How often do you guys test different primers to help with accuracy?

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engineer40

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Pretty much just what the title says... how often do you guys test different primers to help with accuracy?

I test and track results of many variables with my reloading. I had a small epiphany this morning. I never really try different primers.

What are your guy's thoughts on this? Have you ever tightened up a group by using a different brand of primer?

Thanks!
 
alot of times i just go with federals but when i was working up loads for two 221 rifles i have i started with rem 7 1/2s then tried fed 205's and they showed a very noticeable improvement. with a 22k hornet 205's gave poor accuracy but cci 400's gave good accuracy. i will always start load work with federals in cartridges that use large rifle primers but a primer change is always worth a try if your accuracy isn't what you want. different primers don't ignite the powder exactly the same way altering pressure curve and barrel time.
 
I also begin load development with feds as a standard.
In the past I've started load development over again, with a change in primer, if my best with feds wasn't good enough.
That is, I've tested seating, worked with powder, changed powder or bullets, but getting flyers and/or high ES.

I probably won't be changing primers anymore. Some testing convinced me that different primers respond differently to an action's adjusted primer striking. With this I was able to adjust out/in/out of primer striking nodes. I think primers of each make favor a specific striking over others.
In other words, with my firing pin, spring, released protrusion setting, trigger sear distance, bolt frictions, CCIs may seem best, while Rems seem best in someone else's system and same cartridge, similar load.

Across the internet primer results seem an abstract, and all the while few mention any strike tuning(spring, trigger hanger, pin mass, pin protrusion). Why should this be so ignored when any single change to striking shows up across a chronograph?
 
Some people tend to criticize a primer as bad when they change to it, but what they do not realize is that you need to fine tune the load to the primer. It is like tuning the carburetor of an old car. When having a good accurate load in say Fed205 and you change to CCI400 you need to load a little more powder due to the fact that Federal is generally hotter than CCI. However, when changing from CCI400 to Fed205 you would probably have to lower the powder. I have found both CCI and Federal to be accurate, but I prefer Federal for the reason that I never had any misfires with them in the past 30 years. On the other hand I had some misfires with CCI400 primers in my Marlin .357Mag rifle, but to be objective I must say that CCI500 is the intended primer for pistol cartridges. The cup of the CCI400 is, as it seems too thick for the hammer of the Marlin to set it off properly. However I never had any misfires with my bolt rifles.
 
I have seen groups tighten by changing the primer. the change was from a 215 magnum primer to a CCI match primer. Tried it just to see if match primers made a difference. it made a big difference on this load that didn't shoot 1 1/2 MOA. It tighten the group under to 3/4 MOA just from primer change.

Yes primers can/will make a difference in groups. As said before you usually can get a load to work with the primer you choose. But when your having trouble a change in primers can make a difference
 
engineer40,

Every time I work up a load I start with Federal 215 Magnums. Once I pick a powder to go with the bullet and over all length, I switch primers without changing anything else. Some times the groups are cut in half or more.
 
I do find diffrent primers are a variable that's changes group size also. That being said I don't often chase that variable in my pursuit of accurate loads I normally just run CCI 200's or CCI 400's they shoot well for me and I have several local vendors that carry them. I have issues finding the federals in stock locally on a regular basis.
 
This may be dumb but is there known primers that work better for certain primers? Like a certain cci or Winchester would work for a certain caliber better than a fed?
 
Primers are related to pressure, pressure is related to velocity, velocity is related to harmonics! Harmonics are related to accuracy! In order to keep that velocity as close to the same as possible sometimes you need to change primers! Say you shoot 10 shots of a specific load. Everything is the same, charge weight, brass, seating depth, bullet weight primer ect, 1 shot is outside the rest of the group, chrony says it was faster or slower, the primer is most likely the cause if you aimed at the same spot as the rest!
 
engineer40 said:
Pretty much just what the title says... how often do you guys test different primers to help with accuracy?

I test and track results of many variables with my reloading. I had a small epiphany this morning. I never really try different primers.

What are your guy's thoughts on this? Have you ever tightened up a group by using a different brand of primer?

Thanks!
Click to expand...

b267910a-6e1c-4953-82df-8295aac8725d_zpsav9wtwmt.jpg
 
midmo said:
This may be dumb but is there known primers that work better for certain primers? Like a certain cci or Winchester would work for a certain caliber better than a fed?
Click to expand...

I'm assuming you meant if any primers are better for a certain cartridge...

No, as long as the primer can reliably fire the intended charge weight....
Two caveats however; 1. I try to stay away from CCI primers in overbore cartridges as they are sootier to start with and if I'm seriously overbore I do not need any lower shot count to fouled out. 2. some powder/ primer combinations aren't very compatible chemically... for instance Magpro and Fed 215 primers will often produce hangfires... I talked with Sierra about this years ago and they said that a switch to Winchester might fix the problem as some Accurate powders do not do well with Fed primers...
 
Thanks for everyone's responses! I really appreciate it!

I've always stuck with 1 primer mainly because I buy in bulk. Well, this all has me thinking that I should pick up at least 1000 of a few different kinds of primers in Large Rifle. Which is the majority of my reloading.

Reloading is fantastic. If I were speaking to someone who didn't reload, and told them how many primers I have stock piled... and then told them I'm going to buy more, they would look at me like I was crazy!

But maybe us reloaders are a little crazy at times. :)
 

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