303 British Load data for 150gr speer sp flat base !

[Parashooter]

Interesting hydraulic effect on the thinner necks, Ray

Looks like some further explanation is needed. In fact, the brass is normally thicker at the neck than at the shoulder and the forepart of the body. This is because the case is drawn as a cylinder with gradually tapered walls. When the final forming is applied, the reduced diameter of the neck results in the brass there becoming thicker than before neckdown, while the area just aft of the neck remains nearer the original thickness.

Information

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[armenjs]

Parashooter

You're seeing soot on the necks because the bullet base is leaving the case before the neck has expanded to seal against the chamber. This is to be expected with a short bullet and a ~34000 psi load, which is what you're shooting.

If the soot bothers you, there are several approaches that may eliminate or reduce it -

Heavier/longer bullets
More powder
Faster powder
Seat bullets deeper
Anneal necks
Size necks only to depth bullet is seated

Thanks parashooter great feedback Wow! To maximize my POI, i seated close to the rifling, and with 150gr i will get some soot like you said. i don't mind its good. check out my thread on the Enfiled side of this forum.