp shooter, but I am 41 ans spent my entire teenage years as a chem head with pyrotech. Along the way, I learned a little about bp, propellants, deflagrants and stuff that moves faster than bp.

Just some fun facts. It helps me stay aware of when I pour 60 gr of ffg into a barrel and seat a ball. I make sure that it goes all the way. I have significant scars and a variety of parts imbedded in me due to pyro youth and I know what having a problem develop feels like up close and personal.

Hey I am tossing the question out again, about a boutique bp mfgr to compete directly for the US market against Swiss BP.

If you folks could buy super clean, real bp, a few buks less than goex, that delivered velocities of Swiss ans better, would you patronize the US manufacturer?

Not meaning to hijack the thread.

I love bp.

Mike

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Mnshooter posted this 16 May 2011

I would likely patronize the US manufacturer at equal price as I am sure would others. There are a few that only shoot GOEX as it is made in America. The bulged barrel I saw from a short started load was interesting in that the individual cut it out and it was not only bulged but there was a heat cutting action in a ring around the barrel.

DP

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Dollar Bill posted this 16 May 2011

corerf wrote: Hey I am tossing the question out again, about a boutique bp mfgr to compete directly for the US market against Swiss BP.

If you folks could buy super clean, real bp, a few buks less than goex, that delivered velocities of Swiss ans better, would you patronize the US manufacturer?

Not meaning to hijack the thread. Mike, didn't you try it before and run into some problems in the production?

I'll attest to the problems caused by an air gap. I loaded 50 45-70 rounds with 61gn of Goex 2F, calculated to give me .050 compression. I used a 30” drop tube, a walters wad and a 525 gn Postell. By the time I got to the range, about 40 miles away, some over dirt roads, the powder had settled. I didn't know it right away but the first 10 rounds had circumferential case cracks where the base of the bullet sat.

Now I use 65gn, vibrate the charged cases and use a compression die. No problems.

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corerf posted this 16 May 2011

Bill,

I ran into the state of california, not production problems, which by years end will be 3000 miles behind me. Then the industry will get some new blood and the USA will be number 1 again.

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corerf posted this 16 May 2011

Bill,

I ran into the state of california, not production problems, which by years end will be 3000 miles behind me. Then the industry will get some new blood and the USA will be number 1 again.

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Dollar Bill posted this 16 May 2011

corerf wrote: Bill,

I ran into the state of california, not production problems, which by years end will be 3000 miles behind me. Then the industry will get some new blood and the USA will be number 1 again.Outstanding! Put me on your customer list. Shooting 38-55 and 45-70, so 1.5 to 2F is what works for me.  

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w30wcf posted this 30 May 2011

In cartridge guns, I have not seen any issues except for increased fouling and less accuracy.

Muzzleloaders that use 100+ grs of powder are another matter entirely.

w30wcf

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Mnshooter posted this 02 June 2011

The affected barrel I saw was with 50 grains of powder in a 50. Not a heavy load. I shot a short started unseated load and had no problem, so it does not happen every time.

DP

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bpd303 posted this 07 July 2011

I have been shooting BP for about 50 years and have seen detonation in loose powder loads. I always compress cartridge loads with kapok as filler with wax wad. Been fortunate that none of the detonations have destroyed any of my firearms.

The BP cartridges I load are 45-70, 577 Snider, 43 Spanish, 43 Mauser, 577-450 Martini, 41 Swiss, 32-20 WCF, and 12 ga shot shells. Muzzle loaders are 45, 50, 68 cal + 12 & 20 ga.

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lkydvl posted this 13 July 2011

I have switched over to KiK powder. Its not USA made but its quite a bit cheaper than Swiss and works just dandy. Even the “experts” on the BPCR and Shiloh forums are starting to take notice of and use it. Andre`

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tturner53 posted this 07 September 2014

Hasn't there recently been an artcle in The Fouling Shot re. BP cartridge loading that disputes the 'air gap' issue? Something about old military 45-70 ammo with air space between the powder and bullet base? I'm looking but haven't found the article. I know my new to me book says NO air gap, period. Myth?

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blixem posted this 09 September 2014

I guess some don't mind doing it in either BP muzzleloaders or BP cartridge guns. But I'm not going to do it- no matter if Fouling Shot or any other media printed an article about it. I simply can't find a reason to not load any of my BP firearms to 100% load density, muzzleloader or cartridge.

While everyone concentrates on gas pressure and concentrated gas pressure ring at or near the base of the bullet, I believe the problem with airspace and BP is more related to compressed unburned solids in the BP acting as a projectile. In other words kinetic energy. The amount of unburned BP solids blown out the muzzle is fairly high. 

Another way to think of it would be: if there were no potential for a problem then why not just put a card wad on top of the powder (regardless of powder type) and leave an airspace between the powder/wad and base of bullet? ”¦. not to be confused with a low density filler of course”¦ two completely different things! 

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303PV posted this 09 September 2014

Breech seating will leave an airspace. It is considered a safe practice.The Chassepot has the “Chambre ardente". Also a considerable airspace. TTurner is looking for the trial with ever increasing airspace with 45-70. I have read it (can't find it back). If I remember correctly the conclusion was that the pressure was lower with increased airspace. I have also read somewhere that filler (wool for Martini -Henry) was used to prevent the BP breaking down into smaller kernel size during transport thereby changing the burn rate . Therefore I can only conclude that the question has not been answered yet. Only a trial under controlled conditions can provide an answer... . 

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blixem posted this 09 September 2014

Since I haven't rung or bulged a chamber in a cartridge gun or a barrel in a ML, I can't speak to first hand experience, although I've looked at a few of each. 

In breech seating it may depend on amount (distance of air space). Obviously a little won't matter as much as a lot. Even in breech seating there's always the option to load in such a way so the wad in the case mouth is up against the base of the bullet or conversely, use a bullet of correct design where the breech seated bullet's base it at a point so the wadded case it up against it.

As to the argument that goes, “it's always been done"”¦ all fine a good, but I've looked at a lot of old BP cartridge chambers and guess what, many or most, if they've been fired a lot in their history, have a small ring in the chamber neck right at the point where the bullet base would be seated in the loaded round. My theory is that is the effect of many firings of BP rounds where the charges were not loaded to 100 or + load density or the charge settled from handling before firing. Those rings are usually small but unmistakable. My theory is they are the result of the cumulative effect of kinetic peening. Of course older and possibly softer barrel steels could account for some of that.        

577-450? That's a different issue. The design (or poor design if you will IMO) of that monster has always led to various attempts at reducing the powder charge, which is especially tricky in a bottleneck design. Various types of fillers have been used in addition to internal case base wads and inserted cardboard tubes, etc. When filler is used it may depend on how dense it is and the amount used and the “length” of the filler column (distance between powder and bullet base). 

I shoot a lot of different old original BP guns and have simply chosen to follow the 100% or + BP load density theory. Additionally, I shoot a lot of BP equivalent pressure/velocity smokeless loads in some of these cartridge guns and do use low density dacron filler with certain smokeless powders. In the end, it doesn't matter to me how someone chooses to load a BP cartridge or muzzleloader.          

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Ken Campbell Iowa posted this 09 September 2014

i have finally decided that BING knows more than i do, so i BING for opinions on most everything. i found lots of opinions, all interesting ” air space black powder ” . here is a photo of an old dupont booklet .



 ************** keep in mind that a consensus of opinions doesn't guarantee validity ... remember that is how our politicians get elected ( g ) . ken

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John Grantham posted this 12 October 2014

I have used an air space between the bullet and the powder column. As much as an eighth of an inch. I've always used a sixty thousandth card wad over the powder. This was  all done in a breech seating situation.  No rings. No bulges.  No blowups. The guns always seemed to shoot better with the bullet thirty thousandths ahead of the case. Some feel that I was lucky not to have a problem. Most of the powder was Goex.

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