223 cases split necks

[Alan2791]

I suspected as much. It can be a problem if they allowed the reamer to wallow out the neck.

That being said, I still think there is an issue with the chamber being slightly too deep.

As a recommendation, I'd suggest you conduct a simple test. Load a .223 case with a mild charge, and seat the bullet long, so it is in the lands/grooves. This will allow the case to remain against the bolt face as ignition happens, and limit case growth. Then measure the case length and shoulder length against some of the factory .223 cases you shot/fireformed in your chamber. This will give you a very good idea of what is happening in your chamber.

Thanks for your input I’ll give it a go…

 

[Alan2791]

A few ago I had the same issue with neck splitting after 1st firing.
6.5x284 Lapua brass.
I sent the cases back to Lapua for investigation.
Their conclusion was the brass was too hard from them in manufacturing.

So maybe nothing you have done....

I did think it was an issue with the brass at first

 

[the prowler]

Looks like there's a slight edge between shoulder and the neck on your case's. Try some sako brass if you can.

 

[Kiwiguy]

I did think it was an issue with the brass at first

The brass in your photo appears to have been polished, is this the case and if so what do you use to polish it with please?

If I was having this issue I would email your photo to the guys that own AMP and ask their advise on what may be causing your issue. The following is their email address.

info@ampannealing.com

 

[Alan2791]

The brass in your photo appears to have been polished, is this the case and if so what do you use to polish it with please?

If I was having this issue I would email your photo to the guys that own AMP and ask their advise on what may be causing your issue. The following is their email address.

info@ampannealing.com

I use one of these to clean my brass..thanks for the advice I will contact AMP to here there thoughts…
LEM Exclusive Electromagnetic Brass Case Cleaner