If comparing two different bullets for velocity,everything being identical(except the bullet) should the OAL be the same?I measure the ogive point because of tip varience.In other words,if one bullet was seated .030 off the lands and the other was .080 off the lands would that make a difference in velocity?

Jim

Most definitely, but it would be hard to estimate what the difference might be because there are so many factors involved. Such as, bullet hardness, neck tension, powder type, case capacity, loading density, just to name a few. The only way to fairly judge one bullet against another is to load them excatly the way you would intend to shoot them. JMHO

Ray

It may, but I doubt you would see it. The change would likely fall within the extreem spread of the load. I found this difference once with my Kimber M84 in 260 when I was curious... didn`t prove much.

BBL 22"
140 gr Hornadt SP
H4831sc
WLR primer
Remington case
OAL at the lands with the comparator included in the measurment;

3.275" vel 2701 (just touching the lands)
3.260" vel 2699
3.250" vel 2687
These were 5 rd averages with 10 rds for the 3.260" OAL, and the extreem spread of the load was 44 fps for 20 rds.
highest vel - 2718 fps
lowest vel - 2674 fps

Jam the bullet in the leade or seat it so deep as to make a notable change in the case capasity might just be different.

Ol Joe

Your test was with the same bullet seated to different depths, and I'd have to agree that it wouldn't make much difference. But Jim asked about two different bullets seated to two different depths. At least that's what I think he asked. That could make a big difference.

Ray

Yes,two different bullets.One bullet seated out as far as nagazine allows for proper function and a different bullet that the manufacturer suggests to seat at least around .050" off.
Jim

I know that with the same bullet velocity difference wouldn't be much.

I loaded 83grs. of H-1000 with the TSX @ .030" off the lands for an avg.vel. of 3195 fps.Loaded a 165gr. Accubond which the ogive measurement is .080 off for 3162 fps.Not that the velocity difference matters,just wondering why a lighter bullet would be slower than a heaver bullet.The only thing I can think of is a reduced bering surface with the TSX design???

quote:

Originally posted by Jim Hundley:
I loaded 83grs. of H-1000 with the TSX @ .030" off the lands for an avg.vel. of 3195 fps.Loaded a 165gr. Accubond which the ogive measurement is .080 off for 3162 fps.Not that the velocity difference matters,just wondering why a lighter bullet would be slower than a heaver bullet.The only thing I can think of is a reduced bering surface with the TSX design???

Hey Jim

I'm a little confused. Since you say the 165 is a little lighter, I assume you are shooting the 168 gr TSX, right? Why did you seat the Accubond farther from the lands (.08"), to fit the magazine?

A couple of observations from my spreadsheet:

180 gr TSX seated .02" off lands / 74.5 gr RL19 / 3093 fps
180 gr Accubond seated .02" off lands / 74.5 gr RL19 / 3065 fps

200 gr TSX seated .02" off lands / 79 gr H1000 / 2983 fps
200 gr Accubond seated .02" off lands / 79 gr H1000 / 2967 fps

These were loadings where I was comparing directly the accuracy of the TSX compared to the Accubond, loaded at the same time, shot at the same time. In both of these cases the Accubond shot 1/8" smaller groups.

Bullets will be different and your differences are not large enough to come to any conclusion, IMO.

Woods,
I guess what I am asking shows up in your load examples.Why is the Accubond a slower bullet when loaded the same?Is it the bearing surface of the Accubond greater therefore more resistance(friction).
Thanks,Jim