Good groups bad muzzle velocity stats

[stan_wa]

Hello,
Pretty new to reloading for my seeking element 28 nosler 1/8.6 twist with a 22" barrel. Am about 200 rounds in to the rifle and the load development. Currently my groups are looking great and I'm very happy with them. lets call em .5 moa for 3 shots on average.
But with my best load I am having some issues with Muzzle velocity. Below is some data. I have tried 3 different primers. Row 1 and 3 are the same load but i made some changes in process. on row 1 i used a gem pro scale and trickled and seated primers to .003 sub flush.
on row 3 i used a new charge master supreme, cleaned flash holes, seated primers all they way to the bottom, cleaned the case neck to insure no lanoline was inside. these changes seem to have no effect.
row 4 and 2 used different primers. The CCI 200 primers had the worst groups of all my load testing.
Any one got any ideas? i want to avoid running a bunch of random test and the load is shooting so accurate that i don't want to mess that up.

my retumbo is stored with a humidity controlled packet at 50%
The brass is ADG fired 3 times.
I don't have a way to anneal the brass ATM
*its worth nothing that for row 4 is i throw out the one outlier sd is 11 and es is 25*

Resize

Primer

Powder

Bullet

BC (G1/G7)

Bullet Weight (gr)

Charge (gr)

CBTO (in)

Jump (in)

# Loaded

1 shot data

MV AVG (fps)

MV Hi (fps)

MV Lo (fps)

MV SD (fps)

MV ES (fps)

Group Size All (moa)

Group Size Best 3 (moa)

2.238 headspace

CCI 250

Retumbo

Berger 195 EOL

0.755/0.387

195

79

2.872

-0.04

5

2812.4​

2841​

2763​

29.35643​

78​

0.7

0.2

2.238 headspace

CCI 200

Retumbo

Berger 195 EOL

0.755/0.387

195

79

2.872

-0.04

5

2797.6​

2829​

2776​

27.78129​

53​

1.5

0.65

2.238 headspace

cci 250

Retumbo

Berger 195 EOL

0.755/0.387

195

79

2.875

-0.037

10

2795.5​

2838​

2760

27.49242​

78​

1

0.5

 

[willfrye027]

Shoot it at the farthest distance you would hunt and see what the vertical dispersion is. You would think that ES has to be very low to group good at distance but in reality your impacts may be just fine. I used to be very hung up on low ES but have found it to be a waste of time and components. One of my long range loads has an ES of 35 or so but at 600 yards the vertical dispersion is 2 inches.

What was your procedure for load work up?

 

[Justin Crossley]

What chronograph are you using, and have you shot any of these loads at distance yet?

 

[IrkedCitizen]

Unknown Munitions and Whaley precision rifles will anneal your brass if you ship it to them. Inconsistent neck tension will affect SD/ES.

Out of those I would run row 4 if you can get the ES lower.

 

[stan_wa]

What chronograph are you using, and have you shot any of these loads at distance yet?

magento speed, and no its hard to shoot distance here. but I want to.

 

[stan_wa]

Shoot it at the farthest distance you would hunt and see what the vertical dispersion is. You would think that ES has to be very low to group good at distance but in reality your impacts may be just fine. I used to be very hung up on low ES but have found it to be a waste of time and components. One of my long range loads has an ES of 35 or so but at 600 yards the vertical dispersion is 2 inches.

What was your procedure for load work up?

due to the high BC of this bullet, it will minimize the dispersion at distance. ill look for a place to go shoot long range.

for load work, i found max pressure.
shoot groups at of 5 in .5 grain increments below max pressure picked best group 79 grains
shot 15 round groups at 78.79.80 grains decided 79 was the best
shot 10 shots groups for seeting depths at 79 grains with a jump of .2. ,.025, .030 ,035. 040 .05 decided 79 grain and .040 jump was best called that baseline. then went to check MV and got what you see in the post.

 

[Nateskate11]

I would do exactly what the one individual above mentioned. Shoot out at distance and see what it does. Chasing low ES is often a never ending chase and can be a bit of a waste of time/resources. You can try and diagnose it if it is bothering you that much but if the rifle is shooting and shooting well at distance than the ES doesnt mean much to me.

 

[willfrye027]

due to the high BC of this bullet, it will minimize the dispersion at distance. ill look for a place to go shoot long range.

I’d say unless you are reloading for fun and enjoy the whole process, I’d focus more on the actual results at distance rather than the numbers. Plus if you want to hunt at long range you really need a lot of practice and verification at distance anyways.

Also it may just be a bullet/powder combo issue. Especially if you’re struggling to get good accuracy. If you have a different powder in similar burn rate that could help.

 

[Rob5589]

Have you tried a different powder? I've never achieved good results with Retumbo in my 7 mags (RM not 28 Nos).

 

[Rich M]

Looks like you gotta go shoot. I'd confirm that .2 inch group at the top and then stretch it out as far as you can, see if it holds together. If it does, scrap the data and just enjoy a great load.

 

[axeforce6]

magento speed, and no its hard to shoot distance here. but I want to.

Distance will tell you more. Sd and es are great to know if your shooting past 1000 or more. Hunting. Inside of the 500-600 yard mark I wouldn’t worry to much about it. Your groups at distance is what will matter the most. They may group awesome at 100 and open up past 200. Find ya a range to stretch that dude out.