Using different small primer brands - impact on power factor?

[jimbullet]

Does anyone know if using different primer brands would yield different power factor results?

 

I had a load for major PF on 40 which gave me a PF178 a couple of years back. Moved to a different recipe for a while due to supply issues of projectiles. Now I managed to get reloading components identical to the old recipe I had with the exception of changing primer brands.

 

I previously used Fiocchi small primers and switched to Winchester small primers (not the magnum small primers). When I chrono'd my load, this resulted to a PF 185!

 

I made sure my OAL is the same, crimp specs, same, new starline brass....so is it possible for a change in primer brand to have a huge difference in power factor? 

The powder I have used is still the same brand, Win231 which I have also just recently bought.

 

Would appreciate thoughts please?

[Farmer]

1 hour ago, jimbullet said:

Does anyone know if using different primer brands would yield different power factor results?

 

I had a load for major PF on 40 which gave me a PF178 a couple of years back. Moved to a different recipe for a while due to supply issues of projectiles. Now I managed to get reloading components identical to the old recipe I had with the exception of changing primer brands.

 

I previously used Fiocchi small primers and switched to Winchester small primers (not the magnum small primers). When I chrono'd my load, this resulted to a PF 185!

 

I made sure my OAL is the same, crimp specs, same, new starline brass....so is it possible for a change in primer brand to have a huge difference in power factor? 

The powder I have used is still the same brand, Win231 which I have also just recently bought.

 

Would appreciate thoughts please?

Yes! Depending on your bullet weight your only talking about 38 or so fps and I’ve seen 40-80 FPS between brands. You also could have some component stacking as in, new lot of powder is faster, new cases are softer and grip the bullet better, case volume from maybe a different brand that you used before ect. 

Edited March 5, 2022 by Farmer
Sp

[jimbullet]

34 minutes ago, Farmer said:

Yes! Depending on your bullet weight your only talking about 38 or so fps and I’ve seen 40-80 FPS between brands. You also could have some component stacking as in, new lot of powder is faster, new cases are softer and grip the bullet better, case volume from maybe a different brand that you used before ect. 

thanks for the inputs. "component stacking"? If I am using the same brand of powder, why would new lot of powder be faster? If I am using the same powder brand, then it should generate consistent and the same pressures right?

[Farmer]

14 minutes ago, jimbullet said:

thanks for the inputs. "component stacking"? If I am using the same brand of powder, why would new lot of powder be faster? If I am using the same powder brand, then it should generate consistent and the same pressures right?

Don’t quote me but I believe there’s a 5% allowed variance that they can vary somewhat in burn speed. That’s why companies warn about mixing primers and to test new Lots of powder. I once had two jugs of H110 that were totally different. One was so much slower that I couldn’t achieve the same velocity as with the other. The load was compressed and it was still 75 fps slower than the original. Faster powders don’t seem to have that much extreme difference but a little here and there adds up. I’m betting that most of yours is coming from the primer swap. 

[AHI]

Fiocchi primers are some of if not "coolest" primers available. The winchesters on the other hand are a "hot" primer.

(That is without going into all the technical Terms.) Powder varies from lot to lot. In pistol powders. The worst I have seen is .3 +/-. Have seen

a 3grain difference in rifle  some powders.

[jimbullet]

7 hours ago, AHI said:

Fiocchi primers are some of if not "coolest" primers available. The winchesters on the other hand are a "hot" primer.

(That is without going into all the technical Terms.) Powder varies from lot to lot. In pistol powders. The worst I have seen is .3 +/-. Have seen

a 3grain difference in rifle  some powders.

ok at least I know I'm not going crazy...the exponential increase must then be the winchester primers then. Quite amazing how a change in primers could result to excessive pressures. Since standard division PF is 170, I am trying to get close to 175 (settled at 178) which I did before and a change in primers just got me to dangerous levels of  PF 185, which is going 1030 fps on a 180 gr projectile.

[usmc1974]

I think it is much to do about nothing. I use a magna speed 3 and with the same exact loads I get a high vel and a low vel then an average vel. I generally have a SD of less then 10 single, staging my rifle rounds. So any difference a primer will make will be minimal at best. Guns and ammo did a study years ago and found Generally a small pistol primer is a bout 15-17 fps a large pistol is about the same. I use a Dillon SDB for my pistol rounds weighing about every 100 or so round. I now only use SRP and notice little change in velocities.

[HesedTech]

On 3/4/2022 at 11:40 PM, jimbullet said:

Would appreciate thoughts please?

Yes switching primers can change the velocity, but unless you're loading at minimum PF or near the max pressures recommended it will be an insignificant change.

 

What is a potential issue is the depth of the primer, especially if you're using light hammer springs. I have found substantial differences between depths of various primers enough so to make sure the seating depth in the brass is checked and adjusted (Dillon 1050).

[usmc1974]

1 hour ago, HesedTech said:

Yes switching primers can change the velocity, but unless you're loading at minimum PF or near the max pressures recommended it will be an insignificant change.

Exactly, how ever I have found because I only use Small rifle primers I have make sure my primer pockets are very clean.

[Farmer]

Years ago a test was done using a variety of bolt spring tensions to see the effects on velocity from light to heavy primer strikes. As I remember there was a considerable amount from light to heavy, as in enough to to not make minor/major if that was the case. This was done on a rifle but I don’t see why it wouldn’t have some affect with a pistol round also. 

[Nuncles]

I think I read that extreme primers we’re either similar to CCI or rebranded CCI but I can’t verify that. Made these test loads at the same time just switching primers. Numbers to the right is PF.

Edited May 30, 2022 by Nuncles
Added info

[Leezway]

I am to assume that these are SPP’s and not SRP’s? I have substituted SRP’s in pistol and have not found that the spike to be negligible. My Minor PF I try to achieve for my loads are around 130-135 and with either primer I’m within range. I have not really noticed much difference and I am using CCI for both primers (#500 SPP & #400 SRP)..

[Nuncles]

Yes all SPP. These are all 9mm. I know that the thread is under 10/40 but the OP just asked about primer brands. Figured it didn’t matter  much about caliber.  Just a side by side comparison of three different primers.