In rifles, the difference would be even more pronounced. I loaded 2 .308 loads, with the 168grn Nosler, using IMR4895 and IMR4064... they weren't exactly the same velocity, but very close... within 100fps... and at 700yds the IMR4895 load was all over the place (except the target
) but not the IMR4064 load. I suppose if they were exactly the same velocity things might have turned out different... and that might be a fun project, some day.... working up 3 or 4 powders to the same velocity and seeing how they did at distance.
Bullet stability is something that is not discussed, or even alluded to, in the popular press. I am unaware of bullet manufacturer’s testing bullets for stability, or bullet stability sensitivity to conditions at distance. What I have read, is that bullet manufacturer’s have indoor ranges, the longest was 300 yards. In my limited experience, firing 223, 6.5, 277, 308, 35 caliber rifle bullets, all these bullets have remained stable at 300 yards, and the loads I copied from others, pretty much remained stable at 600 yards. Those that I copied were target loads. I cannot comment on the 30-30 at 300 yards or beyond, only fired two three hundred yard targets and the bullets were in the black, but that was about it. I have not fired low velocity bullets at 300 yards, such as the 45/70 or 22 lr. My long distance testing is limited to the facilities available to me, which is CMP Talladega, which has 200, 300, and 600 yard targets. A 600 yard range is a big piece of property , and in so far as 1000 yard ranges, they are very few east of the Mississippi. I have shot in 1000 yard matches and learned from my own unfortunate experience that that the 168 grain 308 bullet won’t remain stable at 1000 yards. But, you won’t find that in the popular press.
It was well known in the long range community that the 168 Match bullet would go unstable past 600 yards. Back in the day when the M1a ruled the Across the Course firing line, the 168 grain bullet was the preferred bullet out to 600 yards. However, having tried this myself, the 168 would go unstable before it hit the 1000 yard target. The theory was, the 168 would go unstable during the transition from super sonic to sub sonic, which is about 1000 to 900 feet per second. The old military 173 FMJBT was in fact, better at 1000 yard than the 168 match, even though the 173 was a less accurate bullet out to 600 yards. It was not until the M1a faded from the firing line, around the year 2000, that Sierra introduced their 175 SMK, which looks identical in shape to the old military bullet, but is a hollow point. I have shot the 175 SMK and it is a great bullet, all the way out to 1000 yards, at M1a velocities.
As for current bullets, what we read in the popular in print press, are product placements by shills who get their talking points from corporations. I think we have all read the fluff, the gunwriter claims that a round has 700, 800, 1200, even 1500 yard lethality. All based on numbers on a page. And then the gunwriter goes out and shoots three round groups at 100, sometimes, at 50 yards. We, the readers want to believe these guys know their stuff, and what they write much be true, but we should not believe any of it. All of their assertions are untested, they are simply repeating the talking points of the Corporation who financed the product placement, and we have no idea what the Corporation has done, if anything, to validate their claims. Surely 100 yard, three shot groups prove nothing at 1000 or 1200 yards.
Only because I have been able to trundle down to CMP Talladega have I found inconsistencies that have lead me to change my ideas that any bullet can be trusted to remain stable, “all the way out”, until it has been proven so at the range.
Recently I removed the featherweight barrel on a pre 64 M70 and had installed a SAKO contour barrel in 270 Win.
I also purchased a boat load of Federal pulled bullets. A significant percentage had deep pull marks.
I sorted them out, and shot the best for group size
For the 150 grain bullets, I started off with my vintage collection of 150 gr Speer SPFB. For 50.5 grains IMR 4831, the velocity average was 2720 fps. I had the chronograph up in front of my rifle and was able to get real time velocities for the day. These bullet did well at 300 yards,
But were horrible at 600 yards, all over the place.
With the Federal Fusion pulled, 50.0 grs IMR 4831 velocity average 2673 fps gave a good group at 300 yards
But they puked at 600 yards, the group was as randomly distributed as the 150 grain Speer flat base bullets. I don’t have a picture, I did not take one was I was disgusted with my shooting. I actually thought my rifle or scope had broken, because for two loads in a row, my 600 yard groups were all over the place. I grabbed my scope, and it was not loose, and I was about to go home when I decided to burn up the 150 grain Federals with 50.5 grs of IMR 4831 velocity average 2714 fps
Three hundred yard group
For a lark I went to 600 yards, and the bullets were grouping!
Just half a grain more of powder and about 25 fps more velocity, and the bullets were stable at 600 yards (more or less). However, some distance past 600 yards, they would have to go unstable.
I have been told the great 168 Match bullets in 308 would lose their stability when they went from super sonic to sub sonic velocities. Well, I guess they are not the only ones. One 308 bullet that was great, all the way out to 1000 yards, is the 175 Sierra Match king, which is based on the old 173 FMJBT that the military used in the National Match ammunition. (bullet weight varied by plus or minus 2 grains, so you can get into arguments with some whether the bullet is a 172 grain, or 175 grain bullet) It says, 173 on the package, so go bite me.
For whatever reason the 175 SMK is stable after dropping below supersonic speeds. I have shot the 308 155 gr Palma Match bullet at 600 yards, at very slow speeds, and they grouped at 600 yards, so maybe the Palma bullet transitions well.
One bullet that absolutely shocked me, was the 308 grain 190 Sierra Match King. Shot well at 300 yards
And they absolutely fell apart at 600 yards!
Years ago I talked to Sierra about the velocity goals I should have for the 190 SMK in a 308 Win, and Customer Service told me to keep the bullet above 2500 fps, as it would still be going 1200 fps at 600 yards. Well, my loads were surely going faster than 2500 fps, as I chronographed that day. And they tumbled, for that has to be on the only explanation the bullet grouped nicely at 300 yards, but were all over the place at 600 yards.
I have loaded up 190’s in my 30-06, took the rifle and loads down to CMP Talladega in March. I shot in the CMP Spring Games, but the big range was totally occupied and I did not have time to test to see if a little more velocity would keep the things stable at 600 yards. I have talked to buds who shoot 185 and 200 grain Bergers in F Class, and they are pushing their 190’s faster than I push my 168’s! I cannot increase the velocity in my 26” match 308 bolt guns, because the primers will blow.
I am of the opinion that bullet stability is a unknown, unknown, because few in the community have access to long distance ranges, and industry ain’t talking about it. But it is real. And the only way to know if the bullet is stable, out to distance, at the velocity you are pushing it, is by shooting it on target. Atmospheric conditions make a difference too. High humidity and high air pressure will slow the bullet down, so the bullet may be stable at some high elevations, but unstable at distance at low elevations.
I am going to claim, that the accuracy issues you saw, were due to the bullet, not the powder. The slower 168's tumbled earlier. The faster ones would have too, some distance beyond.
