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Author Topic: Another build from "The Hanger"  (Read 27589 times)

Offline Wingman

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Another build from "The Hanger"
« on: August 31, 2014, 03:36:43 PM »




Offline Oonyx

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Re: Another build from "The Hanger"
« Reply #1 on: August 31, 2014, 03:38:39 PM »
I wonder what would it be like!

Online Mintie

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Re: Another build from "The Hanger"
« Reply #2 on: August 31, 2014, 04:05:56 PM »
Another 308?
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Offline Hidayat

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Re: Another build from "The Hanger"
« Reply #3 on: August 31, 2014, 06:35:53 PM »
Smell like hand cannon... :)
« Last Edit: August 31, 2014, 09:25:55 PM by Hidayat »
NOTHING IMPOSSIBLE

Offline Jason C

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Re: Another build from "The Hanger"
« Reply #4 on: August 31, 2014, 08:47:28 PM »
I agree with Hidayat, and judging by the .30 pellets and .308 hp, could be a .357?

Offline Wingman

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Re: Another build from "The Hanger"
« Reply #5 on: September 08, 2014, 08:38:09 PM »
It is indeed a .30 cal pistol.  ;D
This build started as I had a short off cut of air vessel tubing from a length used on a rifle build..
However it is VERY short on big bore standards as they require a large section of tube in the rear to accommodate a large valve, hammer stroke and hammer spring, in this case if I was to build the same action as the .30 cal bullpup it would account for 3/4 of the length of the tubing which would be kind of pointless as there would be no volume left for air.



My goal is to keep this pistols OAL to 300mm  which means not just adding a larger rear cylinder end cap to extend the hammer springs working stroke rearward which would have been easy.
This is where my challenge started and I am building a bit of a prototype to test a few new dimensions and components.
The first thing I wanted to achieve was the longest barrel and the shortest receiver length I could possibly get away with which meant shifting the valve body as far rearward as I could without loosing so much
hammer travel that power would suffer. 

I have used a different hammer spring which is shorter and larger in diameter than the one I used in the .30 Pup which gave me 12mm less length on the springs total bind length when cocked.
Also being a short barrelled pistol a lighter hammer can be used to shorten dwell time on larger valve ports to get similar velocities form a larger but shorter burst of air, this gained me another 6mm.

The last and most drastic design change was the valve body its self, it is 8mm shorter rear of the transfer port than the rifle length valve and I have manage to claim back another 13mm by recessing the valve return spring into the rear of the valve.



Another change Ive made is reduced the poppet valve shank from 1/4" to 5/32" and made a stepped collar with a retaining grub screw that locks down on a filed flat..





A recessed valve spring seat means a flat or slightly recessed faced hammer can be used meaning more weight and a shorter hammer.



The new valve is much shorter in total length and still has loads of meat for countersunk retaining cap screws and still within the minimum safety measurement to the edge of the material. The smaller 5/32" valve shank means I can use off the shelf M6 X 6mm cap screws to retain the valve in the cylinder and they still wont breech the bearing surface of the valve shanks bore like it did in the rifle valve with the 1/4" shank which required the cap screws to be cut very short.
The over all valve travel remains the same as the rifle sized valve.



The valve spring I have used a stiff little bugger too which should help with efficiency not that that will matter much with this little pistola as it will have a low shot count with maximum power tune.
The best part is the new dimensions make the back end super short which will give me a 7" barrel and a 130mm receiver compared to the 150mm of the pups, which will be low profile and made from a smaller material than the pups, the greatest advantage is I now only have a 140mm section of tubing behind the air reservoir for the firing mechanism compared to the 200mm of the rifles design but will have the same air delivery only with the dwell tuned to a pistol length barrel.
If all goes to plan this will lead to future pistol builds being shorter lighter and have more air capacity for a higher shot count.
I will be using a rotary multiple barrel transfer port design in this pistol which uses 3 smaller rotary ports within a cut groove rather than one large transfer port cut into the lower section of the barrel. This will allow me to use smaller cast bullets, round ball and JSB pellets without the problem of them dropping into the transfer port and jamming things up. more on that later.
« Last Edit: January 07, 2015, 10:21:16 PM by Wingman »

Offline mojo

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Re: Another build from "The Hanger"
« Reply #6 on: September 09, 2014, 06:56:38 PM »
Looking good wingy, Is interesting following along with your build approach and philosophy, Danny.

Offline Ecko

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Re: Another build from "The Hanger"
« Reply #7 on: September 10, 2014, 03:31:36 PM »
Looking forward to seeing the grip design. Have you got any ideas on it?

Offline Wingman

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Re: Another build from "The Hanger"
« Reply #8 on: September 10, 2014, 09:15:13 PM »
Looking forward to seeing the grip design. Have you got any ideas on it?


As most of you know wood is by far not my favourite media to work with however Im quite looking forward to making the grip for this one.. it seams a little less daunting than a full sized rifle stock and some of the past bullpup stocks I've tackled leave me saying "never again"..
I will be making an ambidextrous target style grip for this one.
Part of my attraction to this dusty project is that I have been saving some very special pieces of timber for just such a project.. a really nice piece of heart walnut with some great colour and grain and also a piece of rare Wenge timber.
Wenge is the product of the Millettia laurentii tree. Native of the Republic of Congo, Cameroon, Gabon and equatorial Guinea. The tree was put on the endangered list due to the destruction of its habitat and over exploitation for timber. This piece was brought to NZ by a south African Knife maker and after many years of sitting on a wood rack came to my possession.
The colour of the wenge is a nice dark misty brown with almost black striped grain.. a very beautiful colour when oiled. It is VERY hard and was often used for knife handles and inlaying etc.



« Last Edit: September 10, 2014, 09:51:41 PM by Wingman »

Offline Wingman

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Re: Another build from "The Hanger"
« Reply #9 on: September 10, 2014, 09:51:07 PM »
Well Ill try to cover a little of what I missed on the last bullpup build on this one so it doesn't all just get repetitive and boring..

I got the cylinder all marked out, centre punched and milled all the counter sink cap screw holes and transfer port into it ready to seal up and pressure test.







Then it was onto the fill probe so I could get air into this new high pressure vessel..
I went with a different idea on this build as I want to keep smooth lines and minimal length I didnt want extra material out the front off the front plug to drill in the probe port like I did on the pup so I drilled these front plug retaining cap screws 180 degrees to the valve retaining screws and drilled an 8mm probe port between and forward of the two lower cap screws.. this puts it out of sight and no need for unsightly protruding Foster fittings.



Due to the new location of the port  I couldnt use the probe I made for the Pup because it was longer and would have come too close to the top cap screw so I made a special "pistol" probe and included a male foster into the design to save the need for a screw on adaptor. This way it plugs straight on to my whip line.








Online Mintie

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Re: Another build from "The Hanger"
« Reply #10 on: September 10, 2014, 11:41:08 PM »
Looking great! These are always such a good read!! Do you plan to take the learnings from the pistol design into a smaller carbine rifle at any point? I always liked the compact carbine look, a bit like the brocock super 6?
Lots of airguns

Offline Wingman

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Re: Another build from "The Hanger"
« Reply #11 on: September 11, 2014, 05:28:31 AM »
Yea if all proforms well all my pistols will be of this shorter action design but the rifles will be a hybrid mix. They require a longer valve dwell time and heavier hammer with a longer stroke and hammer spring than the pistols do so it wont be quite as compact as this but a lot smaller than the bullpups action.
My next carbine build will be a .357 (9mm) with a 19" barrel, open sights and a full length classic manlicher style walnut stock with loads of brass accents.
« Last Edit: September 11, 2014, 06:32:57 AM by Wingman »

Offline Pauly5

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Re: Another build from "The Hanger"
« Reply #12 on: September 11, 2014, 11:03:28 AM »
Great stuff. I do wonder where you get the time, maybe between changing nappies.  :)
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Offline Wingman

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Re: Another build from "The Hanger"
« Reply #13 on: September 11, 2014, 12:51:27 PM »
Great stuff. I do wonder where you get the time, maybe between changing nappies.  :)


My workshop time has certainly been taxed Paul but you just got to make time to do the things you love  ;)

Is a month old too young to learn the workings of a lathe?  ;D






Offline Pauly5

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Re: Another build from "The Hanger"
« Reply #14 on: September 11, 2014, 12:58:00 PM »
Good on ya mate.
HW98
HW97k
Tx200
S510
HFT500
Bobcat
Matador R2.5
HW40 (copy)
Daisy 953
P-Rod
1377
Zoraki 22