156 EOL Load Question

[CanisLupus]

Any suggestions where to start ?View attachment 321409

I'm always curious when I see plots like this...from what I can interpret, you took one shot at each charge. I see folks (me included) do this regularly, and want so badly to draw a sensible conclusion from the results. Just curious, what if you started by shooting this same string again (and maybe once more, and perhaps even once more)...then you would have more than one data point at each powder charge. Would the 'peaks' and 'valleys' and 'flat spots' end up in the same location?

 

[whirlwindjml]

I'm always curious when I see plots like this...from what I can interpret, you took one shot at each charge. I see folks (me included) do this regularly, and want so badly to draw a sensible conclusion from the results. Just curious, what if you started by shooting this same string again (and maybe once more, and perhaps even once more)...then you would have more than one data point at each powder charge. Would the 'peaks' and 'valleys' and 'flat spots' end up in the same location?

A lot of people do things different ways. I'm usually interested in spot where a few increases in powder don't make a big difference in speed. It makes for a forgiving load and the e.s. and s.d. are Not all over the place. That important for the long range game

Then ill see how it's grouping. And mess with seating depth. I had a great load quickly for my 26 nosler this year with the 156 doing this.

 

[Shane Lindsey]

I think you should work .004", .007", .010" on both sides of what ever this pic is.

I think I was at about .025" off the lands when I settled. This one didn't do as well as the 140 in mine so I never really chased it. Couldn't get enough velocity to outweigh it.

 

[Mike Matteson]

I would note that the loads are hot at the upper end. Would like to what the primer were tell you. Ejector mark are way over on pressure. Your primers should have told you that the loads were getting hot, even before the ejector marks.

 

[D$tring]

Shots 4 & 5 especially if they correspond to the flat spot in the graph at 55.6-55.9. I would load one (to save components) or three (to shoot groups) at 55.5, 55.6, 55.7, 55.8, 55.9, and 56.0 to confirm the node. If speeds are still flat through there, you are in the money. If groups are tight then stick with it, if not I would then pick a charge in the middle or the middle of the upper half of node and play with seating depth to tighten groups.

 

[sean30ber]

I would note that the loads are hot at the upper end. Would like to what the primer were tell you. Ejector mark are way over on pressure. Your primers should have told you that the loads were getting hot, even before the ejector marks.

At the 55.8 the primers looked real good. No excessive cratering and nice round edges. Once I got to the top two loads they obviously started flattening and the top load tested had excessive cratering to boot. 55.8 was nice and 3/10th higher and lower were within 10fps avg of 55.8. Im shooting seating depths at .015, .020. 025 this morning soon as it warms a touch more.

 

[D$tring]

30 degree difference from this morning. velocity was avg 2940. Best group was 55.8 with an SD - 4.5, ES-11.
3 shot group was .63 at 020., .65 at 010, then went up over 1 inch the further seated I went. Im shooting this 1/4 moa with 140 Hybrids. Id like to get this under 1/2 before ill hunt with it. Really wasnt feeling it this afternoon. My 140 Gold Dots with RS Magnum are 1/3 moa. I think Ill reshoot at -015 -020 -025 another day to see if it was me or the load. If its consistent I might try magnum primers. The SD,ES was nice though.View attachment 321539

I had a 6.5-284 that loved the 140s at either a significant jump, like .150 or better or at that .025-.030 range. Anything less than that or in between those was a larger group. Most of my rifles are in the .020-.030 jump range (if the magazine will allow) with the modern low drag bullets. I would stick in the .020-.025 range and shoot again on a different day. And start by shooting a rifle and load you know is good—that will get your confidence up and let you know where you are with technique etc on that particular day. If your groups are on point with that known rifle, then switch and shoot this one. If your groups are a little more open on your known shooter, then either allow a little wider margin on this rifle as you verify, or choose to verify on another day. it doesn't take much variation from the shooter for a group to jump open or much variation in environmental condition to open a group up. FWIW .63 MOA is pretty good. I always shoot for .5 moa as a standard. I bet the groups tighten up as the barrel breaks in over the next 50-100 rounds.

 

[vancewalker007]

6.5-284, 28 inch, Load data on attachment. 40 degrees this morning. Meticulous loading practice. It seems 56.2 is an oddity although 56.8 jumped right back up. Not sure how to read this. Shots 4,5,6 no vertical. Shot 7 not even a bullet width higher. If you take the horizontal out they would have been 1 hole. all other shots were obvious vertical. Ejector mark at 57.1 and Ejector plus slightly heavy bolt lift at 57.4. Any suggestions where to start ?View attachment 321409View attachment 321416

If it were me I'd drop to 56.9 and do some bullet seating tests. You have a fairly stable velocity in the region and from your statement above that you're hitting pressure.

 

[sean30ber]

My issue is my testing is at 40 to 60 Degrees and I regularly shoot up to 110 here in the desert. Even with temp stable powder. being so close to pressure, it would put me back over pressure when we get hot again. The fun of load development. trying to find the perfect spot for a wide variety of situations.

 

[Shane Lindsey]

Then work the lower node. Start at 52gr and work up again. You will still be in the 2800 range, and that ain't no slouch...

 

[whirlwindjml]

If your shooting retumbo at 100 degrees maby you should be on the early side of the sweet spot. 55.6 and hopefully a good jump off the lands.

Retumbo in the lots I have @338l and .300rum seem to get hot in 85 degree area but ofcourse I'm just backed just off of pressure.

But I read the retumbo is a top choice for the 6.5_284. so congratulations for finding some.

 

[D$tring]

If it were me I'd drop to 56.9 and do some bullet seating tests. You have a fairly stable velocity in the region and from your statement above that you're hitting pressure.

Would your lower node (at 55.6-55.9) be okay at higher temps? I would stick with that one until you can verify at higher temp. I personally try to work loads up around 40-50. So that I'm good to go at hunting temps from 90 all the way down to 0. I also shoot them at those extreme temps to know the corrections.

 

[Greyfox]

While Retumbo is my go-to powder in my 6.5x284's using 140 class bullets, I found that R26 produced higher velocities, at lower pressure with the 156 EOL's. Results were similar with my two rifles with 1:8 twist, 26 inch barrels. The sweet spot with both rifles was 54.2gr at 2995FPS/SD 5. Accuracy in both the rifles is sub.5MOA to 1000 yards. I have attached some of my load data and finished load results.

 

[sean30ber]

Wish I had me some RL 26. Fairy dust says I !!! I have tons of Retumbo. I shot the other two seating depths. Both .6 range just like yesterday. Then shot my 140s to make sure it wasnt me. .26 . I have a nice flat velocity curve from 55.5 to 56. es is almost nothing every .2. Best is 55.8. Ive shot from touching the lands back to .050 in 10 thousandths increments. Best i get is .6s. I wonder if I should test all the way back to .150? Took my Creed with me also just to play, shot bug holes, so im shooting good.