Bullet seating problem

[MoreIsLess]

Using my Dillon 550b with Dillon dies I am having a problem with the bullet being seated to deep on about 1 out of every 5 rounds (200gr 45acp). The other 4 out of 5 are fine. What could be causing the flucuation, am I flaring too much or not enough and the bullets scraping the neck of the case and getting shaved off, or something else entirely. It seems odd that some of the rounds are OK while others are not.

Any ideas?

 

[longdayjake]

Did you check the case length?

 

[Walkalong]

Sizer too large, expander too big, thin brass (RP). Over expanding.

Every 5th or so speaks to some thin cases.

 

[MoreIsLess]

After pulling the bullets from the cases in question I measured the flare and it's about .468 on about all the rounds that have the bullet seated too deep. Don't know if that could be part of the problem.

 

[Potatohead]

I feel your pain. Ive had this trouble before. Sucks.

 

[Blue68f100]

Sound like you may not have the right seating stem in the die for your bullets. My guess is it's catching and edge and setting it to low.