Bowling Ball Mortar Question

[CAV Trooper]

Hi all,

After a really long absence, I’m back.

I’ve got a bit of a dilemma and need some expert advice from all of you bowling ball mortar owners. I recently completed my own BB mortar and have been requested to do a live fire demonstration next Saturday. Here’s the details:

The mortar tube is 18” long and made from an old compressed gas cylinder. It has a welded on powder chamber made of 1018 steel with exterior dimensions of 4.5” in diameter and 4” long. The dimensions of the actual internal chamber are 1.75” diameter by 2.5” deep. The tube is mounted on its base at a 70-degree angle, as I want altitude rather than range when I launch a ball.

I’ll be shooting into a lake that has a small island 420 yards from where the mortar will be placed on the shore.

I currently have two 16-pound bowling balls but am hopping to find more this week.

Having never shot one of these things and not having enough bowling balls to do a load workup, my question is: What would be an appropriate powder charge to lob a ball about 200 yards down range? I have all grades of powder available including cannon.

I’m guessing that the black powder won’t completely fill the chamber. If this is the case, is it necessary to fill the void between the powder and the ball with something like flower or powdered coffee creamer?

Thanks in advance for any and all advice. I'll try to get some pics posted soon.

[GGaskill]

Assuming you have control of all the land between the mortar and the water's edge, I would start with 4 ounces of cannon grade, although wind will have a significant effect if present.  A splash will entertain if you miss the island on the first shot.  Adjust charge based on results of first shot.

Go to your local bowling alleys and see if they have any old house balls they want to get rid of.  You should be able to get some for free if they are getting rid of any as most lanes have to pay someone to haul them away.

Also try bowling pro shops; they might have some trade-ins they don't want.

Offer to bring back some video to anyone who gives you some.

[moose53]

We had a incident at Grantspass Oregon in the 70s where a shooter was using a high angle on his bowling ball motar . He shot a bowling ball and the wind up high was sufficient to blow the ball back behind the firing line . We could all hear it coming  down and it was pretty freaky not knowing where it was going to hit . The ball landed about 200 ft behind the line and did not hit anything . We only shoot lower angle now , just be aware it can happen . Included is a photo to show high angle used.

[Cat Whisperer]

I've done that with a water filled soda can.  But it was a stiff wind (dead of winter in the middle of Iowa on a frozen river).  We KNEW  it was going to be blown in the wind, moving slowly it was easy to track and being out in the middle of nowhere there was nothing but windswept ice for it to hit.   

[CAV Trooper]

Thanks for the replies.
The mortar will be sited about 50 feet from the water and we control everything in the area. As I said in my original post, there's an island right at 420 yards out that I plan on aiming at. However, I don't want to hit it. Instead, I'm going for the humongous splash when the ball hits the water. By my way of thinking, that has got to be much more of a crowd pleaser.

I had originally thought about using 2 oz of cannon grade. Since GGaskill suggested 4 oz but implied that the ball could reach the island, I think I'll start with 3 oz, see what happens and adjust from there.

I appreciate the advice about the wind since that could definitely be a factor. We should be OK though since the wind here in South Florida is generally out of the east and we'll be shooting east to west.  I had already done some thinking about the possible effect of wind on the ball and had decided that on the day of the shoot, if it's coming from the wrong direction, we'll call things off.

I absolutely don't have as high an angle on my tube as the one in the picture. That looks like it's almost vertical.

Using a leveling device against the side of the tube I get a reading of 30 degrees from the vertical which I gather translates to 70 degrees from the horizontal. I didn't want to go with 45 degrees since that gives maximum range. I'd like to be able to watch the ball in flight without having it disappear over the horizon.   

Looks like I'm going to be spending lots of time bugging the local bowling alleys for junk balls.

[moose53]

30deg from vertical is 60deg from horizontal . 60deg should be plenty safe for what you are doing . The range from 90deg to 70deg from vertical needs to be watched carefully .

[Artilleryman]

If you're looking for a large splash, I think a lower angle would give you a better splash than a high angle.

[Double D]

I absolutely don't have as high an angle on my tube as the one in the picture. That looks like it's almost vertical.
 
Using a leveling device against the side of the tube I get a reading of 30 degrees from the vertical which I gather translates to 70 degrees from the horizontal. I didn't want to go with 45 degrees since that gives maximum range. I'd like to be able to watch the ball in flight without having it disappear over the horizon.   

Looks like I'm going to be spending lots of time bugging the local bowling alleys for junk balls.

Most mortars of the era were fixed angle at about 45 degrees so.  Some adjusted moderately.  Range was controlled by  increasing and decreasing the powder charge.  Elevation of the barrel was for adjusting the plunging angle to loft the ball over walls and barriers. It also increased penetration of the target some what although.

Actually in my Dom Dictator mortar, I get maximum range at 50 degrees.  You won't see many of the Original shot any where near 70 degrees except for s special fire mission.

The flatter trajectory will not go as high and will be easier for people to see  be less affected by the wind.   High angle shots are hard to follow and more affected by wind. 

Lets see how do I tactfully say this with out being offensive.. People who know understand the guns, will wonder if you really know what you are doing when you set one of these guns up to shoot high angle.  45 degrees is optimum.

[Cat Whisperer]

Hmmm.

Having shot one or two at a degree or two off vertical - not recommended - I was younger then - the impression is that it doesnt appear to go very high.

I'd be tempted to shoot one or two at LOW angle - near horizontal - to see if I could skip it off the water.  But then, the mortar would definately slide several feet.  (ok - it's not recommended either)

Having seen a lot shot at 100 to 400 yards, the most impressive ones are the close-in ones - 100 yards is GOOD.

[smokemjoe]

 I shot a 10 lb ball. last fall at 55 Deg. with 4 oz. of 4FA  with fuse powder, It got out to about 75 yds. and the wind hit it, You could see the wind push it 3-4 feet to the right. Just like how the bowlers make a hook shot, With the wind the ball went 800 yds.
  Go to the Good Will stores, DVA , Missions stores,  Here I get balls from 1-2 bucks,  By the time springs gets here I ll have 112 ,

[Cat Whisperer]

Hmmm.  4 oz per shot, 4 shots per pound

112  /  4   =   28 lbs of powder.

[CAV Trooper]

30deg from vertical is 60deg from horizontal . 

DUH!!! Of course it is. I was probably having a senior moment. I have a app on my iPhone that shows degrees of angle so once the mortar is set in place, I'll recheck the tube angle before we fire.  Since the ground has a gentle slope down to the water, the tube will most likely be at less than 60 degrees.

I'll let you all know how it goes.

Oh yeah...I have a bowler friend of mine checking for old bowling balls. 

[smokemjoe]

Catwhisper: Dont forget to stop in at Carter Fireworks when you come through and get powder,Makes it cheaper to shoot. Joe
 The pic. was only 400 yds. but 16 Lb. ball

[GGaskill]

Wow, what a green range.  Do you ever have problems with fools coming into the range area from the trees?

[smokemjoe]

 Sometimes deer or turkey walk out , Mushroom hunters on atvs, What do you think when they find golf and bowling balls this spring,  This is our cast bullet assc. range south of Davenport Ia.

[1Southpaw]

I use FG grade BP .  My powder chamber is 1.55 x3" as I recall.
With a 3.5 oz charge and a 10 lb ball I can get over 700 yards @ a 45 degree angle.
With a 2 oz charge and a 15 lb ball range is 200 yards
With a 1.5 oz charge and 15 lb ball range is 100 + yards .
The mortar is the one pictured in Avatar .
10 lb. balls will float .
Hope this is of some help.
Did I see some one lives @ Grants Pass ?   We will be in the area for a few days next week.

[moose53]

Nope just shot there at Josephine park during the 70s, I live out of Eugene in Oakridge 

[1Southpaw]

I plan on stopping in Eugene to visit my God Mother , if she is still living .

May give you a call when we get there.

[moose53]

Southpaw sent contact information by PM, just to make sure you get it 

[quaker4u]

  Hi my mortar has a 8- 5/8" bore - length is 11.5- chamber is 2.25 by 1-1/4 deep and I launch a 16# ball
550 meters with 3oz cannon grade powder. about 350 with 2oz. the overall length of the barrel is 18".
quaker4u