Primer hardness rankings

[spacecoast]

I've been looking around the 'Net for what others have found as far as which primers are harder/softer than others, and have found the following rankings (from softest to hardest). I would be interested in what those here have observed or (even better) measured:

Federal
Magtech
Winchester
Remington
CCI

Federal
Winchester
Wolf copper (old)
Remington
CCI
Wolf nickel (new)

Federal
Remington
Winchester
CCI

Seems pretty obvious that Federals are the softest and CCI is among the hardest. Has anyone investigated Tula primers, or others, to see where they might rank? Any difference in match vs. "regular" primers?

[Unclenick]

Tula and Wolf are both KVB primers (check their part numbers). I believe they are all out of the same plant in Tula, Russia, even though their assembled ammunition comes from different factories.

One reason you don't usually find primer charts in load manuals, even though they affect powder burn and pressures, is the manufacturers keep changing primer specs without telling the public, so that information becomes obsolete more quickly than powder characteristic information does. This article by a CCI employee mentions this and is worth reading for general background on primers. It's yet another reason to work loads back up again when your primer lot number changes, because the primers may have, too.

[Slamfire]

One reason you don't usually find primer charts in load manuals, even though they affect powder burn and pressures, is the manufacturers keep changing primer specs without telling the public, so that information becomes obsolete more quickly than powder characteristic information does. This article by a CCI employee mentions this and is worth reading for general background on primers. It's yet another reason to work loads back up again when your primer lot number changes, because the primers may have, too.

UncleNick: The link did not take me an article by a CCI employee.

I agree with your post, manufacturers do not have to meet any standard other than "SAAMI" specs. Which are voluntary, and wide enough that no one's product line fails.

CCI is the only company saying they are making a mil spec primer, the #41's and #34's, so those primers are likely to meet some spec from lot to lot.

The rest, they will be what they are at the time of creation.

[spacecoast]

Actually my inquiry was about the softness of the primer cup (in reality ease of ignition is what I'm trying to get a sense of). Does that vary from lot to lot? Anecdotal evidence says that Federal is the softest as a rule, etc.

[Unclenick]

Slamfire,

Looks like ST took the links to old articles down. I'm bummed, as I wasn't finished going through them all. Now the link just re-directs to the home page. Too bad. That primer on primers was informative.


Spaceghost,

The sensitivity can change. At one point ten or 15 years ago Winchester increased the sensitivity of their small rifle primers in response to some complaints, and it became a contest between them and Federal. I have a bunch of those in a lot of factory primed .223 brass I still haven't used up. You can tell them because there's no nickel plating on the more sensitive ones (brass colored). Later reports of slamfire problems with them in the .308 and .30-06 service gas guns got the nickel and some portion of the hardness back. Kind of inbetween, now. So, in short, no, you can't be sure the sensitivity ranking will stay the same, though I have to say I don't think Federal ever produced a hard primer.

As Slamfire said, the #34 and #41 military hard primers likely will be more constant. #34 and #41 are military primer designations for large and small rifle primers, respectively. The military imposes specific upper and lower sensitivity limits. Actual mil-spec primers (CCI makes those, too) don't have the nickel plating the CCI commercial #34 and #41 primers do. My guess is the nickel is just a quick identifier for telling the commercial and mil-spec versions apart. The difference is probably only that actual mil spec primers are subjected to a specific lot testing regimen to qualify, and CCI doesn't want to add that cost to the commercial version.

In addition to the hardness specification, military primers are magnum primers, which are used for cold weather ignition reliability. The missing article pointed out that in cases that are not well-filled with powder (common with .30-06 Garand loads for example) the magnum primer can produce better muzzle velocity consistency by better pressurizing the empty space.

The article also introduced the concept of setting the bridge in a primer, wherein the primer is seated to touch the anvils down in the primer pocket, then pushed some number of thousandths further (Federal says 0.002" for small primers and 0.003" for large) to compress the priming mix between the cup and anvil, thus setting how much priming mix thickness bridges the gap between cup and anvil. Doing this correctly optimizes sensitivity and minimizes ignition delay between firing pin strike and powder light up.

[nitro-express]

http://www.shootingtimes.com/ammo/am...motaip_200909/

[Bart B.]

That article's comment about seating primer cup flat .003" to .005" inch below flush with the case head tends to let the cup mouth (or bottom) be against the primer pocket bottom. Seating primers fully pushes the anvil up to set the proper amount of priming mix between the cup and the anvil tip. There's been articles on 6mmbr/accurateshooter mentioning they get better velocity control and accuracy with primers so seated with proper crush fit.

.003" to .005" is about the measurements I get on new primers from their cup bottom edge to the anvil leg tip. If you uniform your primer pocket bottoms flat, you might measure their depth from the case head, then measure primers from their anvils to their flat (or round part) then determine how much below case head they need be seated. Or just seat them until the tactile feedback pressure suddenly increases indication the primer cup's bottomed in the pocket.

Primers need be smacked hard and deep to detonate uniformly across them. Factory spec firing pin rating as well as .055" to .065" primer protrusion of the uncocked firing pin tip from the bolt face helps a lot. Lower numbers mean greater spreads in muzzle velocity and a lower average velocity.

[Sunfish]

... and even a lighter titanium striker to factory specs
Will of course be primer choosy
and make one rethink going back to factory 5# spring & horrible trigger pull (even w/3.5# connector) and resulting in fewer bullseyes.

From fewest misfires to most in my limited experience and still searching, asking mfr what they use:

Federal target ammo
Federal PD ammo, Winchester
Fiocchi, S&B (factory spring lights these up fine)

Gun store refuses to stock Remington (personal failure experience I think), CCI stocked only for smallest calibers

Reports on low cost ammo found on AmmoSeek.com:
Precision Ammo = CCI primers
Freedom Ammo & others = no response

Posting to this OLD thread only b/c there's no primer ratings out there that have lab quality reviews.

[Unclenick]

The CCI #34 and #31, the Federal GM205MAR, and the TulAmmo KVB7.62 NATO and KVB5.56M NATO primers are all made to military sensitivity specs. These are tested for firing pin energy in a fixture which holds a properly primed case upside down in a shell holder with a floating firing pin resting on the primer, then dropping a 3.94 ounce weight on it from different heights in inches. This is also called the H test. The table below shows military values. If you are ambitious about testing, you could build your own H-test apparatus and report the 50% failure to fire drop height for comparison. Those of us too lazy to do it will be pleased to applaud you and copy the results.

If you want to study ignition energy, that can be done by making a primer-fired ball-bearing gun and comparing the velocities achieved.

If you want to study ability to ignite, then a couple of standard loads, one with easy to ignite powder like 4198 and one with hard to ignite powder, like H380, and measuring relative velocities produced by each and standard deviations produced, should give some idea. I understand there is fancy analytic equipment the military has that studies gas volume, flame temperature and heat output directly, but that's going to be expensive to build and probably expensive to maintain.


To update the original thread posts, I put in my own copy of a current link to the article in the post where I first mentioned it. The 0.003-0.005" below flush mentioned in it seems to work out for most commercial brass as-produced. The cup does not hit the bottom, as most have anvil feet sticking up higher than that would require and they would be over-crushed when the primer got there. What you want to do, as the article mentioned, is "set the bridge" correctly. The bridge is the amount of primer material between the inverted tip of the anvil and the inside bottom of the primer cup. Old military specs (McDonnell-Douglas report from the mid-70's) refer to the act of putting adequate crush on the priming mix as "reconsolidation" of the primer. It is is not set correctly at the factory because the factory knows there will be a primer pocket depth tolerance. The original version has Remington and Olin both recommending 0.002"-0.006" of crush of the anvil into the primer as optimal. A later (early 80's) versions of the same document has NOIH recommendations of 0.002"-0.004" based on their testing. This fits with the recommendation Federal gave John Milosovich for the 1995 Precision Shooting Reloading Guide, which was 0.002" for their small rifle primers and 0.003" for their large rifle primers. Federal did not provide a tolerance.

K&M makes a tool called the Primer Gauge tool that allows you to measure exactly how much you are setting the bridge by zeroing simultaneously on the depth of each individual case primer pocket and on the height of the individual primer, including anvil, that you will seat into it. Others designed to control primer seating depend either on feel or on fixed depth settings below flush with the case head, in which case you must uniform pocket depth for the best results.

[Don Fischer]

I have always understood that the softest primer's were CCI and Federals were hard. That hardness and softness is what makes reading primer's for pressure inaccurate. You see a primer flattened by pressure one time and you'll never forget it. The primer will be flat even to the edges of the pocket. The only reason you can tell where the primer ends and the case begins is the case is a different color. I pay little attention to the primer hardness,So long as they fire well, all is good. I don't know of any test you could run to show hardness. More important is how hot the primer is. I've read a lot of people like Federal's because the seem to be hot. I don't change primer's without retesting the load. But I have also never seen the primer change the pressure of the load that much either. Probably the best thing you can find, and I can't prove it, is how well the primer burn's consistently.

[Unclenick]

It depends whether "soft" or "hard" are referring to the cups or to how much energy it takes to ignite the primers. Most often, it's the latter, but the two are related and the priming mixture's native sensitivity and anvil rigidity also play a role.

Large rifle primer cups all seem to be about the same thickness. Small rifle primers vary a good bit (See this article). The walls of the cups are usually about half the thickness of the bottoms after forming from sheet.

CCI made their small and large 450 and 250 magnum primers still harder to fire to meet military spec by widening the anvil leg angle, but leaving the cups alone, then renaming them as #41 and #34. Besides sensitivity, they are not mil spec in any other way. CCI does make military primers, too, but they have a more onerous reliability qualification process to go through than these commercial versions do and they are not nickel plated. Federal, on the other hand, in making the GM205MAR military sensitivity spec primer, opted simply to make the cup thicker to reduce sensitivity, leaving the rest alone. (I got both those bits of information from the respective horse's mouths in email from CCI and Federal.)

I don't know how Tula goes about achieving NATO sensitivity specs.

[jetinteriorguy]

I don't have any experience with Federal SPP's, but have used a few thousand S&B SPP's and to me they seem soft. Compared to CCI's and Winchester primers the S&B's will crater and even flow at pressures that appear normal in other loads. I've also noticed that the S&B primers when seated already look just like flattened primers, even on new S&B factory ammo they look this way. I have relegated them to only use with moderate loads like in my .38sp and some lighter loads in 9mm. Maybe I'm being overly cautious, but I feel better safe than sorry, besides I have good access to primers likeCCI and Winchester on a regular basis so no biggie.

[Jim Watson]

I can't say about rifle primers, most of my rifle shooting has been careful slow fire and not in huge volume, so I usually load CCI BR or Fed GMM.

In pistol primers I find Federal, both large and small, to be the easiest to fire, important for double action revolvers with limber springs. Federal uses a different priming compound which is said to be more sensitive. They apparently use softer or thinner cups, I have had flattening and cratering of Federal primers in handbook loads that do not show "pressure signs" with other brands.

The Winchester "blue box" unplated primers seem next easiest to fire. They are ALMOST usable in my very soft Python.

Older "white box" plated Winchesters are less sensitive.

I bought one batch of Wolf small pistol primers during The Panic. They gave right at 0.1% misfires, one per 1000 shots in 9mm P.

I got a Deal on some Remington 1 1/2 small pistol. They are weird. They behave as though the cup is soft or/and thin; with ironed out indents. Misfires are common in some guns; I have one gun that fires them reliably and it will get the rest of my supply.

[Unclenick]

Remington changed their priming mix at some point about 15 or 20 years ago. Less sensitive. When my dad was still coaching the Ohio State University pistol team, the Remington rep offered the team free .22 LR ammunition in return for branding privileges, but dad refused it because the aging club guns had so many misfires with it that they were guaranteed to lose some rapid fire events over double alibi's with Remington ammunition.

The nickel plating does harden brass some. Winchester took it off in response to complaints about inadequate sensitivity, but now some complain they pierce too easily.