Tuning a load to your rifle quickly and economically

[stokesrj]

Here is a way to tune a load to your rifle without spending an inordanant amount of, time, energy, or components. I recently bought a .308 barrel for my R8 to shorten and thread for my silencer but this was a used barrel that had a bit of rust at the muzzle. This wasn’t a big concern to me as I planned to cut away the compromised portion of the barrel anyway, but I still wanted to make sure it shot ok and gather some velocity data for comparison once it is shortened.
I’ve noticed that often when I do work ups in a ladder even at short range (100 yards) the answer is right in front of me even when only firing one shot per charge weight to check for pressure signs. So I decided this time I would use that method using the 168 grain Sierra Tipped Match King seated to 2.805” COL and charge weights of IMR8208XBR in .5 grain increments from min to max loads using Hodgdons Data. Using my Lab Radar, this is what I found.
39.0 2425
39.5 2475
40.0 2503
40.5 2548
41.0 2578
41.5 2643
42.0 2649
42.5 2705
43.0 2706
43.5 2744

There were two obvious accuracy nodes around 2475 fps and just a little over 2700 FPS as you can see in the picture below the first three shots at 39, 39.5, and 40 grains formed the group at the top of the target and the 42.5, 43, and 43.5 grain charges formed the three shot group at the bottom. This was discovered with only ten shots.

I then loaded three rounds at the range using 43.3 grains and shot the three shot group (bottom pic) which measures .525” with an average velocity of 2710 fps, extreme spread of 1 fps and SD of .5 fps. With only 13 shots fired.

46CA874A-4280-440E-BEF0-1DC0BBB7D604.jpeg

[ebrownw2]

Interesting. Thanks for sharing. As a novice reloader I appreciate all knowledge shared from you more experienced loaders.

[9.3x64]

Thankyou Bob, very much appreciated.

[SPEEDY]

The two biggest things I've found about accurate loads in a hurry are yse Nosler BT projectiles and seat them out as far as you can.
Any rifle I've done that with shot damn good, but this could be an additional method to try.
Combine the 3 and I doubt I could shoot good enough to notice the improvement.
But it might be something to try with my 168gn Zmax load, any improvement is a good improvement.

[secondtry]

Getting it all set up with the chrono, target, and rifle where they all need to be has always put (lazy) me off trying this method.

Maybe I should reconsider

[SPEEDY]

I always crony when working up a load anyway, best way I've found to find when I'm rraching maximum pressure.

[9.3x64]

Bob,
Why did you choose exactly 43.3 Grains to test and not 43 or something similar?

[9.3x64]

Getting it all set up with the chrono, target, and rifle where they all need to be has always put (lazy) me off trying this method.

Maybe I should reconsider

Yes I can relate to that, but if you can afford it a labrader makes it so much easier and quicker.
I purchased one a couple of weeks ago and it is easily the best single piece of reloading equipment I have ever purchased.
I have developed the below load for my 7x64 and 175 grain Woodleigh PPSN's at 2725 fps 7.3mm centre to centre, but the big difference between my load development is it was done with a magneto speed. Sure I got there in the end with a great load, but it took over 100 rounds .
Now I have the labrader I will definitely be trying Bobs method.

[mchughcb]

Im definately getting lazy. If its 20mm @100m i go hunting.

[9.3x64]

Im definately getting lazy. If its 20mm @100m i go hunting.

Nothing wrong with that attitude Chuck, because that's all you need.
I guess I do it because I actually enjoy the process and find it very interesting, not because I need to.
If I was honest with myself 2 inch groups would do absolutely everything I needed to do.

[SPEEDY]

Yep works for me.
Target and LR small game might need 1/4moa but for hunting out to 300m even 2moa is fine, but 1moa is standard these days from almost any new rifle.

[secondtry]

Getting it all set up with the chrono, target, and rifle where they all need to be has always put (lazy) me off trying this method.

Maybe I should reconsider

Yes I can relate to that, but if you can afford it a labrader makes it so much easier and quicker.
I purchased one a couple of weeks ago and it is easily the best single piece of reloading equipment I have ever purchased.
I have developed the below load for my 7x64 and 175 grain Woodleigh PPSN's at 2725 fps 7.3mm centre to centre, but the big difference between my load development is it was done with a magneto speed. Sure I got there in the end with a great load, but it took over 100 rounds .
Now I have the labrader I will definitely be trying Bobs method.

Thanks for that. I knew of the existence of Labradar, but had never bothered checking it out. That would truly simplify things, but I think I really need to have bought one before they existed

With a Blaser and a good scope, I can usually work up a load and be sighted in with under 20 rounds total, but it does take longer, and require more range visits to get it done than it would with a Labradar. I can get similar results with a similar round count using a good aftermarket barrel.

[stokesrj]

Bob,
Why did you choose exactly 43.3 Grains to test and not 43 or something similar?

I was loading at the range using my Jones Measure, arbor press and hand dies, and had in my notes a setting for the Jones that was 43.3 grains so I loaded five rounds just to see how it did. Keep in mind I wasn't trying to fine tune, because this barrel is getting chopped back to 16 1/4" for use with my moderator.
I'll repeat this ladder and then fine tune once I get it back from the machinist.

[Joe338ST]

Wow that was quick and to the point. Using Labradar is so much easier. Magnetospeed is good but it does shift POA and harmonics. So with the latter you've got to 1st find your group and then find the velocity. This method looks seamless. I'll have to give it a go when working up the 338WM and 243 barrels....

Joe

[9.3x64]

Bob,
Why did you choose exactly 43.3 Grains to test and not 43 or something similar?

I was loading at the range using my Jones Measure, arbor press and hand dies, and had in my notes a setting for the Jones that was 43.3 grains so I loaded five rounds just to see how it did. Keep in mind I wasn't trying to fine tune, because this barrel is getting chopped back to 16 1/4" for use with my moderator.
I'll repeat this ladder and then fine tune once I get it back from the machinist.

I see, makes sense.
I think I will give this method a go with the BD14, but of course I will need 2 trips to the range.