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Old 05-11-2007, 02:50 PM
Daryl Daryl is offline
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Join Date: Sep 2006
Location: Prince George, B.C. Canada
Posts: 4,266

First of all, I don't have a VT, or .221 for that matter, but considering the .204, on the same basic case is loaded to 57,000 PSI, and the .223 slightly higher (apparently), the .221's case should take the same amount of pressure in stride. This, of course, in brass of the same quality, hardness, etc, of the longer rounds.
: We all know that all brass isn't created equally.
Old 08-16-2007, 02:35 PM
duckman duckman is offline
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Join Date: Aug 2007
Posts: 11

Is the bolt "clicking" responsible for the slight drag mark showing on the cases? Or do you think that is from the extractor?
Old 04-25-2008, 02:22 AM
T.Zimm T.Zimm is offline
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Join Date: Dec 2006
Posts: 256
Default question.

You fellows are more experienced than I in the small case game. When I start getting pressure signs I back off to the next lower accuracy node. My question is how narrow is a typical node? I have noticed over the last couple of years that my .17's show very narrow accuracy nodes. Basically one tenth of a grain will show an accuracy node. Is this typical? I use an RCBS chargemaster to load all my cartridges. If you get variations in your charge of plus or minus half a grain this would throw you out of the node. Is the accuracy node this narrow because of the small case size? When you get even smaller cases than the Mach IV/Fireball do they get even touchier?? How do you deal with that? How can you safely work with a Velociraptor?
Old 04-25-2008, 04:03 AM
rpbill56 rpbill56 is offline
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Join Date: Sep 2006
Location: N.W. Missouri
Posts: 442
Default My Cooper VT

I made my VT brass from new .17 Fireball brass. First I used a Hornady .204 die to get it to 20 cal. The expander worked perfect. I had to run them in a Redding FL die so they would fit in my gun. I guess that's what you meant by a tight chamber. I've never had a gun that wouldn't chamber new brass.

About loads and FPS. All loads were with CCI BR4 primers
18.5gr - H4198/32gr V-Max 3708 avg
18.7gr - H4198/32gr V-Max 3720 avg
18.9gr - H4198/32gr V-Max 3740 avg
19.1gr - H4198/32gr V-Max 3820 avg

I couldn't see any difference in the primers from 18.5gr to 19.1gr. The bolt lift seemed to be the same too. My smallest group was .260 and the worst was .585.

I settled on 18.5 grains for now. I've never shot anything that knew how fast the bullet was going. I've also shot some of my best groups with this load.

Last edited by rpbill56; 04-25-2008 at 11:32 PM.
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