The AirGun Guild

General Category => General Airgun Forum Discussion => Topic started by: steveoh on January 10, 2017, 09:35:54 AM

Title: Contemplating an Airgun version of Open Source
Post by: steveoh on January 10, 2017, 09:35:54 AM
As I was driving in the rain to work this morning, my mind drifted off into airgun land, and I somehow contemplated an Open Source Airgun project similar to something the like AR15 phenomenon. You know, basic military type specifications for an Airgun where anyone can build the basic parts, and improve on them, but with the goal of always have bolt on bits and pieces.

Since there is already a huge industry behind AR15 clones, furniture and custom bits and pieces, it made since to me that an open source design could start there.

I realize that there are already designs that due to their 350 chevy like popularity, such as the Marauder,  they are almost open source. Almost being the keyword. I'd not be surprised that a large manufacturer such as Crosman get involved, but perhaps it would behoove a group such as the Guild to collaborate on such a project.

If there were such a project what would folks like to see?

Steveoh
Title: Re: Contemplating an Airgun version of Open Source
Post by: oldpro on January 10, 2017, 10:23:37 AM
The Marauder is that and more already Allen and all the parts can be bought cheaply from crosman so I dont think you need to look further.
Title: Re: Contemplating an Airgun version of Open Source
Post by: Alan on January 10, 2017, 10:43:18 AM
Do you mean Steve or Alan?

I agree with Travis. A recent post dealing with a folding stock adapter is a good example.

There is one thing I can't find, even though I have looked, and that is a rubber tail piece for the buttstock. I typically shoot over the top of my pickup (standing in the bed), and one has to be careful when resting the buttstock so you don't mar the paint.
Title: Re: Contemplating an Airgun version of Open Source
Post by: rsterne on January 10, 2017, 12:58:49 PM
John Kopaz approached me last spring with this idea, and Lloyd Sikes and I have spent a lot of time on it over the summer.... We have made good progress, but there is still a lot to be done.... It uses the MRod Gen 1 or PRod trigger groups, but virtually everything else is new or different.... The concept is a good one, though, with only a few basic concepts and dimensions that must be adhered to.... for example the attachment points between the upper and lower assemblies, and the triggers.... It's pretty tricky to control some parts, yet leave as much freedom as possible for others....

Since this was primarily to be a Big Bore, our original idea was to start with a (custom) Cothran valve (to reduce cocking force), but leaving lots of room for future balanced valve development.... When we found out that the Powerhouse valve couldn't produce a bell-curve and needed to be in a regulated PCP, development stalled at that point.... The project isn't dead, but it may be on life support at the moment.... The design was intended to use Titanium tubes, and have a MSWP of 4500+ psi....

Bob
Title: Re: Contemplating an Airgun version of Open Source
Post by: mobilehomer on January 10, 2017, 12:59:02 PM
Alan, have you looked at a slip-on recoil pad? Everybody from Wally World to sporting goods stores carry them.
Title: Re: Contemplating an Airgun version of Open Source
Post by: Alan on January 10, 2017, 01:31:02 PM
Yes I have, and I do have one I bought at a local gun show for just $2! What I want to do, is find a used bipod that I can adapt for the use. There is another gun show this week end, and you never know!
Title: Re: Contemplating an Airgun version of Open Source
Post by: steveoh on January 10, 2017, 02:06:44 PM
This is what I had in mind. The ability to use off the shelf parts that exist or can exist without dealing with lawsuits from a manufacturer such as Crosman.

Seems like the hard part is getting folks to agree on the basic design and details.

The whole idea is to open up a cottage industry, and to allow folks to put together pieces and parts that best represent their ideas, while not having to do one's own machining. Components can be the basic bits like the trigger groups you mention, but can also be super fancy trigger groups that folks would design and machine and offer up for purchase. Make the sky the limit!

I'm ready to buy a basic big bore rifle as you mention, and then add to it as I see fit!



John Kopaz approached me last spring with this idea, and Lloyd Sikes and I have spent a lot of time on it over the summer.... We have made good progress, but there is still a lot to be done.... It uses the MRod Gen 1 or PRod trigger groups, but virtually everything else is new or different.... The concept is a good one, though, with only a few basic concepts and dimensions that must be adhered to.... for example the attachment points between the upper and lower assemblies, and the triggers.... It's pretty tricky to control some parts, yet leave as much freedom as possible for others....

Since this was primarily to be a Big Bore, our original idea was to start with a (custom) Cothran valve (to reduce cocking force), but leaving lots of room for future balanced valve development.... When we found out that the Powerhouse valve couldn't produce a bell-curve and needed to be in a regulated PCP, development stalled at that point.... The project isn't dead, but it may be on life support at the moment.... The design was intended to use Titanium tubes, and have a MSWP of 4500+ psi....

Bob
Title: Re: Contemplating an Airgun version of Open Source
Post by: steveoh on January 10, 2017, 02:11:12 PM
And.... could set up a store on the Guild to let folks pick and choose their pieces and parts. 

The Airgun Guild Custom Shop!

Make it easy for vendors to sell their stuff, and make it easy for buyers.
Title: Re: Contemplating an Airgun version of Open Source
Post by: oldpro on January 10, 2017, 03:11:58 PM
 Alan that would be a bad idea on so many levels I couldnt list them all.
Title: Re: Contemplating an Airgun version of Open Source
Post by: olddog on February 01, 2017, 05:52:32 PM
In the engineering world (systems engineering) the black box concept is important.  The systems guy deals with matching up what we lovingly call "guzentas" and guzouttas".  If you match the guzentas with the guzaouttas properly everything works.  Why is that important?  Because it lets you drop a black box into a system and it just works.  The systems engineer doesn't care how the black box transforms the guzentas into guzouttas he just wants it to do that job.

Let's apply that to this idea:
We already have an industry that produces many, many parts that fit an existing platform.  Those parts are black boxes, they attach to some point on the system and perform some function.  Maybe they are a sight, maybe they are a butt stock, maybe they are a trigger group.  What does that mean, well it means the outside of your system has already been built.  So don't reinvent that wheel.

Your imaginary platform must be dimensionally and attachment compatible with the AR platform.  If you do that you leverage the entire world of AR aftermarket.

What remains is for some smart guy (there are plenty of them here) who wants to build a platform that essentially takes an existing PCP mechanism and lets it accept after market parts while making the aftermarket parts think they are attached to an AR.  All you need is an envelope (a receiver group) that accepts an existing PCP mechanism internally and provides interface points externally for AR aftermarket parts.

I'm not a mechanical engineer but there are some here.

Your mission, should you accept it, is to design an PCP mechanism that pretends to be an AR upper/lower so that all the worlds AR parts can be used to customize it...

Title: Re: Contemplating an Airgun version of Open Source
Post by: Alan on February 02, 2017, 05:21:21 AM
After putting some thought into this, and adding to what Travis already alluded to, the Benjamin series of airguns is about as close as you're going to get to an AR-like assembly.

While I haven't been in this "business" all that long, I can't think of another brand or model with as many available after-market parts and accessories (blackboxes)! I challenge the Guild members to come up with another one, save the Crosman CO2 line.
Title: Re: Contemplating an Airgun version of Open Source
Post by: rsterne on February 02, 2017, 08:56:26 PM
I've got a suggestion for a starting point.... How about a quality 2-stage trigger group with a drop sear, that functions like a PRod, but that accepts a standard AR grip.... If it also happened to bolt onto a PRod / Gen 1 MRod / 22XX / Disco (which all share the same bolt pattern and sear location) then whoever made them would have a marketable product whether or not the Open Source gun ever happened.... I can't believe there isn't one on the market already, with all the Crosman guns around it would fit....  ::)

There are two MAIN interfaces for AR accessories.... the pistol grip mount and the 1-3/16"-16 socket on the back for the buffer tube / stock mount.... Don't most of the other accessories simply fit on a Picatinny Rail?....

Bob
Title: Re: Contemplating an Airgun version of Open Source
Post by: match on February 02, 2017, 10:03:19 PM
Bob, Lloyd, and I have put together a very solid big bore AG design with many interesting (and unique) functional and safety features which we intend to put into open source, but as Bob said our effort stalled on the Cothran valve's performance in Dec. and we have not yet resolved how we want to move forward.

As part of our effort we have discussed in (painful) detail the geometry in a receiver/trigger/stock combination that would provide an equivalent shooting experience as the AR platform and have a solution using the PRod trigger as a compromise.

But we think there is niche to be filled for a two-stage, drop sear pistol trigger group with a sear position between that of the PRod trigger and the Gen I MRod - and as Bob said this new trigger group would also use the AR pistol grip mount interface and geometry.

I floated the idea of putting together a "request for quote" on this forum to see if anyone would like to design and build a trigger group to our specifications but at that time we thought it was premature to do so.

We have the dimensions if anyone is interested in taking a shot at prototyping this pistol trigger group. (pun intended)

edit: To be clear the dimension we are talking about changing is the sear to trigger relationship - the sear to rear mounting screw distance and the mounting screw pattern would be identical to that of the Gen I MRod  and PRod trigger groups.
 
Title: Re: Contemplating an Airgun version of Open Source
Post by: rsterne on February 02, 2017, 10:33:12 PM
Hey, John, LTNS.... Welcome back!....

Bob
Title: Re: Contemplating an Airgun version of Open Source
Post by: match on February 03, 2017, 03:11:22 PM
Hey, John, LTNS.... Welcome back!....

Bob

Vacation, family, and work getting in the way of play.... oh well.

Back now.