300 PRC load data suggestions

[blacktailcentral]

I am about to start load development with the 300 prc running 199 gr hammer hunters with retumbo powder and cci 250 lrm primers and adg brass. Hoping to get close to 3,000 fps +-. Any suggestions on distance off the lands and powder charge for the ladder test? I will be shooting this out of a 24” 1in9 twist proof barrel.
Thanks!

 

[Vicomb]

I haven’t tried Retumbo because I scored 16 lbs of RL 26. But just shot this past weekend with 199 HH - 76.4gr rl 26 - fed 215m getting over 3100 fps. 40 thous off lands.

 

[blacktailcentral]

I haven’t tried Retumbo because I scored 16 lbs of RL 26. But just shot this past weekend with 199 HH - 76.4gr rl 26 - fed 215m getting over 3100 fps. 40 thous off lands.

I am going to start 40 thous off the lands too. And try 78,79,80,80.5 gr retumbo with cci 250

 

[blacktailcentral]

I haven’t tried Retumbo because I scored 16 lbs of RL 26. But just shot this past weekend with 199 HH - 76.4gr rl 26 - fed 215m getting over 3100 fps. 40 thous off lands.

What length barrel and twist rate?

 

[Vicomb]

Browning X-Bolt Pro 26" 1-8 twist

 

[hburggunner]

22" proof 300 PRC here 1:9

78g Retumbo
2.930" CBTO (max CBTO in my chamber is 2.960" measured with modified case + Hornady OAL Guage) 30 thousands off lands
212 ELD-X
CCI 250

not chrono'd but grouped .0356' 4 shots @ 100yds

 

[SloppyJ]

22" proof 300 PRC here 1:9

78g Retumbo
2.930" CBTO (max CBTO in my chamber is 2.960" measured with modified case + Hornady OAL Guage) 30 thousands off lands
212 ELD-X
CCI 250

not chrono'd but grouped .0356' 4 shots @ 100yds

I just loaded up a bunch of test rounds to break my barrel in. I'm running the same 22" Proof. I'm using 215 Hybrids for now and I'm trying Staball HD, H1000, and I talked myself into doing a batch of Retumbo too.

I'm glad I did if you're getting those results with it. I'm at 2.95 with my comparator 20 thousandths off the lands. Using lapua brass.

Did you find pressure there? The max load from Hodgdon was at least a few grains higher. I loaded up in 0.2 grain increments to find pressure.

 

[hburggunner]

Only light extractor marks for me, with no real pressure issues. The primers look good.

I did chrono this load at avg fps = 2801fps. Since this is a 22" and I'm suppressed, that's slowing them down some. This chrono was with the suppressor as it will be shot that way primarily.

Now to work on getting the ES and SD down a tad. My ES was around 25, SD around 10. This was once-fired Lapua with no real direct prep other than sizing.

I'll now re-size these, and run them through a .3065 expander mandrel, powder charge, and seat. This should give me the consistency in neck tension to get those numbers down.