Carl, Gabe (Carl's crazy brother-in-law), Gary (Gabe's buddy), and I met at a parking lot beside the highway and drove to some public land near Lancaster.  We also met up with Glenn Olson (ramjet researcher) at the shooting site.  Just after we had unloaded all the gear a park ranger drove up to see what was going on.  This guy looked like he had been out the in sun for a while.  Slightly wrinkled and in his late 50s or older.  The first words out of his mouth (as I recall) were something like, "What the H...... is all THIS!  Someone please tell me there is no shooting involved."  I can read between the lines and quickly replied something like. "No sir, no shooting here, no fuel, no combustion, nothing burns, no shooting."  We went on to explain how it worked and invited him to wait a few minutes and we could show him.  He said something about looking for people shooting rifles and neighbors complaining, then drove off not be seen again.  We quickly made plans to fire a low pressure load if he did come back to check it out.  We figured a can of beer going 150 yards should make him laugh and go away.  We would keep our mouths shut about what Howie was able to do at full pressure.

Shooting cans of beer:
The first thing we shot were some cans of beer Carl had.  The first one we could not find.  So I went down range and off to the side to see the second one hit.  Once I found the second one the first one was also found nearby.  Then two more were fired, one at 45 and one at 35 degrees.  The first two were fired at 40 degrees.  Here is the data we recorded.
 

CO2 Pressure PSI	Angle deg.	Range (yards)	Velocity ft/sec
100	40	378	382
100	40	402	415
100	45	388	380
100	35	368	405

I noticed the 35 deg. shot did not burst the can as bad as the other shots.  It looked like it skipped off the ground a little more instead of splattering everywhere, like the others.  The range was measured with Gabe's laser range finder.  The velocity was measured with my homemade chronograph.  Carl had made a tube for me to mount the sensors on.  The tube was plugged into the coupling he has for a muzzle protector.  Here is a photo of Carl and Glenn (on the right) setting the firing angle on Howie.  The chrony sensor tube is the black extension on the muzzle.  Some of the photos are not very good because they were captured from a copy of Gabe's video.  I guess some clarity was lost in the translation/copying.

Beer tipped missile:
Carl had a box full of different bullets he had been working on.  The one everyone wanted to see was made of thin walled 2" PVC pipe with a full can of beer mounted for the 'warhead'.  In front of the beer was a plastic easter egg half.  The egg half was full of lead shot (I think).  The total weight was 636 grams (22.4 oz).  The tail of the bullet was flared to fit the barrel.  Here is Carl holding the bullet. Notice Howie in the background.  When this bullet was fired, Howie went into heavy recoil tipping over the elevation block at the base of the gun (video).  The chrony tube was also knocked off.  It looked to me like the gun recoiled and the tube was left behind to fall to the ground.  No damage done.  The bullet hit hard, blowing the beer can apart.  Something like half of the can was still stuck to the missile.  The front part of the can was several steps away.  Here is another video shot of Howie firing.  This shot is looking up the barrel from a shot near the ground.

Gabe:
Carl always says, 'my crazy brother-in-law'.  So I am interested to meet him.  He was the first at the parking lot, after me, and I was guessing he was part of the shooting crew and ask him if he was waiting on Carl.  So Gabe and I got to talk a little before everyone else got there to slam him.  Gabe is a great guy and the butt of everyone's jokes.  Later in the week I met up with Jose (another of their friends) who made constant sport of slamming Gabe.  So I caught on that this is what everyone did.  It seemed that no amount of coaxing could get Gabe to go down range with me to see the bullets fall.  Hiding behind a truck was not even safe as far as he was concerned.  Every time Carl yelled, 'Pressurizing' Gabe would make sure he was behind the car.  Here is a video that shows Gabe's reaction when Carl yelled.  Gabe was a little closer than he wanted to be, and beat it off in the other direction (video).

Dan's darts:
I use the term dart because they are smaller then the bore of the cannon.  Range of bullets (size of the barrel) and darts (smaller than barrel) should not be compared with each other.  A slim dart will generally have less drag the a bullet of larger diameter.  The week before Carl and I went shooting I did some testing with this new design.  Here are the results from my gun.
 

Pressure	Range (approx. yards)
20	480
40	750
47	850-900

Based on calculations it looked like Howie would need about 30 PSI to shoot the same bullet at the same calculated velocity.  It was important because you cannot see where these darts land.  We needed a good estimate of the range so we could find the bullet.  The first shot from Howie was at 30 PSI.  Followed by 60, then 100 PSI.
 
 
 

CO2 Pressure PSI	Dart mass (grams)	Angle deg.	Range (yards)	Velocity ft/sec
30	211	40	560	285
60	211	40	830	361
100	211	40	1138	483
100	216	40	1110	560
100	216	40	1112	532

At some point the velocity readings off the chrony started going up higher than expected.  This is the symptom of weak batteries. So at some point, the recorded velocities were no longer considered even close to being right. I think these are the last group of shots with good velocity readings.  Here is a photo of Gary holding my darts (note chrony tube on Howie).  The two in the foreground are 1" dia while the one behind them is 3/4".  All darts were pushed with a soup can for a wadding.  They all laid in the barrel with no sabot.  The 3/4" was fired one time, weighed in at 250 grams, and went 974 yards.  I expected better range from it than that.  After talking to Jose and Gabe at dinner Wednesday I think I now know why.  All darts were just laying in the barrel,  with nose against the barrel wall.  This made the dart leave the barrel at an angle a little less than the barrel's firing angle.  The 3/4" dart would have it's nose further from the center of the barrel than the 1" darts.  This would produce a lower exit angle than the 1" version and could be the reason for a shorter shot.  Someday I will try to repeat a test between the 1" and 3/4" darts with something to hold the nose of the dart parallel with the barrel.  Notice in the photo the dirt marks on the nose of the darts.  The ground was very hard.  The 1" darts went in about 6" and the 3/4" went in about 8".  All stuck in and stood with the tail up in the air, except for the first (30 PSI) shot which made a hole and fell over.  It was the hardest to find.

Down range impacts:
After the first two 100 PSI dart shots it was clear (to me) that we could move down range and be pretty safe.  I made a quick mental note as to where the two had landed.  Gary and I went down range in his new Explorer very close to where the last two had landed.  I pointed and said, "Go right over there".  We got out of the truck and called on the radio to fire.  Gabe gave the countdown and we could see the puff of vapor from the gun.  At 1100 yards the sound was a full 3 seconds behind the muzzle 'flash'.  We waited and waited.  I thought, 'How could I have been so far off, to position ourselves out of earshot of the impact'.  Some seconds later we heard a whooooosh, thud (turn up the sound and click here).  The impact was about 40 yards to our left (we were facing the gun).  Gabe calls on the radio, 'Do you see it?'  Gary and I were about crazy with excitement, laughing and going on.  I told Gabe, 'Watch'.  I quickly ran to the bullet and said, "It's right here."  From Howie's position the 40 yards must have looked very small.  I ask Gary, 'You think maybe we should move the truck'.  He did not have to think long before saying, "Yes".  We left the first bullet in the ground and moved the truck closer to Howie and a little more to the right.  The second shot landed about 18 steps further down range from the previous shot.  Gary then pulled an old washer tub out of the ditch and marked the impact spot.  On following shots I managed to put my camcorder behind the old tub and record audio of a shot hitting the ground (see link above).  In that recording you can hear the gun go off.  Add to that 3 seconds for the speed of sound delay, plus the bullet flight time and you get 15.5 seconds it took for the bullet to travel to the point of impact, about 1110-1140 yards downrange.  Also to be noted, these darts were going to about 1500 feet in altitude when fired at this angle.

Coke cans 1/3 full of concrete:
I also took some Coke cans that were about 1/3 full of concrete.  I cut the top open (inside the pop-top area) and put in the concrete.  With the lightweight tail and heavy bottom forward I figured they might do pretty good.  When they left the barrel they rocked side to side quite a bit.  This made a whoo-fa-whoo-fa-whoo-fa sound as it went down range.  We did not record the range because we had a hard time finding them.  We did find one and I think it was in the 350-500 yard range, if I remember right.  The can hit so hard that it was crumpled a little even where the concrete was.  Carl had glued an easter egg half on two of the cans to see what a rounded nose would do.  Without extra weight to move the balance point forward, they went crazy and ended up falling on their side,  in a flat spin.

Afterthoughts:
All in all it was a great day.  We got real cold.  Gabe said it was about the coldest he had ever been for a long period of time.  We did manage to pick up most of our projectiles (I think we lost some of Carl's can parts because of the explosive landings, when full of beer).  One dart suffered a chipped fin from the pusher can, but later shots proved it to be no problem.  The angle on the fins seemed to be worth while.  It seemed to keep the wind from blowing the shot off course as bad.  The 3/4" dart had straight fins and was the only dart to not land right in line with the gun.  We may have used more CO2 because of the cold weather.  I got the impression we were using more that Carl expected.