Testing a Soda Can Mortar

[waynef]

If I can learn how to post pictures I'll report my findings on testing the soda can mortar with various projectiles.
Using one of Mr. Carpenters fine 2.5" mortars along with the following projectiles filled with "MORTAR" mix.
Tennis Ball = 1/2lb, 8oz soda can = 1lb 3oz, 12oz soda can = 1lb 12oz

 

[Cat Whisperer]

Wayne - nothing came through on the image (just [img] [img] ).  Send me the pix by email & I'll try to patch it in.

[Cat Whisperer]

Wayne - nothing came through on the image (just [img] [img] ).  Send me the pix by email & I'll try to patch it in.

OK, now it's working.  Something happened by magic.

[Cannoneer]

Waynef,

 That's a good looking Dominick built Coehorn; I'm going to venture a guess that you had some considerable fun conducting your experiments.

[waynef]

BoomJ,

Yes, I did have fun working up loads for this Mortar (3lbs of 2f so far).
As soon as I get my daughters camera back from her, I'll upload some additional photo's along with the results of shooting this piece.
With the help of others on this forum I finally learned one way on how to post a picture.
The only thing on my Christmas list this year is a digital camera...

Wayne

[Artilleryman]

Wayne, 3 pounds of ffg, or did you mean 3 ounces?

[Evil Dog]

I hope that he means a total of 3 pounds used so far in working up loads.... not a single 3 pound charge.

[Terry C.]

Yes, I did have fun working up loads for this Mortar (3lbs of 2f so far).

I hope that he means a total of 3 pounds used so far in working up loads.... not a single 3 pound charge.

That's the impression I got.


Wayne, what kind of range are you getting with the cement-filled tennis balls?

Do you have problems keeping them round during/after filling?

[Cat Whisperer]

I've seen the tennis balls - they are AMAZINGLY spherical!

[waynef]

I have used a total of 3lbs of 2fg Goex in working up loads for this mortar.

I was holding off in listing load data until I was able to post some more pictures but may as well start now.
I cut a 1" hole(hole saw) in the each tennis ball and filled with "MORTAR" mix. This yielded a 1/2lb projectile.
Placing a target(old broken flat screen comp monitor) out to 200yrds and using the two stake method of lining up the mortar with the target we commenced firing. After the first shot and corrected for windage we were able to obtain a 10 shot 15' group with the closes tennis ball impacting 5' from the target. Each tennis ball rolled abt 4 to 8' after impact. I got to admit, I was impressed. The load to achieve 200yrs was 165gr of 2fg Goex with a 50 deg angle on the mortar. The barrel was cleaned between each shot and the use of the adjustable platform allowed for the piece to be lined up the same way for each shot.
This mortar's powder chamber will hold a max of 250gr of 2fg. Next outing I'll try a max load to see what range and accuracy can be achieved. With the impact area being of sand and Bermuda grass the tennis ball can be used over and over again. So far I have shot 12 tennis balls 6 times each.
Next post I'll report on the 8oz and 120z soda can projectiles and hopfully have some more pictures.

Wayne

[Cat Whisperer]

It's good to see some serious target work being done with mortars.

I generally don't bother, getting carried away with the thrill of the noise, smoke and anticipation of the round hanging in the air waiting to rip off a branch coming down in the forrest.

Did you find the dispersion of the rounds was circular or eliptical?  I would think that it would be slightly eliptical being longer on the gun-target line.

50 degree elevation is close and may be your best elevation for distance.  (With pointed bullets that the 105 and 155mm howitzers use the greatest distance for a given powder charge is about 37 degrees and the commonly accepted wive's tail number for spheres is 45.)

[GGaskill]

45° as the optimum angle of launch for maximum range is correct only on the moon (no air resistance) or in high school algebra books (sometimes they say to ignore air resistance as they are trying to show that the flight path is a parabola) or for ignorant TV talking heads (a bullet shot into the air comes down at the same speed it started out with.)  The force of air resistance on a flying projectile is many times greater than the force of gravity but it is much more complex and hard to express in a simple mathematical formula.

[waynef]

GGaskill,

45deg did provide 230-240yrds vs 200yrds at same powder charge. Two reason I did not continue with 45 deg is the tennis balls rolled an additional 15-20' and the mortar recoiled 4-5" vs 1/4" at 50 deg.

Wayne

[GGaskill]

I would expect you would get even greater distance at 40° but you would definitely get more recoil as the push becomes more backward than down.

[Double D]

45 degrees is a rule of thumb, not a old wives tail....A rule of thumb is a starting point that can be adjusted, a wives tale, as the names implies is just pure meaningless nonsense.   You guys need to under these highly technical scientific terms.    Do we have any women here...if so you you are about to see another scientific phenomenon...spontaneous ignition, no not combustion, ignition.   

[waynef]

                 
Just another fine day at the range. 68deg, partly cloudy & winds quartering from 3-5 O'clock at 10-15mph.
What I wanted to determine today was just how far would this 2.5" mortar shoot these three differant projectiles and how effective are the use of sighting sticks.
Three shots were fired with each projectile: Tennis ball at 1/2lbs, 8oz soda can at 1lb 3oz & 12oz soda can at 1lb 12oz.
All shots fired with a max load (full powder chamber) of 250gr Goex FFg. The mortar tube set at 45deg.
TB achieved 340, 346 & 350yrds and the mortar recoiled 3". 8oz can achieved 272, 275 & 278yrds and recoiled 4". 12oz can achieved 263, 268 & 274yrds and recoiled 7".
As can be seen from the one photo I used sighting sticks, string and a pointing board (12" ruler) to dial in the shots.
The max distance spread was only 11yrds(12oz can). The use of the sticks and ruler allowed me to adj for windage and it was quite effective. The second photo is an action shot firing a 8oz soda can to 278yrds.

Till next weekend,

Wayne

[waynef]

I'm still trying to figure out posting pictures.

[waynef]

I can only post one picture at a time so far....

Wayne

[Artilleryman]

Wayne did your ranges increase with each three shot series?

[waynef]

Artilleryman,
Only one series did. I just listed them in assending order. They were actually in the following order:
346, 350 & 340. TB
272, 275 & 278. 8oz
268, 263 & 274. 120z

What I was surprised at was there is not a hole lot of difference in distance between the 8oz(1lb3oz) & the 12oz(1lb12oz) cans.
Once I corrected for windage (both soda cans) the left and right spread was only 15yrds. Not a bad group.

Wayne

[Double D]

Okay posting pictures.  Go to the top of the forum and read the sticky on posting pictures.

[seacoastartillery]

    Wayne,   we are following this thread very carefully. This just the sort of thing Mike and I love to do. If you can get a photo of how you aligned the gun for successive shots, it might be educational.  When we use the 4 Inch, 1797 mortar at longer ranges than the BINGO Contest afforded us, we use a landscape log platform and a solid steel forward stop and two steel pins aimed at the target post on the right side of the carriage one inch away.  To align the mortar bed we place a straight hard maple spacer board between the pins and the bed, then remove it after loading is complete and prior to discharging the piece. 

     Have you used "mortar mix" in all of your projectiles?  We find that steel soup cans work very well with this size tube and last much longer than the aluminum cans which are only .004" thick, about the same as a piece of inexpensive printer paper.

Waiting for more,

Mike and Tracy

[Cat Whisperer]

I am envious of your shooting range!

I've used the soup cans for years as they are the same size as the old beer cans - with the rim to the outside - the shift was 1974/75 RIGHT AFTER I bored my first mortar!

Look below the box you type the text in;
Pick the "  Additional Options  "
see ATTATCH - use it
see at the end of the line "   (more attachments)   "

[intoodeep]

 Ok, I'm a bit confused.

 Shouldn't the bore be 2.625" for soda cans, tennis balls and soup cans? As, for the 2.5" wouldn't that be for cans such as "Coorslight" ?  I know that the Coors cans slide right into my Lyles and they are 2.5".

[Cat Whisperer]

One should MEASURE the candidate can in question.  Add the right amount of windage and that's the bore size.

When I made my first mortar in beer-can caliber mortar (1974) the rim of the can was larger than the body of the can.  Therefore when they made the lid and bottom smaller the bore diameter was smaller.  My resort was to use the current soup can (steel ones) that still have the top with the rim as it was (some have just a swelled base integral to the sides, some have a separate added lid on the bottom).

[dominick]

Ok, I'm a bit confused.

 Shouldn't the bore be 2.625" for soda cans, tennis balls and soup cans? As, for the 2.5" wouldn't that be for cans such as "Coorslight" ?  I know that the Coors cans slide right into my Lyles and they are 2.5".

The mortar I built for Wayne is 2.625".  A tennis ball or soda can is 2.600"  Since there no size variation in soda cans or tennis balls and the bore of the mortar is short, the windage can be less than 1/40th.

[Ex 49'er]

I've been using a 3.8 ounce olive can which measures out at 2.592. It is about 3.222 in height. When filled with mortarmix
it weighs 16.25 oz. This can has skirt on the bottom that is about .09 deep. It is of ribbed construction and
has the seam from top to bottom. The bore on my mortar is 2.745 and I prefer a 4 oz. mushroom can which is 2.668 around, is
smooth sided with a .135 deep skirt. With mortarmix it weighs 13 ounces. This can is 2.660 high. Sorry for the confusion with the
different can sizes.

[Double D]

I was just up in the kitchen and just before I got ran off I noticed something.  Can contsruction has changed.  Food cans use to be made of a sheet of steel that was rolled and sealed along the seam.  Then the top and bottom were added with a sealed rim.  These rims are slightly larger diameter the can body.

New cans are drawn steel unibody drawn into seamless "cup" There is no side seam or spearate bottom.  The tops are still sealed on with a rim.  There is an embossed rim around the cup bass but iti is not the same diameter as can rim.

If you drop one of these new cans down the bore it going to lay in the bore sideways and can only tumble in flight.  The only can in my short foray in the Wife's ammo locker that is going lay flat in the bore was the rebated rim beverage.


Sure wish it would warm up aq bit so I can test the theory.
 


 

[GGaskill]

Can construction has changed.

It's to eliminate the soldered seams; you know, that dangerous toxic lead exposure that the left is trying to save us from.  Here in the peoples' republic, they have already partially banned lead bullets to save the condors, even though there is no evidence that any condors have died from lead poisoning.

[Cat Whisperer]

There are several methods of can construction.

Early ones were tabbed and soldered.

Then came a rolling weld.

And then the drawn cup.  SOME of them have a belled end so the top and bottom have the same diameter, others a belled end that is slightly smaller than the rim of the lid.

Today's soup cans (steel) will have a belled bottom end and the top will be identical to the pre '75 beer cans.