ELD-M Issues out to a mile

[Edwin Gideons]

I 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?

 

[Milo 2.0]

The bc of your bullet is deteriorating as you go farther. Too bad you could not have taken it out more. With your Kestrel, and link ballistics on your phone you can create a custom profile, which is over my pay grade. I usually just build a 2nd profile for the gun starting at a specific distance, adjust MV or BC or both to get it to match up.

 

[ronemus]

Is the bullet going trans-sonic before 1600 m? The bullet may be unstable and coning and/or tumbling, increasing the drag.

 

[Blaster-37]

My 7 Shehane, a winning 1000 yard gun, did about the same with 195s and 8 twist at 3015 fps. It grouped ok at 1 mile, slight wind variables, and quickly became a subsonic with nothing consistent beyond 1 mile. I have already started my 338 AI project for consistently beyond 1 M.

 

[jimbo88mm]

My 7 Shehane, a winning 1000 yard gun, did about the same with 195s and 8 twist at 3015 fps. It grouped ok at 1 mile, slight wind variables, and quickly became a subsonic with nothing consistent beyond 1 mile. I have already started my 338 AI project for consistently beyond 1 M.

What 195? Berger? Im pretty sure hornady doesn't make a 7mm 195gr bullet.

 

[Edwin Gideons]

The bullet is not close to transonic at 1 mile...it's around 1700FPS and shouldn't reach transonic until 2000M. I have cross posted this topic and have dwindled down my options for an explanation to either the ballistic tip re-surfacing some type of issue at that speed and distance or I was cross-eyed when I read my Kestrel...but that was multiple Kestrels and other programs producing the same firing solution and several pairs of eyes on it so I think the former is looking more and more likely.

 

[dkhunt14]

Are you near the max elevation of scope? Maybe funky things are going on If you are. As a side note we shot a 338-408 Cheytac and at around 1300 yards the bullets went crazy. It was not coming out of transonic at the velocity and range or even close to it. Matt

 

[Edwin Gideons]

I wasn't even using half the elevation available in the scope (13.5mils) but just in case there was a tracking issue I put it back to zero and held the firing solution answer (12.0mils) and got the same result. We had several other rifles engaging the mile target as well which eliminates some weird downdraft or lighting condition that would cause this. Probably the strangest part of this is the consistency with which I could engage the mile target even though I needed that much elevation correction. If the bullet was coming apart it was doing so very consistently.

 

[dkhunt14]

I wasn't even using half the elevation available in the scope (13.5mils) but just in case there was a tracking issue I put it back to zero and held the firing solution answer (12.0mils) and got the same result. We had several other rifles engaging the mile target as well which eliminates some weird downdraft or lighting condition that would cause this. Probably the strangest part of this is the consistency with which I could engage the mile target even though I needed that much elevation correction. If the bullet was coming apart it was doing so very consistently.

The bullets didn't come apart in the Cheytac. They just went crazy. I saw some of the bullets in the spotting scope. One climbed like a bottle rocket. It was almost Impossible to hit a barn once it got past 1300 to 1400 hundred yards. Matt

 

[ShaunBrady]

The bullet is not close to transonic at 1 mile...it's around 1700FPS and shouldn't reach transonic until 2000M. I have cross posted this topic and have dwindled down my options for an explanation to either the ballistic tip re-surfacing some type of issue at that speed and distance or I was cross-eyed when I read my Kestrel...but that was multiple Kestrels and other programs producing the same firing solution and several pairs of eyes on it so I think the former is looking more and more likely.

I shoot those bullets a few times a month to 2200 yards without the problems you're describing. The steps on our range are 1185, 1460, 1615, 2197 yards. The BC does drop with speed, but not as much or as suddenly as the issue you're having would require. Depending on the day, they're below 1000 fps at 2200 yards out of my gun.

I'm using a 1:8 32" 7/300wsm and shooting them at 3035 fps. With other cartridges, I've run them and the 195 Bergers fast enough to smoke them, but it doesn't sound like you should be quite there unless there are a lot of rounds through the barrel. With the big cartridges, they were fine to 3350 fps until the barrel wore and started tearing them up. When things went south with the barrel, they did so at all distances, starting with vertical stringing out of proportion and even direction to velocity spreads. We shoot ELR with a Labradar.

I'm interested in real experience with the 7 practical, so please let us know what you figure out.

 

[normmatzen]

Although it sounds like fun, I have never shot longer than 1000 yds. I shoot F Class to 1000 and long range BR at 600 and 1000. my F Class gun is a straight 284 WIN in a 1-9 28" barrel and 180 ELD-M bullets allow it to shoot at 600 and 1000 as good as my 6mm gun does.
Last Saturday, I shot in our monthly 1000 yd F Practice match. We had some rally twitchy wind/mirage conditions and most shooters had very low scores due to 1 MOA flyers in every which direction.

Don't you think that at a mile you increase the tendency for wind and mirage to do some really screwy things? And, any off axis weight distribution could do screwy things based on different velocities?

 

[Ledd Slinger]

I 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?

Scope is screwed up. Get a Kahles.

Then ditch the Hornady bullets and shoot Berger or Sierra.

 

[Delfuego]

Please re-read the 2nd post. This is the issue and the solution. Sierra specifically uses stepped BC for this reason. I had the same experience with my new 7mm barrel shooting 180 Hybrid. Tracked perfect to 1350 then fell apart at 1650. As Milo said, the AB "custom curves" address this. I don't use AB, so I need to step my bc down.

The bc of your bullet is deteriorating as you go farther. Too bad you could not have taken it out more. With your Kestrel, and link ballistics on your phone you can create a custom profile, which is over my pay grade. I usually just build a 2nd profile for the gun starting at a specific distance, adjust MV or BC or both to get it to match up.

 

[Edwin Gideons]

Please re-read the 2nd post. This is the issue and the solution. Sierra specifically uses stepped BC for this reason. I had the same experience with my new 7mm barrel shooting 180 Hybrid. Tracked perfect to 1350 then fell apart at 1650. As Milo said, the AB "custom curves" address this. I don't use AB, so I need to step my bc down.

100% correct. 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.

 

[Edwin Gideons]

The bc of your bullet is deteriorating as you go farther. Too bad you could not have taken it out more. With your Kestrel, and link ballistics on your phone you can create a custom profile, which is over my pay grade. I usually just build a 2nd profile for the gun starting at a specific distance, adjust MV or BC or both to get it to match up.

Thanks for pointing out my issue early on...I didn't not believe you but I don't have much experience in ELR and wanted to explore all of possible issues. It was honestly a really good review on all the elements that go into precision shooting, especially ELR.

 

[Delfuego]

Had I known this before I would have had a 1st round impact on my first attempt at a mile,

You would have had to nail the wind call too

You're welcome. Glad it's working out.

 

[Milo 2.0]

Thanks for pointing out my issue early on...I didn't not believe you but I don't have much experience in ELR and wanted to explore all of possible issues. It was honestly a really good review on all the elements that go into precision shooting, especially ELR.

I think just from the shear speed you're running them it held true to 1500, if you were down around 3000fps, I bet it would have unraveled at around 1200 yards.
Delfuego said he sees the same in a 180 hybrid, where I see the opposite, at around 1650, it seems to fly even better till it hits transonic, then it's all over, not going to repeat anything.

 

[Delfuego]

A buddy and I were speaking yesterday. He tried running the 180 ELDM and the jacket were failing on them at around 3150fps. I don't know if it is related at all, but food for though.

For what it's worth, I am running the 180 Hybrids at 1980fps and think my issue is related to the calculator solution rather than the bullet.

 

[SageRatSafaris]

100% correct. 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.

The Applied Ballistics phone app has a $1.99 custom drag model for 140gr ELDM. I wonder how it compares to the Hornady 4DOF solver.

 

[SageRatSafaris]

The Applied Ballistics phone app has a $1.99 custom drag model for 140gr ELDM. I wonder how it compares to the Hornady 4DOF solver.

Well, I bought the $1.99 AB drag model to satisfy my curiosity.

140gr ELDM @ 2710 fps. Elev 4350, station pressure 25.62, temp 84F, humid 28%, 300 yard zero (standard sea level zero).

1000 yards 4DOF: 23.65, AB CDM: 24.7 moa
1500 yards 4DOF: 51.59 , AB CDM: 53.4
1800 yards 4DOF: 76.66, AB CDM: 77.2
2000 yards 4DOF: 97.33, AB CDM: 96.1

Now I need to go shoot it and figure out which one is correct. Maybe this weekend!

The Hornady 4DOF doesn't appear to let me set the atmos for zero.