Best Load Testing Sequence

[dataforce1@gmail.com]

Hi, I am new, and have searched to no avail about this query.

I wonder what is best sequence for testing and working up a load for .308. I shoot 100 yd and 600 yd.

equipment is Bartein bull sporter on a Rem 788 action. I glass bedded myself. What do I do first, work up best load, and then test OAL, where does ladder test come in?

here are the steps I would like to take. Please recommend additional if I err.
Current bullet is sierra 165 hpbt. ( I hunt and target, and next bullet batch will be 168 sierra matchking)
OAL to lands: I test .01 to .05 off lands in .01 increments.
load: current 4064 from 41 to 43.5. ( work in .4 grain increments)
Ladder test for sweet spot. (not effective at 100yds, better at longer range)

I prep brass, trim, deburr only neck not primer pocket yet. Measure every load, drop with a lee powder measure and measure with lee scale. I full size and neck size with lee full size die and lee collet sizer.

I seat with LC wilson seating die.
I prime with lee hand primer.

Thank you. JR

 

[Keith Glasscock]

First of all, welcome!

In you load workup, do yourself a favor and plagerize a load from someone else. 168's in the 308 aren't any real magic, they are pretty easy to tune. If you can tell us which make of brass you are using, I bet someone out here has the load close enough that you won't have to work too hard to get the rifle shooting good. For example, Federal uses 42 grains of 4064 in 168 grain FGMM ammo at a OAL of 2.800. It shoots pretty darn well in most rifles.

Having said that, if you work up a load for a bullet, do this:

Fire a series of increasing charges to determine where max is - take small steps as you near the top end. This is important information that you will need later. The 5 or 10 rounds expended will be worth it. Chronograph if you can.

If you have chono data, look at the velocities. Are there any too slow for your needs? If so, exclude those loads and start above them. Shoot 3 shot groups to determine which powder charge(s) shoot best.

Take the best shooting load you have and fire a couple of 5 shot groups before messing with the seating depth - knowing where you really are is important.

Now, change the seating depth in .003" (.010 is too much in my experience) increments and shoot 3 shot groups until the load shoots really well.

Stop, shoot a couple of 5 shot groups and compare the results to the ones before. You should have a well tuned load at this point.

 

[dataforce1@gmail.com]

Thank you. I use R P brass, but can certainly standardize on a suggested better brass.

Can I move ahead of suggested max loads if not seeing pressure issues, I do measure fire ring expansion with caliper. As suggested in Pet Loads book.



JR

 

[Larryh128]

Very nice advice from Busdriver, I wouldn't go above published max loads UNLESS your chrono reading was a LOT slower than the published velocity. ONCE in a while, you will get a barrel (bore) that is a little oversize & it will take another .5 gr or so to get to the printed velocity. NORMALLY, when you hit the max charge for your rifle, there really isn't much of an increase in velocity past that point, only noise, recoil & pressure.

 

[Keith Glasscock]

RP works fine, I use it in my Varmint loads.

You will probably find your load near the top end of your powder charges - around 43.1-43.5 but I don't have any data for that powder and case on hand. I'm sure someone here does.

 

[wapiti25]

I like to test at 300yds when developing loads. I use 300 because of the range I have access to. The differences at 300 are easier to see as they are 3 times bigger than the 100yd ones, look at the vertical spread for long range shooting.