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Which is more Accurate ELD-X or ELD-M at Long Range

  • ELD-X 308 178g with .552 B.C.

    Votes: 2 66.7%
  • ELD-M 308 178g with .547 B.C.

    Votes: 1 33.3%
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Discussion Starter #1
Our mission is to find Which is More Accurate Long Range ELD-X 178 or ELD-M 178 .308? What are the differences? My goal is to prove the SCAR 17 Can be accurate at 1,000 yards. What are your Long Range Experiences with the SCAR 17 OR shooting both the ELD-X (which has a higher B.C. than the) ELD-Match.
 

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Discussion Starter #2 (Edited)
The 178g ELD-X is Longer Than the 178g ELD-M. Will This give it More Stability?

The 178g ELD-X is Visibly Longer Than the 178g ELD-M. Will This give it More Stability in Flight? 178g ELD-X= 1.411 inches Long While the 178g ELD-M= 1.317 inches Long. I believe the 178g ELD-X's Longer shank might give it More Stability in the barrel and make the rifling more influential on the longer shank of the bullet. Will This give it More Stability in Flight?
 

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Discussion Starter #3 (Edited)
The 178g ELD-X has a smaller and more curved Boat Tail Than the 178g ELD-M.

The 178g ELD-X has a smaller and more curved Boat Tail Than the 178g ELD-M. The Diameter of the ELD-X Boat Tail is .190" and the Diameter of the ELD-M Boat Tail is .211"
 

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Discussion Starter #4
I estimate that the longer shank of the 178g ELD-X and the small and rounder Boat Tail of the ELD-X is why the B.C. (ballistic coefficient) of The ELD-X is higher than the same weight 178g ELD-M. Will this combination make it more accurate at 700-1000 yards? It should give it more velocity and allow it to stay above the speed of Sound if we can find the right powder charge to put behind these Extremely Low Drag bullets.
 

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Discussion Starter #5
The 178g ELD-X has a Larger Heat Resistant Polymer Tip Than the 178g ELD-M.

The 178g ELD-X has a Larger Heat Resistant Polymer Tip Than the 178g ELD-M. Hornady advertises their Heat Resistant Tip Deforms less than other manufactures polymer tip giving it better long range aerodynamics.
 

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Discussion Starter #6
I just got the 2018 Hodgdon(Manufacturer of Varget) Annual Reloading Manual and it shows starting load of 42.0g and max of 45.0g* compressed load for the civilian 308 brass for 175 SMK's and Varget powder. My Lyman Load data shows the max charge at 45.2g* of Varget compressed. Remember that using Lake City Brass or other military surplus brass requires less powder and generates more pressure than the slightly larger inside diameter civilian 308 brass!
 

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Discussion Starter #7 (Edited)
After Doing a lot of research and studying the advice of other SCAR 17 owners and long distance shooters, I will use VARGET powder in part due to the Huge Temperature extremes ( -40 degrees Fahrenheit January 1st to +108 last July) where I live and Shoot in Montana. I will also use Lake City 7.62 brass that was "fire formed" (shot when new) in my SCAR 17 and I will reload. I will only use the same Year of manufacture brass and separate the brass by uniform weight for my long distance Testing. I will also use Winchester WLR primers from the same Lot because I have 2000 on hand.
 

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Discussion Starter #8
After reading some more of the great posts on this forum about loading for accuracy, I measured my SCAR 17 Chamber length to Lands With the ELD-X bullet(this measurement will be different for every individual rifle and every different bullet) several times to be sure. My Chamber Overall Length was 2.905. I measured my Magazine with an internal diameter of 2.865. I have read on a couple of different forums that in order for your SCAR 17 to feed reliably your Maximum Cartridge Over All Length should be .030 less than your Magazine. So Am I correct in estimating that my Maximum CartridgeOAL (to feed reliably from the magazine) should be 2.835? Has anybody had reliable results using a COAL of 2.835 or longer from their magazines into their SCAR 17?
 

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Discussion Starter #9 (Edited)
2.834”worked great in magazine no FtF or FTE in 22 rounds

* WARNING This Load Data is For MY RIFLE Only and could be DANGEROUS in ANYONE Else Rifle! This Showed Pressure signs as cratered primers** I tried 22 rounds in my SCAR 17 178g ELD-X C.O.A.L 2.834" Lake City brass 43.5g Varget WLR primer. 2.834”worked great in magazine no FtF or FTE in 22 rounds; but checked Last 2.834" round in magazine was compressed to2.820” after 22 shots- 2 shots hand fed But shortening maybe due to hand extraction frommagazine
 

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Discussion Starter #10
* WARNING This Load Data is For MY RIFLE Only and could be DANGEROUS in ANYONE Else Rifle! This Showed Pressure signs as cratered primers** I tried 22 rounds in my SCAR 17 178g ELD-X C.O.A.L 2.834" Lake City brass 43.5g Varget WLR primer. 2.834”worked great in magazine no FtF or FTE in 22 rounds; but checked Last 2.834" round in magazine was compressed to2.820” after 22 shots- 2 shots hand fed But shortening maybe due to hand extraction frommagazine
Does Anyone else get cratering primers like this without more flattening of their primers, in their SCAR 17 in a below max load? I know it can be caused by having a larger firing pin hole than firing pin. I believe I am below Max pressure because I don't see much marks on the Head stamp on the base. WHat do you see from your SCAR 17?
 

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Not only does the color play an important variable, but rather you left the sticker on or not is definitely a key component you must consider as well. Good thread and idea. Going to test any other powders?
 

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Primer flowing is one of the first signs of excessive pressure. IMO, you’re making too many assumptions with reduced case capacity. I find that LC brass is 1.5-2 grains lower in capacity to Winchester, other brass is probably similar. I’d use the A-Max bullet table instead SMK, I’d be closer to an actual load.

Id back off until the primer stops flowing, or at least less than what your getting.
 

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If there are no other pressure signs except for the flowing of the primers, i would consider going to a hardened primer first like the CCI34 military primers. Also, how did you swage your brass primer pockets? Did you remove brass or reform it?
 

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Discussion Starter #16
If there are no other pressure signs except for the flowing of the primers, i would consider going to a hardened primer first like the CCI34 military primers. Also, how did you swage your brass primer pockets? Did you remove brass or reform it?
I had issues reliably priming the brass after using my friends Swager; so I switched to a rcbs "military crimp remover" reamer. it removed some brass from the head. after reading the good advice in this forum ; I "pulled the trigger" and ordered a chronometer so I can check the velocity and calculate the pressures of my future loads. I don't want to over pressure my SCAR 17 and all my components; BUT I do Need to be near top recommended pressure in order to stay above the sound barrier to stay stable to the 1,000 yard target. I figured only knowing the velocity would be a reliable/easy way to check pressures and keep them safe while developing high powered but under Max loads. p.s. I just loaded up some 43.3g loads (.2 grains lower than my last accurate load) to see how they compare.
 

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Discussion Starter #17
I tried reducing the Load .6 grains and the primers still look just as cratered And the grouping loosened up. I then did a ladder working my way back towards the 43.5g load which does show pressure signs (slightly swiped head stamp) and I got 3 Good Groups at 100 yards with 43.3g of Varget, 178g Hornady ELD-X bullets, Winchester WLR primers(reputation for being soft), Using Lake City 7.62 brass at 2.835"OAL or 3.191" using Hornady COAL ogive bushing comparator. The Best 3 Shot Group was .52" center to center spread.
 

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Discussion Starter #18
I bought a Chronometer, but it has been unreliable in the late afternoon sun or the below 32 degree weather. Does anybody know of an online calculator to convert velocity, bullet weight, barrel length and twist into an estimated chamber pressure?
 

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I usually get the same firing pin primer craters when using WLR on my SCAR17.

I have observed these craters before & after pressure increase causing flat primers and head stamp marks.
 
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