.338/300 Ultra Case Forming

[mkf350]

I'm about to purchase some brass, I want to know if it would be better to go with .300 RUM brass and size up the necks or get .375 RUM brass and reduce the necks? /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif I believe both cases are same L.O.A. Just don't know which the pros/cons of each..

 

[Shawn Carlock]

You can go either way if you want a tight neck in a factory spec chamber cut use the 375 and turn the necks. If you want simplicity use the 300 and simply run it in a die. I understand Federal has brass available for the handloader now, although I don't know where to get it.

 

[mkf350]

Well this is going to in a Pac-Nor super match chamber. You were right about the Federal Brass but only in .300RUM. I was thinking of getting some of the Federal because I'm hearing the Rem isn't that good. But I don't know if by sizing up I would be creating thinner necks. But if I went with .375RUM I could neck turn them down.

 

[Shawn Carlock]

I have been sizing up the 300 case with great success for a long time now.

 

[mkf350]

Shawn Would you care to share any load data. /ubbthreads/images/graemlins/smile.gif

 

[sniper2]

Necking the 300 up is the easiest and works great for me too!You are going to love this round!!!

 

[Shawn Carlock]

I have used H1000 with the most consistant success. RL25 and Retumbo work well I understand.

300 GR SMK
OAL 3.775"
.020" OFF LANDS
CCI LR MAG PRIMERS
REM BRASS
H-1000 start @ 90.0 gr my final load will run somewhere between 92.0 to 96.0 gr. depending on chamber throat length etc.

This should put you in the 2900 + fps range.

I have built 14 of them and they will shoot 2900-3000 depending on each rifle all with 30" tubes. Good luck and hope you enjoy it.

 

[mkf350]

Do any of you anneal the necks? And how is the case life?

 

[ricka0]

Annealing

ricka's annealing page

I anneal every other time. RUMS eat brass, esp with hot loads. Expect 3 reloadings
300 RUM brass Thread

 

[3sixbits]

Re: Annealing

Thanks B1g_bOre for that link on annealing. I wish I would have had that for another thread on the same subject. I purchased the Hornaday kit serval years ok and It has been great. Again thanks!

 

[Shawn Carlock]

Re: Annealing

I don't anneal the necks and can the brass after 6 loads. I'm hot to get my hands on some federal brass.