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Posted: Tue Sep 13, 2011 10:52 pm
by Atattack
I would model it but I don't know what the pressure on 2" gun will be that will be max that I can handle.
Posted: Tue Sep 13, 2011 11:37 pm
by Mr.Tallahassee
Technician1002 wrote:I wonder if the dealership heard it land on the roof.

I'm certain they're trying to figure out how in bloody hell a chicken lays an egg in flight.

Posted: Tue Sep 13, 2011 11:46 pm
by Technician1002
Atattack wrote:I would model it but I don't know what the pressure on 2" gun will be that will be max that I can handle.
Anything under 500 Ft/Lbs should be no problem. Anything over 1,000 Ft/Lbs could be problems depending on if you are a lightweight.
Posted: Tue Sep 13, 2011 11:48 pm
by Zeus
Mr.Tallahassee wrote:Technician1002 wrote:I wonder if the dealership heard it land on the roof.

I'm certain they're trying to figure out how in bloody hell a chicken lays an egg in flight.

In a less than 13 second flight at that. My chickens draw out the process.
Speed laying anyone?
Posted: Wed Sep 14, 2011 12:59 am
by Labtecpower
I've shot my QDV from the hip with a 475 gram projectile. I think the whole thing weighs about 4kg.
I calculated the energy, and it's about 2150 joules or 1585 foot-pounds.
Posted: Wed Sep 14, 2011 1:16 am
by jackssmirkingrevenge
It's not about muzzle energy but momentum.
From another thread:
A 50 cal rifle firing a 50 gram projectile at 800 m/s would generate 40.0Ns of recoil.
A hybrid firing a 100 gram projectile at 565 m/s would have same muzzle energy as the above, but generate 56.5Ns of recoil.
After reading muzzle brake thread I think I am leaning towards a suppressor because will have numerous people around when using this and am a little concerned about people saying muzzle brakes can be very loud. Anyone know how suppressor compare to muzzle brakes as far as recoil efficiency?
The noise issue will affect people around you more than the shooter, unless your brake directly pushes the air backwards.
Remember, air coming out of holes in the barrel does so at 90ยบ to the projectile travel, so it does reduce recoil, but doesn't fight it.
Directing that air back will actively try and push the barrel forwards, against the recoil.
Have a look at
this project to get an idea of the forces involved.
As to a recoil system, what you want is the barrel and chamber mounted on some sort of cradle where they are free to recoil, and then you will have to incorporate some sort of buffer system to hold that recoil - bungee chord, large spring,
gas strut, lots of options available.
The Barrett M82A2 is a good illustration of a shoulder fired big bore rifle:

Posted: Wed Sep 14, 2011 8:00 am
by Atattack
I was doing some research last night on how to do the recoil absorpotion system. I some some linear rail systems that were over $150. I'm sure there is a more economical way to do this. I am trying to make this gun look as nice as possible so any ideas would be appreciated.
I think I am going to focus of recoil absorpotion system first and then look into suppressor. The fact of muzzle brake increasing noise makes me want to fire gun first, figured this would be an easy addition
Posted: Wed Sep 14, 2011 8:27 am
by Crna Legija
you could use a shock absorber from a small mountain bike might need to put a lighter spring on it
Posted: Wed Sep 14, 2011 8:36 am
by Atattack
I am trying to figure out how to mount it to my chamber. I am going to have a bar come straight down from chamber to act as the stock.
Posted: Wed Sep 14, 2011 8:49 am
by jackssmirkingrevenge
Here's a basic idea of what you should be aiming for, green is the barrel-valve-trigger-chamber, purple is the part that rests on your shoulder and grey is a spring.
It's unlikely you'll find a coil spring that big that won't be too stiff, but as I said, the spring can be replaced with a gas strut that can be found reasonably cheaply on eBay or from your local automotive outlet, bungee chords or slingshot elastic are also a viable solution.
Posted: Wed Sep 14, 2011 9:10 am
by POLAND_SPUD
I'm sure there is a more economical way to do this
there is
make the gun as heavy as possible - that will reduce the recoil
Posted: Wed Sep 14, 2011 9:12 am
by Atattack
I see, I am gonna wait and see how bad the recoil is then decide on what to do. I was originally trying to weld a track system to the bottom of the chamber and have a single gas strut.
Not sure if that would work since it would not distibute force evenly.