Primers or something else?

[Jagged 77]

Loading some hunting rounds for my .260 and encountering an unacceptable amount of misfires (4 in 60 rounds). The primers are CCI 200’s probably around 10 years old, they might have been subjected to temperature swings with the seasons and possible high humidity. 

I’ve stripped and cleaned the bolt, primer strikes don’t look light. Cases f/l resized and primer pockets tight for the most part. As a belt and braces checked headspace and all good not that it should affect it. 
 

The only other variable I could think of is that the RCBS priming tools seating pin needs replacing as the thread has stripped (so not sitting tight and centred as it should). I have a back up hand primer which I’ll use next. The primers I’ve loaded however have been seated correctly and not crushed in (muscle memory after tens of thousands of reloads)
 

My thoughts on the culprit is the primers and I shall find some new ones, however can anyone else think of anything else it could be failing that? 

[Leeman]

Firing pin spring getting weak?

[No i deer]

Could there have been moisture in the cases after ultrasonic cleaning when you primed them 🤔

[No i deer]

I ultrasonic cleaned some of my cases a month or so back..

I thought they were bone dry until I annealed them in my AMP and I had several that I could hear the water evaporating when the case got hot 

[Jagged 77]

23 minutes ago, No i deer said:

Could there have been moisture in the cases after ultrasonic cleaning when you primed them 🤔

I did load the first batch which had been SS cleaned 5 days before and the thought occurred it might have been a rouge drop of water. I’m usually quite cautious about making sure the cases are dry.  However the batch I just loaded was bone dry.

I’m 99% certain it’s the primers but just wondered if anyone had experience similar. Rifle is a T3. 

[No i deer]

I've had a T3 which started out as a 25-06..

Shot that barrel out then had it rebarreled into 6.5-06.

I put 2500 rounds through it and had it rebarreled in 284 and that's done 2700 odd shots and it's never missed a beat.

The T3 action is as slick as an action could be..

I can't fault it..

[Catch-22]

Did you seat the primers deep enough to hit the bottom of the pocket?

If you don’t, when the firing pin strikes, it essentially seats the primer deeper and doesn’t meet the resistance needed to actually set the primer off.

[No i deer]

I think the primer needs to bottom out and seat tight so the anvil is compressed so the firing can ignite the primer 

[Jagged 77]

This is a long but fascinating read on the subject:
 

https://www.africahunting.com/threads/it-dont-go-bang-fires-hangfires-short-order-cooks.55913/

[Fox Tales]

 Excessive headspace can also result in light strikes . Hornady had an issue with 223 ammo a while back , all of which had been sized excessively. The primers rely on percussion to detonate , poor chamber fit will allow the cartridge to ride the punch .

 I'm not dismissing the primers .

 I store mine in a plastic box with silica gel packs , I'm not sure if it makes any difference , it's more preventative medicine .

[snakeman]

7 hours ago, Jagged 77 said:

This is a long but fascinating read on the subject:

 

Highly informative and an excellent read 👍

ATB

[No i deer]

I got so far and stopped..

What was the outcome then..?

[Jagged 77]

41 minutes ago, No i deer said:

I got so far and stopped..

What was the outcome then..?

Buy fresh primers, store them in an airtight ammo box, make sure your action is true. 

[snakeman]

I got so far and stopped.....     but why? 🤔

What was the outcome then...?         ahhh, that'll be top secret, can't tell 😁

[No i deer]

I'm easily bored..

Long reads are not my thing 🥱