Examining .308 Accuracy nodes

[Front Royalty]

Would like to start by saying that I'm a newer reloader. During OCW testing, it appears that I have two nodes right around 1 gr from one another, 41.4 & 42.3 grains powder. Equipment used: 10 FCP-SR 20", 168gr Hornady HPBT Match, LC15 brass weight sorted, IMR 4064, and CCI 200 primers. Just wondering if this is normal? I'm aware that there will be a low and high node, just unsure whether they would be so close to each other. Thanks in advance!

[LongRange]

Yes its very possible...im not shooting a 308 but i had 3 good nodes in my last OCW test.

[Front Royalty]

Thanks. I guess the paper doesn't lie!

[Robinhood]

Sounds about right.

[LongRange]

id load up 6 rounds at both charge weights and shoot 5 shot groups with each to see which groups the best and then work from there...i say 6 rounds just in case a shot is pulled you have a back up to verify...then when your happy with the results at 100yds shoot the same load at 300 to 500yds to make sure it holds together.

[WinnieTheBoom]

It's very easy to hit accuracy nodes with close to minimum charge weights but your velocity is going to be way down. Using the same bullet/powder combination, I'm getting 2,620 fps with 44.0 grains of 4064. You can go all the way up to 46.0C, which I wouldn't recommend, but just to give you an idea of what charge range you're dealing with...

I use 42.0 grains as my go-to sighting/fouler round, but trajectory validation with any wind beyond 400 yards is a nightmare. Velocity was just over 2,500 fps, and while it's good for 1-200 yard accuracy, anything beyond that range it is pretty tough going.

[Front Royalty]

It's very easy to hit accuracy nodes with close to minimum charge weights but your velocity is going to be way down. Using the same bullet/powder combination, I'm getting 2,620 fps with 44.0 grains of 4064. You can go all the way up to 46.0C, which I wouldn't recommend, but just to give you an idea of what charge range you're dealing with...

I use 42.0 grains as my go-to sighting/fouler round, but trajectory validation with any wind beyond 400 yards is a nightmare. Velocity was just over 2,500 fps, and while it's good for 1-200 yard accuracy, anything beyond that range it is pretty tough going.


I'm getting an average of 2560 FPS with 41.4 gr in LC Cases out of a 20" barrel using CCI 200 primers. 42.6 gr is pushing capacity in this thick brass.

ETA: Didn't get the chrono opportunity for the 42.3 loads, but definitely will next time.

[wbm]

shoot the same load at 300 to 500yds to make sure it holds together.

Loads that may be accurate at 100 may not be at 500....low extreme spread values are very important at longer ranges.

[Front Royalty]

Loads that may be accurate at 100 may not be at 500....low extreme spread values are very important at longer ranges.

Good info. Thanks.

[LongRange]

Loads that may be accurate at 100 may not be at 500....low extreme spread values are very important at longer ranges.

i agree and exactly why i said to make sure it holds together.

[WinnieTheBoom]

I'm getting an average of 2560 FPS with 41.4 gr in LC Cases out of a 20" barrel using CCI 200 primers. 42.6 gr is pushing capacity in this thick brass.

ETA: Didn't get the chrono opportunity for the 42.3 loads, but definitely will next time.

I'm using Hornady brass, so that might be the discrepancy. 44.0 gr was 2,620 fps with the spread being just under 10 fps. The 42.0 gr load was shooting about 100 fps slower with the SD being about 12 fps. Primers were the same. I guess using the thicker brass would definitely contribute to that difference.

[Front Royalty]

I'm using Hornady brass, so that might be the discrepancy. 44.0 gr was 2,620 fps with the spread being just under 10 fps. The 42.0 gr load was shooting about 100 fps slower with the SD being about 12 fps. Primers were the same. I guess using the thicker brass would definitely contribute to that difference.

How long are you letting the barrel cool between shots? My ES was way more than 10. More like 100. Since then I've sorted the brass and bullets by weight, and am hoping that more diligent powder measuring will bring that number way down. I figured due to hotter barrel and chamber, higher pressure, etc.

[Front Royalty]

i agree and exactly why i said to make sure it holds together.

Definitely, and thank you! I see the .260 is treating you well.

[LongRange]

Definitely, and thank you! I see the .260 is treating you well.


Love the 260...its a fantastic cartridge,very versatile and easy to load for.

[WinnieTheBoom]

How long are you letting the barrel cool between shots? My ES was way more than 10. More like 100. Since then I've sorted the brass and bullets by weight, and am hoping that more diligent powder measuring will bring that number way down. I figured due to hotter barrel and chamber, higher pressure, etc.

It does help letting the barrel and chamber cool between shots - I've noticed that my rifles always shoot a lot better when it's not getting super heated.

The biggest thing with reloading is consistency. Make sure you're using brass from the same lot, setting the shoulders back the same amount, cutting them to the same length, using powder from the same bottle, making sure charge weights are perfect, and there's no discrepancy in seating depth. I'm talking anything more than .001" variance and I'll start over again. It can be very tedious sometimes to pay that close attention to it, but I think the attention to detail is ultimately what pays off.

Weather is also going to have an effect on certain types of powder. I've had my best luck with 4064 and Varget in my .308, but ymmv. It's just a matter of finding what shoots best in YOUR rifle, not what anyone claims shoots well in their's... even if it's the same exact model. No two rifles are going to be the same, so go through the process top to bottom, even if you think you're being overly compulsive. Guarantee you'll find a load that shoots.