Sig Cross light primer strikes

[shooterpunk]

I've shot 50 rounds through my new Sig Cross 6.5 Creedmoor now and have had three light primer strikes.

Starline brass, CCI 200 primers, Barnes 140 match burner and h4350.

I ran the new brass through a full length sizer die. I measured to the shoulder of the latest round that didn't fire and it measured 1.49".

Do you think it's issues with the brass? I'm not new to reloading, but I don't know a lot about it to be honest.

 

[epeet]

Could be you need a few more pounds of firing pin spring. If you have other primers, try those first?

 

[Milf Dots]

Post some pics of the rounds- the reloading gurus will probably know if your primers are seated correctly.

It might pay to run a box of factory ammo thru it, as a control... If they don't give an issue then you know it's your handloads.

 

[huntnh]

Could be you oversized the brass try some factory and go from there

 

[shooterpunk]

Good idea. I'll try some factory ammo.

 

[shooterpunk]

Just thinking, assuming factory ammo works great, what would be my issue with brass? How would I fix that? Like I said it only happened to 3 out if 50 shots.

 

[huntnh]

Buy oversized I mean the brass is sized shorter the factory which gives you more headspace and light primer strikes(round is shorter and seated farther into the chamber firing pin can’t reach it)

 

[ormandj]

What FL sizing die are you using, and how did you set it up? Measure a fired case and one of your sized cases, see what the difference is. Grab a Hornady comparator (or other similar tool) and make sure you're only pushing the shoulder back 0.002" (most bolt rifles for easy chambering) to 0.003" (semis).

Also, how are you seating primers? What's your firing pin protrusion measure?

 

[huntnh]

Exactly like you stated bump it back .002 as for primers Iv always used the rcbs universal priming tool never really worried about it to much just checked to make sure there properly seated

 

[shooterpunk]

I'm using Redding series A full length sizer.

New brass is 1.91 and shot brass is 1.905.

I'm using the reloader to prime when I bring it down from sizing.

No idea what the firing pin protrusion length is. How do I measured that?

How do I bump the shoulder?

 

[KnowNothing256]

I'm using Redding series A full length sizer.

New brass is 1.91 and shot brass is 1.905.

I'm using the reloader to prime when I bring it down from sizing.

No idea what the firing pin protrusion length is. How do I measured that?

How do I bump the shoulder?

Where are you taking those new/fired brass measurements? At the shoulder, using a comparator tool, or from base to case mouth?

Firing pin protrusion is how far out the firing pin tip sticks when you press the trigger. I'm not familiar with the Cross, but you can usually check protrusion by holding the main bolt body and twisting the bolt shroud (at the rear of the bolt) in the direction of the big "scoop" machined out of the rear of the main bolt body.

Pics attached. In the one with the colorful arrows, rotate the bolt shroud in the green direction until the part the red arrow points to is in the yellow spot. Included a pic of what it looks like after rotation, as well as what the firing pin should look like afterwards. Using calipers, measure how far out the pin sticks from the bolt face.

 

[shooterpunk]

Measurements were from case mouth to base. Sounds like I'm going to need to buy a few tools to measure these things appropriately.

Thanks!

 

[KnowNothing256]

Measurements were from case mouth to base. Sounds like I'm going to need to buy a few tools to measure these things appropriately.

Thanks!

Yeah, case mouth to base, esp without resizing, isn’t super meaningful. The comparator clamps onto your caliper jaws; I recommend getting one that takes inserts for both shoulder and bullet ogive measurements. Hornady’s works fine for me, but some scoff that it isn’t accurate enough. It’s been plenty repeatable for me, but I’m also not looking at 0.0005” measurements on shoulders or ogives. There are always fancier and more expensive options out there!

 

[ormandj]

That’s probably your problem (measuring case mouth setback and not shoulder setback). You’ve probably sized the brass a bit too much. Grab some comparators and go to town. That said, the manufacturer instructions for the FL die will generally have some get-you-in-the-ballpark instructions.