Fiocchi 40 grain vmax 204 ammo question.

[McCraggen]

hey guys im new here, G'day from down under.

Im a very new 204 owner (T/C venture 22 inch sporter 1-10" twist)

I have found that this rifle is very accurate with Fiocchi 40 grain ammo, but there is a little problem, sometimes the brass has slightly raised primers. My only concern is the ammo is too hot and or dangerous.

Anyone else had a similar experience or chronied the ammo?

Thanks!

 

[McCraggen]

 

[Walkalong]

Pics would help, high primers in fired brass can be low pressure.

 

[McCraggen]

Here ya go hornady superformance vs fiocchi rifle extrema

 

[Walkalong]

They look fine, especially the Hornady.

There has to be a tiny bit of head clearance for rounds to chamber, some folks call this headspace. When the firing pin hits the round it moves forward until it is stopped by the shoulder in this example, so when the round fires the softer front of the case grabs the chamber walls, and the case head backs up to the breech face (Which is where case stretching happens and why we do not want excess head clearance or headspace in rifles) reseating the primer which backed out before the pressure built up enough to move the case head back to the breech face reseating the primer.

Hope that made sense, I'm not fully awake.

This thread touches on this some. It's all about headspace, head clearance, case stretching, proper sizing, etc.

In a revolver the same thing happens, the round fires, the primer backs out, the pressure pushes the case back over the primer and against the breech face reseating it.

Fire a primer in .357 brass in a revolver with no powder primer and the primer will back out and stay out.