Was testing some new to me bullets today, 243 cal. 75g sierra FB HP at 100 yds., When i got to the top of the ladder for near max charge, a 3 shot group had only 1 bullet show up. How can you tell when a bullet disintegrates before it hits a target at 100 yds? Im shooting a Rem 700 with a heavy 26 inch barrel with RE-16, 3 shot groups, 43g, 43.5 and 44g, near max. The 43g group was good at only 3/8 inch, the next of 43.5 was 1 1/2 inch, and then, like I said the third and last group at 44g only 1 bullet on the target, and I know it was'nt me, because my groups that morning were all 3/4 inch or less, and these 2 bullets did not show up anywhere on a 3ftx4ft target. I decided not to use my chrono today, because I had load data for the same load only a different bullet, a Hornady 75g vmax, which I chroned before at 3587fps. Im pretty sure that this one was a bit faster, because I had to seat the bullet .030 deeper in order not to jam the lands on my short throat new Shaw barrel. Any ideas where my other 2 bullets went?
Do Sierra FB hollow point bullets have a thin jacket?
- Thread starter lugerstew
- Start date
Grey splatter across the target if it happens close enough to the target. If it happens less than 1/2 way to the target you won't see anything on paper, you need to watch the bullet flight path for a "puff" of grey. Had this happen years ago with a 22-250, old timer at the range had to show me what was happening.
The bullets may have jacket flaws.
Sierra had this issue with 308 168 grain match bullets from one lot they sold to the Army and Navy rifle teams. Max loads from service rifles had half the bullets fly apart about 50 yards down range as I observed. In the reduced loads used in the Army free rifles, they held together with excellent accuracy.
Sierra had this issue with 308 168 grain match bullets from one lot they sold to the Army and Navy rifle teams. Max loads from service rifles had half the bullets fly apart about 50 yards down range as I observed. In the reduced loads used in the Army free rifles, they held together with excellent accuracy.
Lugerstew,
Another possibility is core stripping. This is where the angular (rotational) acceleration of the bullet is so great the core slips inside the jacket, extruding it longer against the rifling indentations on the inside. This results in two problems: one is that the core is rattling around inside the jacket, yanking the bullet around every which way from Sunday. The other is that the jacket winds up spinning faster than the core. Upon exit from the muzzle, the rates or rotation equalize in proportion to the angular momentum of the two spinning masses (the jacket and the core) with the result that the whole bullet can end up spinning too slowly to stabilize and ends up whizzing off to the side. Watching where the impact kicks up dirt to the side of the target is the only way I know to identify this from the firing line. But if you have no hole (they didn't all go through the same hole, did they?
) and you saw no dust kick up, that's a good sign of the inflight disintegration you suspect.
Another possibility is core stripping. This is where the angular (rotational) acceleration of the bullet is so great the core slips inside the jacket, extruding it longer against the rifling indentations on the inside. This results in two problems: one is that the core is rattling around inside the jacket, yanking the bullet around every which way from Sunday. The other is that the jacket winds up spinning faster than the core. Upon exit from the muzzle, the rates or rotation equalize in proportion to the angular momentum of the two spinning masses (the jacket and the core) with the result that the whole bullet can end up spinning too slowly to stabilize and ends up whizzing off to the side. Watching where the impact kicks up dirt to the side of the target is the only way I know to identify this from the firing line. But if you have no hole (they didn't all go through the same hole, did they?
) and you saw no dust kick up, that's a good sign of the inflight disintegration you suspect.No, ive done a few groups in the same hole at 100 yds, but this was not the case, the first 2 of the 3 rounds were no where, the third round showed up about where it was supposed to. Thanks so much for the advice on this, it helps me understand a phenomena that spooks me a bit, I think I had it happen a couple years ago, shooting a 52g hornady HP through my 223 that my cousin used in his 22-250, they did not disintegrate in his 22-250 at high speed, but they did in my 223 with 1 in 7 twist, and he had a lot slower twist than that. Always great to hear the knowledge of the experts here.
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.243 75gr hollow point flat base bullets??
Those are considered to be varmint bullets and will have thin jackets compared to heavier bullets made for heavier game and controlled expansion.
That being said, they still shouldn't be coming apart in flight due to rotational stress (or any other factors).
Shoot a few more, just to be sure if it was a fluke or not. IF not, then..
CALL SIERRA!!
Explain exactly what's happening, give them the lot# of the bullets with the problem. They don't intentionally send out defective bullets. If something has gone wrong in the manufacturing process AND is getting past the normal QC, they can't find, or fix it until they know about it. Once they do, they will.
Those are considered to be varmint bullets and will have thin jackets compared to heavier bullets made for heavier game and controlled expansion.
That being said, they still shouldn't be coming apart in flight due to rotational stress (or any other factors).
Shoot a few more, just to be sure if it was a fluke or not. IF not, then..
CALL SIERRA!!
Explain exactly what's happening, give them the lot# of the bullets with the problem. They don't intentionally send out defective bullets. If something has gone wrong in the manufacturing process AND is getting past the normal QC, they can't find, or fix it until they know about it. Once they do, they will.
44Amp, I'm not positive, but I think part of the reason the 2 of them flew apart, is because I must have been overspeeding them, the 43g, 3 in a 3/8 group, 43.5 the group opened up quite a bit and 44g is when it happened, and I also did not mention, that I rexamined the 44g brass when I got home and noticed minor overpressure signs of slight primer cratering and slight ejector marks on the brass, like I said I think I was overpressure because of seating them .030 deeper than the load data said, as to not jam my lands, I've decided to just load the rest of these with a slower load that worked just fine with RL15 and not buy these bullets again, and just stick with the hornady 75g Vmax bullets that I had really good luck with and no overpressure signs.
respectfully, I disagree. Consider this,
you're shooting a .243 with a 26" tube, So, top end speed would be what? 3500fps range? My data (admittedly not with your powder) shows general max from a 24" barrel and 75gr bullet in the 3400fps range, your longer barrel should give a bit more. Lets be generous and say you got to 3600fps. That bullet should still take it, and not break up in flight.
Also, you need to determine if it was just a couple of flawed bullets that beat the odds and you shot them both in the same group, OR if there is a flaw in the entire batch. Bullets #1 and #2 went poof on the way downrange but #3 hit normally. Fine. Now shoot 4,5,&6 and some others and see if there is a pattern or not.
You got pressure signs on the 44gr load cases, ok, fine, don't go beyond that, and yes back down a little for general use.
Even if you don't have any more "poofs" I still say call Sierra and let them know what happened.
Thanks 44 AMP, I will definitely keep a watch on the rest, I just finished loading up the whole rest of the 100 sierra bullets in question with everything the same, except using 36.5g of RL15, I had already chronoed these earlier at about 3220 fps using 75g hornady Vmax bullets, so I'm guessing these will be similar.
The reason i don't expect any problems is because the same day I had the 2 that disintegrated, I had already shot about 30 of these sierra the same time but they were all roughly 200fps slower, and not one of these showed any problem at all, in fact shot pretty well, about 1/2 moa at 100 yds, it was only these overpressure group that had the problem, but, as you suggested, who would expect a high speed varmint bullet to behave this way? I will shoot the other 70 sierras and let you know if I have any issues, and if so, I will give Sierra a call. Thanks again
The reason i don't expect any problems is because the same day I had the 2 that disintegrated, I had already shot about 30 of these sierra the same time but they were all roughly 200fps slower, and not one of these showed any problem at all, in fact shot pretty well, about 1/2 moa at 100 yds, it was only these overpressure group that had the problem, but, as you suggested, who would expect a high speed varmint bullet to behave this way? I will shoot the other 70 sierras and let you know if I have any issues, and if so, I will give Sierra a call. Thanks again