6.5 CM 144gr Long Range Hybrid Target load data

[Max_The_Phoenix]

Hi Everyone
Please help me choose the right powder charge for my 6.5 CM

components:
Berger 144gr LRHT
CCI 450
Lapua SRP 1x fired
H4350
Defiance Ruckus Action
28" Bartlein M24 barrel

I did 2 tests, first one 3 shot groups and second one 5 shot groups on a different day
For first test barrel had 100 rounds down the tube, second test 150 rds.
ran a 3 shots per charge ladder from 41.1 to 42.5grs, I had heavy bolt lift starting at 42.1grs all the way up to 42.5grs
So after I found 41.3 to 41.7 is the area I want to play with, I went ahead and loaded 5 rounds each from 41.2 to 41.6( I know should have loaded up to 42grs)

Same exact brass prep
Powder RH was monitored and it was the same, for the second test temp was probably 10deg warmer

Last time 41.3 and 41.5 gave me really low sd but the speed jumped a bit, after 42.1grs

I see 41.5 has a low sd on both tests
But there is no similar speed +- 0.1 grs

Should I just go with the 41.5 and test with 20 rounds? Or You think it’s better to test 41.6 to 41.9 in 0.1 inc to see if there ie any node there?

3shot groups se/es Low speed

41.3 2792. 1.2/3 low 2791
41.5 2814. 1.6/4 low 2812
41.7 2817 6.9/17 low 2808
41.9 2822 4.5/11 low 2817
42.1 2843 2.6/5 low 2842
42.3 2847 1.5/3 low 2845

New 5 shots
41.2 2799 4.7/13 Low 2795
41.3 2802 9.1/23 Low 2792
41/4 2803 5.8/17 Low 2793
41.5 2816 5.2/12 Low 2809
41.6 2828 2.5/6 Low 2825

 

[GIXXER2000]

AI-AX
26 in Bartlein 1-8
Norma Brass
210M
H-4350 42.6
AVG FPS 2830
SD 6.9

Best groups were right at .500 so I went back to the 140 Hybrid pick up 77 FPS and had group avg .0.387 till the barrel went and 1700 ish rounds.

 

[Niles Coyote]

140's with 41.3 has been a known load with lapua brass 41.5 with Hornady for some time. If your groups are consistent in that range, rock on.

That said I'll be exploring the powder charges that drop me into the high 2600's to low 2700's for match use with 144's when i put that barrel back on.

 

[Max_The_Phoenix]

140's with 41.3 has been a known load with lapua brass 41.5 with Hornady for some time. If your groups are consistent in that range, rock on.

That said I'll be exploring the powder charges that drop me into the high 2600's to low 2700's for match use with 144's when i put that barrel back on.

Thanks
I didn’t shoot for accuracy and unfortunately that day I hadn’t enough sleep so my group was garbage.
But you are right 41.3 look like in the middle of a node, just have to tighten the ES since this is my budget long range gun lol

 

[DeathBeforeDismount]

A 3 shot group is not telling you anything. Those ES/SD mean jack shit.

Aim for a target Velocity / Pressure. Make sure its well bellow max so you dont get into issues on hot/wet days. Winter time load development will bite you in the ass come summer if you ignore this.

Jump the bullet at-least .030, ideally more like .050-.080. Hybrids like more jump and it will make them less sensitive.

Then shoot a 10-20 shot string to see what the groups/SD/ES are. If you aren't happy, play with seating depth or buy a tuner.

Its really that simple with good components. Annealing with an AMP and using an AT/ST if you aren't already are going to be the 2 biggest things you can do to shrink ES/SD. Assuming you are mandreling (controlling neck tension) and trimming as well.

You should be able to get to sub 5 sd with those components and proper reloading techniques.

if you are finding pressure at 42.1 at this time of year, I would back off at the absolute minimum .5 and more like .8-1 grain. This is your margin.

 

[Max_The_Phoenix]

A 3 shot group is not telling you anything. Those ES/SD mean jack shit.

Aim for a target Velocity / Pressure. Make sure its well bellow max so you dont get into issues on hot/wet days. Winter time load development will bite you in the ass come summer if you ignore this.

Jump the bullet at-least .030, ideally more like .050-.080. Hybrids like more jump and it will make them less sensitive.

Then shoot a 10-20 shot string to see what the groups/SD/ES are. If you aren't happy, play with seating depth or buy a tuner.

Its really that simple with good components. Annealing with an AMP and using an AT/ST if you aren't already are going to be the 2 biggest things you can do to shrink ES/SD. Assuming you are mandreling (controlling neck tension) and trimming as well.

if you are finding pressure at 42.1 at this time of year, I would back off at the absolute minimum .5 and more like .8-1 grain. This is your margin.

Yes I am using Super Trickler, annealing everytime after firing, bump the shoulder 0.0015-0.002 with SAC FL sizing die, mandrel for 2thou neck tension, trim with Giraud. Neo Lube before seating the bullet. so 42.1-0.5=41.6, before 41.9 I have zero pressure signs just veryyyy tiny bit feel on the bolt lift.
I want to try tighter bushing before mandreling maybe I get more consistent neck tension and ES. any suggestion will be appreciated.

 

[OREGUN]

Lots of numbers. Not much data.
I’d load 41.3 and shoot 20 over your chrony to even begin to understand your statistics (sd/es).

Looks to me like your speeds are pretty normal around 41.2-41.4. Go with that and try different seating depths if it’s not as accurate as you expect. Perfect your brass prep, charge weight, and neck tension to bring your es/sd down…and send AT LEAST ten over the chrony before you even look at those numbers (should be more like 20 but ain’t no one got time for that).

I’d stay at least .5 away from heavy bolt lift to save your brass, your sanity, and your face.

 

[DeathBeforeDismount]

Yes I am using Super Trickler, annealing everytime after firing, bump the shoulder 0.0015-0.002 with SAC FL sizing die, mandrel for 2thou neck tension, trim with Giraud. Neo Lube before seating the bullet. so 42.1-0.5=41.6, before 41.9 I have zero pressure signs just veryyyy tiny bit feel on the bolt lift.
I want to try tighter bushing before mandreling maybe I get more consistent neck tension and ES. any suggestion will be appreciated.

Sounds great. I would suggest doing a little more bump to keep the gun running when its dirty or ammo gets wet. Since water doesn't compress you could run into issues of not chambering. .003-.004 is a safer bet and honesty brass life difference is negligible.

I run Lapua brass as well in my 6.5cm. .291 bushing and .2630 Mandrel. Gives you about .001 of neck tension.

 

[Max_The_Phoenix]

Lots of numbers. Not much data.
I’d load 41.3 and shoot 20 over your chrony to even begin to understand your statistics (sd/es).

Looks to me like your speeds are pretty normal around 41.2-41.4. Go with that and try different seating depths if it’s not as accurate as you expect. Perfect your brass prep, charge weight, and neck tension to bring your es/sd down…and send AT LEAST ten over the chrony before you even look at those numbers (should be more like 20 but ain’t no one got time for that).

I’d stay at least .5 away from heavy bolt lift to save your brass, your sanity, and your face.

Thanks man.

 

[Max_The_Phoenix]

Sounds great. I would suggest doing a little more bump to keep the gun running when its dirty or ammo gets wet. Since water doesn't compress you could run into issues of not chambering. .003-.004 is a safer bet and honesty brass life difference is negligible.

I run Lapua brass as well in my 6.5cm. .291 bushing and .2630 Mandrel. Gives you about .001 of neck tension.

My chamber is minimum saami chamber.
What is your ES/SD ?

 

[OREGUN]

I also bump around 4 thou, for any normal use rifles. I usually quit chronying around 15 rounds and I expect to have single digit sd and an ES of roughly 3x SD (sd times 3). It’s not the most robust data (n is too small) but I’m not a statistician and I don’t have endless components for data gathering.

 

[Max_The_Phoenix]

I also bump around 4 thou, for any normal use rifles. I usually quit chronying around 15 rounds and I expect to have single digit sd and an ES of roughly 3x SD (sd times 3). It’s not the most robust data (n is too small) but I’m not a statistician and I don’t have endless components for data gathering.

Do you usually find your charge weight at the middle of the 2 consecutive charge weight with close average velocity? Cause sometimes beginning or end of the node has better ES/SD to begin with!

 

[Conrad]

I’m shooting all the same components except in a 24” Proof CF 7.5 twist and TL3 action

42 gr H4350 and 144 at -0.050” off, 2765 fps. I took it further and then backed off to this 42 gr load. I believe at one point I thought I was good at 42.5 and another day had pressure so I continued to back down.

Shoots excellent.

That said you should load to what your rifle is telling you. Backing off to the low 41s sounds like a good plan.

 

[MediumSpeed]

I run these at 41.3 gr H4350 with br2 primers,and norma brass in a 24" 1 in 8 - I get 2735 fps and 1/2 moa groups.

 

[Max_The_Phoenix]

Ok I confirmed the powder charge for the third time today,
41.3gr H4350
Cci 450
20 thou off the lands
2806 fps
SD:3.7 ES:14 with 10 shots group
Now need to work on the seatings depth but running low on bullets lol