12ga Big Bore



Author Topic: 12ga Big Bore  (Read 2262 times))

Offline TPL

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Re: 12ga Big Bore
« Reply #40 on: January 29, 2019, 12:45:16 PM »
Make, was it 3500 or 3600J? The max with sabots?

Well it doesn't matter much anyway.
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Offline fpjeepy

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Re: 12ga Big Bore
« Reply #41 on: January 29, 2019, 12:48:38 PM »
You might get 600 FPE at 3500 psi using an 18" barrel with a .58 cal.... if you do everything right.... It will, of course be VERY noisy, because with that short a barrel the residual muzzle pressure will be very high....

Bob

All 300gr @ 950fps is 600fpe, not all 600 FPE is 300gr @ 950fps. I'm not interested in 600gr @ 680fps. If 58 cal can't do it how about 62 cal (20 gauge) ?

And the idea behind the short barrel is to make room for a large can...
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Offline TPL

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Re: 12ga Big Bore
« Reply #42 on: January 29, 2019, 01:36:19 PM »
I agree with Bob, you should be good to go with .58 IF you do everything right.

It shouldn't be even max limit but quite close to it anyway. With air I mean.
« Last Edit: January 29, 2019, 01:38:25 PM by TPL »
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Offline MJP

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Re: 12ga Big Bore
« Reply #43 on: January 29, 2019, 01:38:42 PM »
Nice .58 Brian!
Well you just need to build it and see what happens. And if it's not powerful enough, swap a bigger barrel. Just make the valve large enough from the start.
It was 3600J

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Offline Brian W Cook

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Re: 12ga Big Bore
« Reply #44 on: January 29, 2019, 01:54:33 PM »
Thanks Marko !
Itís probably my favorite airgun. Iíve killed a few deer with the round balls and one with the hollow point i shot in the video.   
Works great . 
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Offline MJP

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Re: 12ga Big Bore
« Reply #45 on: January 29, 2019, 03:37:23 PM »
Do you use balanced valve?
I have one .58 blackpowder in my safe, fun to shoot as well.

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Offline Brian W Cook

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Re: 12ga Big Bore
« Reply #46 on: January 29, 2019, 04:21:44 PM »
Itís a conventional poppet for now .   
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Offline rsterne

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Re: 12ga Big Bore
« Reply #47 on: January 29, 2019, 04:28:30 PM »
You asked about 300 gr. @ 950 fps, which is 600 FPE.... I didn't think it was necessary to repeat that, but yes you should be able to do that in .58 cal  with an 18" barrel at 3500 psi....

Bob
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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), .22 QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Bench PCP, 6mm Regulated PCP and .257 Unregulated, Three BRods.

Offline Doug Wall

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Re: 12ga Big Bore
« Reply #48 on: January 29, 2019, 05:01:09 PM »
Has anyone ever set up a .58 with a 500gr Minie ball? That might be interesting.
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Offline fpjeepy

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Re: 12ga Big Bore
« Reply #49 on: January 31, 2019, 08:58:11 AM »
You asked about 300 gr. @ 950 fps, which is 600 FPE.... I didn't think it was necessary to repeat that, but yes you should be able to do that in .58 cal  with an 18" barrel at 3500 psi....

Bob

I apologize. I thought you were trying to better your argument by modifying things slightly.
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Offline rsterne

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Re: 12ga Big Bore
« Reply #50 on: January 31, 2019, 12:48:49 PM »
I am well aware that using a heavy bullet at low velocity is a good way to "inflate" FPE numbers.... My "lofty goal" predictions are always done with a bullet weight of 1/2 the FPE, so that is at 950 fps.... You're pretty new around here, so you wouldn't have known that....  ;) Ö. Oh, and welcome, BTW....  8)

I think the idea of a short barreled 12 ga. is a cool way to get lots of FPE.... I am just trying to show you it's not the only answer.... and realize that quieting a 600 FPE beast with a short barrel is going to be a TALL (or at least "long") order....  ???

Bob
  • Coalmont, BC, Canada
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), .22 QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Bench PCP, 6mm Regulated PCP and .257 Unregulated, Three BRods.

Offline fpjeepy

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Re: 12ga Big Bore
« Reply #51 on: January 31, 2019, 03:21:12 PM »
I am well aware that using a heavy bullet at low velocity is a good way to "inflate" FPE numbers.... My "lofty goal" predictions are always done with a bullet weight of 1/2 the FPE, so that is at 950 fps.... You're pretty new around here, so you wouldn't have known that....  ;) Ö. Oh, and welcome, BTW....  8)

I think the idea of a short barreled 12 ga. is a cool way to get lots of FPE.... I am just trying to show you it's not the only answer.... and realize that quieting a 600 FPE beast with a short barrel is going to be a TALL (or at least "long") order....  ???

Bob

You've done a good job convincing me. I'm definitely thinking 12gauge might be a little overkill. 20ga at 62cal looks better. and might have an advantage over the 0.58 in that it might work even if everything isn't perfect. 
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Offline fpjeepy

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Re: 12ga Big Bore
« Reply #52 on: January 31, 2019, 03:35:19 PM »
Also, does anyone have any decibel readings for their big bores?

I'm seeing that the Maxim 50 suppressed muzzleloader is 140 dB. I think that is the quietest gun you can buy without a stamp and use for deer at the moment, as well as the .357 Bulldog (w/ pitbull mods - 94dB) and .45 Texan. Which are a little more marginal in my opinion.

I think the goal would be under 100 dB which might not be backyard friendly for a lot of people.
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Offline Jim Holmgren

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Re: 12ga Big Bore
« Reply #53 on: January 31, 2019, 03:48:58 PM »
A roundball in .73 weights around 500gr and have a bc about .10
If you have bullet in cal .73 that weights 300gr it would be way shorter then wide, maybe around .35 inch long :o.
It will of course work but you BC and long range performance will not be the best.

If you raise the pressure to 4500psi then you could even make you goal in .50cal for little better BC.

Accurate molds have mold close to 300gr in 20ga anything lighter would probably be needed to be custom made.
http://www.accuratemolds.com/bullet_detail.php?bullet=62-340S-D.png


Will this be a bullpup or a pistol? It will be awesome power in that compact of package! ;)

Has anyone ever set up a .58 with a 500gr Minie ball? That might be interesting.

What a great idea! convert a old reproduction muzzleloader to PCP ;D
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Offline MJP

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Re: 12ga Big Bore
« Reply #54 on: January 31, 2019, 03:58:11 PM »
Well i know one guy who did one very nice muzzleloader pcp.
Lets see if I can find a picture or if Timo has some pictures?

Marko
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Offline rsterne

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Re: 12ga Big Bore
« Reply #55 on: January 31, 2019, 08:01:11 PM »
I think the idea of a 20 ga. might be a great compromise....  8)

Bob
  • Coalmont, BC, Canada
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), .22 QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Bench PCP, 6mm Regulated PCP and .257 Unregulated, Three BRods.

Offline PikeP

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Re: 12ga Big Bore
« Reply #56 on: January 31, 2019, 10:56:41 PM »
Hey Fielding, originally from Maryland myself...you have some ambitious goals set but I think all can be met within reason and if necessary some compromise. Attached are some approximations I ran for a .58 cal with the parameters shown. Look forward to seeing if you commit to the build!

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Offline fpjeepy

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Re: 12ga Big Bore
« Reply #57 on: January 31, 2019, 11:55:20 PM »
A roundball in .73 weights around 500gr and have a bc about .10
If you have bullet in cal .73 that weights 300gr it would be way shorter then wide, maybe around .35 inch long :o.
It will of course work but you BC and long range performance will not be the best.

If you raise the pressure to 4500psi then you could even make you goal in .50cal for little better BC.

Accurate molds have mold close to 300gr in 20ga anything lighter would probably be needed to be custom made.

Will this be a bullpup or a pistol? It will be awesome power in that compact of package! ;)

Has anyone ever set up a .58 with a 500gr Minie ball? That might be interesting.

What a great idea! convert an old reproduction muzzleloader to PCP ;D

I was definitely thinking along the lines of custom bullets. With the 73 cal it would need to be a mix of metal and polymer to get something decent looking at 300gr.

At 62 cal I modeled a copper pellet at 320gr that looks decent. I would need to be custom turned and be expensive enough to warrant its use solely for hunting. But the link you posted above would be a good plinking round and preppers supply.

Bullpup with integrated suppression. And I would like to avoid 4500psi to be able to use standard equipment.



 
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Offline fpjeepy

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Re: 12ga Big Bore
« Reply #58 on: February 01, 2019, 12:00:29 AM »
Hey Fielding, originally from Maryland myself...you have some ambitious goals set but I think all can be met within reason and if necessary some compromise. Attached are some approximations I ran for a .58 cal with the parameters shown. Look forward to seeing if you commit to the build!

Can you run the same for 0.62? I'd be curious. What is that software?

And I'm not sure that I have the time or knowledge base to do the build myself. I would likely have to commission someone else to do the building.
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Offline MJP

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Re: 12ga Big Bore
« Reply #59 on: February 01, 2019, 01:40:00 AM »
If you are giving parameters to builder 18" and 600fpe I think it will remain a pipe dream.
Or at least it will be difficult to find a builder willing to take the chance of failure meeting the goals.

Not to put you down but it's not an easy task to accomplish.
Like Bob said, everything must be just right, and it will take time and money to hone all the details.

Good luck to your endeavor, will be interesting to folow how it comes together if you find the right builder.

Marko
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