SpudFiles

Thought you guys might find this interesting. The accuracy of the lead ball seams to be way better. In the pic you will see lots of holes, the ones with a blue dot next to them are the lead balls, the others were marble slingshot ammo. Both were muzzle loaded with a greased patch and shot with this cannonhttp://www.spudfiles.com/forums/ongoing ... 13286.html

I was using it at low pressure, between 110psi and 130psi, as the compressor drained and refilled. Obviously I would have gained accuracy if I had made sure the pressure was always exactly the same.

Also, I replaced the scope with regular sights, because I wasn't sure if I was trusting the scope, but now I do. I will probably be putting the scope back on.

I'm thinking that I would probably have had more accuracy at 350-400 psi, but that would have been alot of pumping.

The shots were all taken at 25 feet. I thought I would get better accuracy, I guess the fact that it is smooth bore has more effect than I thought it would. Especially at such short distances.

I was using a chair as a rest so I'm pretty sure my aim was very close to the same every time, as I can get inch groups at 50 yards with my 22.

Also I should say that I wasn't trying to hit the bulls eye, I was only using it as some thing to aim at for shot to shot accuracy. obviously it needs to be adjusted.

any questions or comments are welcome.

Lock

More weight would probably make the projectile keep more consistent trajectory and be less susceptible to bullet drop. This would also make it less susceptible to wind currents due to more momentum. Here is somthing to try stand 20' from a target throw a foam ball and throw and tennis ball and see which is more likly to hit the target. Sence the tennis ball is heavier it keeps better trajectory and is less susceptible to wind currents. Just somthing to have brain farts about.

Sticky tape, I was thinking the same thing. The extra weight really helps out.

Here is something else you guys might find interesting. I used a plastic sabot and dropped about 10 or twelve .177 lead pellets down the barrel and put a piece of foam on top to keep them in the barrel. Pumped it up to 300psi and shot it at a piece of 1/4" osb from 25 feet away. The first picture is the front and I drew double circles around the pellet holes.
The second picture is the back of the osb.

Lock

Sticky_Tape wrote:More weight would probably make the projectile keep more consistent trajectory and be less susceptible to bullet drop.

Less susceptible to bullet drop? Unless you've developed material that is shielded from gravity, everything is equally susceptible to it.

However, the lower velocity of a lead ball would actually mean the drop would be higher. More time to target, more bullet drop.

This would also make it less susceptible to wind currents due to more momentum.

At 25 ft, wind is seldom a problem. My own guess is that the higher weight of the lead balls mean that they are less likely to pick up spin from the muzzle blast or have their initial trajectory affected by the same.

I find that in a spudgun, the muzzle blast is the main source of inaccuracy at short ranges. Barrel whip is also something of a problem, particularly in PVC. The problem with the muzzle blast is why air strippers around the muzzle are a wise investment of effort into a cannon where accuracy is fairly key.

One of my cannons had a serious problem with putting spin on the projectiles, and often this would mean spud slugs would go less than about 50 yards because of the extreme drag.
After I added an air stripper... well, I almost thought I had forgotten to load the cannon, because the spud - now flying straight - moved so fast it could barely be seen in the air.

The results spoke for themselves. It's well worth trying if you want more accuracy - the only real expense is a little more length on the end for the porting/air stripper.

Tha's nice damage with the pellets you pwned osb.

Ragnarok wrote:

Sticky_Tape wrote:More weight would probably make the projectile keep more consistent trajectory and be less susceptible to bullet drop.

Less susceptible to bullet drop? Unless you've developed material that is shielded from gravity, everything is equally susceptible to it.

However, the lower velocity of a lead ball would actually mean the drop would be higher. More time to target, more bullet drop.

This would also make it less susceptible to wind currents due to more momentum.

At 25 ft, wind is seldom a problem. My own guess is that the higher weight of the lead balls mean that they are less likely to pick up spin from the muzzle blast or have their initial trajectory affected by the same.

I find that in a spudgun, the muzzle blast is the main source of inaccuracy at short ranges. Barrel whip is also something of a problem, particularly in PVC. The problem with the muzzle blast is why air strippers around the muzzle are a wise investment of effort into a cannon where accuracy is fairly key.

One of my cannons had a serious problem with putting spin on the projectiles, and often this would mean spud slugs would go less than about 50 yards because of the extreme drag.
After I added an air stripper... well, I almost thought I had forgotten to load the cannon, because the spud - now flying straight - moved so fast it could barely be seen in the air.

The results spoke for themselves. It's well worth trying if you want more accuracy - the only real expense is a little more length on the end for the porting/air stripper.

Don't quoteme on anything else but did you try my exspirament with the foam ball and the tennis ball?

is an "air stripper" the same thing as a muzzle break? Or more like a baffled supressor in design? I'm not having much luck with the search function.

Thanx

Lock

lockmanslammin wrote:is an "air stripper" the same thing as a muzzle break? Or more like a baffled supressor in design? I'm not having much luck with the search function.

Well, JSR has a decent picture of some airgun air strippers here: http://www.spudfiles.com/forums/viewtop ... tml#127921

The one I made... hmm, I can't find a picture right now, I'll need to conjure up another one.
Basically, it was just a load of holes drilled into a piece of pipe the same size as the bore, and all fitted on a twist lock system.

The idea was to let air out from behind the projectile while it was still supported by the pipe walls, keeping it stable.

You might find more information if you search venting - porting is another name that gets used, but that also relates to valve port diameters, so there will be a lot of chaff to search through.

would a cross or Tee attached to the muzzle work as an air stripper?

Poland, I was kinda thinkin' the same thing, except with crosses/4 ways, and then cutting them off at backward angles, just for looks. But I think I would rather try and find a thicker kind of pipe that will slide over the end of the barrel nicely and drill a nice pattern of holes all around it.........

Never mind I just got back from ace. I found the parts I will use. 1/2" cpvc 4120 fits perfectly over a 1/2" x 12" copper repair coupling. This way It will slide onto the end of the barrel, there by not reducing effective barrel length. I will solder a piece of 1/2" partway into the repair coupling glue the cpvc over the repair coupling(to add thickness for looks) and drill my hole pattern. Then paint it black. Wadduyu think?

Lock

Alright, I finished the air stripper/ muzzle break. Tomorrow I hope to shoot some groups to see how well it preforms. Also I will try and do a little mspaint drawing of how it is made and post a pic of the actual thing as well. I wish I could test shoot it tonight , but my landlord/ downstairs neighbor is parked on the other side of the garage right in the , hehe, shooting range, so I can't.

Lock

Well, no such luck on the test shooting this morning, he is still parked in the way.
I did take a couple pics and make a (not to scale) drawing for you though.
The whole thing at this point is just pushed onto the end of the cannon so it is still removable. The plastic is a tight friction fit over the coupling and the two copper parts inside are soldered together. The holes were spaced by eye so they aren't super accurate, but good enough for me. They are pretty much pilot holes at this point I may enlarge some after testing, that is why no paint job yet. There are 8 rows of holes.
Here are the pics,

<a href="http://s117.photobucket.com/albums/o75/ ... CF3217.jpg" target="_blank"><img src="http://i117.photobucket.com/albums/o75/ ... CF3217.jpg" border="0" alt="Photobucket"></a>

<a href="http://s117.photobucket.com/albums/o75/ ... CF3216.jpg" target="_blank"><img src="http://i117.photobucket.com/albums/o75/ ... CF3216.jpg" border="0" alt="Photobucket"></a>

<a href="http://s117.photobucket.com/albums/o75/ ... ripper.jpg" target="_blank"><img src="http://i117.photobucket.com/albums/o75/ ... ripper.jpg" border="0" alt="Photobucket"></a>

Lock

That looks pretty good.

You might find you need larger holes to get the optimum results, but that should help your accuracy noticeably anyway.

looks good... you can easily upgrade it into a silencer if you want to

yea that's true, i say make the holes a bit bigger, but its your gun