6.5 CM Load Development...Next Steps??

[Mark71]

COAL numbers in a book don’t mean much as that number does not relate to your chamber that you have already measured and found the lands. The tip of the bullet is floating in the air, not touching anything, so ignore the COAL once you know the distance to the lands using your bullets and your chambering.

How far is too deep when seating? Once you start to hear the powder crunch and you now have a compressed load.

I agree with your comments about COAL. I just referenced the book COAL because I was surprised with what I found. If someone with less knowledge and/or tools did not measure jam to determine CBTO and just loaded this bullet for this rifle based on the COAL listed in the Nosler manual they would be jammed about 0.025" into the lands which could result in a nasty outcome.

I read lots of stuff where guys who reload don't own or even know what a comparator is.

 

[6.5 forever]

I've successfully started my 142 SMK out in front of the doughnut. It surprised me it liked it.

 

[Bc'z]

Bc'z, thanks for the seating depth tips...seems to be paying off.

I have some H4831SC...may have to give it a try too.

Glad to help
It won't be as fast as 4350 but the accuracy with a 140 class bullet is stellar, look between 44-45 gr brass and bullet dependent.
Establishing seating first helps save on components in the long run, it also helps identify your charge windows tune more easily.
Have fun keep us posted!!

 

[DiRTY DOG]

I shot a bracket group Friday of 41.6, 41.7 & 41.8 (5 shots each charge).

View attachment 1571875

Based on the groups I got I settled on a charge of 41.7 gr and moved on to trying some different seating depths, increasing depth by 0.003" and this is what I got.

View attachment 1571873

I was a little surprised to see the velocities decrease slightly with each slightly deeper seating depth. I was expecting them to increase slightly?? I may try going another 0.003" deeper to see if it tightens up a little more or starts to fall apart, but I'm just slightly compressed already on the depth shown in group 4, so not sure I want to go deeper. Shots felt good, but who knows, shot #2 on the last target being slightly left could have been me too. I may just load 10 at this seating depth and see what that looks like.

Thanks again for all the advice!

There's no way that's repeatable. You have major shooter error in that test, or something is wrong with your system. There's no way that 41.6 shoots so poorly, but 41.7 is tight, and then 41.8 opens back up again. All within 0.3gr of powder? Nope. You prove it yourself by testing seating depths at 41.7, none of them shoot like your original 41.7 group. Sorry, it looks like garbage to me.

 

[Bc'z]

There's no way that's repeatable. You have major shooter error in that test, or something is wrong with your system. There's no way that 41.6 shoots so poorly, but 41.7 is tight, and then 41.8 opens back up again. All within 0.3gr of powder? Nope. You prove it yourself by testing seating depths at 41.7, none of them shoot like your original 41.7 group. Sorry, it looks like garbage to me.

Actually his seating depth target is looking pretty good.
All loads of 41.7 and a person can clearly see its tighted up at .032 jump.
I'd test a lilbdeeper in .002 increments to make sure he's seated on the front side.
Now if we reference back to his original charge weight test it really got small at 42.1.
Once final seating depth is established pour the gas to it in .2gr increments looking for the powder tune

 

[Dave M.]

Wanted to post my results and get some opinions on moving forward based the load development results I got.

Barrel: 26" Krieger 7.5 twist
Powder: H4350
Primer: Federal 210 LR
Brass: Starline (virgin)
Bullet: 140 gr Nosler Ballistic Tip seated 0.020" off the lands.

New rifle with about 100 rounds through the tube. The first two targets below were shot on the same day.

Group# / charge weight / avg velocity / ES / SD
#1 - Fouling shots
#2 / 40.0 / 2666 / 36 / 15
#3 / 40.3 / 2675 / 4 / 2
#4 / 40.6 / 2690 / 12 / 6
#5 / 40.9 / 2714 / 18 / 8
#6 / 41.2 / 2727 / 5 / 2

View attachment 1571057

Group# / charge weight / avg velocity / ES / SD
#1 / 41.5 / 2740 / 13 / 6
#2 / 41.8 / 2756 / 5 / 2
#3 / 42.1 / 2782 / 7 / 3

View attachment 1571058

Based on what I saw at 41.8 and 42.1 I felt like I was coming into another node so I loaded up a couple of higher charge weights and shot them a couple of days later which is shown on the target below.

Group# / charge weight / avg velocity / ES / SD
#1 / 42.4 / 2791 / 20 / 9
#2 / 42.7 / 2801 / 28 / 13

View attachment 1571060

The following is the velocity graph for all charge weights.

View attachment 1571061
I really like the group I got from the 42.7 charge and it showed no pressure signs, but I'm concerned about running this hot with regard to barrel life and brass life.

The POI for charges 41.5 & 41.8 are very similar and knowing somewhere around 41.5 is usually a node I am leaning towards loading 3 rounds each of 41.6, 41.7 and 41.8 again to see how they compare. Pick the best out of these three and move onto seating depth testing.

Wanted to throw this out there and get some feedback on how others would move forward.

Thanks in advance for the feedback.

42.1-42.4g of H4350 has always been a sweet spot for our 6.5’s. All three of them started to shoot smaller in that range.

 

[Bc'z]

42.1-42.4g of H4350 has always been a sweet spot for our 6.5’s. All three of them started to shoot smaller in that range.

Spot on

 

[JFrank]

How many of you guys are shooting starline brass like @ Mark71

 

[Bc'z]

How many of you guys are shooting starline brass like @ Mark71

Peterson, Norma, Hornady

 

[Mark611]

I have used some Starline Brass in my 6.5CM, I also work my loads around the 147gn ELDM's with 41gns of RL16, I have also tried the SRP and LRP cases, I prefer the LRP brass, I get more velocity with the same charge weight using WLRP, the CCI450 SRMP in the small primer cases are around 40 to 50fps slower than the LRP cases, I have also been searching for the seating depth, using the same measuring tools you have, my COAL off of touch was like 3.002 IIRC? with the 147ELDM, but I started off at 10k 15k and 20k off the touch, 20k showed the best groups of the day but were still not as good as it could be IMO, so I started over and went in 3k increments, from 10k to start, anyway at 23k 26k and 29k off the touch, I saw the accuracy tighten up a bit, I have some loads worked up but I have not had time to test them, but for the barrel I'm using which is a Sav 24'' 1&8 110 Tactical, with less than 100 down the tube, it's a work in progress, and if it doesn't get the accuracy I want? I have a new 26'' Criterion 1&8 BB to replace it with and new Peterson brass :}

 

[Ryan66]

How many of you guys are shooting starline brass like @ Mark71

I’m using the srp variant of starline brass. I have 4 reloads on them now and they seem to be fine, size well, pockets still tight but of course that’s not a lot of reloads - time will tell. I have no complaints or regrets about the brass though.
I’m using a mild load of 41.3 of h4350 with cci450 and 140 eldm jumping a mile. Velocity right around 2695.

 

[Mark71]

There's no way that's repeatable. You have major shooter error in that test, or something is wrong with your system. There's no way that 41.6 shoots so poorly, but 41.7 is tight, and then 41.8 opens back up again. All within 0.3gr of powder? Nope. You prove it yourself by testing seating depths at 41.7, none of them shoot like your original 41.7 group. Sorry, it looks like garbage to me.

Shooter error...me...no way. LOL I thought the same thing when I shot those groups.

I never had an original 41.7 group. The original powder test went from 41.5 and then 41.8. If you compare the first 41.8 to the second 41.8 they are very comparable both in vertical and horizontal offset with shots from the first 41.8 impacting in almost the exact same spots as the second 41.8 group. I decided to pursue that area because on the original powder test the vertical POI at 41.5 and 41.8 are very similar. The seating depth tightened the groups but I'm concerned this may be a very small window....or it was me. Only more testing will show if it's repeatable.

If not I may drop back to 40.6 and test more around this charge as it looked promising as well. The group at 42.7 was very good, but I feel that is pretty hot and I'd prefer to stay off that high end.

 

[Mark71]

Glad to help
It won't be as fast as 4350 but the accuracy with a 140 class bullet is stellar, look between 44-45 gr brass and bullet dependent.
Establishing seating first helps save on components in the long run, it also helps identify your charge windows tune more easily.
Have fun keep us posted!!

I've read quite a bit about starting with seating depth first. Seems to be more people starting their load development that way.

When you start with seating depth first what is the approach to selecting a charge weight to start with? Do you start with a charge near the bottom and run with it? Start at say 0.020 off the lands and then back off in 0.003 increments still?

 

[Bc'z]

Mid way between min and max.
Word of caution..
Working with a new to me cartridge and mono's I found I was achieving Barnes published data 2.1gr back of thier max with a 2" shorter barrel. Trying to match thier charge weight would've been a recipe for disaster.

 

[Mark71]

42.1-42.4g of H4350 has always been a sweet spot for our 6.5’s. All three of them started to shoot smaller in that range.

This area looked good and there wasn't a big velocity jump between 42.1 and 42.4, but I'm pushing 2780 - 2790 and felt that might be a little hot for barrel and brass life reasons.

 

[Mark71]

Mid way between min and max.
Word of caution..
Working with a new to me cartridge and mono's I found I was achieving Barnes published data 2.1gr back of thier max with a 2" shorter barrel. Trying to match thier charge weight would've been a recipe for disaster.

Thanks. The next time I do a load work up I'm going to try starting with seating depth first and try it out.

 

[Mark71]

Actually his seating depth target is looking pretty good.
All loads of 41.7 and a person can clearly see its tighted up at .032 jump.
I'd test a lilbdeeper in .002 increments to make sure he's seated on the front side.
Now if we reference back to his original charge weight test it really got small at 42.1.
Once final seating depth is established pour the gas to it in .2gr increments looking for the powder tune

I shot 0.035 jump last night. It was a nice triangle but it opened up slightly to .656 so I would say somewhere in that 0.031 - 0.032 jump area is the right seating depth.

 

[Chilly807]

It's been my experience that small powder windows (nodes) aren't easily managed
Slight condition changes have you chasing your tail.

From another angle..
I just started to see light at the end of the tunnel with a 223 that has been a source of irritation for over a year. It would shoot tiny groups of 3 or 4 shots, then throw a flyer. It turned out to be a bedding issue. A good chassis and 60 inch lbs of torque on the action screws has made a lot of difference.
Load development can be hugely frustrating without a reliable platform to work with.

I've recently been doing a powder ladder first to get flat groups, or at least not a lot of vertical. Then refine the seat depth to make the groups more round.

I used to think I'd be able to find a spot that was flat on the powder vs velocity curve, something forgiving that would tolerate minor errors and condition changes. Sometimes that happens. Sometimes it doesn't.

I do know that the smaller the case capacity, the narrower the tune window will be. For a 25 grain capacity case like the 223, I do my final powder ladder in 1/10 grain steps. I hope to find a spot that's .2 or .3 grains wide that gives me decent ES and SD. If the speed doesn't stay the same in that window from top to bottom, that's just the way it is.

For larger cases like 6.5CM or 308 (40-45 grains of powder), I tune with .2 grain steps once I'm in the right ballpark for speed. Again, I look for a flat spot with good ES and SD.

None of my rifles seem to have any degree of positive compensation. Slow shots hit low, fast shots hit high.

I watched a Keith Glasscock video a while ago about whether high-dollar digital scales were really any better than a good balance beam. What I came away with was that if you were loading a small case like the 223, any improvement in accuracy in powder charge was often overshadowed by the other uncontrolled variables in the equation. Things like primer, actual case volume (not weight), subtleties in neck tension, etc.

In other words, each component in the load has its tolerance. If those tolerances cancel each other out, you'll have very consistent ammunition. When they stack, you won't.

A bit of a ramble on my part.

 

[Bc'z]

I shot 0.035 jump last night. It was a nice triangle but it opened up slightly to .656 so I would say somewhere in that 0.031 - 0.032 jump area is the right seating depth.

.032 was looking good, I'm thinking powder tune will tighten it up better yet.
Taking notes from the long rage BR crowd they will load in .001 increments to really nail down the most precise seating depth. Generally shot at distance. 1 POA 3 shots each depth with colored bullets to plot seating depths and overlap.
Finally...
The only time I've used H4350 in a CM was a buddies hunting rifle, we landed at 42.3gr with a 143eldx and Hornady brass.
This mimics what @Dave M. stated above.

 

[Bc'z]

I shot 0.035 jump last night. It was a nice triangle but it opened up slightly to .656 so I would say somewhere in that 0.031 - 0.032 jump area is the right seating depth.

Pm'd phone number