300 PRC OCW Test and Questions

[BStark78]

Alright heres what I am thinking. Increase neck tension a little to increase initiation pressure and tighten up your velocity spreads (possible incomplete burn at 26")

If you have a limb saver or other after market recoil pad remove it.

.7" at muzzle for a 30 cal is not a heavy profile. Make sure the barrel cools down as much as possible in-between groups. 5 shot groups for a varmint or less profile barrel might be more shots than that barrel can pump out consecutively.

Are you shooting these round robin or complete groups?

How are you measuring this powder?

How good of a group shooter are you? Can you shoot small groups? Do you shoot magnums often? Flinch can happen with big boys.

If it has a break make sure it is securely attached.

I’m running 2 thou neck tension now and have the 3 thou bushing

I’m using an adhesive barrel temp strip and waiting between shots until temp returns to ~90’ range.

I’m using an A&D FX-120
w/Auto trickler v3 for powder.

Shots are round robin per OCWReloading website.

I have a APA break on the rifle tightened per mfg instructions and find the recoil to be very manageable.

 

[JFrank]

Many People Say, round robin testing is the way forward and I've put an effort don't misunderstand but i'm not so sure that we are only adding an additional layer of unnecessary complexity to simply reading the target as shot and wind influence of the day.

 

[BasicMagic]

I’m running 2 thou neck tension now and have the 3 thou bushing

I’m using an adhesive barrel temp strip and waiting between shots until temp returns to ~90’ range.

I’m using an A&D FX-120
w/Auto trickler v3 for powder.

Shots are round robin per OCWReloading website.

I have a APA break on the rifle tightened per mfg instructions and find the recoil to be very manageable.

Yeah id add some neck tension and check a lower powder charge range, keep in mind regular groups are going to be smaller than round robin.

 

[BStark78]

I thought I would post an update…

Before I try a new powder I wanted to test a few other suggestions. First that I would find a node around 75.5. Below are the groups of 75.4 (2760 ES 45/SD 16.9), 75.5 (2765, ES 20/SD 7.5), and 75.6 (2774 ES 18/SD 7.1). I also added a bit of neck tension, +1 thou to 3 thou. ES and SD dropped about 15% for two of the loads vs. the previous loads at 2 thou.

The sighters are clean/cold bore at 74.6 w/ an ES of 12 and SD of 5.1. The cluster of three are shots 2-4 (1 is the lowest).

I’m happy to see the ES/SD numbers come down a bit. I’m hoping with a different primer I can trim that another 15-20%. The vertical shift is still rather extreme for a very small power change.

I’ll most likely stick with 74.6-74.9 for now. It’s exhibited the least vertical shift of all series of shots across 3 sessions.

I’m working on picking up some new powder and have 2 new primers to try. I also picked up some Lapua brass when it came available recently.

As a note, at 75.7 w/ADG brass I see light ejector marks (Hodgdon published max).

 

[seymour fish]

I don't see a node. With that high capacity I would look at a wider charge range at 0.5 increments, which I think a ladder test may show more clearly than ocw.

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