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jdrslyr75
02-13-2014, 04:28 PM
Hey guys I am attempting to design a bullet mold for 6.8 SPC and I have some questions. This will be a hunting bullet in the 110-120 grain range, gas checked of course. I was playing around with Dan's design creator and pretty much figured out what I want. My main question pertains to ogive. I have figured out my max bullet length for twist, max bullet length for cartridge, nose length, and shank length, but I guess I don't have a real good understanding of ogive and can't decide if I want secant or tangential, or if it needs to be a bore rider or not. Any help would be appreciated!

runfiverun
02-13-2014, 09:56 PM
tangential.
use the nose shape in front of the front band to fill your leade area.
a little bore rider is fine, a full bore rider doesn't support the nose well enough during rapid acceleration .
a flat point will really help your efforts.

jdrslyr75
02-14-2014, 01:12 AM
Thanks r5r! I'm thinking 50-60% meplat for the nose. Now to the Mountain Molds website for some fine tuning!

Socal147
02-14-2014, 01:17 AM
Awesome choice. I have two Mountain Molds with another enroute. Top shelf all around.

jdrslyr75
02-14-2014, 05:01 PM
R5R: is a tangential ogive pretty much the rule for cast rifle bullets, or just for this one? And also, why? No disrespect, just trying to gain some knowledge.

SoCal: did you buy Lee handles for yours? If so, how did they fit?

375RUGER
02-14-2014, 09:41 PM
Lee handles fit just fine.

runfiverun
02-15-2014, 12:09 AM
it's not the standard but it is very strong especially when combined with the flat point.
the other aspects I described gives you a better mechanical fit to the rifle.
the mechanical fit and boolit design [strength] allows you to get away with rapid acceleration and higher velocity's while maintaining accuracy.
the trick is picking say one 30 cal boolit over another for a different saami cut throat.
the 30-06 and the 308 both have different angles cut into the lead.
the nose strength and the larger base of the nose allows you to kinda cheat around them both whole maintaining the boolits integrity.
and still have a decent throat fit without having to shoot a grossly oversized boolit.
the trick is in the seating depth, case thickness, and powder speed.
this allows the boolits nose and sloping forward band to center the boolit better before it enters the barrel fully.

Socal147
02-15-2014, 01:46 AM
Lee handles fit just fine.

Plus 3 literally ... LoL

jdrslyr75
02-15-2014, 04:18 PM
Thanks for all replies gents! Great explanation R5R!

jameslovesjammie
02-17-2014, 08:39 AM
Just out of curiosity, whose barrel are you using? I'm assuming SPC II chamber?

Are you trying to get it to cycle the action or just single load it?

Whiterabbit
02-18-2014, 02:09 PM
careful on meplat for a feeding rifle. Too big and it wont make it up the feed ramp. 7mm NOE hunters wont feed in my rifle.