6.5 creed guidance

[PKR]

After an 8 year break from loading I’ve picked it up again for the initial purpose of an NRL hunter rifle I’ve put together. Planning to shoot 140’s from the proof CF 1/8 on a CDG action I had a reputable smith chamber and fit for me.

With 140’s I need to hit 2715 to make power factor.

Loads go as followed.
New Lapua srp with CCI 450’s, H4350 & Hornady Aeromatch bullets. Bullets seated .020” off the lands (or what I found with my method to be off the lands)

37 grains made 2435 fps ES 10.5 SD 3.9
Worked up to 41 grains with 1 grain steps to get 2682 fps ES of 24.5 & SD of 8.9
All 5 shot groups, all speeds moved up incrementally with charge and all grouped around .5-.75 moa
No heavy bolt lift noticed
However, when looking at the primer there looks to be some flow or cratering, see pic.
But the primers don’t look to have set back or flattened.

Left is Horn 140 eldm factory, middle is my 37 grain and right is 41 grain.


I’m thinking I might need to back off the lands and seat a little deeper.

Right now it’s at 2.252” to O give with lands being around 2.272”

Hornady eldm was 2689 fps for a 10 shot sample

 

[Stache Attack]

I saw this with white river primers for my 6 creed load dev. I never had heavy lift or ejector swipe I feel it is the batch of primers. Tagging in to learn started low at 39 and went up to 42 all look the same. On my 6.5 creed I run 42.5 h4350 with Hornady brass and 210ms no crater

 

[AndrewMT34]

I'm also shooting a 6.5CM in NRL Hunter, using alot of the same components.

Barrel is a 22" 6.5CM Proof Prefit and I used my headspace gauge tool to measure the lands at: 2.895".

Prefacing with your gun may be different and safely work up, but here's the load I ended up with:

140 ELDM
Lapua 6.5 CM SRP Brass
CCI 450 Primer
42gr H4350
COAL - 2.850"
CBTO - 2.228"
2740 FPS

I don't really watch ES or SD but according to my garmin chrono a 5 shot group of this load was SD = 4.3, ES = 11.9

I don't see any pressure signs in my brass or primers.

Good Luck!

 

[wind gypsy]

Primer cratering varies based on firing pin to bolt face fit, primer choice, and of course pressure. Seems like your bolt face just craters 450s easily.

You can typically go above 41.0 gr h4350 behind a 140 in a saami creed chamber with 140s in lapua brass, seems like you'll need to do that unless your barrel speeds up a bit to get power factor.

 

[alexnelon]

I don't see anything that would keep me from just going to 41.5 grains and putting 150 rounds through the barrel and see how much it speeds up.

 

[PKR]

I questioned my method of finding bullet OAL/ogive by lubing the bullet on a long loaded dummy round with a case lube, chambering and removing to measure.
Initially I had variance between #1 & #2 so I did 5 in total to find OAL. All had differences so I took the lowest.

However I did some interneting and came across the Frankford OAL tool using a cleaning rod and kinda made my own version. I cut off an old cleaning jag, squared it up and marked the rod with painters tape at the muzzle.


What I found was a shorter OAL in the chamber vs out by around .020”
Loaded long 2.965
Chambered OAL 2.909
Removed OAL 2.933
(Had very similar results with a Berger 140)
Reseated to 2.909 put the ogive at 2.250”
Which meant I was only .002-.003” off the lands with my initial load.

With 2.250 -.020” = 2.230” closer to what @AndrewMT34 has above

I do agree, I’m gonna have to go up on the powder charge but I’m going to try a shorter seating depth and give it another go.

 

[Castle Rock]

Try some REM 7 1/2 primers, they seem tougher than CCI these days

 

[Lawnboi]

If have a hard time not loading them to 2.8” coal with 41.5 of h4350 and letting it rip till the barrel is broken in.

Srp have thinner cups and will crater much easier than a LRP in the creeds, even with tight actions.

 

[Finaddictions]

CDG actions are known to have an oversized firing pin hole which causes the cratering. Have the bolt bushed and that problem will go away. It’s not your seating depth or high pressure causing the cratering.

 

[43.6N]

That looks like an oversized firing pin hole.
You have round primers still.
The primer flow is the same on the low charge as the high charge.

Resize your once fired brass.
Try 41.5gr H4350
2.8100” overall length

See how it shoots, and what velocity you make.

I just did a similar work up for a new 24” proof barrel for my NRL rig. (Incase you need another data point for a similar barrel):

Lapua brass
140 Bergers
41.0gr H4350.
Federal gold medal primers.
2.81”

Came out at 2760fps.