Staball 6.5

[Torque]

I am trying to develop a load for 25 Creed using 120g Partitions. I know these are not the most accurate of bullets, but they are great on game.

I loaded 3 charges 44.5, 45.0 and 45.5, five rounds each to get a starting point.

I shot them at 9:30 am and the temp was 58. I wanted to test the results again. So, I loaded up 15 more of the same charges and shot them again at 5pm. The temp was 84.

The resulting velocities showed a 100fps increase from the morning to evening shots with all powder charges. Nothing else about the brass or reloading process changed. The rounds went from being pressure safe to leaving slight extractor marks for the top load, 45.5.

I do not know if 100 fps differences are normal for temp stable powders, but it rather surprised me.

Has anyone else had this experience with this powder?

 

[Blake C]

Definitely not normal. Maybe the scale doesn't work right

 

[NWBLKTAIL]

Hmm I’ve shot it in those temps and never noticed velocity swings like that, like a few hundred rounds worth

 

[hoooogan]

I just did two temp tests with 6.5CM. 0-100 degrees was 15fps spread with ok SD, follow up in another session tested different load at 0-75 was 19fps with better SD and another load at 0-75 at 15fps ok SD. 5 shots a piece.

I second the scale being the issue. What are you using for a scale and have you confirmed consistency throughout your loading session and even between sessions?

 

[alexnelon]

Scale/measuring problem or your chronograph is lying.

You’re not using a photo sensor chronograph are you?

 

[TravOC]

I had this same problem with h1000 actually which is a pretty well known temp stable powder. I was using a relatively cheap scale. An entry level RCBS scale that was over 10 years old. Bought a nicer OHAUS scale to replace it cuz I had a feeling that was the issue. Never had any problems since!

Also comparing weighed charges with the old RCBS was astounding, the RCBS could be up to a full grain off...

 

[Torque]

I am using a True Ballstics radar chrono which has always been accurate. When paired with my father's Garmin, they always read within 5fps of each other.

I don't think it can be the chrono because there were pressure signs in the second batch that were not present in the first. Logically, I think my chrono wasn't lying.

I am using a RCBS Chargemaster 1500 as a scale. I calibrate it fully before every use, without fail.

I have confirmed the loads vs. a balance scale in the past and it has always been accurate. I will check again to make sure nothing has changed.

 

[streamerfish]

Hmm....A little weird.

I don't have a ton of experience with that powder. I would guess that your probably very close to or at max pressure at 45.5gr load, depending on the COAL your running at. So, it may not take too much to just nudge that load into showing pressure signs.

I got nothing for you on the 100fps swing in 26 degrees difference. I would suspect that something odd is going on there, that kind of swing is basically unheard of regardless of the powder. That's almost 4fps per degree.

While staball 6.5 isn't know to be the most temp stable powder out there, its on the better end of the scale so to speak.

Something has gone haywire on ya I would suspect.

 

[SippyCup]

I have no expirence with the staball 6.5, but I’ve been playing with the staball match powder lately. Mainly been using it cuz it’s $12 cheaper a pound compared to Varget. Good brass, CCI 200 primers and a 168 hpbt from a 308 I’m getting very comparable results to Varget. SDs, groups and even the powder charge weights are close. It meters better too. I have yet to test the temp stabilty of it tho

 

[TravOC]

I am using a True Ballstics radar chrono which has always been accurate. When paired with my father's Garmin, they always read within 5fps of each other.

I don't think it can be the chrono because there were pressure signs in the second batch that were not present in the first. Logically, I think my chrono wasn't lying.

I am using a RCBS Chargemaster 1500 as a scale. I calibrate it fully before every use, without fail.

I have confirmed the loads vs. a balance scale in the past and it has always been accurate. I will check again to make sure nothing has changed.

Great to know you are using a good chrono, I couldn't remember the model of scale my RCBS was, double checked and it is a charge master 1500 as well. Mine is probably pushing 15 years old. I still use it to throw charges and then I titrate the weight appropriately with the OHAUS. Good system and still cheaper than the uber fancy auto ticklers that cost 2k lol

 

[Torque]

I posted the same question on a different forum, and here is an updated I just made which may shed a little more light.

Thank you all for the responses.

"
So, first let me say, I had my numbers wrong. I apologize for this, I scanned the numbers and had the averages wrong significantly. Instead of 100fps, it was 45-49 fps.

The brass for both AM and PM shoots was all virgin brass from the same lot. I did not used fireformed brass for the second shoot.

I calibrate my scale before each use, which I believe is what the manual says to do. I use the provided calibration weights. I am a molecular biologist who works in pathology. I use electronic scales often and daily calibration or calibration after a shut off is standard procedure. If the RCBS isn't meant to be used in this manner, it may be where I am messing up.

The loads were sitting under a covered shooting bench before and during shooting. They were not sitting in the sun.

Here are the shot strings:

AM Shoot:
44.5g 3058, 3045, 3054, 3047, 3037 Avg. 3048 ES 21 SD 8.16
45.0g 3074, 3067, 3092, 3075, 3082 Avg. 3078 ES 25 SD 9.46
45.5g 3085, 3122, 3096, 3130, 3121 Avg. 3110 ES 45 SD 19.39

PM Shoot
44.5g 3085, 3090, 3088, 3110, 3097 Avg, 3094 ES 25 SD 9.97
45.0g 3134, 3123, 3137, 3129, 3122 Avg. 3127 ES 15 SD 6.59
45.5g 3155, 3164, 3152, 3143, 3160 Avg. 3155 ES 21 SD 8.04

44.5g Avg. velocity difference: 46 fps
45.0g Avg. velocity difference: 49 fps
45.5g Avg. velocity difference: 45 fps

I am using virgin Peterson 25 Creedmoor LRP brass. I prepped and loaded the brass in the following manner prior to loading:
1. Expanded the necks with a 21 Century 25 cal expanding mandrel to push all imperfections to the outside.
2. Turned the necks with 21 Century neck turning tool to .014"
3. Uniformed and deburred the flash holes with a 21 Century tool
4. Sized the cases with a SAC Creedmoor die using a .283 bushing. This set the necks to a uniform .002" neck tension. Each case was checked with a Forster tension gauge before loading.
5. SS pin tumble cleaned the cases
6. Dried in a Lyman Cyclone
7. Chamfered/Duburred the case mouths
8. Primed all the cases with Federal LRP primers
9. Calibrated the scale
10. Seated each 120g Nosler Partition (seconds from Midway) bullet with an SAC seating die as each charge was dispensed.

To determine the load, I measured the average case volume of 10 clean, virgin cases. I used this volume in Quickload which gave me a 100% fill rate at my bullet seating depth, at the highest charge of 45.5, and under max pressure.

I appreciate all the responses and I again apologize for the incorrect data I originally stated. The actual increases in velocity seen are still more than I would have anticipated given the relatively small increase in atmospheric temperature."