Federal 100 Primers Soft?

[Bzcraig]

My last two range trips shooting handguns revealed that; Fed100 in 38/357 were fine but in my 9mm they flattened out and cratered. The result was the same with starting charges as well as full charges. e.g. 128gr hp, 3.0-3.8gr Acc#2 OAL 1.100. I used Lyman 4th data for a Lyman 125gr hp with an OAL of 1.010 thinking of reducing pressure while a work up a load since Acc#2 wasn't listed. I also loaded some with W231 which was listed with a starting load of 4.0gr at 1.010 but I loaded out to 1.100.
Am I missing something? Don't have a chrono.

[MtGun44]

Fed primers have been well known to be easy to set off with a light
hammer/firing pin strike for many decades. Not sure about high
pressure signs, never noticed it myself. I am guessing your loads
are too hot in the 9mm. Try a different brand but I think something
is amiss.

Bill

[btroj]

Long as it isn't causing a functioning issue or piercing I would just learn to ignore them.

Many like the softer primer as it gives good ignition when using a softer hammer spring.

[Bzcraig]

Long as it isn't causing a functioning issue or piercing I would just learn to ignore them.

Many like the softer primer as it gives good ignition when using a softer hammer spring.

If I had not looked at the primers, I would not have known any difference.

Bill - if I had not used published data and starting loads I would have thought the same thing.

BTW, I did have two primers I didn't get quiet seated in 38, so when I got home I pulled those down using a kinetic puller. One of those primers detonated on the second wack. Scared the snot out of me. Thank God the boolit released and powder did not ignite but the primer blew out the top of the hammer.

[GabbyM]

Good chance primer flattening is a headspace function in a 9mm. Firing pin drives the case forwards. Ignition, then primers gets pushed out of case. Then case move back over primer with bolt face seating primer. This action will cause face of primer to have a sharp radius edge or even a flared head larger diameter than the primer pocket. That’s a poor description but. As long as they aren’t blowing I’m not sure this hurts anything.

I head space my 9mm loads off the bullet not the case mouth. You don’t want them to tight though.

Another thing to check is case brand. Some European brands have such small case capacity that pressure goes through the roof with published loads. Geco comes to mind as one I’d find with opened up primer pockets after a few firings. Thirty- five years ago.

[fecmech]

IME Fed SP primers show flattening way before any other SP primer. They are the easiest to fire and were used almost exclusively in PPC Da revolvers to get the DA pull as light as possible. Just a characteristic not a problem.

[Reverend Al]

Our local PPC revolver builder tunes the actions on his DA only guns with Federal 100 sp primers and they are the only primer that he'll guarantee 100% ignition with his tuning work. They have been pretty much known as the softest cup sp pistol primer on the market for years.

[Outpost75]

Base cup metal thickness of Federal 100 small pistol primer is 0.015, +0.0015, -0.0000 similar to Remington 1-1/2

Federal 200 "Small Rifle and Magnum Pistol" primer, is 0.018, +0.0015, -0.0000 similar to Military 9mm or .30 M1 carbine primer, or Remington 6-1/2

Federal 205 "Small Rifle Heavy Cup" is 0.019, +0.0015, -0.0000, similar to Military 5.56mm primer or Remington 7-1/2.

[MtGun44]

Just because the loads are starting loads in a book DOES NOT MEAN THAT IT IS
IMPOSSIBLE FOR THEM TO BE HIGH PRESSURE IN YOUR GUN!

Unlikely - YES - impossible - NO. I know of at least one instance where a revolver from
a very big maker had a problem and was WAY overpressuring with starting loads.
We eventually discovered a manufacturing problem, but it is possible to overpressure
with starting loads.

The only way to know is substitute some CCIs - known for harder primers and see
what you get. It is either the primer or it isn't, easy to test.

Bill

[w5pv]

My 380 functions good with 2.3grains of titegroup under 102 grain lrn and Federal small pistol primers that flatten no other signs of high pressure so I go ahead shoot and make out that everything is ok