Author Topic: Designing/Drawing the 30-210-HBC-A  (Read 355 times)

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Offline Aladin

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Designing/Drawing the 30-210-HBC-A
« on: November 24, 2003, 11:40:34 AM »
Ok. You might remember two yrs ago or so on shooters trk/Tim and I had a longish thread drawing up a 30 caliber spitzer of high ballistic coefficent. Wound up I had my '329 mold recut for a 'speriment and have stuck with that. It flies nice to 600 yds as dos the LBT 170 I shooten. I have a Rapine on hand now to test thanks to Forrest which I need to spend some time with also.

But... the cast spitzer continues to be in a cloud of false assumptions. This is sad.. we're much more knowledgeable as a group but the old wives tales still exit. Like the greatest factory varmint rd ever.. the 220 Swift... idiocy has kept that number from wide spread useage. 'Nother story..

Are the potential buyers of a Lee spitzer project out there? Let me know..

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Thread update:


--decided to use the '329 ogive. I've fired this one to 600 yds varying the arrival speed and always get nice, round holes. Meaning there's no transition bug going from super to subsonic speed-- or above and below the speed of sound at around 1107 fps.

--Tom Meyers last yr figured a BC exceeding .50 for a 1.25" version of the 329 lengthened from 1.17+".

--essentially what I've done recutting the original 329 ogive with my mold is taking the bore rider and making this a front driver... with some strength. We're around .150" for that driver and something on the order of .050 or so of leade taper [.309 down to .300]. This mimics the short 'porch' of the LBT spitzer that I've sent downrange by the thousands with excellent accuracy.

--understand this recut 329 length at 1.17" is THE BULLET in my friend's 30/30 break open Topper. At 309 dia going down that 3065 bore groups run an easy inch at 100 in still air- this only visually inspecting the slugs. We've gotten some screamer clusters of 3-4 buried in one hole. The load is around 13.7 grs of 4227 and Rem 9 1/2M's-- seated to engage at closing and just AC'd.

I'll be boxing up some 329 samples today to send to our Draw-er Trk to get duplicate figures on this ogive and front driver arrangement.

Thanks to all,
Jay

If you interested in one-- let me know. Design drawing will be posted soon..
Aladin

"that's my story and I'm stick'n to it"