6.5 CM accurate load seems oddly low? 38.2gn H4350 ELDM 120

[james67]

I'm new to 6.5 CM and somewhat new to reloading at 2-3k so far (most of that 308), and my most accurate load so far seems odd at 38.2gn H4350 with ELDM 120s around 2550-2610fps shooting around 0.65" at 100 yards. Seems every forum post or article I read has loads reaching hotness in the 41+ and 2899+. Again I'm fairly new to this and thrilled with my results so far and not going to argue with results, but it seems odd and I'd appreciate some opinions on it. I just did some ladder loads and anything over 40.5 was literally all over the paper. and anything around 38-39 excellent.

I believe I have the OAL dialed in well, stumbled onto it somehow then got a gauge, confirming what I stumbled on was pretty damn close, a little longer than gauge says but with what I'm shooting now I don't see a reason to spend the days ladder loading and testing at this point. It's ringing 24" steel at 600 reliably and my range goes out to 1,000 so obviously that is the goal. Haven't gotten to shoot paper at 600 with it yet so 100 is the only measurable I have so far.

Gun is made of Odin Works 22" with xl gas, lantac heavy bcg, suppressed.

 

[hlee]

2600 fps is really slow for a 120 grain bullet. My accuracy load is a 147 gr ELD-M at 2700 fps…

 

[GUNNER10]

I'm new to 6.5 CM and somewhat new to reloading at 2-3k so far (most of that 308), and my most accurate load so far seems odd at 38.2gn H4350 with ELDM 120s around 2550-2610fps shooting around 0.65" at 100 yards. Seems every forum post or article I read has loads reaching hotness in the 41+ and 2899+. Again I'm fairly new to this and thrilled with my results so far and not going to argue with results, but it seems odd and I'd appreciate some opinions on it. I just did some ladder loads and anything over 40.5 was literally all over the paper. and anything around 38-39 excellent.

I believe I have the OAL dialed in well, stumbled onto it somehow then got a gauge, confirming what I stumbled on was pretty damn close, a little longer than gauge says but with what I'm shooting now I don't see a reason to spend the days ladder loading and testing at this point. It's ringing 24" steel at 600 reliably and my range goes out to 1,000 so obviously that is the goal. Haven't gotten to shoot paper at 600 with it yet so 100 is the only measurable I have so far.

Gun is made of Odin Works 22" with xl gas, lantac heavy bcg, suppressed.

While your rounds are slow, I am not sure I would chase velocity if you are not shooting to the outer limits of the cartridge thats going to be really mild on your brass. Now I would however experiment with other projectiles to see if you can a more efficient combination.

 

[bfoosh006]

How high of a charge weight did you try ?

 

[james67]

How high of a charge weight did you try ?

Max charge I tried was 42.00 H4350, lapua brass, in sets about .01 and .02 off the lands, both shot in the area of 2850fps. No pressure signs. But they would sometimes land in the wrong rings. (edit to add quote)

 

[james67]

While your rounds are slow, I am not sure I would chase velocity if you are not shooting to the outer limits of the cartridge thats going to be really mild on your brass. Now I would however experiment with other projectiles to see if you can a more efficient combination.

Exactly what I'm thinking on not chasing velocity for its own sake, my goal here is to hit things much more than it is to hit things 200fps faster, so my main curiosity here is whether those 200 missing fps make an issue in the longer range accuracy?

I bought a 500 pack of SMK 120s last week so going to try those out hopefully this weekend.

 

[GreenGO Juan]

my main curiosity here is whether those 200 missing fps make an issue in the longer range accuracy?

Its going to add to the time wind can affect it. 200 fps in a full value(90deg) 10mph wind is .2 mil (almost 5”) at 600 and around .45 mil at 1000yards(15”). So you are going to need to be more on top of your wind calling game. It also limits your max range. So yes

that seems god awful slow for that weight projectile.

 

[Precision Underground]

I shoot 123 elds at 2890 from our 20” 6.5cm gas gun. That’s pretty hot but you’re just on the other end of the spectrum. There’s nothing wrong with it and at 100-700 it prob won’t make any difference. My 123 gets close to subsonic around 1000 yards so I’d guess yours will get there around 800. That’s when it will really start to matter.

 

[james67]

Its going to add to the time wind can affect it. 200 fps in a full value(90deg) 10mph wind is .2 mil (almost 5”) at 600 and around .45 mil at 1000yards(15”). So you are going to need to be more on top of your wind calling game. It also limits your max range. So yes

that seems god awful slow for that weight projectile.

Ah wind of course. Alarm bells were going off about future trouble with not doing The thing that the cartridge seems to be known for… but being new at this I have tried to avoid anything that feels like multiplying improbabilities on things I haven’t really encountered a lot of. Thank you you answered my whole original question there.

I am going to take away that I shouldn’t just accept this and go load up another few hundred simply because they rock at 100 yards and ring all the steel at 600.

Back to the bench.

 

[GreenGO Juan]

Ah wind of course. Alarm bells were going off about future trouble with not doing The thing that the cartridge seems to be known for… but being new at this I have tried to avoid anything that feels like multiplying improbabilities on things I haven’t really encountered a lot of. Thank you you answered my whole original question there.

I am going to take away that I shouldn’t just accept this and go load up another few hundred simply because they rock at 100 yards and ring all the steel at 600.

Back to the bench.

I think you should be able to keep similar accuracy and get another 2-300 Fps. You are at 6.5Grendal velocity with none of the benefits.

 

[james67]

I shoot 123 elds at 2890 from our 20” 6.5cm gas gun. That’s pretty hot but you’re just on the other end of the spectrum. There’s nothing wrong with it and at 100-700 it prob won’t make any difference. My 123 gets close to subsonic around 1000 yards so I’d guess yours will get there around 800. That’s when it will really start to matter.

Thank you that is really helpful and exactly what I was concerned about but not sure if I was just excel-warrioring about. No reason to keep loading these up just because they are great at a few hundred then. Knowing there is a load that will rip up nickels at 100 is great, but there is still work to do

 

[GUNNER10]

Thank you that is really helpful and exactly what I was concerned about but not sure if I was just excel-warrioring about. No reason to keep loading these up just because they are great at a few hundred then. Knowing there is a load that will rip up nickels at 100 is great, but there is still work to do

Its all part of the process and each barrel, even if its the same spec, is going to respond differently to different loading.

A Fast 120 class bullet will offer similar ballistics to a slower 140 class bullet. The question is what bullet performs better in your rifle. Also, I would be affraid to mess around with different powders or OAL with the 123's doing a little trial and error. Its only going to help you understand reloading better. I wouldn't let it drive you crazy, but just take it as an opportunity to learn how all this stuff ties together.