Berger 155.5 Fullbore

[CChastain]

I've been shooting Berger 155.5 Fullbore bullets in my 700 Varmint 308 with excellent results . Opened up a new box of 500 today that's a different lot number and began to load only to find that they are .065 shorter from base to olgive . This creates a problem with my factory chamber . Is this common with Berger bullets ?

 

[JayBeeYou]

Would suggest try shooting them with same load data as with prior lot. It may make a difference but very good possibility they will shoot the same as before. The 155 Fullbore has a well earned reputation as one of the more forgiving bullets. It is common even with Bergers to get variations in different lots of bullets.

 

[CChastain]

I'm mostly concerned about seating depth . If loaded to the same length which is .020 jump , there's not much bearing surface in the neck .

 

[JayBeeYou]

I'm mostly concerned about seating depth . If loaded to the same length which is .020 jump , there's not much bearing surface in the neck .

If concerned about amount of bearing surface then that may well require a new load workup. Or maybe post a WTB for that specific lot number that you were happy with. I would try just seating them a little deeper though. I have shot a lot of fullbores and found it was harder to find a bad load than a good one. Others experience may vary of course.

 

[CChastain]

Thanks . I'm probably gonna give them a try .

 

[Ned Ludd]

Exactly how much bullet shank will be left in the case neck with the new Lot of bullets when they are seated at .020" off the lands? It doesn't take much.

I'd certainly prefer to have at least half a caliber worth of bullet shank seated in the neck, but you can get away with less. If it's a concern, you can always use a slightly smaller bushing to give a little more neck tension (interference fit). Test with your fingers - if you can't move the seated bullet with your bare fingers, it isn't going anywhere. In any event, an average bullet base-to-ogive variance of .065" between different Lots of Berger bullets is substantial, but not totally unheard of. In the past I had a new Lot of Juggernauts that changed by about the same amount, except they were longer, not shorter. That created a whole different set of issues from what you're dealing with, but I was able to successfully re-work the load.

 

[markgrabowski]

That’s a surprisingly big difference between lots...