Difference in primers

[Poconolg]

What is the difference between regular large rifle primers and match primers?

 

[Slamfire]

What is the difference between regular large rifle primers and match primers?

Consistency.

CCI Benchrest primers:
In benchrest competition, there’s no such thing as a group that’s “too small.” Everything has to be tuned to the highest degree to produce match-winning results. That’s why we make CCI Benchrest primers. Only our most experienced skilled personnel put the priming mix in the cups, so you get the same flame, shot after shot. We also use specially selected cups and anvils for added consistency. An independent researcher identified the use of CCI Benchrest primers as one of two factors that were the most significant contributors to tiny groups. We can’t add much to that!

http://www.cci-ammunition.com/products/primers/primers.aspx?id=27

This article is worth reading as it is an excellent primer, on primers.

Mysteries And Misconceptions Of The All-Important Primer

http://www.shootingtimes.com/ammo/ammunition_st_mamotaip_200909/

I had a bud who worked with the ammunition industry. Manufacturers have instrumented “mules” that measure every primer characteristic you could ever dream of. Things like mass ejected, flame temperature, duration, gas volume, etc, etc. He told me that workers on the production line are given cash awards if their primer mix is the most consistent on the mule. A further interesting part of the discussion was that the most consistent primer cake is an “artifact”, that is, who makes it varies, and no one always makes the most consistent primer cake.

I recall reading that CCI weighed their benchrest primers along with lot testing.

Most competitive shooters I know use CCI benchrest, but there is a smattering who use Russian primers (which are really good) and Federal Match. Based on my reading, CCI benchrest may have a dedicated line, Federal Match comes off the same production line as standard, but is sorted out by lot consistency.

I conducted a primer test, where I held the bullet, cases, charge all the same and varied the primers, and I saw differences between the groups. The results could have been shuffled if I then proceeded to play with bullet seating depth, charge weight, etc. The home reloader just does not have the instrumentation to directly measure primer characteristics and consistency, and that any errors attributable to primers is buried by the huge errors people have in aiming and shooting.

There are differences between match/standard primers and mil spec primers. You will find that standard primers are more sensitive than mil spec primers. Military weapons tend to have heavy, free floating firing pins, and the kinetic energy of a firing pin rebounding off a primer will cause ignition if the primer is sensitive enough to ignite. For that reason mil spec primers are less sensitive on the average than commercial primers. Military weapons also tend to have robust ignition systems which reliably ignite mil spec primers. Many commercial firearms are a disappointment in this regard, their ignition systems are infact weak, and they will misfire if mil spec primers are used in them.

 

[emcon5]

Federal Match comes off the same production line as standard, but is sorted out by lot consistency.

I contacted Federal a while back, when the Gold Medal large rifle match primers (210M) were impossible to find, and I was almost out. I asked them if the standard Federal Large Rifle (210) primers could be substituted without having to work up new loads.

This was the reply:

The GM primers have tighter specs, but both primers have the exact same components and result in the same output and can be substituted without changing the load recipe.

 

[F. Guffey]

home loaders

The home reloader just does not have the instrumentation to directly measure primer characteristics and consistency, and that any errors attributable to primers is buried by the huge errors people have in aiming and shooting.

I do not even know why they (home reloaders) try. There is always a reason or excuse why they can't do 'it'.

F. Guffey

encon5, Forgive, thanks for calling. that one beats the story about the delivery driver blowing his tail-gate off.

 

[NoSecondBest]

Having kept pretty meticulous records of my loads for the last several years, I can tell you that I can see differences in group size by changing from one brand to another but haven't as yet seen any difference in these primers from using match vs. regular.

 

[603Country]

I always use CCI BR primers, large and small. But, back when primers were hard to find, I bought a good number of CCI 400 for my 223. Lately I've been using some of those non-BR primers in my excellent shooting rifle. Granted that I don't have any hard data proof of more accuracy with the BR's over the 400's, the groups were slightly (and to me, noticeably) smaller with the BR primers. I shot them (BR and 400) on the same day, under the same conditions. Same brass, all Lapua. Same powder. Same bullet. I'll stay with the BR primers. The accuracy diff would not matter to a hunter, or most hunters. I'm just picky.

 

[Unclenick]

You generally can measure smaller standard deviations in velocity with the match primers if you seat both type optimally. The difference does not reflect pressure changes nearly great enough to take a load outside SAAMI's Maximum Extreme Variation (MEV) standard. They are, however, large enough to account for some measure of vertical stringing that would be apparent shooting at 1000 yards. If you see an accuracy difference at 100 yards, however, unless you are consistently shooting bugholes, it is more likely just that one of the particular lots of primers you got is producing barrel time that is slightly more favorable to your gun's barrel deflection timing, or that a small differences in how carefully the anvil is inserted is affecting primer ignition timing and vigor.

If you want to sort that out, as previously described, using identical components and bullet seating depth, except for the primer, use your chronograph to adjust the powder charge to get a velocity match with the less accurate lot of primers to the more accurate lot, and see if that doesn't tend to tune the less accurate lot's group size in to match. Note that this does not mean you can tune in by matching velocity with different brass or especially not with different powder, as that can result in very different peak pressure values even though the bullets are going the same speed. It is only with the other components matching that this is safe to undertake.

I'll also mention that I doubt most people seat their primers carefully enough to get the best performance out of them to start with. In such a situation, it would be hard to tell match and standard primers apart, even at 1000 yards, because you might do a better seating job with the standard primers and a poorer one with the match primers just based on the average difference in anvil protrusion.