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  #1  
Old 01-28-2008, 02:30 AM
ogre6br ogre6br is offline
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Default Necking down question?? how far is possible

HI
Due to $$ limits I HAVE to convert 7.62x39 to .20 PPC instead of using 220Russin.
It's either that or make my .20 cal out of 223 brass derived case.
I really want to push the 39/40 at 3800+ FPS and thats unlikely with a 223 based case.
The action I wish to use wont take a .20 BR case or I'd use that as I have heaps.

I want to take the 7.62 down to .20 PPC.

I have ordered a .238 neck on the chamber on my .20 PPC chamber- but that can be changed if you guys suggest a better option.

Is it possible to just change the bushings in a Redding FLS bushing 6PPC die as I slowly take the necks down??
Was thinking of going 7.62 to 7mm to 6mm to 22 to .20

With a neck turn somewhere in there somewhere - at 6mm as I have access to the gear at 6mm to do it.

Or is there a better way?? less steps or ???

This will be my first major reforming project so please be gentle on this brass forming newbie

Thanks
later
P
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  #2  
Old 01-28-2008, 03:00 AM
Rodgervich Rodgervich is offline
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Necking from .30 to .20 cal is not outrageous but it does take care and patience. The more steps you do the better they will come out and less likely to crush, fold, crack or fail in some other way. I have only seen one Redding bushing and they do not appear to have much of a chamfer on the "lead in" so you cannot get to aggressive in the diameter change per bushing. Probably not more than .020" per pass and .015" more likely, some other guys here have done it with the Redding sets so they can point you to the right steps. You can go the step increments you indicate but not sure if the bushings will allow that much change per pass.
You will have to experiment with turning the necks at 6mm then neck all the way and measure then adjust turning amount until you get the right size. Might be tricky but you can get there.
I neck .38 specials to .17 cal, it takes a lot of steps but the cases don't crack and I go down in size by .031" for a few then down by .015" for a few. I think it takes 8 passes plus FL size.
Take a look at the "Small Caliber Load Data" page here on Saubier, there are several loads for a .204 Ruger that push the 39gr over 3800ft/s. You should get a .20 Tactical/.20 Practical to duplicate that without much trouble. Both can be done as "off the shelf" reamers/dies, or even just go with a factory .204 Ruger chambering.
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Old 01-28-2008, 04:48 AM
Cranky Bugga Cranky Bugga is offline
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Hey Ogre, I made a set of dies as shown by Rodgervich . Do a search for 17 scamp


I offered to lend them to you before, but no reply to my pm

I have done 357max down to 17 and had to anneal as the max brass was way too hard. You may find the Lapua brass will go down to 20 ok, just have to try it

Cheers

Last edited by Cranky Bugga; 01-28-2008 at 04:54 AM.
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Old 01-28-2008, 05:37 AM
ogre6br ogre6br is offline
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Sorry Cranky- must have missed the PM.

Yes please- lets try PM again- I'll pm you my email addy.

Thanks
later
P
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  #5  
Old 01-28-2008, 06:06 AM
georgeld georgeld is offline
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When first starting on these 5.7's I made it six steps of about .010.
The last few times' I tried to skip acouple in the middle and got them working at three steps.

The real trick is highly polished bore, right lead in taper as paul said, and good slick 'em. I use RCBS as it's water soluble. Once all the forning is done, then they get the primer pockets and inner mouth chamfered a light touch. Then rinsed real good in hot water and set on the heat register over night to dry. They come out nice and clean and ready to prime at that point.

Good luck, take it slow, polish good, lube and you should have it.
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