Thinking about a redundant wildcat

Nhenry

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Hello all,

I was told a while back on the forum that the 280AI was pretty limited on the Tikka platform because of the magazine length. So that got the cogs turning.

This wildcat is based loosely on the principles of the 6.5 Creedmoor, but I'll explain.

The creed was designed for long, high BC projectiles in a short action.

This is the creed, but I literally used the stretch command in AutoCAD to lengthen it for a Tikka long action, I necked it up to 7mm, and gave it a few different shoulder profiles.

It's around the same amount shorter than the 30-06 as the 6.5 creed is to the 308.

The only real benefits over an already existing cartridge is that it will fit in a Tikka mag while being able to touch the lands, and would hypothetically be more powerful than a 284 Win.

This fills no unfilled niche, so don't tell me it's pointless because I know. Everything is redundant nowadays anyways, might as well chip in.

Its working name is the 7mm Redundancy. I also have other calibers on my CAD file that are on the same case.

Thoughts? Has this already been done?

And yes I know I left out some dimensions on the diagram.

Capture.PNG
 

ImBillT

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Looks a lot like a .284 Shehane to me.
Not even close. .284 Shehane is a 284Win with a the shoulder blown forward. That’s shorter than a 7x57, which is pictured on the left, and it’s fatter than anything pictured.
 

ImBillT

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I have three thoughts.

1) why not a 7SAUM? It’s 280AI capacity that will fit in a Tikka. Yours is less than 280AI capacity, and requires fireforming, which is a significant expense in terms of components and barrel life. Not to mention a custom reamer which costs more than a reamer that already exists. Are you gonna buy custom die or grind down 280AI dies?

2) as the owner of a 1.500” 6BR, I can tell you that trimming more than .010” in a case trimmer is HORRID. I would never recommend building a cartridge that requires substantial trimming where no trim die is readily available unless it offered some serious advantages. 7SAUM in a Tikka, or 280AI in a 700/700clone. There are too many good options available to shorten a 280AI.

3) Have you calculated volume? I doubt it’s larger than a 284Win, and would be blown away if it’s larger than a .284Shehane. I’m a big sucker for wildcats, but dang, this one is a lot of work and neither one of us sees a reason to do it.
 

Nhenry

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I have three thoughts.

1) why not a 7SAUM? It’s 280AI capacity that will fit in a Tikka. Yours is less than 280AI capacity, and requires fireforming, which is a significant expense in terms of components and barrel life. Not to mention a custom reamer which costs more than a reamer that already exists. Are you gonna buy custom die or grind down 280AI dies?

2) as the owner of a 1.500” 6BR, I can tell you that trimming more than .010” in a case trimmer is HORRID. I would never recommend building a cartridge that requires substantial trimming where no trim die is readily available unless it offered some serious advantages. 7SAUM in a Tikka, or 280AI in a 700/700clone. There are too many good options available to shorten a 280AI.

3) Have you calculated volume? I doubt it’s larger than a 284Win, and would be blown away if it’s larger than a .284Shehane. I’m a big sucker for wildcats, but dang, this one is a lot of work and neither one of us sees a reason to do it.
Excellent points, to which I have answers.

1) Because I have components conducive to staying with a long cartridge with a 308 bolt face. Primers, lots of proper powder, and the biggest thing: a standard bolt faced tikka action. Along with that, I want to eventually do a full custom on a Sako 85 action, and the magazine for that platform doesn't really fit a 280/280AI because of the shoulder stops. This would work around that. I'd be going all out for this one if I were to do it.

2) I own a 280AI in a full custom Rem 700. Well, it's being built still but it's almost complete (just have the trigger, cerakote, and bolt knob left). But as I said, there's so many redundancies that it's pointless to do anything new, but it's fun regardless. I'd like to hunt and use something that I made up, which sounds good. Yeah, the case prep would be a nightmare for a bit, but I'd eventually figure out a way to do it better.

3) I suspect it'd be somewhere around 280 Rem's volume, being that it's wider and has better shoulder profiles, and only slightly shorter than a 280. There's no real need to do this, but it seems fun and I haven't been able to cease thinking about it for a while. Honestly, I don't need this, but it would be cool. It wouldn't be a 280AI, but it would certainly be enough for my needs -- if I did it.
 

ImBillT

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Excellent points, to which I have answers.

1) Because I have components conducive to staying with a long cartridge with a 308 bolt face. Primers, lots of proper powder, and the biggest thing: a standard bolt faced tikka action. Along with that, I want to eventually do a full custom on a Sako 85 action, and the magazine for that platform doesn't really fit a 280/280AI because of the shoulder stops. This would work around that. I'd be going all out for this one if I were to do it.

2) I own a 280AI in a full custom Rem 700. Well, it's being built still but it's almost complete (just have the trigger, cerakote, and bolt knob left). But as I said, there's so many redundancies that it's pointless to do anything new, but it's fun regardless. I'd like to hunt and use something that I made up, which sounds good. Yeah, the case prep would be a nightmare for a bit, but I'd eventually figure out a way to do it better.

3) I suspect it'd be somewhere around 280 Rem's volume, being that it's wider and has better shoulder profiles, and only slightly shorter than a 280. There's no real need to do this, but it seems fun and I haven't been able to cease thinking about it for a while. Honestly, I don't need this, but it would be cool. It wouldn't be a 280AI, but it would certainly be enough for my needs -- if I did it.

As long as you wanna do, by all means feel free, but if it ends up at 280Rem capacity, the 284Win is setting right there.
 

Nhenry

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I was doing some revisions and thinking about a case that would yield better performance than the one I had originally come up with, and then I realized the RPM case had a lot of potential.

So hypothetically, shortening it to the same length would yield capacity on par with or greater than a 280 AI, but still in a package that fits well within a tikka mag.

This is also necked up to 7mm.

f Model (1).jpg
 

Wind Gypsy

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Mar 12, 2017
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I was doing some revisions and thinking about a case that would yield better performance than the one I had originally come up with, and then I realized the RPM case had a lot of potential.

So hypothetically, shortening it to the same length would yield capacity on par with or greater than a 280 AI, but still in a package that fits well within a tikka mag.

This is also necked up to 7mm.

View attachment 223636

Was just reading through and was going to opine the only one that would really make sense instead of 284 is a 7 RPM wildcat.
 

std7mag

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Ok, the RPM is essentially a stretched 284 Win case with 35° shoulder.
The rated pressure for the 6.5 RPM is 65,000 psi.

So even if you shorten it, as planned, you should come fairly close in volume. And with the 5,000 added psi, you might sit squarely between the 280 Rem & 280 AI velocity wise.

Oh, and just to clarify...
The Creedmoor was designed to fit long, heavy match bullets in an AR type MAGAZINE without the bullet encroaching into the powder.
The ACTION length had nothing to do with it.
 

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