Was shooting some ELDM 140 at 276 yards today and using the ballistics x app to give me dope. First shot a touch high. Made on click correction and was dead center the next 3 shots. I plugged in the correction into the muzzle velocity truing and it spit out 2,848. Can that be correct. Rifle is Savage 10 6.5CM with 22” barrel, 1/8 twist. I have 2,700 plugged in for velocity with the 147’s and it was right in with the apps dope call.
Range Report ELDM 140 muzzle velocity 2848?
- Thread starter Cfshooter
- Start date
That could be it. I am back on zero now and will go right to 276 next trip out to see how it goes.
Remember, add in even if the zero offset is tiny.. that tiny 100y offset does weird shit if you try to tune velocity later and don’t account for it.
It seems that way. When I plug in the .25” that my zero was off into the zero offset and put my velocity back at 2700, it gives me the exact dope I used.
I don’t know if this helps, but if you’re speaking about factory loads I believe it. I’ve pulled several eldm rounds and weighed the powder to find out their loaded really hot from factory. 43.7 was about average only being off a grain or two here and there. Same for hornady bulk 140 bthp. I reload mine at 41 grains of 4350 and get 2700 fps avg and 2690 with Berger hybrids. Maybe someone else can chime in here that’s loaded hotter I’m not sure if 2+ grains will give you an extra 148fps increase or not but Id bet it’s probable. Good luck.
So, ES of over 100 if I’m reading that right?
The worst lots I’ve seen of eldm have been 40-60 ES.
130...$175 chrony may have something to do with it. But the occasional super sticky bolt lift tells me thee was major variation.
If you're chambering the round from the mag, then waiting the 20 seconds to fire, then the cartridge is heating up as it sits in the chamber........., and so is the powder.
As successive shots are made, the chamber heats up more, causing higher powder Temps and would contribute to the increasing velocity Trend.
As successive shots are made, the chamber heats up more, causing higher powder Temps and would contribute to the increasing velocity Trend.
^^ yep. Fire one , extract immediately after follow thru and leave bolt open , dont rack another one if you are testing ES / SD.
Once you are back on target and comfortable , rack another and fire asap. Bout 5 rounds per set is enough unless you are in really
cold conditions . You can easily test the effects of cooking a round if your chrono is working properly ; try running 5 shots in 30
seconds or less , then leave the 6th shot in the chamber for at least 30 seconds before firing .
This issue is one of my biggest problems teaching ELR classes ; its right next to guys taking 15 seconds to shoot after a
wind call ....... Borrow a better chrono if you can , Magnetospeed or Labradar will tell the truth pretty quickly .
Once you are back on target and comfortable , rack another and fire asap. Bout 5 rounds per set is enough unless you are in really
cold conditions . You can easily test the effects of cooking a round if your chrono is working properly ; try running 5 shots in 30
seconds or less , then leave the 6th shot in the chamber for at least 30 seconds before firing .
This issue is one of my biggest problems teaching ELR classes ; its right next to guys taking 15 seconds to shoot after a
wind call ....... Borrow a better chrono if you can , Magnetospeed or Labradar will tell the truth pretty quickly .
I’m likely going to start using the method @Lowlight has been mentioning lately.
Only use chrono to check for ES/SD to make sure loads are consistent.
Zero at 100. Take it to 300, note the drop, input in the calculator and let it tell me what muzzle velocity it wants to use. Then take it out to distance to tweak BC if needed.
Why use the middle man (chrono) and fight against the calculator if I have range available to true data.
Only use chrono to check for ES/SD to make sure loads are consistent.
Zero at 100. Take it to 300, note the drop, input in the calculator and let it tell me what muzzle velocity it wants to use. Then take it out to distance to tweak BC if needed.
Why use the middle man (chrono) and fight against the calculator if I have range available to true data.
Exactly. I chrono with my magnetospeed the first 3-5. Confirm my zero. Then send it out to 500-700 to true BC. Call it done for that load.
whole lot of this. almost every shot gets faster as chamber heats and powder cooks getting hotter and hotter
The only issue with 300y and super fast loads 3,000 fps types and small MV variations, is the vertical component is often hidden in the noise of the load.
The gravity component between 3000 and 3015 average MV at 300 is just over 1/10 of an inch, where as if you run it out a tiny bit to 450ish it will be over 1/3" and a heck of a lot easier to see & verify.. Of course even lower differences will be harder~
something to think about
The gravity component between 3000 and 3015 average MV at 300 is just over 1/10 of an inch, where as if you run it out a tiny bit to 450ish it will be over 1/3" and a heck of a lot easier to see & verify.. Of course even lower differences will be harder~
something to think about
I learned my lesson one time with this:
A while back, I was doing some positional practice and let about 20-30 rounds go in about a 3-4 minute time span. Decided to shoot a couple of my "borderline" high pressure/velocity rounds I was testing and had shot 10 or so of them at the beginning of my session when my barrel was cool.
Chambered one, got distracted for about 30 seconds. Fired it. Pierced primer, heavy bolt lift, had to pound the bolt to extract.
I was able to take a dental pick and pull out the primer by hand, had the most distinctive ejector swipe I have personally ever seen.
So, lesson learned. Get on target, chamber, then shoot within a couple/few seconds. OR don't be in a rush and just let the chamber cool down.
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