If you ever doubted....

[ftrrookie]

That your choice of Primers makes a difference check out these 2 targets. The load is identical except for the primer. Top target is with Winchester LR and the bottom I used CCI BR2s fired at 300 yds

 

[jcampbellsmith]

I'm not sure I follow the point you're trying to make. Did you work both these loads up independently? Or did you work one up and then just change the primers for the second load? Or what?

You've got me confused.

JCS

 

[ReedG]

Your results surely do show the difference in primers, but what JCS is referring to is that just shooting the exact same load with a different primer is not a true test of the primers. You should work up a load using each primer and see then if there is a glaring difference on the target.

 

[ftrrookie]

The load was worked up using BR2s and is my go to load for this rifle. But I'm running low and wanted to see if I could use WLRs as a replacement. So I built 10 of each to compare. Firing them in round robin fashion. The range master called a cease fire after only 7 of the 10 rnds were fired but it's enough to let me know that a direct swap isn't going to work.

 

[dkhunt14]

You may have to change amount of powder to make the other shoot. I would chronograph the two and see if there is a difference. Matt

 

[ftrrookie]

Yeah. I'm not new at this. I knew there was going to be a difference. I just didn't expect this much. I mostly posted this for any folks new to reloading and not aware of the difference changing from 1 primer to another can make

 

[stacy]

THAT'S WRITE

 

[pacificman]

I appreciate your primer test as to me that is what makes this sight the place to be. My 22 hornet did the same thing as your rifle. I had several loads worked up with different primers and the Rem. 7.5 was the one for the greatest accuracy. Most info advised to use a small pistol primer for the hornet but when I tried the Rem. 7.5's the groups were surprisingly very tight in my rifle. Thanks for the test!

 

[bdale]

Was the barrel cleaned between test or were they fired one type after another, could be that fouling has some effect :

 

[ftrrookie]

They were shot in a Round Robin fashion. This means 1 at the top target then 1 at the bottom target ...

 

[BigDMT]

My father in law and myself have been telling people about the importance of primers for years. He taught it to me and I always make sure to pass it on to new reloaders. So many people overlook the primer as a primary component to finding top level accuracy.

Many times a simple primer change can save you many trips to the range in tuning a load. I have seen primer changes only make a difference of 1/2 MOA in accuracy. I've seen a primer change make no real measurable difference at all. And on many occasions, I have seen a simple primer change in a load make a VERY significant difference.

The most significant difference I can recall was when my father in law's cousin was testing loads for his 7mm Rem Mag hunting rifle. Couldn't get the thin to shoot very good at all. # shots would post groups from 6"-7" at only 100 yards. We changed the primer in his load and BAM! He was shooting 3/4" three shot groups at 100 yards, which for that particular rifle was very acceptable.

If you have different primer types on hand, It's always worth a try to see what a primer change can do if you are having trouble getting a certain powder to shoot well. That's exactly why I keep nearly every type of large rifle and small rifle primer, both magnum and standard, on hand.

 

[Drop Port]

I appreciate your primer test as to me that is what makes this sight the place to be. My 22 hornet did the same thing as your rifle. I had several loads worked up with different primers and the Rem. 7.5 was the one for the greatest accuracy. Most info advised to use a small pistol primer for the hornet but when I tried the Rem. 7.5's the groups were surprisingly very tight in my rifle. Thanks for the test!

Seen the same thing with a 17 Ackley squirrel. Everyone said to use pistol primers and it shot like crap until a 7.5 was put in it.

Also the BS about mag primers not working in smaller cartridges. I had a 257 Rob. that was an MOA rifle with everything until I put a LRM in it and it was a sub 1/2 MOA load.

 

[jsthntn247]

If u would have worked the load up up with the win primers then change to the cci's, you would have seen the same thing in reverse.

 

[BigDMT]

If u would have worked the load up up with the win primers then change to the cci's, you would have seen the same thing in reverse.

Not necessarily.
You don't know what charge of the powder used would have produced accuracy with the Winchester primer, or if the Win primer would have shot decent at all with the same powder. When the charge amount or powder type changes, you would have to re-test this scenario and there would be no way to guess the results.

Using a different amount or type of powder to charge the case may find a node that accepts both primers and maintains good accuracy. But you just don't know til you try it.