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 Post subject: handmade BB gun
PostPosted: Sun Mar 25, 2018 4:21 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
Been workin on this for a while now, obviously with one glance you will recognize it isn't entirely my own design...it is for the most part all handmade from steel, front sight included. The internals were made of tool steel which was a real pain in the azz to drill even before hardening but after a few broken drills and a cpl soaks in the forge I managed. Barrel I made from seamless hydraulic tubing and rifled with a homemade rifling bench I made a while back, it's 1 in 20 left twist 10 groove .375x16 inch and is polished out so hardly rifled untill the last several inches. Why .375? well thats the size material I had around to make a barrel from and also I already had the mold for the lead ball and figured lead ball would be easier to make a mag work. Valve is actually a 2240 back half modified and with a disco stem, mounted in a steel bracket on the side of the gun. Feed line is just steel line and flare fittings, gonna neaten it up at some point, seems to hold pressure fine, mag holds approx 18 bb and is just a tube with a spring and rod to push up the rounds and a cover I built from sheet steel, grips are some kind of hardwood salvaged from a pallet slat that caught my eye (been forging some knives too so I'm usually on the lookout for scale material) Soooooooo to answer the first question I know is comming....no, no it does not cycle in full auto, I have to manually rack the bolt for each shot although a cpl times it brapped twice in a row. I am using around 1000psi so it may not be enough pressure to recock the gun, and I'm good with that as I have to cast the shot myself and dont have a HPA fill station. I am getting 384fps high and around 360 low, hoped for a bit more but im sure there's room to improve a lil bit, totally not practical at all but still fun to smash tin cans with and at 360 fps sounds pretty weak but remember its 80 grains of lead so this bb gun is no joke! Sorry for the pics, I was tryin to prop it up for a photo and just ended up droppin it in the snow anyway....any comments or suggestions for improvements are most appreciated.

Cheers-matt


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 4:42 pm 
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Joined: Thu Sep 01, 2005 11:08 am
Posts: 1862
Location: Montreal, Quebec
Cool gun. Looks like the trigger is off of a paintball gun. What did you use to build the receiver?


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 4:51 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
Thanks Webstien! the entire gun is handmade from steel, reciever is 1x1 sq tube, trigger was block of steel, gaurd is 1/8 steel simply bent and welded. having no machine tools really sucked :lol:
If you take a closer look you may recognize what the original design was :wink:


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 6:09 pm 
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Joined: Sun Aug 19, 2007 11:44 am
Posts: 358
Location: Interior BC
Very nice Matt!
Wish I had that much talent.
Hey that's 26.2 fpe...!!! That's great!!
Love to hear it fire... maybe YouTube...or Vimeo?


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 6:35 pm 
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Joined: Sun Nov 06, 2011 2:16 pm
Posts: 1672
Location: 1/2 Way From Ottawa and Montreal,
I don't pay attention to BB Gun's so your lucky I read this post.

But this is nice it's not a BB gun is a airgun that shots led round balls :P

I like it It looks like a German gun from WWII I forget the name ...... Grease Gun I think.


https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8


https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8



https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8


Hope my links work.

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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 6:49 pm 
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Joined: Mon Aug 08, 2016 7:23 am
Posts: 4259
Location: Somewheres near the Atlantic
FRANK wrote:
I don't pay attention to BB Gun's so your lucky I read this post.

But this is nice it's not a BB gun is a airgun that shots led round balls :P

I like it It looks like a German gun from WWII I forget the name ...... Grease Gun I think.


https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8


https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8



https://www.google.ca/imgres?imgurl=htt ... mrc&uact=8


Hope my links work.


M3 Grease Gun was American. You're thinking of the MP40.


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 25, 2018 8:38 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
Thanks guys, I will give you a hint....there are plans available for this online and it was originally designed to shoot 30 cal cast bullets, I just changed the appearance very slightly :wink:


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 Post subject: Re: handmade BB gun
PostPosted: Mon Mar 26, 2018 1:48 am 
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Joined: Wed Oct 17, 2007 3:27 am
Posts: 2761
Location: Winnipeg, Canada
Nice work!

I hope to be set up with a small shop area, a reasonable lathe, and drill press by retirement...
Maybe then I'll have time to take on some "real" projects. :wink:

-D.S.

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 Post subject: Re: handmade BB gun
PostPosted: Mon Mar 26, 2018 9:01 am 
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Joined: Wed Dec 21, 2005 11:27 pm
Posts: 2220
Location: Toronto
matt wrote:
Thanks guys, I will give you a hint....there are plans available for this online and it was originally designed to shoot 30 cal cast bullets, I just changed the appearance very slightly :wink:


Is this based off the Casselman?

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"...await the right moment for one, and only one well-aimed shot" - Vassili Zaitsev


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 Post subject: Re: handmade BB gun
PostPosted: Mon Mar 26, 2018 10:50 am 
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Joined: Mon Feb 11, 2013 12:46 am
Posts: 5698
TriggerHappy416 wrote:
matt wrote:
Thanks guys, I will give you a hint....there are plans available for this online and it was originally designed to shoot 30 cal cast bullets, I just changed the appearance very slightly :wink:


Is this based off the Casselman?

kind of looks like it.. doesn't it.... :wink:

Image

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 Post subject: Re: handmade BB gun
PostPosted: Mon Mar 26, 2018 4:17 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
you got er! it is based from it but I changed a cpl things to fit what I had for materials, with no machine tools it took a full cup of patience and a lot of hand fitting to fabricate the springs and little parts in the action to work together, and like I said it's not full auto but it does function. :D

Cheers


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 Post subject: Re: handmade BB gun
PostPosted: Mon Mar 26, 2018 6:20 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
Pretty thrilled with a mild tinker on this gun, netted me 418 fps! :D and a decent fpe which was my goal on the low pressure im running.......im sure theres more though... :lol:


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 Post subject: Re: handmade BB gun
PostPosted: Fri Aug 17, 2018 6:39 pm 
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Joined: Fri Jul 03, 2009 10:13 pm
Posts: 391
Location: Annapolis Valley, Nova Scotia
Well guys, I have to admit I can't do anymore on this one, have tinkered more on it a little bit when I had a spare moment, not a fail, but didn't work out quite as well as I had hoped. Still functions nice n smooth, best fps was mid 400's and around 360 with a 3 shot burst that was only on occasion. I am NOT qualified to and nor do I want to mess with the output on the 3000psi/1000psi -out gaurdian tank on the gun, I have made several changes to bolt, hammer springs, bolt probe seals, ect. my conclusion is that its just too big a projectile for the pressure/setup to push any more out of it. It's still kind of a cool air gun, but most likely this winter will be recycled for it's barrel and parts, and used for something else. :cry:


cheers-Matt


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 Post subject: Re: handmade BB gun
PostPosted: Sat Aug 18, 2018 5:05 am 
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Joined: Wed Oct 29, 2014 10:49 am
Posts: 258
Location: QC
Very nice work!

This build based on the Caselman was running on 850 psi for 35 ft lbs on energy with .30" lead balls. The maker refined the design somewhat to make it function at this pressure, however it's odd that you cannot get it to cycle. Yes you have lower chamber pressure, but that also means you should need a less powerful spring to knock the hammer valve open.

One possible refinement is a balanced valve that greatly reduces the effective pressure keeping the valve shut, meaning you can open it with a much less powerful hammer spring which therefore gives less work to the gas attempting to re-cock the action:

Image


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 Post subject: Re: handmade BB gun
PostPosted: Sun Mar 24, 2019 7:47 am 
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Joined: Wed Oct 29, 2014 10:49 am
Posts: 258
Location: QC
As a follow-up to this, I can say that applying the Caselman direct blowback principle to a PCP with a balanced valve works very well, even as low as 500 psi ;)


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