Ballistics calculation : Can this be possible ??

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Cameron Mc
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#16 Postby Cameron Mc » Tue Aug 07, 2012 6:09 pm

Brad Y wrote:.............

Cameron I think Rod was referring to the 6.5x284 I originally suggested.


Brad, that makes sense. 6.5x284 = short barrel life.

Cameron

Woody_rod
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#17 Postby Woody_rod » Thu Aug 09, 2012 11:19 am

Cameron Mc wrote:
Brad Y wrote:.............

Cameron I think Rod was referring to the 6.5x284 I originally suggested.


Brad, that makes sense. 6.5x284 = short barrel life.

Cameron


Yeah....that is what I meant. I am looking at rebarrreling to 284 for FO. ive had this idea for some time to make a 30-284 to get that tiny bit of capacity that the 308 needs for the heavier projectiles. Anyone got ideas on this? Bit like a 30-06 but with the fatter case.

AlanF
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#18 Postby AlanF » Thu Aug 09, 2012 11:44 am

Rod,

Paul Janzso had a 30-284 about 5 years ago. He never really went on with it, not sure why. He now shoots a 300 WSM and seems very happy with it. With the 30-284, you might be up against the primer pocket expansion problem that I see with the 7 Shehane.

Alan

Woody_rod
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#19 Postby Woody_rod » Thu Aug 09, 2012 12:23 pm

AlanF wrote:Rod,

Paul Janzso had a 30-284 about 5 years ago. He never really went on with it, not sure why. He now shoots a 300 WSM and seems very happy with it. With the 30-284, you might be up against the primer pocket expansion problem that I see with the 7 Shehane.

Alan


Alan, on doing some research now on this exact thing. My main thing is to use the 12,05mm bolt face of the 308 - no need then to have two bolts etc. The fatter case of the 284 gives so much more capacity than the same length 308. There other options, the obvious one to just use a std 284.

bartman007
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30-284 why

#20 Postby bartman007 » Thu Aug 09, 2012 12:34 pm

Rod,

I'd suggest that the 30-284 will be limited to running 175 or 180 grain projectiles due to pressure issues, and the requirement to run slower! Is this good enough for F Open? Of course you could always push the 155's quicker, but is there any merit in that, not really.

I reckon that is why the WSM would be more appropriate in this case.

Woody_rod
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Re: 30-284 why

#21 Postby Woody_rod » Thu Aug 09, 2012 12:42 pm

bartman007 wrote:Rod,

I'd suggest that the 30-284 will be limited to running 175 or 180 grain projectiles due to pressure issues, and the requirement to run slower! Is this good enough for F Open? Of course you could always push the 155's quicker, but is there any merit in that, not really.

I reckon that is why the WSM would be more appropriate in this case.


Probably true. 185s run perfectly well in the 308 - so no point really for that size. I would be using the heaviest projectiles - 210-230 grain. There would be no benefit othewise.

IanP
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Re: 30-284 why

#22 Postby IanP » Thu Aug 09, 2012 3:41 pm

Woody_rod wrote:
bartman007 wrote:Rod,

I'd suggest that the 30-284 will be limited to running 175 or 180 grain projectiles due to pressure issues, and the requirement to run slower! Is this good enough for F Open? Of course you could always push the 155's quicker, but is there any merit in that, not really.

I reckon that is why the WSM would be more appropriate in this case.


Probably true. 185s run perfectly well in the 308 - so no point really for that size. I would be using the heaviest projectiles - 210-230 grain. There would be no benefit othewise.


Woody the 284W case is not upto what you want to do! Its a magnum size case with a 308W head which expands quite readily with med/hot loads and 180gr projectiles in 7mm. I have pushed this case to its limits and beyond in 7mm and its achille's heel is the case head expansion. I think you would be blowing primers out backwards with 210-230gr projectiles and the amount of powder you would need to launch them at competitive velocities.

For what you are proposing to do I'm afraid you need a magnum head size bolt and a magnum case! Paul Janzso gave me some of his 284-30 cases to neck back down to to 284 and use with 7mm projectiles. Maybe Paul can enter into this conversation?

Ian

DaveMc
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#23 Postby DaveMc » Fri Aug 10, 2012 7:10 pm

we have a couple of guys up here that run 30-284's.
They run 180-185 class as suggested. They make their own pills and are always in the running. Another guy runs 155 HBC at 3200 fps and he goes pretty well too.

but I cant see any advantages over the straight 284??

Rod - One thing I was very tempted to try was a 284 shell blown forward like your 260CINCH with Shehane taper -was going to call it the 284MACKS

With a 284 you have to run at about 13% less pressure than straight 308 case. The Shehane capacity almost gets you to the 2950 node (does in some barrels) but a 284 MACKS should!


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