I have three brands of 230gr. FMJ .451 , two were .655 in length the other was .647. Is that normal for bullets of the same grain & diameter but differ in length? The reason is I'm shooting a mild load for practice , with the same powder charge . Haven't seen any difference at 21' but I'm sure there is a difference in velocity. Isn't there a standard for length in a bullet like the hardball fmj .
Loaded up some 45acp fmj
- Thread starter cw308
- Start date
The military ones are even longer. It has to do with the nose shape. Some are made shorter by having a nearly hemispherical nose profile, while others are made longer by having a semielliptic nose profile.
That said, your difference at 0.008" is so small, I've seen bullets out of the same box with that much difference just because they came off different tooling sets. You can ignore it, but if you want to be exact or you get a more serious difference in length, then what matters to using the same powder charge is mostly seating depth:
Seating Depth = Case Length + Bullet Length - COL
or, to find matching COL:
COL = Case Length + Bullet Length - Seating Depth
You can use the formulas to get a matching powder space volume under the bullets.
That said, your difference at 0.008" is so small, I've seen bullets out of the same box with that much difference just because they came off different tooling sets. You can ignore it, but if you want to be exact or you get a more serious difference in length, then what matters to using the same powder charge is mostly seating depth:
Seating Depth = Case Length + Bullet Length - COL
or, to find matching COL:
COL = Case Length + Bullet Length - Seating Depth
You can use the formulas to get a matching powder space volume under the bullets.
