17 June 2001, 22:56
<Don G>What velocity or load were you using in the 308? 1:14 should be plenty for a 168.
(Don't be embarassed, I've had days when I was all over the target at 600 yards, too! 
)
Don
Don
quote:
Originally posted by montero:
This weekend a will be trying some long-for-the-caliber bullets. If my rifle happens to shoot them accurately at 100 meters, making neat perfectly round holes at that distance, can I assume the will follo on, properly stabilized at the lower velocities of, lets say, 300 yds?
Thanks in advance.
Montero
IME, no. They may work, but then again they may not. You could get away with it on a hot day, but when the temps go down the groupsize might go up - even if the bullets don't fully keyhole. A cold day with a lot of moisture in the air might work, with dry air it might not.
The only way to know is to shoot them and see.
-- Mats
Mats brings up a good point. On any given day if the bullets are stabilized at 100 they will remain stable until the velocity drops to the transonic region (let's say 1200 fps to be safe).
But if the bullets are barely stable at 100 yards on the hottest day of the year, they might not be stable on a cold winter's day. (The denser air requires more twist.)
Conversely if the load works at 100 yards on both the hottest day of the year (when you worry about maximum chamber pressure) and on the coldest day, then you should be OK any time.
To be absolutely safe, I would try the bullet at 10% slower velocity. If it was stable from the rifle at that velocity at 100 yards, it will surely be stable on any given day when driven (and spun) 10% faster.
Don
On the other siide of the coin, == I tried some 6.5 mm 155 grn.Matchkings in a 6.5X55 Target rifle (1/8 twist) with all the Vit 165 that I dared to pack in the case. At 200 yards 10 shots went into a neat 1.8" group from a rest, all of the holes were the shape of littel boats,(pointed on one end,and rounded on the other,and almost twice as long as they were wide) Moving back to 600 yards, I found that I needed 5 minutes of elevation above my std.140 grn. match load to zero ( 30" more drop!!)After zeroing the load shot 198/5X for 20 shots.(possible 200) All of the holes were perfectly ROUND, Go figure !!,sometimes it works and sometimes it don't, best bet is to shoot them at the distance your going to shoot them.
Good Luck
Charlie S.
What velocity or load were you using in the 308? 1:14 should be plenty for a 168.
(Don't be embarassed, I've had days when I was all over the target at 600 yards, too! )
Don
FWIW Charlie S.
I thought the Palma guys used a lot of 1:15 for the 155s. Been wrong before!
Good Luck!
Don
So Have I, Maybe someone else Knows ?
Montero,
Good Luck with your Long Bullets
Charlie S.