My elevation is 395 feet. Running 2766 from my Norma. Stability calculates to 2.32 with my 9 twist barrel at that velocity. Temperature was 38°, with about 83% humidity.
Hammer bullets at long range….
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Zen Archery
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Had similar issue with Berger bullets back in the day. Solution at distance was switching to a bullet.
Doozy
Well-Known Member
My understanding is that bullets are supposed to become more stable during the course of the flight since the rate of spin decreases at a far slower rate than the decrease in velocity.
If what you're saying is true, I would guess the most likely option is that there were some pockets of wind at the further distances.
But if the problem were the bullet, the only thing that I can think of would be the copper is heating up and becoming softer during the duration of the flight, causing some sort of failure at longer distances due to the spin rate.
If what you're saying is true, I would guess the most likely option is that there were some pockets of wind at the further distances.
But if the problem were the bullet, the only thing that I can think of would be the copper is heating up and becoming softer during the duration of the flight, causing some sort of failure at longer distances due to the spin rate.
At 950yds 1moa is 9.423" . A six inch group is still way under a minute and under 3/4. Still not bad for that kind of distance, If that was the average and not the best of course. Maybe there was environmental influence closer to the target that wasn't apparent, cross wind coming out of cut or tree line?
Charlie Brown Jr.
Well-Known Member
With a 338 Edge, shooting 285 Hammers at 2920 FPS in a 9" 28" long Brux bbl. Only 300 ft. above sea level, I could get 1/2" or better groups at 100 yds. and 3/4" at 200 yds. Shooting at 500 yds we were having trouble keeping rounds on a 12" gong. We looked at the hits on steel and they looked football shaped, so we set up a paper target at 400 yds, and out of 5 shots 4 rds made perfect key holes, but we still had a 4" group. The bullets must have been stable to 390 ish yds. I called the guys at Hammer and they sent me some 260 gr bullets, and that solved the problem, we were killing antifreeze jugs at 1400 yds with the 260s. Looks like if you're shooting in thin air you can get away with shooting the 285s with a 9" twist. I built a 338 Lapua Imp. with an 8" twist and it shoots the 285 accurately way beyond the distance they will expand. I've only shot 4 different Hammer bullets 7mm, 30 cal. and 338s, They all shoot like match bullets, lots of bug holes. You just need to find the right twist at sea level.
You're close…
Hammers are my favorite hunting bullet, but had an anomaly with one rifle:
I had tried several of the .375's and had outstanding results until at some point they just fell off. Up to 1000 they shot great! Now 1200 meters would be plenty for some folks but not in this rifle. They would have stayed supersonic well past a mile and had a SG of well over 2. Something just happened at that range and the groups went to something you couldn't call groups. Not environmentally related, not when I can grab my .300 WinMag right after and make a first round impact followed by several more to make sure.
RockyMtnMT
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The 285g .338 cal Hammer Hunter calculates at 1.5 sg in a 9" twist at standard atmosphere. We have found that adding altitude to the Miller formula with copper bullets does not work. I think all the calculators are flawed.
Then comes dynamic stability for which there is no calculator. The longer for caliber the bullet gets the more trouble there is with dynamic stability.
Then comes dynamic stability for which there is no calculator. The longer for caliber the bullet gets the more trouble there is with dynamic stability.
You guys are making sense, and I'm glad to see I'm not the only one who's experienced this. I've never seen a bullet just 'fall off' before. The 300 MatchKings have always shot great, but I've been curious to look into solid coppers…
DoneNOut
Well-Known Member
I think you need to check if this happens on another range trip. I find a lot of times it is the indian and not the arrow.
One other thing to consider is the sample size of your ES of 10 fps. Was that for every shot fired? Just 1 round fired that is closer to 20 fps off can account for close to 3-4" vertical @ 950, but only cause about 1" @ 600.
I'm not putting that much time and money into anything a particular bullet doesn't like. For me I don't want to take the time and I do t have the money to just start swapping gun parts and buying the same thing that is not working. Shoot it several times at the needed ranges. If it flat sucks and does not shoot like you want change bullets.
Bruce Treloar
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Back in another life I had a graph based on projectile diameter, length, velocity and twist needed to stabilize. Unfortunately knowing the bullet speed at various distances was difficult to calculate except boat tail remained stable for some distances after the flat base became unstable. The graph gave the boat tails a 10% advantage over the flat base.
Based on this information you have two options, 1 increase velocity or find a suitable bullet a little shorter in length. Would also be useful to try boat tails that will extend the distance it becomes unstable.
Based on this information you have two options, 1 increase velocity or find a suitable bullet a little shorter in length. Would also be useful to try boat tails that will extend the distance it becomes unstable.
