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Miscellaneous

What are pressure signs in reloading?

What are pressure signs in reloading?

These signs include very flat primers, slightly cratered primers, ejector marks on the case head, and stiff extraction. All these case head signs indicate high pressure, and loads should be reduced until these signs disappear.

What is the pressure in a gun barrel?

When the firing pin in a firearm strikes the primer, it ignites the powder inside the case, creating an explosion that generates a large amount of pressure, often exceeding 50,000 PSI (344.7 MPa). This pressure in turn pushes the bullet out of the case mouth and into the barrel.

At what pressure does brass start to flow?

Softer brass like some batches of Hornady will show brass flow at under 63,000psi, medium like Remington, Norma etc around 64,000 to 65,000psi, and hard brass like RWS or Lapua won’t show it till around 70,000psi.

Does barrel length affect pressure?

223 is listed as 55,000 psi. The 3 inch port pressure we measured was 55,744 psi using M855 (average of 9 rounds). 1. Pressure in the bore (uncorking pressure) increases exponentially with decreasing barrel length.

What is the pressure of a 9mm bullet?

The service pressure Pmax of the 9mm NATO is rated at 252 MPa (36,500 psi) where CIP rates the 9mm Luger Pmax somewhat lower at 235 MPa (34,100 psi).

What causes blown primers?

This is usually referred to as “blown” primer. However, it can also occur because a gas-operated, semi-automatic rifle is not properly timed. In other words, the bolt unlocks before the case releases its hold on the chamber, and the primer pops out.

What is a SLAP round?

The saboted light armor penetrator (SLAP) family of firearm ammunition is designed to penetrate armor more efficiently than standard armor-piercing ammunition. In the US it was developed by the Marine Corps during the mid/late 1980s and was approved for service use in 1990 during Operation Desert Storm.

Do shorter barrels have less pressure?

1. Pressure in the bore (uncorking pressure) increases exponentially with decreasing barrel length. Maximum velocity is in a 20 inch barrel.

How can you tell if a primer is too high pressure?

If the primer seems to have a sharp, square edge along the primer pocket, or it seems distorted in any way, that is an immediate sign of high pressure. (Many reloaders refer to this as a ‘flattened primer.’)

What happens if the firing pin hits the primer?

This pressure sign in particular is unmistakable: If the primer is pierced where the firing pin hit it, the pressure was too high. If you experience a pierced primer, stop firing the rounds immediately. This problem is more than a minor inconvenience; it can cause serious damage to the firearm.

What happens when you blow primers on a case?

This will almost always result in extreme pressure being transferred to the base of the case and through the action. This particular customer mentioned above did this enough to where you could actually see the words “Hornady 6.5 Creedmoor” imprinted on his bolt face, and the bolt face was permanently damaged due to blown primers.

How do you tell if a primer has been flattened?

(Many reloaders refer to this as a ‘flattened primer.’) Also, look at the firing pin mark: if the dimple made by the pin has a raised crater on its edges, this is an example of the pressure blowing the metal in the primer backward and around the firing pin. It’s highly indicative of excessive pressure.