Load Development Help

[TSparger]

So I’m fairly new to handloading and I ran what I consider my initial load testing as seen on attached graph. These were 5 shot groups at each charge weight. I’m kind of perplexed as to what my next steps should be. I’m thinking pick what appears to be the optimum charge (I’m thinking based on the graph to be 39.8) and load some rounds with varying seating depths. Any advice would be greatly appreciated. By the way I’m loading for PRS comps primarily.

 

[TheOfficeT-Rex]

Two thoughts -
1.Did you pressure out on this test? 2672 is about 75 fps slower than a 'standard' 140 load, unless you have a naturally slow barrel. What does factory ammo run, speed wise, in your set up?
b. I find that I have problems with CCI 400s in anything larger than 223. I tend to pierce them at higher pressure, even in a mellower 6BR load. YMMV.

 

[Steel head]

I’d go higher unless you found pressure.
Your pretty slow and well under common loads.

Keep an eye on those CCI 400’s, could be your weak link.

 

[TSparger]

Two thoughts -
1.Did you pressure out on this test? 2672 is about 75 fps slower than a 'standard' 140 load, unless you have a naturally slow barrel. What does factory ammo run, speed wise, in your set up?
b. I find that I have problems with CCI 400s in anything larger than 223. I tend to pierce them at higher pressure, even in a mellower 6BR load. YMMV.

I did not see any pressure signs. Factory was running about 2700 FPS. I was doing this load development in the first couple hundred rounds through my new barrel. Wish I could get my hands on some 450 primers but we all know that situation now.

 

[Steel head]

I did not see any pressure signs. Factory was running about 2700 FPS. I was doing this load development in the first couple hundred rounds through my new barrel. Wish I could get my hands on some 450 primers but we all know that situation now.

Yea
400’s are just the weakest small rifle primers made.
Even Remington and federal small rifle are better options for large, higher pressure cartridges.

There has been some of the military CCI SRP out lately.

 

[Newbie2020]

Unless you’re dying for max velocity it Looks like 39.4-39.8 are all good. Now shoot an OCW test of those three for group size and roll on. I’m shooting 130 gr Noslers at 2,650 and loving the light recoil.

 

[stello1001]

If I were you I'd burn through factory ammo until barrel speeds up and collect brass to reload. Or do the same with reloads but just run a low charge weight and fire form brass. I too think your MVs look low.

If I had to pick from those charge weights though, I'd do 39.6. It's right between two charge weights with low SD & ES. But regardless, I still think this data is irrelevant. Your barrel may speed up a bit later since it's new. Regardless if it speeds up or not, this is not enough data to make a final determination.

 

[Steel head]

Unless you’re dying for max velocity it Looks like 39.4-39.8 are all good. Now shoot an OCW test of those three for group size and roll on. I’m shooting 130 gr Noslers at 2,650 and loving the light recoil.

That’s got to be really mild!

 

[DellaDog]

JMO, but forget the chrono for now. 40.7 to 41.7gr 4350, .015 off the lands in .03 gr. steps with 140s and see what the target tells you. You’ll probably end up around 2750 with a 26” barrel like many others.