300 Winchester Magnum reloading question

[Presto]

I know that this has been touched on earlier, but I may be able to shed a little light from my own experience. I have had the same frustration in the past, and I found a simple solution. The measurements that you are getting at the major angle of the case shoulder of your finished ammunition are in line with what I was experiencing. I found that when I seated the bullet and crimped in the same operation with a bit too much crimp, the case would bell at the shoulder. They would not chamber the last little bit. I started seating and crimping in seperate operations, and only using a minimal crimp, so the shoulder would not deform. I should also note that the area just above the belt also had similar dimensions becuase the brass had started buckling in becuase of the same situation.

For what it is worth, I had this problem with .300 Win Mag as well. I've never seen it happen with any other chamberings that I have loaded.

When it first started happening, I thought I didn't have enough crimp, and the mouth was jamming into the chamber, so I increased the crimp, and easily noticed the belling at the shoulder. I kept a couple of the worst examples to remind myself not to do that again. I'll try to dig one up and post a picture.

I hope this helps, and I also hope that you don't loose the joy of loading over this. It can be very rewarding when you get things sorted out.

Presto

 

[MEHavey]

Daniel,

In light of what Presto says above, a real important question: Have you simply full-length resized an empty case -- no primer, no powder, no bullet, no seating operation, no nothing....

... and seen if it will chamber?

 

[Presto]

Shoulder deformation picture

I found one. This was probably the worst of the lot that I loaded, and the shadows make it look a lot worse than it really is, but it illustrates what I was talking about pretty well I think.

 

[Innovative]

It's hard to imagine all of the wierd mistakes that handloaders can make. I'm sure I haven't seen them all.

However . . . .
​

I've sure seen a whole lot of unbelievable looking handloads. Excessive crimping can make some of them look pretty far out! This one was made with a progressive Dillon 550 press that had one adjustment a bit off the mark.

- Larry

 

[Daniel Boone]

I don't have " " a bad case - they all come out exactly the same with the dimensions I supplied.

My dad full length resized all of the cases and they were all shot out of the one rifle.
I cannot tell you if they fit in the rifle after they are ejected - because I never saved a box - just for that purpose - but I have a box of once fired empties upstairs and will try it sometime in the future.

I had a bad experience once - putting some 30-06 empties in my dad's 721 Remington.
I broke the extractor clip and it cost me $50 for a new bolt.
Since then, I have reservations about putting fired rounds into a chamber - " " to see if they fit.

 

[Innovative]

Daniel .....

If your case had the dimensions that you provided, it must have been a "resized" case that was extremely bulged below the shoulder. I guarantee you won't be able to chamber it in any rifle.

Compare those dimensions to one of your fired cases, and you'll see the quality of you're handloads. Be sure to zero your calipers before taking measurements.