Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 68 users online :: 5 registered, 0 hidden and 63 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Back Stop

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Back Stop

Unread postAuthor: DinerKid » Wed Jul 29, 2009 9:43 am

So i recently got a sch 120 barrel for my paintball cannon and while the pbs fit really nicely they still curve like crazy. i found some marbles that fit the barrel well and they are flying straight as an arrow. i want to reuse the marbles cause they are still in fine shape after hitting the cardboard targets i made. right now i am just searching for them on the ground with about a 50% recovery. i would like to make some kind of a backstop to stop to catch them after they hit the cardboard target.

i am looking for

simple
will not cause bounce-back
catches the marbles

i have been thinking of using cloth to absorb the blow but every kind i tested gets pierced by the marble.

any ideas?

Thanks
~DK
  • 0


DinerKid
Corporal
Corporal
 
Posts: 67
Joined: Fri Aug 29, 2008 6:21 pm
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed Jul 29, 2009 10:02 am

Simplest is probably a box full of old newspapers, just replace them as you go along.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: DinerKid » Wed Jul 29, 2009 10:09 am

well i am shooting about 75-100 yards at a pizza box target so i was looking to make something a bit larger to catch even if i miss.
  • 0


DinerKid
Corporal
Corporal
 
Posts: 67
Joined: Fri Aug 29, 2008 6:21 pm
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed Jul 29, 2009 10:33 am

A large box full of newspapers ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: DinerKid » Wed Jul 29, 2009 10:36 am

i was thinking about possible like a piece of plywood at an angle. looking at the side it would look like a triangle with the plywood as the hypotenuse and some cloth as the base and the target could hang from the vertical part of the triangle. ya get it?
  • 0


DinerKid
Corporal
Corporal
 
Posts: 67
Joined: Fri Aug 29, 2008 6:21 pm
Reputation: 0

Unread postAuthor: geardog32 » Wed Jul 29, 2009 10:49 am

maybe a box with the back wall at an angle covered with some sort of rubber mat and then fill the bottom with sand. i would probably just try to find some more durable fabric maybe double layers of jeans. you could gey alot of jean material for cheap if you just go to the thrift store and buy the size 70 jeans.
  • 0

(\ /)
(0.o)
(><) Copy the bunny to your sig and help him achieve world domination.
User avatar
geardog32
Master Sergeant
Master Sergeant
 
Posts: 173
Joined: Mon Jun 22, 2009 9:20 pm
Reputation: 0

Unread postAuthor: boyntonstu » Wed Jul 29, 2009 10:59 am

A 45* angle over a tub of water?
  • 0

User avatar
boyntonstu
Brigadier General
Brigadier General
 
Posts: 1039
Joined: Sun Jun 28, 2009 8:59 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Big-E » Wed Jul 29, 2009 12:01 pm

A big piece of carpeting or multiple layers of heavy material (canvas, heavy dropcloth, etc) make for a great backstop. you must have a means of suspending the material. I use the frame from an old swingset that my kids don't use anymore in my backyard.

Carpeting works best, if the pile of the carpet faces the shooter, it works like a charm.

The fabric or carpet works because it absorbs most of the energy from the projectile. if you make a trough or bin to place under your backstop material, it will catch most of your ammo. also, make sure your backstop only hangs from the top end, and isn't stretched too tight, otherwise it's more likely to make your shots bounce like a trampoline.

I learned this from shooting air rifles at my pellet trap over the years. works good for most homebuilt pneumatics.
  • 0

-Speed is a question of money; How fast do you want to go?
User avatar
Big-E
Staff Sergeant
Staff Sergeant
 
Posts: 129
Joined: Tue Feb 24, 2009 3:07 pm
Location: Somewhere in Wisconsin
Reputation: 0

Unread postAuthor: Technician1002 » Wed Jul 29, 2009 12:07 pm

Big-E wrote:A big piece of carpeting or multiple layers of heavy material (canvas, heavy dropcloth, etc) make for a great backstop. you must have a means of suspending the material. I use the frame from an old swingset that my kids don't use anymore in my backyard.

Carpeting works best, if the pile of the carpet faces the shooter, it works like a charm.

The fabric or carpet works because it absorbs most of the energy from the projectile. if you make a trough or bin to place under your backstop material, it will catch most of your ammo. also, make sure your backstop only hangs from the top end, and isn't stretched too tight, otherwise it's more likely to make your shots bounce like a trampoline.

I learned this from shooting air rifles at my pellet trap over the years. works good for most homebuilt pneumatics.


At high velocities it doesn't hold up.. Attached is the results of using a carpet over a sawhorse to catch a rolled up t shirt. This was subsonic at just under 400 FPS. It went right through 2 layers of carpet. The carpet over the sawhorse provided a double layer. It went through both layers. Projectile is about 5.6 oz in weight.
Image
  • 0

Attachments
Oops shot data.jpg
Oops shot data. The last coil is off the scale on the right. The last foot measured has a travel time of 2.6 ms for an average speed for that foot of 384.6 FPS. It was still gaining speed.
Last edited by Technician1002 on Wed Jul 29, 2009 12:21 pm, edited 1 time in total.
User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Big-E » Wed Jul 29, 2009 12:17 pm

Hence why I said it works for most pneumatics... if you are using a bigger projectile, or high pressure (like most big PCP rifles) it probably won't work well. since he's shooting marbles, it will probably work ok. it works fine for me.

Your carpet isn't exactly hanging there in your pic, it's more like it's crammed into that sawhorse. your backstop should be able to "swing" a little bit to further absorb the projectile's energy, and redirect it towards the ground.

another solution would be to add more layers.

Another idea would be to use a big bale of cardboard. they work awesome! most of the indoor archery ranges I used to frequent used this method.

the cardboard should be stacked in flat layers, pressed, and strapped together tightly.

When I worked in retail, several of my jobs required me to bale cardboard, they had a big hydraulic compactor that would press the cardboard in bales, then you would use wire or steel strapping to tie the bales. the result was quite heavy and dense. If one of those bales tipped and fell on you, it was all over! we needed hand trucks to move them.

Now, if you are very serious about developing power, do what they do at outdoor shooting ranges, and use an earthen backstop. a few meters of hard packed dirt will stop just about anything.
  • 0

Last edited by Big-E on Wed Jul 29, 2009 12:30 pm, edited 1 time in total.
-Speed is a question of money; How fast do you want to go?
User avatar
Big-E
Staff Sergeant
Staff Sergeant
 
Posts: 129
Joined: Tue Feb 24, 2009 3:07 pm
Location: Somewhere in Wisconsin
Reputation: 0

Unread postAuthor: Technician1002 » Wed Jul 29, 2009 12:30 pm

Big-E wrote:Hence why I said it works for most pneumatics... if you are using a bigger projectile, or high pressure (like most big PCP rifles) it probably won't work well. since he's shooting marbles, it will probably work ok. it works fine for me.

Your carpet isn't exactly hanging there in your pic, it's more like it's crammed into that sawhorse. your backstop should be able to "swing" a little bit to further absorb the projectile's energy, and redirect it towards the ground.

another solution would be to add more layers.

Another idea would be to use a big bale of cardboard. they work awesome! most of the indoor archery ranges I used to frequent used this method.

the cardboard should be stacked in flat layers, pressed, and strapped together tightly.

When I worked in retail, several of my jobs required me to bale cardboard, they had a big hydraulic compactor that would press the cardboard in bales, then you would use wire or steel strapping to tie the bales. the result was quite heavy and dense.


The carpet was draped over the sawhorse. The sawhorse behind it was there to brace it. The impact broke off 2 legs of the rear sawhorse and knocked the front sawhorse over. The shirt continued and hit the bucket in the background that is against sandbags.

I used the carpet to protect the bucket as it was getting beat to death.
  • 0

Attachments
BrokenBucket.jpg
The bucket after the end of testing.
User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Big-E » Wed Jul 29, 2009 12:34 pm

You sir, definitely should have used an earthen backstop :D

I take it the t-shirt was rolled up and rubber banded.

Edit: I appreciate this topic, as I feel it is often the most overlooked aspect of spudgunning. It only took one accidental hole in my shed to make me reconsider my backstop design.
  • 0

-Speed is a question of money; How fast do you want to go?
User avatar
Big-E
Staff Sergeant
Staff Sergeant
 
Posts: 129
Joined: Tue Feb 24, 2009 3:07 pm
Location: Somewhere in Wisconsin
Reputation: 0

Unread postAuthor: boyntonstu » Wed Jul 29, 2009 12:41 pm

Big-E wrote:You sir, definitely should have used an earthen backstop :D

I take it the t-shirt was rolled up and rubber banded.

Edit: I appreciate this topic, as I feel it is often the most overlooked aspect of spudgunning. It only took one accidental hole in my shed to make me reconsider my backstop design.


AFAICR Mythbusters proved that a few inches of water will protect you from rifle fire.

Besides being clean, the marbles will be easy to see and to recover from water.


Splash height velocity calculation?

BoyntonStu
  • 0

User avatar
boyntonstu
Brigadier General
Brigadier General
 
Posts: 1039
Joined: Sun Jun 28, 2009 8:59 am
Reputation: 0

Unread postAuthor: Technician1002 » Wed Jul 29, 2009 12:47 pm

Big-E wrote:You sir, definitely should have used an earthen backstop :D

I take it the t-shirt was rolled up and rubber banded.


The sandbags worked well, but were becoming a pile of sand as the bags broke.

For reloading and re testing, instead of rubber bands, I tied it with mason line.

Behind the sandbags is the woodpile. I didn't get any through that. I did have one ricochet and fly over the fence into the neighbors yard. I didn't always hit the bucket dead center.. :D

Besides being clean, the marbles will be easy to see and to recover from water.


Having water stand upright is the problem.. :D If using a cheap container, it gets holes.
  • 0

Attachments
Shirts and tubes.JPG
Shirts and tubes for a day of testing. The two back barrels are wired with pick up coils. The 4 inch in front has the coils removed. It was tested first.
50PSI in and out.jpg
Jawbreaker was slowed some as it went through this bottle filled with water.
OrangeMilk.jpg
Milk jug full of water hit with an orange.
User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: boyntonstu » Wed Jul 29, 2009 1:26 pm

Having water stand upright is the problem.. :D If using a cheap container, it gets holes.

I wrote a 45* and a tub of water beneath.

No holes unless you shoot low.

OTOH Place the water tub into a hole in the ground and shoot away!

BoyntonStu
  • 0

User avatar
boyntonstu
Brigadier General
Brigadier General
 
Posts: 1039
Joined: Sun Jun 28, 2009 8:59 am
Reputation: 0

Next

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'