ELD-M Issues

[Edwin Gideons]

I recently spent some time in Idaho with my 7 Practical and shot from 1180M to 1600M. At 1600M I had a significant jump in required elevation (1.5 mils) to make hits that didn't track with any of my other engagements. I was only off by .2 mils at 1520M and dead on up to that point. I'm running a 28" 1:8 Krieger, pushing the 180 ELD-Ms at 3190. As strange as the jump in required dope was, the hits were consistent at both 1520M and 1600M. Calculator was a 5700 w/ the latest version of AB. All environmental data was backed up by about 10 other Kestrels, GPS, LRFs and compasses. Any thoughts?

 

[Wagoner]

Were you shooting into a headwind? Winds do not just affect the bullets horizontal path. Even excluding Spindrift winds can do some funny things with your vertical at ELR. Many times downdraft caused by structure or other phenomenon can significantly change your point of impact.

 

[steve123]

I recently spent some time in Idaho with my 7 Practical and shot from 1180M to 1600M. At 1600M I had a significant jump in required elevation (1.5 mils) to make hits that didn't track with any of my other engagements. I was only off by .2 mils at 1520M and dead on up to that point. I'm running a 28" 1:8 Krieger, pushing the 180 ELD-Ms at 3190. As strange as the jump in required dope was, the hits were consistent at both 1520M and 1600M. Calculator was a 5700 w/ the latest version of AB. All environmental data was backed up by about 10 other Kestrels, GPS, LRFs and compasses. Any thoughts?

Something just like that happened to me shooting ELR - 1450Y, 1900Y and 2100Y. I thought my S&B had broke but I found out later that the scope was fine.

During that ELR outing, when I had the big POI shift, the other thing that happened is the accuracy went to crap. Day one was very successful, I hit almost twice as much as the other guys but on day two I couldn't hit anything which was when the POI shift occurred. At that time I didn't check my zero but I wish I had. I think it was fine though.

When I got back home I cleaned the rifle really good, Next time out I confirmed zero, it was on, dialed for the 1122Y plate, hit it and the dope was perfect for the next 3-4 shots. Repeated a week later and all was good. I don't trust this barrel anymore though.

IMO, the barrel was on it's last legs, which makes the bore foul much quicker than it used to earlier in it's life, which I think was the cause of the inaccuracy and POI shift??? I retired that barrel because it had 1600 rounds through it.

Oh, BTW I was using 225 ELDM at 2935 fps in my 30-375R.

 

[Milo 2.0]

Not sure I'm bringing anything to the table here, but I shot 140 eld m's in a 6.5 SLR. I've never had a bullet match up dope wise to my Kestrel like it did, from 300-1600 yards, it was unreal.
I gave up on the bullet after having to redo seating depth 2 times, every 150 rds it changed, horizontal downrange just went whacky.
Bullets do funny things the farther you shoot them, I wouldn't think it would tank in 80 yards, especially at those speeds.

 

[CharlieNC]

What distance does your load drop below sonic?

 

[Edwin Gideons]

The load is supposed to still be pushing 1700 FPS at a mile and starts transonic around 2000M. Other rifles shooting the same target did not have any anamolies to explain what was going on with my rifle. Dope stayed true at that distance for three days so it wasn’t a temporary affect.

 

[6ShotsOr5?]

Even though those tips are made from a more heat resistant polymer could they be deteriorating when they fly far enough at the speeds you were pushing them? I have shot the 0.264” 140 ELD-Ms out to a mile but they are a little smaller OD and I was pushing them a few 100 fps slower. At the altitude I was shooting mine were just going transonic at about 1700 yds. They tracked good but I was shooting at ~1.5 MOA boulders, so not sure if they had begun to drop off a little, but I don’t think they had dropped off the track too much.

 

[Milo 2.0]

If you'd give the parameters entered into your app, (like what bc was used)maybe we can see something amiss. The bc .401 of this bullet that Hornady states it is, is awful high, and may explain degradation of your drops.

 

[Zero333]

When shooting at a mile, Custom drag curves are the best solution over g1 or g7 values.

 

[Rob01]

Shooting in the mountains? Winds can make bullets do odd things. It can roll down hills and push bullets down especially as they are slowing at ELR. Also doesn't sound like an ELD-M issue but an ELR issue.

 

[Edwin Gideons]

The answer has been found and now I have a reliable way to shoot as far as I can imagine! I was waiting to hear back from Hornady and I did today. They have custom drag models for all of their bullets in their free 4DOF ballistics calculator. When I plugged in all of my parameters from 2 weeks ago the firing solution was within .1 mil of what I needed to hit at a mile. Had I known this before I would have had a 1st round impact on my first attempt at a mile, instead of 3 with a lot of come up. The data inside of 1 mile was also perfectly lined up with everything I collected in Idaho.

I appreciate all the replies and I'll keep shooting the ELD-Ms in all the rifles I use for precision...and I'll use Hornady's 4DOF for anything beyond 1K.

 

[Rob01]

Glad the issue was found and that you found 4Dof. It works great even below 1000. I have it on my phone as it's a free app there as well as on the Hornady site and use it at matches.