SD or ES

[Straightshooter1]

Weighing primers


somebody had to say it

While I wouldn't say weighing primers was the single biggest thing that reduced my ES's, it sure can as I was surprised to find out how much that does help.

 

[Emmett Dibble]

Correct powder for cartridge/bullet weight, quality bullets/brass/powder weighing… assuming all of those are constants (never going to have good numbers if one of those are out in left field) the biggest thing that I saw dramatic es/sd numbers being lowered is brass prep/neck tension. YMMV and IMHO but just annealing after every firing and making sure my brass was prepped well dropped several of the cartridges I run from low 20’s/high teens to high teens/low teens and sometimes single digits ES/SD. I don’t shoot past 600 much and only need to stay sub-MOA and am lazy as hell so once I get in the teens, I’m good. That really is what is important. You need to establish the minimum criteria and when you find the easiest way to reach it, Bobs your uncle.

 

[Bottom Fodder]

If matching lots means premium cases and bullets with any weird ones culled, then finding the primer/powder combo that dances together the best is my vote. I use Federal Match primers as the starting point and sweep the powder speed to see which one gives the lowest overall SD in pressure ladders with 5 shot steps.

Rambling on, my take on the 2 big dilemmas for reloaders are:

1. Trying for statistically significant sample sizes to quantify random variations introduces systemic variations. Barrel heating and fouling are examples of systemic issues.

2. The random variations are a soup of several things that may either largely cancel each other in a given group or stack up and ruin your day on the next. Which happened can not be determined with a single 5 shot group.

I try to find the next big chunk in the soup and accept that any one thing may not be a big step. I record the muzzle velocity of almost everything I shoot.

SD is not a function of ES. ES is always only 2 shots. My thoughts are ES is primarily reduced by culling the outliers. The flip side is a 5 shot group isn't large enough for the SD to be a reliable predictor of ES. From either end. It isn't large enough for a reliable SD and even a reliable SD won't predict the ES for a group that small. I shoot a lot of 10 shot strings and the ES seems to almost always be close to 3X the SD plus or minus 1 or 2. My take on that is I've been largely successful in knocking the tails off a true random distribution.

So what is your simple answer for the list

 

[ShaunBrady]

So what is your simple answer for the list

Powder

 

[JFrank]

Weighing primers


somebody had to say it

Gotta seat um at the exact crush also.

 

[shoot4fun]

Seen like a few has got this going down a rabbit hole.
I ask a simple question, if you can give a simple answer to my simple question thank you if you can’t please don’t derail

The rabbit hole is deep here but you didn't qualify what you wanted well enough. The answer to reducing either or both of those is not one single thing. It's the full package.

 

[14Copperhead]

Everybody is missing the most important indicator, look at your results on targets…. That’s the most important indicator and what was done before everyone has gotten a chronograph (or could afford one anyway).

 

[Bronsin]

Everybody is missing the most important indicator, look at your results on targets…. That’s the most important indicator and what was done before everyone has gotten a chronograph (or could afford one anyway).

His question said nothing about the target. It was strictly about SD and ES.

 

[Bottom Fodder]

Everybody is missing the most important indicator, look at your results on targets…. That’s the most important indicator and what was done before everyone has gotten a chronograph (or could afford one anyway).

So what was the thing that made it look better on your target?

 

[14Copperhead]

His question said nothing about the target. It was strictly about SD and ES.

Neither one matters if your target looks like a shot gun hit it.

 

[Bottom Fodder]

The rabbit hole is deep here but you didn't qualify what you wanted well enough. The answer to reducing either or both of those is not one single thing. It's the full package.

Other here said just one thing

 

[Bronsin]

Neither one matters if your target looks like a shot gun hit it.

True, but again, he didn't ask about that.

 

[ELR LVR]

Considering that all components are from matching lots, what Single thing in your reloading process have you found has had the biggest impact on lowering your ES or SD. I would like to compile a list of all the answers.

the right primer mainly
but theres so many other things to then tune in
What all the things others have said play a factor
but primers that are erratic or have big swings in weight seem to be a big contributor to erratic velocities as well.
For example I used to think using F-215's for H1000 was the better way to go
But I kept finding F210's produced less vertical stringing and much more consistent waterline at long distance
Rem 9-1/2's were ok in a pinch but threw a more round shaped group vs a tight grouping
etc
---
Once I started weighing primers it all made more sense why this is
plus different primers have different characteristics such as Brisance
So matching that to your powder helps
--- I find it really amazing how a simple primer switch can make such an impact on group size
not a little impact but a very noticeable one

 

[Bottom Fodder]

Best I can tale something to do primers has the lead right now. Keep it coming especially if you can keep it to a simple answer.

 

[quest450]

note to self.....self DO NOT participate in any threads started by Bottom Feeder

 

[Bottom Fodder]

note to self.....self DO NOT participate in any threads started by Bottom Feeder

Thank you sir I will try to remind you

 

[Steve Donlon]

generally neck tension because it is effected by more than one thing just from what I have seen effected by to much, uneven or inconsistent neck tension. I could see how primers could matter more to some people that shoot larger cartridges and burn more powder but I never noticed that big of a swing with the smaller cartridges I shoot but sounds like I might have to re-think that. I never considered weighing primers. Just when I thought turning necks was going to save me.

 

[Rick Richard]

Another vote for primers. I also saw a difference going from 215 to 210.

 

[Bottom Fodder]

Another vote for both neck tension and primers.

 

[Webster]

Another vote for both neck tension and primers.

Just trying to be funny.
Someone will figure how to take anvils out of primers so they can be measured and weighed, then put back in the cup. How about variation on how much the foil is pressed into the charge. I have some primers where the charge seems to vary a lot. The charge is squeezed above the foil and around the anvil legs. Will look for them and post a pix.