What Ogive for 7mm

[Cane_man]

looking into extending my 30 cal project to include 7mm also, since i decided to get a 30-06 and a 7mm-08 at the same time :bigsmyl2: (hopefully the wife will forgive me, when i tell her)

what is the standard ogive for 7mm flat base, say 140gr... 6s, 8s, or...?

[Utah Shooter]

I have a set of SAS dies and I do believe they are 6s.

[aaronraad]

Cane Man

Get a copy of Bryan Lutz's Applied Ballistics for Long-Range Shooting - 2nd Ed. Lots of useful projectile measurements taken for a range of projectiles not just boat-tail secant ogives.

It's a complicated decision choosing the ogive, but can made easier if you are very clear as to what purpose the projectile is design to fulfil. Short range BR projectiles tend to be between 6 and 9 calibres in radius with a tangent curve. Hunting projectiles with lead tips are usually closer to 6 calibres of tangent ogive. Consider your barrel twist and velocity also if you are looking for accuracy. Bearing surface might also be a consideration to manage you velocity window and static stability.

[Cane_man]

thanks joe and aaron... this will be a short range hunting bullet (less than 200 yards), and for general target shooting (not BR), and mostly just wanting to feed my deer rifle with inexpensive and available bullets.... so it looks like tangent 6s would fit the bill nicely with this FBHP...

i am drawing down 9mm range brass from 0.390 to 0.280 in 6 steps using 3 anneals!

[Cane_man]

Cane Man

Get a copy of Bryan Lutz's Applied Ballistics for Long-Range Shooting - 2nd Ed.

whewww! going for $50 new on amazon

http://ecx.images-amazon.com/images/I/41jxAaGqMoL._SX258_BO1,204,203,200_.jpg




excuse me now as i enjoy home ownership and dig up and repair a broken water pipe, great way to spend a weekend morning :violin:


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[aaronraad]

In that case Cane Man I'd agree with your 6 calibre tangent ogive. I'd aim for a 120 to 130gr finished weight in a FBHP, but you might have to increase weight slightly to get an optimum length projectile. I think 7mm-08's normally have about a 1:9.5" for most factory barrels so you might have to find the best length which will stabilise quickly in your <200y range for the best accuracy.