40 Ex|Page 7|Winchester Hunting, Shooting & Reloading|Forum|Winchester Collector

I shot the 40 EX on June 2nd.  I talked with a friend about the issues with cases #2 and #5 that were showing pressure.  He is way smarter than me.  I did find that the rims on these 2 cases were thicker and have less to no head space.

I also shot one of the cases that I messed up the mouth of the case.  I cut off the bad spot and loaded it the same as the other 5.  I used this as a fouler to warm up my barrel.  It was 61 degrees last time and 68 degrees this time.  No matter the powder you use it will get faster when the ambient temperature  gets hotter.  Some powders are more stable than others.  None are perfect.  A chronograph will prove that. 

All cases were loaded with 31.5 grs. of IMR 4198. 

Fouler – 1,473 Fps.

1 –        1,485 Fps.

2 –        1,454 Fps.  Did show the extractor marks. 

3 –        1,536 Fps.   

4 –        1,503 Fps.

5-         1,493 Fps   Did show the extractor marks. 

I used the wad and toilet paper as before to keep the powder at the primer as best I could.  Here is a picture of a case, card and what is left of one piece of toilet paper. After rolling and sliding the TP into the case I cut off the excess.  As you can see the card is way smaller in diameter compared to the ID of the case where the powder is and the same for the toilet paper.  I am not trying to fill the case, just putting together a column that keeps the powder put. 

[email protected] said
Chuck:
 
I came late to this conversation, but skipped through the entire thread as I am interested in forming for, and shooting, large-bore cartridges.  One thing I don’t see mentioned is making a cast of the chamber.  Perhaps I missed that, but did you try that?  It would have given you both the inside chamber diameter and case length.
Also, did you anneal the cases before sizing them?  I have resized and re-profiled several large cases, and even with smaller cases, have found that annealing the brass makes the process a lot easier.  I make .32-40 cases out of .30-30 brass, and found that it was very difficult without annealing, but no problem after annealing.  I also made .50-100 brass out of .348 and had much better results after annealing that.  
The last post I saw was the one about turning necks for a .284.  Will you be doing more with the .40, or have you gotten all the results you wanted?
Thanks. 
  

I did not cast the chamber.  But when you fire form the brass this gives you the needed measurements the die makers want.  Case length is 3-1/4″.  I have some original cartridges and the parent brass I was using is the same length. I also have 2 books that have all the cartridge dimensions. 

I have an annealer and did use it some but when the brass gets soft it sometimes wrinkles more when I was forcing it through the holes I drilled in the sheet of aluminum.  Reducing the parent brass to the point I could get it into the chamber is the hardest part of the entire process.  I did ruin several pieces of brass while doing this. 

If you read through the process you should know that Lee already made me a set of dies for the 45-125-300 EX.  I’m done with the 40 for now.  I am going to send some fire formed 38 EX brass to Lee Precision and have them make a 4 or 5 die set.  The 1 or 2 extra dies will be for reducing the parent brass so it can go into the full length sizing die.  I will send them the 40 EX after I get the 38 EX done.  I’m hoping the 38 EX reducing dies may work for the 40 EX too.  Lee wants me to send them the 38 EX in July or August when they are not so busy. 

I am working on 2 other rifles right now and the 40 can wait for awhile.  61 pieces of Win 284 brass was neck turned so a loaded cartridge will chamber.  Then I fire formed it in the rifle to make it a Wildcat 284 Shehane.  The first firing straightens the case walls for more powder capacity.  The next firing will move the shoulder forward to determine where to set the headspace.