.308 Load Development Increments...?

[Saluki91]

I’m new to .308, and would like to know how the seasoned veterans develop their loads.

Are .5 grain increments sufficient for a load ladder, or should I look at smaller samples (.4gr, etc).

For my stash of 168gr SMK HPBT, I have some IMR4064, Norma 202, and BL(C)-2 to play with... anything else I should consider? This will be for punching holes in paper, not critters.

Thanks!

 

[IALoder]

I have always done .4-.5gr increments in .308, then down to .1 or .2gr once I find a suspected "node". .3gr increments worked pretty well, but I still did the .1gr after. .5 can cover a pretty wide load range pretty quickly!

 

[AJC1]

.3 is good for inital testing and .1 to establish nodes. 3 shot test groups at .3 and 5 shot at .1.

 

[bluejay75]

IAloder is spot on. In the photo below all groups were acceptable for hunting accuracy with a 180 SGK in 308, 4064 powder BUT 43 was bookended by to groups with less than optimal SDs for 500 yard accuracy. This is going to let me know I cannot just dispense these charges and load. They have to be near exact. Bottom line is you miss too much by having those wide gaps in charges.

 

[bluejay75]

So based on this my next increments will be 43.1 and 43.5 4064 to see what I have there. If the groups stay similar size I’m going with the best SDs. And I’m reshooting 43 to see if the flyer was me. This time 10 shots. Don’t stop at good enough. Almost every reloader out there started that way. Stop when you’re at the best the gun can do. .5 increments will rarely get you there.

 

[Nature Boy]

If I'm starting from scratch I'll go 0.5g increments and if I'm zeroing in on where I think there might be a node I'll go 0.3g increments.

Here's an old thread of mine on load development for .308 win. I was just getting into F Class and started using Eric Cortina's variation on the OCW method. That made all the difference in my load development

https://www.thehighroad.org/index.php?threads/308-long-range-load-development-results.822638/

 

[AJC1]

So maybe the better answer is to use the charge weight range to determine your incrimination. Also commonly successful loads are usually easy to find and using those successes to reduce you component expenditure and time may make a large difference. 308 is hugely popular and has sent a lot of rounds down range.

 

[bluejay75]

@Nature Boy 43.5-44 behind a 180 class bullet and Varget is very forgiving and routinely gives me 2.something SDs for 5 shots. Any luck with getting 4064 to shoot like that. I’m saving my Varget for hard times.

@Saluki91

You need to determine if you want to chase the high or the low node. .5 increments if you want to try from min to max. Low node on 4064 with bullet you listed is from 41.5-43. High node is going to be somewhere between 43.5 and max for your gun/brass/ seating depth combo.

 

[Blue68f100]

I generally jump in 1% increments. So 40gr I would jump 0.4gr. Once I find a indication of a node I fill in the gap.

 

[dgod]

Personally, .2 gr for my ladders, then finalize at .1 increments. Good Luck

 

[Nature Boy]

@Nature Boy 43.5-44 behind a 180 class bullet and Varget is very forgiving and routinely gives me 2.something SDs for 5 shots. Any luck with getting 4064 to shoot like that. I’m saving my Varget for hard times.

I started with Varget but found H4895 better (unfortunately, it's just as hard to find as Varget). My current F/TR load is 185 Berger Hybrids, 43.5 H4895, Lapua Palma brass, BR4 primers, 2,725 FPS. There's a lower node ~42.7g that's easier on brass.

I've not had any success with IMR 4064

 

[Saluki91]

@Nature Boy 43.5-44 behind a 180 class bullet and Varget is very forgiving and routinely gives me 2.something SDs for 5 shots. Any luck with getting 4064 to shoot like that. I’m saving my Varget for hard times.

@Saluki91

You need to determine if you want to chase the high or the low node. .5 increments if you want to try from min to max. Low node on 4064 with bullet you listed is from 41.5-43. High node is going to be somewhere between 43.5 and max for your gun/brass/ seating depth combo.

So much good info here... thanks to one and all!

 

[bluejay75]

I punch more holes in critters than paper so I’m looking at the parameters of terminal performance and bullet minimum impact velocity when I’m building loads. I can always sacrifice a little accuracy to make the bullet perform better for another 75 yards or so. So the target guys might give you a better answer because 1moa, good SDS with a hunting bullet is perfectly ok for me.

 

[jmr40]

I've never had any problem finding a good load using .5 gr increments with any rifle cartridge. If the beginning load is 43.7 I'll round up to 44 and then go 44.5, 45, etc. Most scales aren't accurate enough to reliably measure anything below .3 gr anyway.

 

[Charlie98]

I use .5grn increments to see if a bullet/powder combo is feasible... if I don't see anything worthwhile in a bracket of 1.5grn, I need to change something.

As a matter of fact, I just loaded my final ladder for my .308 Savage bolt gun... .3grn spread with IMR4064 and the 168grn SMK. I've actually already settled on 42.5grn, but I swapped to the SMK from the Nosler CC... just to see if anything magical happens. I've actually got a box of Hornady 168's waiting, too... but I'm going to see how the SMK's do, first.

Now, here's the deal... and I'm being completely honest here... my shooting skill from the bench leaves a little to be desired. Scopes are new to me, so I'm learning how to shoot with it, and I don't have all the truck some bench shooters have... bags and rests and all that. I shoot off my bipod with my fist under the stock to level and steady it. It's probably unlikely I will see much, if any, difference in my ladder loads I've just loaded... unless I just hit one of the nodes square on. Also, my brass prep is not what you would call comprehensive... I just size it, trim it, load it, and shoot. So, in reality, a .3grn spread for me is likely good enough.

 

[Skeptic13]

If it is a new powder I will usually start with .5 gr increments. After I have done an initial run with 5 shot groups then I move to .3 gr increments and adjust from there.