Primer Differences

[Gunmac]

I am currently using WSP primers for my 38 special reloads. Most of the reloads I make do not make the velocity that is shown in the Sierra or Speer handbooks. Both handbooks indicate CCI 500 was used for their recipes.

The reason I use the WSP primers is based on a discussion I had with Brian Enos when I ordered my Dillon Press. He didn't like the CCIs with revolvers and recommended WSP or Federal.

As long as the primer detonates is there any real difference between the primer manufacturers?

[Chris Keen]

Federals are more sensative. If you have a light trigger, you may notice a difference here.

I only trust Federals.

[D.Hayden]

I've never noticed any differences.

Like Chris said, most revolver shooters I know use federals for sensitivity.

[kevin c]

Specifications and dimensions vary slightly from brand to brand, but all of them should make your load go "bang". For primers designed for small pistol cartridges, there isn't, as far as I know, enough consistent difference in primer ignition to see a brand to brand difference in ballistic performance.

I have heard that CCI primers are slightly different dimensionally compared to other primers, and that may cause some problems for primer feeds on presses. There is also deliberate variation in primer cup hardness which affects how readily the primer goes off, or how likely it is to deform or pierce with a hot load. A soft cupped, sensitive primer from Federal, for instance, might be good for lightly springed revolvers, and especially hard cups are used for the hotter rifle primers to prevent primer flow or piercing. Once fired, though, the internal ballistics (the burning of the priming compound and then the powder) are supposedly the same.

That being said, there are some folks who feel there is a difference in external ballistics (including velocity) using small rifle primers as opposed to small pistol primers. At major PF velocities in 40 S&W, what I've seen is a few (less than 25) feet per second more with the small rifle primers from Winchester (WSR) vs the small pistol primers (WSP). That's just my experience with the brand I use and even that is not consistent. Magnum primers, are, of course definitely and deliberately hotter to burn the bigger charges in the bigger cases they are designed for.

Given the exact same powder charge, I'm thinking that the exact bullet, the COAL, and the chamber/barrel that you are shooting out of probably have as much if not more effect on velocity as the primer you are using right now.

Edited November 27, 2006 by kevin c

[George]

Unless you go from standard to magnum or even to a rifle primer you will have negligible difference in velocity from a primer change.

Every revolver shooter I know uses the Federal SP100 primer.

[shred]

Funny.. I thought primers were primers pretty much (within the small/large pistol/rifle divisions, anyway).. until today when I chronoed some 9-major loads. With a Federal Small Rifle primer, they averaged 1330 fps. With Winchester Small Rifle primers, they averaged 1365 fps. Exact same setup on the press except I threw a box of Fed SRs in the middle of the run.. 35 FPS is a lot for a primer to do, so I did 3 back-to-back chrono runs to verify.

[Harmon]

shred, you converting?

[George]

Hmmm! Interesting data. I switched from WW SP to CCI SP and back a couple times for availability reasons and found no V diff with a 9x19 minor load a ways back. I may have found similar primers, or the pressure curve of 9major may be exacerbating the effect. Maybe the SR primers exhibit more variance. 3 possibilities, maybe more?

I couldn't pull a diff out of the chrono results I got using AA7 and a 147gr bullet in 9x19 with CCI vs. WW SP. It was a mousephart load at 134-135 PF using range pick brass. The velocity readings I got were all within the same 25-30fps range for both primers (910-935ish).

I guess you just can't assume one set of results will transfer to other situations using different components?

[shred]

shred, you converting?

I'm still 4/5ths Supercomp, but the steel 9 got some major loads made up to see how it would work. Alison may shoot it at A4 like that.

[Harmon]

cool, im about settled on 3n37 but HS6 was really nice too.

[Gunmac]

After loading 1500 WSP primers with 100% going bang it seems like my GP100 is happy with the choice. I will get a box of the Federal to try them out.

As you can probably tell I am a newcomer to this forum. Very impressed with how many responses you get and the level of detail in the response.

Thanks,