Building a Big Bore Airgun?



Author Topic: Building a Big Bore Airgun?  (Read 2895 times)

Offline Jake

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Building a Big Bore Airgun?
« on: August 27, 2012, 09:47:33 PM »
I'm trying to decide between buying a big bore or making one for coyote hunting.  I know that building one would be a huge undertaking, but I have decent machining experience, and I have friends who are expert machinists that could help.  The reservoir would be fairly easy, but the valve/firing mechanism confuses me a bit, and I'm assuming I could purchase a pre-made barrel blank (say 45-70 govt.) and then use the bullets made for reloading, but I heard somewhere that firearms use a twist rate that's not suitable for airguns, but I could be wrong.  I'd love to hear some opinions from people that've build a big bore, or big bore owners.  P.S. I'm not exactly sure if this post should be hear or the Machine Shop Talk. 
Thanks,
Jake
  • Northwest Indiana
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Offline rsterne

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Re: Building a Big Bore Airgun?
« Reply #1 on: August 27, 2012, 11:07:10 PM »
First of all, do you have any experience with PCPs?.... If you don't, buy a Disco (or some other PCP) and shoot the heck out of it, tear it apart and mod it, and learn what makes it tick before even thinking about making a scratch-built big-bore....

Making your own PCP can be very rewarding.... but there is sooooooooooooo much to learn and it's not really fair to just go into it blind and ask others how to do everything.... While giving help is enjoyable, there are limits to what you should expect from others....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
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.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline Jake

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Re: Building a Big Bore Airgun?
« Reply #2 on: August 28, 2012, 08:50:43 AM »
Very good point, while I've shot PCP's I don't yet own one, and I'll definitely consider picking up a disco.  How much do you think I could get one used with a pump for?
  • Northwest Indiana
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Offline David McAfee

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Re: Building a Big Bore Airgun?
« Reply #3 on: August 28, 2012, 09:54:12 AM »
Very good point, while I've shot PCP's I don't yet own one, and I'll definitely consider picking up a disco.  How much do you think I could get one used with a pump for?

I dunno about used, but you can get a new one, with the pump, from Amazon for $329. That's where I got mine.
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Offline Rescue35

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Re: Building a Big Bore Airgun?
« Reply #4 on: August 28, 2012, 03:18:44 PM »
Bob summed it up pretty well.

My first attempt was a blind shot in the dark. Lots of fiddling to get minimal returns. Now days when I get the urge to tinker the Discovery and Marauder platforms are where I start.  The "hard part" is already done. ie trigger, stock, air tube and fill port. The valve has been "started"and with a few tweaks can produce enough power. A little barrel work and a new breach, you are ready to go.

I will be picking up a disco soon for such a project. I have an Mrod due to arrive today for the same reasons.

If I had the time I would probably try a scratch built again at this point. I have learned a lot from the posts by rsterne and lloyd on this sight (search for posts they have started).

It also depends on when yo want to go coyote hunting. I went just this morning. I use my Dragon Slayer .50. It is nice to have something ready to go out of the box instead of waiting to finish a project before I can enjoy my other hobby.

Since you need a pump anyway (assuming from your post above) a disco combo would be a great setup to get started with. I started out with a used Benjamin hand pump. Converted my 2260 to PCP. Then I purchased the Dragon Slayer used (took an 8 point buck it's first season).

Good luck and post pictures, whichever option you choose.
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Offline Jake

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Re: Building a Big Bore Airgun?
« Reply #5 on: August 28, 2012, 06:18:46 PM »
Bob summed it up pretty well.

My first attempt was a blind shot in the dark. Lots of fiddling to get minimal returns. Now days when I get the urge to tinker the Discovery and Marauder platforms are where I start.  The "hard part" is already done. ie trigger, stock, air tube and fill port. The valve has been "started"and with a few tweaks can produce enough power. A little barrel work and a new breach, you are ready to go.

I will be picking up a disco soon for such a project. I have an Mrod due to arrive today for the same reasons.

If I had the time I would probably try a scratch built again at this point. I have learned a lot from the posts by rsterne and lloyd on this sight (search for posts they have started).

It also depends on when yo want to go coyote hunting. I went just this morning. I use my Dragon Slayer .50. It is nice to have something ready to go out of the box instead of waiting to finish a project before I can enjoy my other hobby.

Since you need a pump anyway (assuming from your post above) a disco combo would be a great setup to get started with. I started out with a used Benjamin hand pump. Converted my 2260 to PCP. Then I purchased the Dragon Slayer used (took an 8 point buck it's first season).

Good luck and post pictures, whichever option you choose.
Very helpful information!
  • Northwest Indiana
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Offline alex77147

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Re: Building a Big Bore Airgun?
« Reply #6 on: September 10, 2012, 10:49:59 PM »
its nice to have the extra power, I myself want a bigbore but is it really necessary for a coyote? I have seen a .22 condor take a couple(havent seen it in person).  Anyway if you are looking to build something I would suggest working off of a qb or 22xx platform, check this link out as an example: http://www.network54.com/Forum/275684/thread/1199255834/9mm+22xx+shooting+120+fpe
« Last Edit: September 10, 2012, 10:51:58 PM by alex77147 »
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