Bird dog training mortar.

[Joe111]

40 years ago when I was a kid, my father had a small mortar he uesd for launching a stuffed feathered thing for the dogs to retrive. Id like to build something like this.
Im a good machinist and have done lots of reloading but not much in black powder.
What are the legalities of something like this?
Any formulas for propelent? My father used to mix sugar and black powder but I dont remember in what ratio.
Thanks

[Cannon Cocker]

Saw a friend of mine training a retriever about 20 years ago and was impressed with the ballistic ability of his dummy launcher.  It fired .22 blanks and launched a kind of stuffed canvas bolt about 75 yards as I remember. 

Here is a link to some of those launchers.  You could check out their design or buy one if building it wasn't your interest.

http://www.gundogsupply.com/retriev-r-trainer.html

[Joe111]

Ive tried those but they dont have much rangs. Perhaps 100ft or so. Id like to do something with a 300 ft range or so.
Id like to do it myself too.

[Double D]

This really isn't on topic here, but the stuff we build could be easily adapted.

Let me suggest my  K.I.S.S. Mortar



Simply enlarge the bore and barrel length to accommodate the larger size dimension of the dummy.  If you will click on the link above you will taken to the post with full drawings.

[Joe111]

Shamless plug.
Well, it will probably end up something like that. But Im still looking for legalities and powder data. Difficult to find straight data for either one.

[Double D]

If you need the legalities write to the  Technology Branch at ATF and outline you design and desires.   Becasue of high workload and limited staff it will take 8-10 months to get the  response.

Not a shameless plug at all.  I don't make these to sell. The design is not patented or copyrighted.  Any one is free to copy it and I encourage you to do so.

[Doc Brown.]

Maybe you could fit a chicken in this. http://www.ebay.com/itm/261137498203?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

[Joe111]

If you need the legalities write to the  Technology Branch at ATF and outline you design and desires.   Becasue of high workload and limited staff it will take 8-10 months to get the  response.

Not a shameless plug at all.  I don't make these to sell. The design is not patented or copyrighted.  Any one is free to copy it and I encourage you to do so.

Joke on the Shameless plug. Hence the smilie.
 
 

[KABAR2]

None of us are lawyers hence we don't get into the legalities, there are no Federal restrictions on muzzel loading cannon, I suggest you check with your state and local law enforcment, if you live in a place like N.J. I doubt you'll be shooting any sort of cannon..... as DD suggested a muzzel loading mortar with a powder chamber would launch what you are desiring to do as far as powder depending on the loading Fg black powder is what most people use and you will have to work up the load for what you are firing out of it, start small and continue adding a little at a time until it throws you Pho-duck far enough.

[Joe111]

I live in Wyoming. No such laws.
I learned long ago that if you want to use things like this you need to have documentation with you to show LE when they show up because people are people where ever you go and THINK that they know the laws and think there are laws against things of this nature. A friend of mine had a perfectly legal semi auto M2 that spent more time in police custody then in his own gun safe because people called the cops when ever they saw him with it. Finaly we printed out the ATF letters and carried them with the gun when ever we shot it. That helped a lot. Same thing with another guys Title 111 guns. Gotta tape the paperwork to the guns if you want to keep them.
So just planning ahead.
So any info about expansion rates and burn rates of FG powder? I searched the internet and couldnt find much. Perhaps Ill write to the companies.Im a good math guy and this is all that im missing to calculate out loads.
 

[KABAR2]

Yes letters are out there for certian modern firearms such as a newly manufactured Semi-auto 1919A4 but as far as muzzel loading cannons/mortars  the only thing I can point you to is ATFE and what they have on their website,
.
 As far as powder charges your getting too scientific on this... burn rates & math...... most people work up loads depending on the cannon/mortar itself,  say a soda can mortar with a 1" dia by 2" long chamber start with one ounce of Fg and see how far it throws your Pho-duck that would be your starting poing and go from there....

[Joe111]

I like scientific. Get to use my Calculus that way.
It makes it more likely Ill live longer too..
If I cant find any real data ill probably do some tests myself.
 
 

[Double D]

This board is full of data.  start with the stickies at tthe topp of the board  called safe loads and construction.  You will find every thing you need there.

What is the diameter of your dummy? What diameter  tube will it fit in.  Divide that diameter by 1.72 and multiply all the measurements in my  K.I.S.S. mortar by that number---and build!

[Joe111]

Ok. Ill whip up a quick model.

[Joe111]

Ok I made a model and I have a few questions.
There are 2 questions on the screenshot and:
Why is the fuse hole threaded? I assume to hold the fuse in?

[Artilleryman]

The fuse hole is thread for a vent piece.  This is particularly important if the barrel is sleeved, as it provides a continuous passage to the powder chamber with no gaps that could hold an ember.  The projectile is seated on the bevel.  The range is varied by using different powder loads.  This means that the powder chamber may be fill part way or all the way.  Generally speaking you do not use any more powder than will fit in the chamber.

[Doc Brown.]

Is it necessary to have a vent liner with a sweat fitted breach?

[Double D]

Ok I made a model and I have a few questions.
There are 2 questions on the screenshot and:
Why is the fuse hole threaded? I assume to hold the fuse in?

http://www.gboreloaded.com/forums/index.php/topic,70859.0.html

There is the direct link to the K.I.S.S. mortar.

If you scroll down to the Vent section of that post you will find the explanation,  The vent hole is threaded to take a vent liner,  I made the first one out of a bolt, since then I make them out of socket head cap screws. Look at the  pictures for an example.  This gives  you a solid hole from the out side of the barrel to the camber.  This covers the joint between plug and barrel and keeps fouling out to prevent corrosion.  Here is a link to the construction of the vent from my K.I.S.S. bowling ball mortar post. http://www.gboreloaded.com/forums/index.php/topic,246774.msg1099549033.html#msg1099549033

Take a look at some of the great slap hammer designs the fellows had have come up with in this post http://www.gboreloaded.com/forums/index.php/topic,269414.0.html.  This would be a better way to fire your launcher.  You still need a vent liner.  Make the base from a solid piece of Channel iron with pillow blocks to hold the trunnion.  Drill 4 holes, one in each corner of the base and use some bridge spikes to anchor the base,

For your application I would leave the  cone shaped section out, just make  a flat face  and increase the capacity of the chamber,  Make a flat disc out of card stock and push it down over the chamber and then push you dummy down to the disc.

 

[Double D]

Is it necessary to have a vent liner with a sweat fitted breach?

Yes and No.  If the vent passes through a seam. you need a vent liner.  But normally the vent will not pass through the barrel wall and breech plug,  into the chamber.  If the vent passes through solid metal and has no seam, no vent liner is needed.

[Joe111]

Thanks for the info.
I was doing some calc's based on this design and I dont believe that the chamber pressure would exceed 300 psi. Probably much less. I dont have the burn rates for the powder. The ball will probably exit the barrel before most of the powder ignites. The velocity will be pretty low. This will throw the ball probaly 120 ft or so give or take along with a huge puff of smoke and a big bang.
 
For my app Id need to lengthen the barrel and possibly reduce the powder charge. I need it to go further and not have such a big bang.
Back to searching for info for me.
 

[Double D]

This design does not make a big bang, a big woof is more like it.  With 24 grains of Fg a golf ball will go right at 30 yards. 

[Double D]

One step up in mortar design might work better for you. 

Here is my  K.I.S.S. Popcan mortar.

I don't have drawings for this one as I just worked from a spreadsheet.

[Joe111]

The numbers dont quite match the barrel tube.
The spread sheet calls for a barrel thicker than the DOM tube.
What is the elevation angle of the mortar in the video?
Judging by the video and time you got about 65 fps muzzle velocity.Im working back trying to figure out the acceleration. My guess would be in the 4000 fps^2 range.  Then I can work out the pressure.

[Double D]

45 degree angle.

What am I missing here?  Starting with 3 3/4" OD 2 1/2" ID  DOM doesn't equal .625 walls?  That is the material you start with, not a finished dimension.
 
 

[Joe111]

The 2.322 minor diameter ID of the tube is smaller than the 2.5In ID of the tube
.
Perhaps im missing something.
Ill make a drawing

[Double D]

That number source is a straight mathematical up scale from the GB Mortar measurements.  The only relevance to that measurement is that it is the minimum  size to fit the breech plug. Since the DOM ID is 2.5 then it is just fine. That section of the mortar does not requiring any machining if you use the  listed DOM.