4th in a Series of "I don't know shit about reloading" Questions haha

[Baron23]

Hi guys - Wow, this certainly has been a learning experience.

So, got my first set of finished cartridges done...first ever...and laid out a charge weight test and shot it. Lots of data below.

Mea culpa....I hated statistics and at 68 I don't remember a damn thing but that's not stopping me from agreeing with those who hold that for a small data set its not possible to seperate out signal from noise. But, I had to start somewhere and this test was done with three shots at each charge weight.

Question is: next steps. I'm thinking to next load a set of cartridges and focus on the 40.9 - 41.2 range and 41.6 - 41.9 and do so in .1 gr increments. That's eight different charge weights and I'm considering increasing the number of cartridges at each weight up to five for this round of testing. If that gives me a smaller range to zero in on, then perhaps for the 3rd go I will go up to 10 shots per weight

Not sure wtf happened at 41.3.

NOTE: I incremented by .3 gr up to 40.9 then went to .2 gr increments with the thought that I wanted more resolution the closer I got to max charge weight. But, in hindsight, that's a bit of a mistake as it skews the slope of the graph so it seems like there is greater increase in V between the lower weight charges than the higher ones but that's due to a greater change in powder charge of those shots.

And I really love this ChronoPlotter software as it makes it easy to see, for example, that the ES of 41.5 is driven by one of the three shots being slow while the other two are pretty much identical. Also, 41.9 shows AVG MV slowing down in increase in charge, but two of the three shots are identical and the AVG MV was pulled down a tad by the last one.

At 42.1, I had a small amount of bolt lift resistance on one shot...that one being the one of the three with the slightly higher MV. I'm new at all of this and so I'm probably more cautious about over pressure that some of you who have more experience. However, I did make a post with pics of the base/primers and it seemed that all agreed that there were no visible pressure signs....no cratered primers, no ejector imprints, etc.

WRT to the group sizes in pic below, I'm not that awesome of a shot that I cannot guarantee a level of consistency that would absolutely attribute group characteristics to the load and not the shooter. And...for an excuse....It was screaming hot and humid and I was being dive bombed by cicadas the entire time while trying to keep the sweat out of my eyes! haha For example, 41.5 and 41.7 are a bit open which pissed me off enough to really tighten up and I think that shows in 41.9. Either than or my barrel just likes 41.9

Once again, I have told you my thoughts and plans but I don't know shit and I'm fully willing to discard my thinking in favor of your informed opinions.

So, what do you guys think the next step should be?

 

[Newbie2020]

@Baron23 your series is actually linear.

The tiny (not small—-tiny...) sample size is teaching you things that aren’t real or true. An sd from three rounds is not valid. An sd from 10 rds is borderline. That’s why the sd bounces up and down—-it’s not real.

It was pretty well hashed out in the other thread that valid flat spots are so rare as to be irrelevant and not worth the large number of rounds needed to find them.

Avoid the high end that caused you pressure signs and pick one you like. Tune seating depth for that charge weight and you’re golden.

 

[Baron23]

@Baron23 your series is actually linear.

The tiny (not small—-tiny...) sample size is teaching you things that aren’t real or true. An sd from three rounds is not valid. An sd from 10 rds is borderline. That’s why the sd bounces up and down—-it’s not real.

It was pretty well hashed out in the other thread that valid flat spots are so rare as to be irrelevant and not worth the large number of rounds needed to find them.

Avoid the high end that caused you pressure signs and pick one you like. Tune seating depth for that charge weight and you’re golden.

Yes, I agree about the lack of statistical validity in small data sets and I have indeed followed the multiple threads started on that subject.
Thanks for the reply

 

[Newbie2020]

I’ll shut up now. Rant over. Haha

 

[Baron23]

I’ll shut up now. Rant over. Haha

Nah! Not at all. Haha

so, on what basis would you pick an charge to use for seating depth testing out of these? Why this one vs that one aside from the high end that had the bolt lift resistance.

Berger loaded 140 hybrids, which shoot quite well in this gun, run about 2875 in my gun w no pressure signs but who knows what powder they use and it’s pressure rise rate. Hndy 140 ELD-M run 2805 and also shoot well.

but I’m not at all sure that the speeds from loaded ammo are all that relevant given the diff in powder, etc.

Where would you go from here, my friend?

 

[nn8734]

Are you married to Hornady brass? If you struggle to find a consistent load, I’d switch to Lapua.

Apart from that, my load development process is very similar to yours except I don’t do anything beyond look at MV on the first round of three-shot groups and POI center relative to the POA on each little target. If I see a string of two or three consecutive charge weights with consistent POi locations, minimum velocity requirements met and no pressure I continue to develop in that charge weight by playing with seating depth until it groups. Then I shoot it at 500-700m and call it good if nothing odd is observed.

 

[Baron23]

Are you married to Hornady brass? If you struggle to find a consistent load, I’d switch to Lapua.

Apart from that, my load development process is very similar to yours except I don’t do anything beyond look at MV on the first round of three-shot groups and POI center relative to the POA on each little target. If I see a string of two or three consecutive charge weights with consistent POi locations, minimum velocity requirements met and no pressure I continue to develop in that charge weight by playing with seating depth until it groups. Then I shoot it at 500-700m and call it good if nothing odd is observed.

Well, I have Hndy brass while finding Lapua in 6.5 CM seems to be near impossible right now.

Looking at my groups, where would you go next? 40.9...and yes, I pulled that one shot left a bit. Same w 41.1. If this was your data, what would you do next?

 

[918v]

How many reloads on your brass right now?

 

[Newbie2020]

Im running Berger 130s w 44.1 gr StaBall 6.5 at 2805 fps and i like the soft recoil.

But I think a lot of guys are running the 140s from 2800-2850.

 

[Baron23]

How many reloads on your brass right now?

It was once fired.

 

[nn8734]

Well, I have Hndy brass while finding Lapua in 6.5 CM seems to be near impossible right now.

Looking at my groups, where would you go next? 40.9...and yes, I pulled that one shot left a bit. Same w 41.1. If this was your data, what would you do next?

If you like the MV at 40.9-41.1, id load up 10 rounds at those two charge weights, record them over lab radar and shoot them (perhaps two five-round groups each) on one of those multi-target
papers and see if 1) they perform similarly SD/ES wise [acceptably low as/Es also]and 2) have identical POI centers relative to each other and 3) group tight.

If the above three things happen I’d roll with 41.1 and take data over the course of the next 30-50 rounds shooting at distance and see if everything holds up then assuming things go as planned, put the load into low rate production (batches of ~200 per prod lot). I would gather data in the winter to ensure it doesn’t have wild swings in performance when subjected to much colder temps vs when it was initially developed and tweak it if need be. Then produce as much as I felt I needed knowing I have a reliable, stable load.

 

[918v]

It was once fired.

From the same lot?

 

[Baron23]

@918v

Yes, came from same case of loaded ammo as far as I recall.

ps just check what was left on my shelf from two cases and they are two diff lots.

 

[918v]

How far from the lands?

 

[Baron23]

Loaded to .010 back from max mag length which puts me at .060 off of lands.

 

[918v]

I’m thinking you have bullet grip issues.

 

[GBMaryland]

@Baron23 - If you need Lapua brass, I've got it NIB for you...

 

[Baron23]

@Baron23 - If you need Lapua brass, I've got it NIB for you...

haha...now you tell me...after I cleaned, sized, and primed 400 Hndy cases!! hahaha

So, any input on which load(s) you think I should pursue further out from the data above?

I'm thinking next step is to load 40.9 - 41.2 range and 41.6 - 41.9 and do so in .1 gr increments and shoot at least five shot groups and then just fucking pick one! haha

 

[GBMaryland]

Basically, I think that' show you should do it... pick a few loads and then run 20 rounds through the lab radar.

 

[DownhillFromHere]

Your data pretty much reflect what I see in both my 6.5CMs (26" Bartlein barrels). After a whol'otta trials with Hornady, Peterson, and Starline brass (the latter two using CCI 450 SRPs), I settled on 41.2gr H4350 and just run it for all combinations of brass and 140gr Berger Hybrid and Hornady 140gr ELD-M. I also saw what seemed to be a node in 41.7-42.0gr vicinity, but accuracy over 50-60 rounds was no better than the 41.2gr load and I had some concerns over pressure if the ammo got really hot in July-August.

A buddy of mine - who also shoots F-class benchrest and cuts powder kernels for 0.01gr perfection, so he's sufficiently anal - likes the 40.0gr node for ~2720fps.

Over a couple thousand rounds, my ES has been in the 25-30fps range. Sometimes I'll get a 5-shot string with single-digit ES (yes, ES) but I dump all my LabRadar info into a spreadsheet and look at it over hundreds of rounds in temps from freezing to broiling. And then again once in awhile I'll have a 5-shot string with 40-50fps spread.

I trim brass to length, but I refuse to go back down the rabbit hole of chasing neck thickness uniformity (been there done that, unh-unh-not-again). I anneal (via AMP annealer) after every firing because it's fast&easy.

The 25-30fps ES has bothered me slightly as I weigh each charge on an FX-120i scale (+/- 0.02 grain). That spread is meaningless for the most part in matches with targets out to 700-800 yards, but when it's a 24" plate at 1000-1100 yards... it matters. So recently I ordered one of the Imperial dry lube kits to see if lubing inside the case neck would do anything to help. I've only fired 10 rounds of Imperial-lubed ammo so far (140 Berger Hybrid / 41.2 H4350 / Starline SRP / CCI450)... Av 2791 / ES 20 / SD 6.7... I'll take that. Hope it stays that consistent.

Good luck.

 

[Baron23]

Your data pretty much reflect what I see in both my 6.5CMs (26" Bartlein barrels). After a whol'otta trials with Hornady, Peterson, and Starline brass (the latter two using CCI 450 SRPs), I settled on 41.2gr H4350 and just run it for all combinations of brass and 140gr Berger Hybrid and Hornady 140gr ELD-M. I also saw what seemed to be a node in 41.7-42.0gr vicinity, but accuracy over 50-60 rounds was no better than the 41.2gr load and I had some concerns over pressure if the ammo got really hot in July-August.

A buddy of mine - who also shoots F-class benchrest and cuts powder kernels for 0.01gr perfection, so he's sufficiently anal - likes the 40.0gr node for ~2720fps.

Over a couple thousand rounds, my ES has been in the 25-30fps range. Sometimes I'll get a 5-shot string with single-digit ES (yes, ES) but I dump all my LabRadar info into a spreadsheet and look at it over hundreds of rounds in temps from freezing to broiling. And then again once in awhile I'll have a 5-shot string with 40-50fps spread.

I trim brass to length, but I refuse to go back down the rabbit hole of chasing neck thickness uniformity (been there done that, unh-unh-not-again). I anneal (via AMP annealer) after every firing because it's fast&easy.

The 25-30fps ES has bothered me slightly as I weigh each charge on an FX-120i scale (+/- 0.02 grain). That spread is meaningless for the most part in matches with targets out to 700-800 yards, but when it's a 24" plate at 1000-1100 yards... it matters. So recently I ordered one of the Imperial dry lube kits to see if lubing inside the case neck would do anything to help. I've only fired 10 rounds of Imperial-lubed ammo so far (140 Berger Hybrid / 41.2 H4350 / Starline SRP / CCI450)... Av 2791 / ES 20 / SD 6.7... I'll take that. Hope it stays that consistent.

Good luck.

Thanks for the great reply. I too dump my Labradar data into a spreadsheet and for the loaded ammo I have been shooting I aggregate it By brand and run calcs for average MV, ES, SD with a much larger data set. Bit illuminating.

neck lubing was recommended to me so I did use Imperial dry lube. I ordered the kit w the application media but that was silly. I have 350 lbs of #9 hard shot and would just use that if I had to do it over again. Bullet seating was VERY smooth and easy.

looks like the range I’m going to further explore matches well w your findings and that really boosts my confidence that I’m on the right track.

thanks again, much appreciated.

 

[nksmfamjp]

I would load 10 at 41.7gr…to confirm sd there is still under 7. If so, I would vary seating depth to see if I could tighten the group anymore.

Generally a person isn’t looking for the best, just good enough. There isn’t enough barrel life to find the best.

 

[LR1845]

41.7 and run a seating test.

 

[Baron23]

I would load 10 at 41.7gr…to confirm sd there is still under 7. If so, I would vary seating depth to see if I could tighten the group anymore.

Generally a person isn’t looking fo red thrr Ed best, just good enough. To here isn’t enough barrel life to find the best.

41.7 and run a seating test.

Thanks for the reply. I will be testing 41.7 for certain.

 

[spife7980]

I would load 41.7, 41.8, 41.9, 42.0, 42.1 and see that it’s still happy there. You’re gonna be hard pressed to beat that load if it’s not a fluke.

 

[Baron23]

I would load 41.7, 41.8, 41.9, 42.0, 42.1 and see that it’s still happy there. You’re gonna be hard pressed to beat that load if it’s not a fluke.

Thank you! That’s what I planned. I thought I got a little bit of bolt lift resistance on one of three at 42.1 but I’m going to incl it again and verify.

Thanks for taking the time to reply.

 

[nksmfamjp]

What program is this?

 

[Baron23]

What program is this?

View attachment 7646129

ChronoPlotter. Extremely easy to use. Was written by a member and posted for free.

There is a thread on it with links if you want to search, but he posts it to github and you can download the software and directions here:

Release v1.3.1 · mncoppola/ChronoPlotter

Removed unnecessary graph annotations from one-shot series Remember previous directory for loading chronograph data and saving graph images Graph title is now used as default save filename Asse...

github.com

 

[Baron23]

Hi guy s- so, I'm pretty sure I have worn almost everybody out with my endless requests for input and recommendations....but maybe I can get a new crop of members to reply! haha joking

I went out for a 2nd round of charge weight testing. For those that think I may be wasting ammo...well, maybe but this is the first time I have done this, I'm retired and need something to keep me occupied (LOL), and at almost 69 I'm not contemplating competing so I'm not terribly concerned about conserving components for match ammo.

Based on the first test (above in this thread), I zeroed in on two ranges to explore further....40.9 - 41.2 and 41.6 - 42.1 in .1 gr increments of H4350.

Brass was from the same sized/trimmed brass as first test, primers and Berger 140 Hybrid targets from the same box, powder from the same jug, measured with the same MatchMaster. Seating was done with the same die which was still in place and didn't move as when I seated the first test.

Seating depth was identical in being .010 off of max mag length at COAL of 2.859 and CBTO of 2.164 for right at .060 off of lands.

Main diff was to go down to .1 gr increments to see if I could better resolve the data AND loaded and shot five instead of three. Still not a statistically valid data set size and I still discount the absolute validity of the resulting ES/SD, but we do what we can practically and this is it.

To help any who want to review and offer suggestions, this is the result of the first test place here again to make comparisons easier
TEST #1

Now, this is the result of the 2nd test.

NOTE: 1) I failed to arm the LabRadar for the first shot of group 1 & 3 and failed to arm it at all for group 2 so I don't have any velocity data on it at all (must have been a bad biorhythm morning haha). Also, note the general differences in magnitude of ES/SD for test 1 vs larger numbers of test 2 which is why I stressed that they were loaded identically in every way I could think of. I personally think this goes to sample size...yeah, while still not statistically significant, five shots vs previous three does give more opportunity for variations to show in the set. I feel confident that if I had continued to shoot either set that after a sufficient amount of shots, the ES/SD would converge on some reasonable numbers.

So, here is the second test results. My uninformed view/plan is to go with 41.2 and leave seating depth where it is. The barrel has approx. 1k rounds thru it and due to throat erosion (and maybe how it was chambered), I cannot get any closer that .060 off of lands without running into mag. length issues. Can't go any further out and I expect over the remaining barrel life (about another 1,500 rounds or so) to have another 45-75 thousands of erosion which will increase my jump from current .060 to .105 to .135. So, I just don't see going any deeper right now.

BUT, I am open to input, recommendations, corrections, or even derision....bring it on. I would love to know what you think of I my test and plan outlined above. Thank you in advance for your time.

TEST #2

 

[918v]

41.1grs play with coal

 

[Baron23]

41.1grs play with coal

Thanks, man.

Looking the data over this afternoon again, I too thought I may go 41.1

Appreciate the reply