Of bullets and things

Talk with other Shiloh Sharps shooters.

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bruce m
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Re: Of bullets and things

Post by bruce m »

further to the above, we do not see bore diameter bullets used with smokeless.
smokeless easliy runs at higher pressure than black, so you would suspect something other than pressure is what causes bumpup into the rifling, transition etc.
just getting back to wadstacks cushioning the blow.
i remember reading about the patch length kenny has found best for his loads, and they are shorter than mine without a wadstack.
it shows you what a balancing act we pursue in this game.
those who do the homework reap the rewards.
ultimately you find something that works and go shooting.
bruce.
ventum est amicus meus
beltfed
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Re: Of bullets and things

Post by beltfed »

Bruce,
INdeed, smokeless loads UNLESS deliberately loaded down will/can generally burn UP TO higher pressure than BP
BUT, it is a progressive burn, and so that initial pressure overcoming of the bullet's inertia is lower at first, and so Much less violent.
Perhaps the "shock wave" in the case of the breech seated/airgap situation with a bore diameter PPed bullet is really the Wad
accelerated by the powder burn/explosion?/gases and then impacting the base of the bullet.
and in the case of a "fixed" bullet, similar -explosion of the powder creates the "shock wave" if you will, of the
violent acceleration of the bullet that upsets into the "space available" if "IF IT IS SOFT ENOUGH"
beltfed/arnie
bruce m
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Re: Of bullets and things

Post by bruce m »

arnie,
however the "shock" is generated, the way it is delivered obviously affects what and how bumpup occurs.
in my breech seating the charge is only droptubed, and then with the airgap it virtually becomes a loose charge on firing.
kenny's wadstack "could" have a cushioning effect slightly reducing bumpup.
smokeless is progressive and so reaches peak pressure when the bullet is down the barrel some, allowing for gas cutting.
whatever bumps up the bullet with black, it must happen instantaneously, or gas would cut the bullet etc.
i believe there are some long range muzzle loaders that use bore diameter greasers, but maybe they use a wadstack that can on its own seal the bore long enough to allow bumpup.
but then a greaser will bump up more in the grease grooves than the bands.
in all this, if you get it working go learn to read the wind.
if you don't yet never give up.
bruce.
ventum est amicus meus
beltfed
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Location: Central Wi

Re: Of bullets and things

Post by beltfed »

My experience with PP bullets in smokeless loading is with Patched to Groove diameter bullets
since we do not have that initial "punch"of BP to upset the bullets to groove dia. IN fact, LINO is a favorite choice
for such smokless PP loads that I have shot in my 30-06 and 375 HH Improved rifles .Loads clock in the 2500-2600fps area.
Also, my 358 win deer rifle load is a 250 gr PP bullet cast of my 9+1 COWW/lino alloy , clocking 2350fps. Great "killer"
with not much meat destruction.
beltfed/arnie
bruce m
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Re: Of bullets and things

Post by bruce m »

yes arnie that seems to be the way of things.
your 375 and 358 are virtually giving full ballistic potential.
i used to load a 225 gn gas check hollow point on my 358 when i had one at full speed.
it is a great cartridge for cast bullets.
bruce.
ventum est amicus meus
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powderburner
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Re: Of bullets and things

Post by powderburner »

Thats the last word for it. Do the work reap the rewards. Whatever you choose
Dean Becker
only one gun and they are 74 s
3rd asst. flunky,high desert chapter F.E.S.
MYWEIGH scale merchant
reclining member of O-G-A-N-T
mdeland
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Re: Of bullets and things

Post by mdeland »

Bruce, BP does not instantly detonate. It actually burns, just at a much faster rate than smokeless. The bore is sealed by the wad and the front of the BP column that has not yet ignited. By the time the front of the powder column is burning the whole slug is well into the bore producing maximum resistance while the pressure from the powder burn is still increasing. At this point in the shot evolution we have maximum pressure and maximum resistance which would tend to support what Mann discovered about full bullet obturation. This occurs several inches up bore if I understood what Mann found correctly.
TNT or nitro glycerine for example, detonate and is the reason they cannot be used as a projectile propellant. The energy release is multiple times faster and stronger than is BP. The reason nitro works in smokeless powder is because the gun cotton or cellulose that hold it acts as a throttle to the energy release. I remember having to physically turn Dynamite (we used it on our dairy farm to blow stumps and field stones to big to move with a tractor) or the nitro glycerine would pool up from gravity, sweat out of the gun cotton paper and become unstable to handle just as liquid nitro is.
To prove this, lay out a line of BP on a side walk and ignite it. Whooosh is the reply not blammo as would happen with a nitro detonation.
bruce m
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Re: Of bullets and things

Post by bruce m »

mike,
i still believe that mann and metford proved that bullets propelled with black powder reach full obturation prior to any forward movement.
maybe they are under more pressure further up the barrel, but full obturation preceeds movement.
this with correcly fitting correct hardness bullets.
otherwise they would gas cut.
i am not sure you can compare burning black powder in the open with in an enclosed space.
i honestly don't know if it burns a little progressively or instantly, but it must be very fast ignition compared to smokeless progressive.
the bullet must seal instantly.
and that is all i need to know.
black powder and dynamite etc are of little interest here due to energy content.
i have burned a line of black powder in the open, and it was more much faster than a whoosh.
i would recommend lighting it with something that will keep you at a distance.
double base powders might contain nitro?
bruce.
ventum est amicus meus
bruce m
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Re: Of bullets and things

Post by bruce m »

mike,
i still believe that mann and metford proved that bullets propelled with black powder reach full obturation prior to any forward movement.
maybe they are under more pressure further up the barrel, but full obturation preceeds movement.
this with correcly fitting correct hardness bullets.
otherwise they would gas cut.
i am not sure you can compare burning black powder in the open with in an enclosed space.
i honestly don't know if it burns a little progressively or instantly, but it must be very fast ignition compared to smokeless progressive.
the bullet must seal instantly.
and that is all i need to know.
black powder and dynamite etc are of little interest here due to energy content.
i have burned a line of black powder in the open, and it was more much faster than a whoosh.
i would recommend lighting it with something that will keep you at a distance.
double base powders might contain nitro?
bruce.
ventum est amicus meus
mdeland
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Re: Of bullets and things

Post by mdeland »

I completely agree that some bump up is occurring when the bullet begins to move in the leade but I believe Mann proved it was still in progress using BP about five inches up bore if memory serves. I need to get his writing out and read it again.
I think that Kurt's and Wasserburger's findings indicate pretty strongly the transition is causing the rings.
This is a interesting question but from a practical stand point I wonder if the rings have any negative effect on accuracy which is really the salient point of all this.
One uses a line of smokeless into a small pile of BP to light it safely. It won't even make a bang just a whoosh unless contained which is how fire crackers work although that is not straight BP in them. I've done it many times. Actually Dynamite will often burn without exploding unless a cap is used as the pressure wave instigates the detonation. It does not need to be contained to explode as does BP.
Dynamite used to come in 40 percent and more potent 60 percent from the hardware store. The less potent was better for stump blowing as it did not tear them apart as much and would tend to lift the whole stump out intact. The 60 percent worked better on field stone because it would fracture the rock so what ever remained in the hole after the blast could be pulled with a tractor and stone bolt or dug out.
I always loved it when Dad would blow field stone!
I relate a personal story, my horse got old and went down one winter with pneumonia and I had the terrible job of putting a bullet in his brain. Being a sentimental slob about it I would not call the dead wagon so decided to pick axe a grave for him.
I tractor dragged his frozen body back on the sand hill above Stoney Lake and thought he would like it there. Well I pic axed and shoveled frozen dirt night after night when I got home from school making little progress but was determined to stay at it until it was done.
My great uncle saw me out there one night as he passed the house working away and so not telling any one he snuck out there during the day and dynamited the hole with quarter sticks of dynamite. Well the frozen ground was like saw dust after that. I remember raring back on the pic axe and driving it half way to China with the first swing! It didn't take many hours to finish after that but my oh my it takes a big hole to bury a sixteen hand horse! :lol: True Story!
martinibelgian
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Re: Of bullets and things

Post by martinibelgian »

Bumpup is a matter of inertia and acceleration. inertia has to be overcome, and before this happens, the rear of the bullet will bump up to whatever size it can whilst trying to overcome the inertia of the front. Nothing about impact, just inertia - although the powder gases hitting the bullet upon ignition is pretty violent indeed. And yes, before making claims about what Mann said, please reread what he wrote. No, bore dia. bullets will not bump up with smokeless - but something like a DDEPP would work indeed without any issues with nitro - and yes, he wrote about that. It is a pretty boring read, though...
Kurt
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Re: Of bullets and things

Post by Kurt »

These three .40 caliber are hard cast and were patched to bore diameter snug. These three are not a DD bullet just straight shank. The dimple is the start of the ogive and that is where I hold the patch.
These three pretty much shows that they get most of the obturation from the initial ignition. I would think if they would show signs from inertia the dimple would at least show a sign of the impression from the patch or from the lands like you see with the softer alloys.
I would say that they are at the hardness limit of bore diameter patching to get full rotation.

I been looking for some results I have using a smokeless loads I shot with the .45-70 using bore diameter PP bullets.
Regardless what is being said that they don't obturate with smokeless is not what I have witnessed.
:D I have a big enough snow pile with out any holes in it I just might put some smokeless holes in it again. I said I'm through doing this but what the hey.....not much else to do but keep moving snow, :lol:
IMG_3177.JPG
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mdeland
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Re: Of bullets and things

Post by mdeland »

Kurt, I think I speak for a lot of folks on here and thank so much for your immeasurable contributions to bullet behavior with your photos. We are all blessed to have your input!
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powderburner
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Re: Of bullets and things

Post by powderburner »

Kurt.
Did the noses set back at all on them three?
Dean Becker
only one gun and they are 74 s
3rd asst. flunky,high desert chapter F.E.S.
MYWEIGH scale merchant
reclining member of O-G-A-N-T
Kurt
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Re: Of bullets and things

Post by Kurt »

Dean, Not that I can tell. The whole bullet lost about .002" in length.
The reason a dog has so many friends is because he wags his tail instead of his tongue.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery"Winston Churchill
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