300 NM Brass Extraction Difficulty

[wind gypsy]

I have a 300 Norma Mag conversion for my DTA and have been having issues with difficult case extraction after firing. The problem goes away when I use virgin brass but the brass exhibiting the problem is only on it's 3rd firing. I did load some rounds warm in the beginning but not crazy hot. I primarily kept it at or below 82.5 Gr H1000, 92.0 Gr RL33, 85.3 Grains Retumbo. Chamber has 0.256" freebore so I can seat the 230 Hybrids about perfect.

Has anyone else experienced this?

 

[culater]

Tell us your reloading equipment you use and the process you go about reloading

 

[Sheldon N]

Case extraction problems (when not related to overpressure) are often the result of insufficient case sizing at the base of the case. What do your cases measure before/after sizing at the base just above the rim?

 

[wind gypsy]

I'm on the road this week but did measure the base of some fired vs virgin brass. The fired brass was a little over 0.002" larger in diameter IIRC.

Process after firing- deprime. SS tumble. quick shot spray lube. typically FL size with minimum bump but have bumped some of these 2 or 3 thou to see if it would help, it didn't (I have used whidden FL bushing and forster FL dies). Quick ss tumble. Lee ez prime. Powder. Seat with Forster micro seating die.

 

[Sheldon N]

I'm on the road this week but did measure the base of some fired vs virgin brass. The fired brass was a little over 0.002" larger in diameter IIRC.

The measurement you need to check is fired vs sized (not virgin). You want to see how much your sizing die is affecting the base of the case.

 

[wind gypsy]

The measurement you need to check is fired vs sized (not virgin). You want to see how much your sizing die is affecting the base of the case.

The dies do not seem to be sizing the base at all. Virgin measures 0.582, once fired (sized or not) 0.584, twice fired (sized) 0.585".

it seems others are having similar issues.

 

[Sheldon N]

I'd start making calls to varying die makers to see if you can get specs for the base diameter of their FL dies. Usually a tech can give you the die measurement. If you can't find one that is small enough to size the base then maybe custom dies are the next option.

 

[wind gypsy]

300 NM Lapua brass is coming in 2018. I'll try that and if i get the same results I'll try custom dies.

 

[Nieko]

I have the same problem with my Norma, just received a new sizing die from Whidden but have not tried it yet. The base was not being sized enough so this is what was addressed with the new die.

 

[wind gypsy]

I have the same problem with my Norma, just received a new sizing die from Whidden but have not tried it yet. The base was not being sized enough so this is what was addressed with the new die.

Did you order a custom die from whidden or did they just change their dimensions?