Thread: Pressure Differences - ELD-M and ELD-X

I have played around with both in 162gr and the ELD-X is a longer bullet which will reduce useable case capacity(increasing pressure) when seated at the same length.
The ELD-X also has a shorter Ogive and will contact the lands around 20thou earlier so duplicating a ELD-M load OAL could also run into pressure issues there.

Originally Posted by Cooper

I have played around with both in 162gr and the ELD-X is a longer bullet which will reduce useable case capacity(increasing pressure) when seated at the same length.
The ELD-X also has a shorter Ogive and will contact the lands around 20thou earlier so duplicating a ELD-M load OAL could also run into pressure issues there.

Thanks mate! Great info!

I know it's a pain, but I would start from scratch. They are different bullets after all.

I've shot both in my rem mag, started with the ELD-M and now use the ELDX. The powder charge for the ELD-M was quite a bit higher than the ELDX from memory, they were very compressed at length but with the ELDX I've got powder moving when I shake the rounds at the same coal.

Hope that helps.

Originally Posted by Rated M for Magnum

I know it's a pain, but I would start from scratch. They are different bullets after all.

I've shot both in my rem mag, started with the ELD-M and now use the ELDX. The powder charge for the ELD-M was quite a bit higher than the ELDX from memory, they were very compressed at length but with the ELDX I've got powder moving when I shake the rounds at the same coal.

Hope that helps.

Yep, I'm reasonably confident starting 1.5g below should be all good, but just in case I will load up one round from start to where I expect finish to be and check for pressure signs. Will use that as my cut off for when I test groupings.

Just out of curiosity does hornady have different min/max charge recommendations for the ELD-X vs ELD-M? Or do they lump them all together? I dont have the hornady manual.

Originally Posted by Hunty1

Just out of curiosity does hornady have different min/max charge recommendations for the ELD-X vs ELD-M? Or do they lump them all together? I dont have the hornady manual.

Nah, Hornady lump all weights by Cartridge. The 162gr weight class is at a max of 68.5gr of H1000

Here they are side by side, 162 ELD-M ON the left, 162 ELD-X in the middle and 175 ELD-X on the right.

How did you get on @Edunn? Have you managed to get out and shoot them yet?

Originally Posted by Rated M for Magnum

Attachment 138503

Here they are side by side, 162 ELD-M ON the left, 162 ELD-X in the middle and 175 ELD-X on the right.

How did you get on @Edunn? Have you managed to get out and shoot them yet?

Topical prompt!

Had quite an interesting experience over the weekend. On Saturday morning I loaded up one round each of the 162g ELDX from 68.5g up to 74.0g (AR2217) - obviously expecting to have to stop shooting around the 72.0g mark. COAL was 3.400", which comfortably fits in my mag (Browning X Bolt) and is 0.020" off lands.

Had faint ejector marks and flat-ish primers from 72.5 through to 74.0, but they all shot fine with no major concerns at the time. Chrono read 3115 for the 74.0g charge.

Thought I was onto a winner here, so loaded up four each of 72.5, 73.0, 73.5, and 74.0.

72.5g shot a 1" group but nothing to be excited about. Faint ejector stamp, relatively flat primer. Waited for everything to cool down, then loaded up 73.0g. First shot, noticeably more felt recoil, and bolt very sticky with a crater-like ejector stamp. Chrono showed 3144 fps. I thought it must have been a rogue load (given the day before was fine), so tried one more with exactly the same result. The tough pill to swallow is both rounds went through the same hole but far too much pressure to use that load safely.

I didn't shoot any more (obviously) and went on to validate my 7mm08 bushpig out to 300, which went really well and saved the day.

Did a lot of thinking about why the difference between the two days last night have come to the conclusion that:

1) Charges were accurate, as I weighed the leftover rounds
2) Sunday was slightly warmer and sunnier than Saturday. But realistically, I'm in Dunedin, so was only a one/two degree difference.
3) I should have paid more attention to the velocities the day before - on review, there was a flat-ish velocity node from 70.5 through to 72.0, then a jump of 97fps from 72.0 to 72.5. Probably indicating that I was hitting pressure around that 72g mark even though there were only very light symptoms. I guess this means that any small changes in conditions could cause a pressure spike? That segues on to my final finding:
4) For some outrageous and unknown reason, I had loaded everything at 3.400" COAL on Saturday and 3.990" on Sunday. I only clicked to that last night when I was re-weighing and re-measuring everything - moral of that story, is have everything written down right in front of me all the time - I follow recipes for a living (scientist) so should have bloody known better than to do it off the top of my head.

So the plan, now, is to load up four of each from 70.5 through to 72.0 in half grain increments and try again.

Very happy to hear everyone's thoughts, laughs, tut-tut-tutting, and somewhat solicited advice.

Cheers,
Elliott

Currently going through the same thing with trying to find accurate loads for a different bullet in my 7mm Mag and know how easy it is to get caught up in the hunt for speed.

I would back it down to around 70.5gr Maybe up to 72 if it flattens out? and look for something that shoots good around 2960fps

Is 3.990" coal a typo?

Originally Posted by Cooper

Currently going through the same thing with trying to find accurate loads for a different bullet in my 7mm Mag and know how easy it is to get caught up in the hunt for speed.

I would back it down to around 70.5gr Maybe up to 72 if it flattens out? and look for something that shoots good around 2960fps

Is 3.990" coal a typo?

Bugger! 3.990" is very much a typo haha. Can't figure out how to edit the post but meant to say 3.390" so 0.010" shorter than the first day pressure test.

Yep that's the plan exactly mate - Pretty confident there will be something in that group of interest. In the pressure test there was only just over an inch variation from 68.5g through to 72.0g.