Accuracy Loading - Primer Selection

[ELR LVR]

I thought I would take the time to help educate some of the more "Less Seasoned"
Reloaders out there with regard to selecting an accuracy Load
----
I see many of you beginners selecting one item such as insisting on using 1 particular powder
And going to town trying to force your gun to digest it, expecting 1 hole groups
Mainly because you search the forums and see everyone else for example
using Varget in their 6mm BR and think you must do the same if you want the same type of accuracy
Not realizing that other person, likely went through extensive load development
BEFORE - deciding to use Varget in their 6 BR
First trying and using 7 different other types of powders
and exhausting every single primer selection out there
before arriving at their Competition Load
------
What I am showing, is the difference a simple primer change can make in your group size
This test was conducted with a 22-250, same load was used for each group
Same Powder, Same powder charge, same bullet, same seating depth.
the only difference being, a different LR primer for each group
When you try to arrive at your most accurate load for your gun
You must try every single possible combination
As opposed to saying "well I got some CCI-250's for a good price so Im just gonna go ahead and use those"
Then that guy, even after some load development, complains his gun won't shoot well. Lol
Now what if I used that logic with the WLRP's here?
I would never shoot beter than a 1 inch group at best
Compared to the F-210 primers which perform noticeably better in "my particular gun"
"With My Particular Powder"

 

[ELR LVR]

And before anyone suggests
"Well is it possible you may have just shot better and better with each group as the session went on?"
these targets show how the same gun regularly performs with the right load
AND
The right Primer for that load

 

[chop house]

Same Powder, Same powder charge, same bullet, same seating depth.

Ah grasshopper, but likely a different pressure curve and possibly a different tune due to differing primer brisance.

It would seem it is not proof a particular primer will not work if the load parameters are tweaked (beyond normalizing the MV)

I believe @Laurie or @BoydAllen has posted work on this matter.

 

[ELR LVR]

Ah grasshopper, but likely a different pressure curve and possibly a different tune due to differing primer brisance.

It would seem it is not proof a particular primer will not work if the load parameters are tweaked (beyond normalizing the MV)

I believe @Laurie or @BoydAllen has posted work on this matter.

Very true,
not that a person may not be able to GET, a certain primer to work
but, what I have found, is some primers are more
CONSISTENT.
So now, we pick a non-consistent primer and try to get it to work
How much more load development, cost, components etc does that take?
---
In my findings over several different various (lets say 18) different calibers
I have found
that by choosing the more consistent primer, I am more easily able to
successfully change various different powders and quickly find another good load.
---
Not so much with a more inconsistent primer
IE: I can with the Fed 210 in this particular rifle
Use 2230-C, W-748, AA-2700
and even Switch Bullets, etc, and quickly arrive at another working load
"More quickly" with very little more load development than a simple ladder test
----------
The Gist of things being, one should look for a primer that is consistent with the powder burn rate they are using.
For example, Rem 9-1/2's are decent to work with also, but a guy may be shooting himself in the foot if he is searching for 1/4" groups, when the primer consistency will only provide 1/2" groups.
And end up chasing his tail until he simply does a quick primer change.
This is something I discovered some 20 years ago, after already been reloading for over 10 years
and kept searching for the magic load in various rifles, when after some discussion with another more experienced bench shooter, he asked me
"Have you tried changing primers?"
And at the time all I thought was
"WHY?" Why would I change primers? why would I need to, dont they all go bang?
I did not know they were that different from each other, even if that difference is slight.
I don't believe many other people realize this either. Other than the more experienced reloaders who also use primer selection in their load workup.
I see many people stubbornly for example, get on here asking advice for instance in their 223
and the same question pops up,
What primer are you using?
Maybe try Rem 7-1/2's instead.
And the person does not realize why.
When often, a person's primer choice is based on price and availability, not realizing why another primer while costing more, is worth the extra cost. (when accuracy is a concern in the equation anyhow)

 

[Laurie]

I recently loaded 50-odd rounds of 308 Win 175gn / StaBALL Match over eight primer makes. Single charge weight only and all components / details identical bar the primer. This wasn't done to show up different performance / precision, but for a different purpose entirely.

Previous wider range tests showed that the rifle doesn't like this bullet-powder combination at all and that groups would be large. I used it again as it was a) a stiff load pressure-wise, and b) I had the powder and no other use for it.

I shot a single 5-round group for each model (plus some 'foulers') and chronographed everything just out of interest. Only a single group for each, so a tiny sample, but a near 4 to 1 discrepancy in the resulting group sizes from just over the half-inch to 2-inches at 100 yards off the bench. Moreover, the 2-incher wasn't of the 4+1 flier, or even 3 + 2 fliers / split group, rather every shot spread out over the four corners. Also, interestingly, to confound the small ES/SD fanatics, the primer that produced the smallest ES value (by far) also produced the largest group, the two-incher. Not that that is unusual!

 

[Rope2horns]

Very true,
not that a person may not be able to GET, a certain primer to work
but, what I have found, is some primers are more
CONSISTENT.

Can you define what you consider "consistent" with a primer? Brand, lot, weight or something else?

 

[L.Sherm]

When often, a person's primer choice is based on price and availability, not realizing why another primer while costing more, is worth the extra cost

It literally is about 3 or 4 cents a piece difference.

 

[L.Sherm]

Brand, lot, weight or something else?

I'll weigh in on this could be all of the above, accuracy is number 1 so that's were Brand comes in then lot# of that Brand or type Mag vrs non mag

 

[ELR LVR]

Can you define what you consider "consistent" with a primer? Brand, lot, weight or something else?

By Weight - (measured in Milligrams)
Over the years I have found F-210 and Br2 primers to offer me the most precise loads
Upon weighing them it was obvious why
those 2 primers I find are the most consistent in weight from primer to primer
and package by package and lot to lot.
Also offering me, the most consistenct velocities.
--------
compared to WLRP and CCI-250's , where they can differ quite a bit from primer to primer in just one package of 100.
----
I will add, my findings are for medium sized cartridges on down
---
I have not experimented much with Larger cases such as 7mm Mag, 300 Win Mag etc other than simple hunting loads.

 

[ELR LVR]

It literally is about 3 or 4 cents a piece difference.

yes, about .04 difference per primer
which looks quite a bit different when you look at the difference of
$80 per 1000 vs $120 per 1000
----
Which is kind of my point here, there is good reason to go ahead and pay the extra .04 per primer if accuracy is a great concern
For instance
Some people may never shell out for the higher priced BR-2's simply because the lower priced others are all too appealing, or reason within themsleves there is no reason to pay that much more for just a primer.
Maybe not for plinking or hunting
and maybe that person does not conduct accuracy only shooting enough to justify it.
Yet in doing so, may not know what they are missing.
It is strange to me...the amount of money some guys may spend on unnecessary items, and gadgets and little reloading fluff tools searching for accuracy. (like a $600 neck turner)
While trying to save a few bucks elsewhere, skimping on the most important aspects needed for the very accuracy they were searching for.
IE:
Do I need a $400-$600 handheld neck turner that is accurate to 1/10th of 1 thousdandth? in search for extreme accuracy - yet skimp on primer selection.
when a $50 Ebay drill powered Forster is accurate to .0005" is good enough.
and the money better spent and more important that I buy more consistent primers?

 

[neckturner]

You must try every single possible combination

Assuming five powder candidates, five different primers, and five bullets (manufacturers, weights, ogive etc.), there are 125 combinations. With 50 test shots each, that's 6250 rounds or at least two barrels, and of course a new barrel often means re-started testing from scratch. So no, you mustn't try every single combination and could not even if you wanted to. If a set of components that should perform doesn't, then one starts to try corner cases (e.g., a different primer, bedding, etc.).

 

[jelenko]

Wouldn't differences in weight of just the cup be more than the variations in amount of primer material?

 

[ELR LVR]

Assuming five powder candidates, five different primers, and five bullets (manufacturers, weights, ogive etc.), there are 125 combinations. With 50 test shots each, that's 6250 rounds or at least two barrels, and of course a new barrel often means re-started testing from scratch. So no, you mustn't try every single combination and could not even if you wanted to. If a set of components that should perform doesn't, then one starts to try corner cases (e.g., a different primer, bedding, etc.).

I just posted in another thread
Think your load development 90% and shoot 10%
Vs Shoot 90% and only think it through 10%
Which is why I plan my load development out ahead before even starting to load ammo.
Yes a guy can practically wear out a barrel or at least halfway out before arriving at the perfect load.
But you get to determine what YOUR perfect load means. is it 1/2" at 100, is it 3 inches or less at 600?
is it 1/2" day in and day out in 30 winter to 90 F summer?
is it never any bigger than a 0.2", etc
---
how bout instead we choose
5 powders
10 shots each
3 primers (the ones that have shown repeatedly to be known consistent primers over all the years you have been loading
as i just mentioned in another thread, "Out-think" your rifle
so now by thinking more than shooting, our equation becomes
5x10x3 = 150
150 x 1 ,,, You build your load around 1 bullet that you intend to use
Just like you build an engine around the 1 cam you are going to use and make everything else tailored to work in harmony with your cam for the most efficiency and performance.
There's shitty cams and there is known proven well performing cams that work with certain combinations of a certain engine..
--------------------------------------------------------------
a 280 Isky Cam works well for any Small Block High Perf Engine
a 69 SMK will work well for any 223 with at least a 10 twist
You want Bigger? The Berger 215 will work well for any Big Block .308
if you want me to work a load for your 30-06 or bigger I will immediately tailor to the Berger 215
Not that other bullets may not work, but I am trying to as efficiently as possible,
So I am NOT - going to start off trying to work around a Hornady just because I am a cheap ass in my bullet selection but have a $6000 rifle I expect to shoot 1 holers somehow.
I want to - Find the load and get the gun done
the gun is not done and reliable until there is a load for it.
--------------------------------------------------------------
I can now arrive at a good tight shooting load with a newly chambered gun usually within 100 rounds now. (this does require the gun be decently smithed or well built, same as an engine must be put together right or it wont work well either now matter what components are installed in it.)
And I'm hoping youre gonna think I'm talking smack
call BS
which means I have to prove it
Which then means
You get to send me your rifle, and I get to prove it.
Honestly, thats more all I do nowadays is load development for different rifles
My guns, friends guns, Long range guns, AR's etc etc etc
Most People dont wanna fork out the dough for a high dollar rifle when you tell 'em how much accuracy costs
but they certainly do want the guns they already have to shoot well.
I try to work within reasonable realms, such as not using a 90 gr SMK in a 223
Thats like overcamming or over carbing your engine expecting peformance
can it be done? Sure, is it really efficient or worth the effort?
-----
So lets say you find a killer load within 150 rounds
NOW - you can play around with trying out different bullets,
or different carbs and different timing and ignition curves etc such as in an engine.
Because you already have a known combination you can always go back to that you know gives you the performance you were looking for
Each one of us sets our own individual performance requirements of our rifle, even the top competitors.
---
I will say that yes there may be a problem child once in awhile that just is a rebellious little prick that doesn't want to cooperate no matter what you do.
But I have gotten the most unlikely subjects to shoot surprisingly well - with good load development
It really does baffle me to be honest when I see some results such as an Old clunky cracked unbedded wood stocked Herters 7 Mag shooting clover leafs at 100.

 

[FDCaptain]

Too much 'busy work' for the casual shooter, not to mention the cost.

 

[Straightshooter1]

One of the things I found out about finding the right load for a rifle is that my shelves end up loaded with a bunch of different primers, powders and bullets.

 

[Doug Casner]

I have better luck with primers with the smallest bang for the case size. Let the powder burn not get blown to hell with mag primers for accuracy. Hunting , I use mag primers. Doug

 

[K22]

I have no doubt that if one wants to achieve the ultimate in precision as benchrest competitors need to do, primer selection and testing have to be part of the load development process.

However, due to lack of patience, cost considerations, hatred for the tediousness of the load development process given the preponderance of combinations, I am guilty of selecting one primer and staying with it. I like Federal match primers with Remington 7 1/2's for small rifle primers a close second.

My rational has always been to establish a minimum precision standard I need for my application which is varmint and predator hunting. This does require a fair degree of precision. My standard has been 1/2 to 5/8" moa for these applications plus a bullet designed to perform on these critters with velocity considerations.

Once I hit on a combination that meets these criteria, I stop testing and move to practical practice to hone my shooting skills and thoroughly test the load under field conditions. This keep the sport enjoyable for me since I hate load development.

With all that said, what I've learn is almost 60 years of precision reloading, albeit, for my application, is that the most influential component affecting precision is the bullet selected followed by the powder. The powder choice is usually much easier since, historically, there are a range of powders known to work well for certain calibers. However, I prefer extruded powders for field applications since they seem to be more tolerate of temperature changes and more tolerate of slight charge changes.

With the high cost of components and the supply chain availability issues of recent years, the quicker I can get to a qualified serviceable load then inventory components to permit mass production of that load, the better it is for me.

 

[CF Junkie]

It is tough to make any conclusions about primers without lots of data and isolate factors that might impact accuracy.

Here is some 6.5mm CM data from two rifles (one with Large and Small rifle primers and one only with Small rifle primers). The data with large rifle primers was gathered first, before Lapua came out with brass using small rifle primers. It didn't take me long to abandon large rifle primers.

12 LRP 6.5mm CM Primer Analysis - All Bullets (130-147 grs)​
All Bullets (130-147 grs)​	Small Rifle​	Large Rifle​
Brass​	Lapua​	Norma & Hornady​
Brand​	Rem​	CCI​	Federal​
7.5​	BR-4​	400​	210M​
Avg.​	0.274​	0.352​	0.381​	0.419​
Delta Inc.​		0.078​	0.107​	0.145​
% Increase​		28.6%​	39.2%​	53.1%​
# 5 Rnd Groups measured​	2​	385​	105​	51​
Brass​	Lapua​	Lapua​	Lapua​	Norma ​
# Reloads per Brass​	23​	23​	4 & 8​
# groups under 0.300​	2​	87​	14​	1​
% groups under 0.300​	100.0%​	22.6%​	13.3%​	2.0%​
12 LRP 6.5mm CM Primer Analysis - Hornady 140 ELD-M​
Hornady 140 ELD-M​	Small Rifle​	Large Rifle​
Brass​	Lapua​
Brand​	Rem​	CCI​
7.5​	BR-4​	400​
Avg.​	0.274​	0.344​	0.381​
Delta Inc.​		0.070​	0.107​
% Increase​		25.6%​	39.2%​
# 5 Rnd Groups measured​	2​	189​	24​
Brass​	Lapua​	Lapua​	Lapua​
# Reloads per Brass​		23​	23​
# groups under 0.300​	2​	51​	3​
% groups under 0.300​	100.0%​	27.0%​	12.5%​

12 FV 6.5mm CM Primer Analysis​
Overall​
Primers​	Average	Median	St Dev	# Groups	# Loads
BR-4​	0.341​	0.337​	0.069​	558​	153​
REM 7.5​	0.307​	0.303​	0.054​	61​	17​
Diff​	0.034​	Rem 7.5​	616​	169​
% Diff​	10.1%​	90.6%​
Stock​
Factory​	Average	Median	St Dev	# Groups	# Loads
BR-4​	0.365​	0.358​	0.076​	199​	61​
Diff​
% Diff​
Oryx​	Average	Median	St Dev	# Groups	# Loads
BR-4​	0.329​	0.326​	0.062​	360​	119​
REM 7.5​	0.307​	0.303​	0.054​	61​	17​
Diff​	0.021​	Rem 7.5​	90.7%​	106.5%​
% Diff​	6.5%​
12 FV 6.5mm CM​	620​	197​
BR4​	Factory​	1​	27​
Total Grps​	199​
# GRPS <0.300​	40​
% GRPS <0.300​	20.1%​
BR4​	Oryx​
Total Grps​	360​
# GRPS <0.300​	117​
% GRPS <0.300​	32.5%​
REM 7.5​	Oryx​
Total Grps​	61​
# GRPS <0.300​	27​
% GRPS <0.300​	44.3%​

​

 

[Benchrest Braxton]

friends dont let friends use winchester primers

 

[CF Junkie]

Looks like trying to copy data to the site's entry area create problems.
It eliminates any merged boxes and puts the data in the wrong columns.
I will have to try another approach.