22cal berger 90 gr'rs vld. O.A.L. question.

[hillbillywilly85]

Evening all

Im loading 223 rem, the bullet i m using is Berger V.L.D 22cal 90gr'rs target. I m wondering something i ve heard 2 sides to before, its bullet jump. Anyway so i ever so lightly necked a fired case. Smoked it over a candle. Put a 90gr bullet in, closed the bolt and took my measurement. It was 2.603in. So can i seat my bullet at the 2.603in an way we go. I ve heard some say you need .02 or even up to .05 bullet jump. I know as i try other depths you decrease .05 increments . But can i leave the bullet on the rifleing? Or do i need the jump to avoid high pressures an or is a running start required? Or running start better practice?
Any answers appreciated.

 

[rnbra-shooter]

The origin of the rifling is the reference point.

It is OK to load the bullet just-touching the origin of the rifling.

You might find you get better accuracy if you have some jump (but then again you might not - you need to test this and see). Berger has an article in which they recommend you try different amounts of jump in .030" increments.

You can also load the bullet *into* the rifling ("jam", instead of "jump"). Sometimes it is necessary to do this in order to get good accuracy. Avoid this configuration if you possibly can, it is quite inconvenient. If you chamber a round and decide not to fire it, it is possible that the bullet can remain stuck in the rifling, so you end up pulling out the case and dumping powder into your action (which can foul up your locking lugs and trigger). It's a real mess and you really don't want to deal with this.

Some pressure changes can be caused by more or less jump. That's why you follow the guidelines for working up loads.

 

[IMagius]

What was already said - with the provision that if you are now using a new OAL, you shoudl start your loads with less powder and work up and find Max again. Changing the OAL is changing the volume inside the case, and can cause differences in pressures - sometimes more than one would assume for such small changes.

 

[762nato]

It is my experience that Bergers do not like to jump. I load all of my Bergers .003" into the lands.