Magnum bump

[Jeff Von Rosenberg]

Need some help. 1'st time reloading belted cases. I have a new heavy gun in 300 WHYB. Magnum. When I full length resize the case the shoulder moves forward! Prior to resize bolt closes easily but after adjusting die it moves shoulder forward about 2 thou. And bolt closes a small amount tighter( just about the right feel) Is this normal for a belted magnum? I realize they headspace off the belt, but I also know the case should fit snug to the shoulder to prevent unnessasary case stretch and cracked necks and shoulders. Am I doing this correctly? JVON

 

[BoydAllen]

Is your die touching the shell holder at the top of the ram's stroke during actual sizing? Because of the down force on the linkage during actual sizing, a die set so that it touches with no case, will develop a gap when sizing. Years ago, on a .220 Swift, I measured the gap, with a feeler gauge as .006, on a Rock Chucker. When you reduce the diameter of the body of a case in a FL die, the shoulder will moved forward slightly until the die is adjusted down far enough for the shoulder in the die to engage the case. As you adjust your die lower, the shoulder in the die will start to have an effect on the case, and as you continue it will be bumped. For once fired brass, because it will generally not have its shoulder as far forward as the chamber will allow, because of spring back, you can set a die to give a shoulder to head dimension that is the same as it came out of the chamber, just be sure to reseat or remove the primer before measuring the fired case. The belt really has nothing to do with this.

 

[Dans40X]

Upon pulling the expander ball back thru the neck you are stretching the radius' at neck & shoulder juncture.

Size a case w/o the primer punch/expander ball installed & test fit into chamber.

Brush the carbon from inside the case neck/mouth.
Measure the diameter of the expander ball in your F/L die & polish lightly to a .305"-.306" diameter.
Lube the expander ball w/ Imperial Sizing Die Wax.
Lube & F/L Size a case
Test fit into chamber

 

[BoydAllen]

One piece FL die, with an expander ball for a 1,000 yard benchrest competition rifle? Really?

 

[Jeff Von Rosenberg]

NO! Using a redding S die without an expander ball ! Using a .330 bushing. Then I run back over an expander mandrel prior to seating bullet with a Wilson St. Line seater and a 21'st Century a Arbor press with Hyd. Seating pressure guage. Seating between 22-24 lbs. case necks are turned to .012 and annealed after every fireing with a Benchsource. Powder charges measured and thrown with a PrimetheusII. Bullet runout not more than .001. So far with 210 grain Matrix VLD's I am getting 4 to 5
in. at 1K. I feel like there are better groups in this rifle, so and suggestions welcome, as this is my 1'st foray into 1K heavy gun! I know there is more potential , because my F class shoots this good and better!

 

[wapiti25]

your die is squeezing the body and the brass is going forward causing the shoulder to move up. I guess the die is a little small in diameter for the chamber.

 

[Erik Cortina]

This is normal, you need to screw the die down a little more to bump the shoulder.

 

[nosualc]

This is normal, you need to screw the die down a little more to bump the shoulder.

+1

 

[CatShooter]

Need some help. 1'st time reloading belted cases. I have a new heavy gun in 300 WHYB. Magnum. When I full length resize the case the shoulder moves forward! Prior to resize bolt closes easily but after adjusting die it moves shoulder forward about 2 thou. And bolt closes a small amount tighter( just about the right feel) Is this normal for a belted magnum? I realize they headspace off the belt, but I also know the case should fit snug to the shoulder to prevent unnessasary case stretch and cracked necks and shoulders. Am I doing this correctly? JVON

When you use a standard FL die to FL size a case (belted or not) as the body is squeezed, the shoulder moves forward several thou... then the shoulder is pushed back in the very last stage of FL sizing.

This is normal. You are not doing anything wrong.

After the first firing, the case will headspace on the shoulder like any other bottle neck case, so don't push it back anymore than necessary to chamber they way you like it - I prefer some crush - the cases last forever.

 

[bigedp51]

Below is a exaggerated drawing of "ANY" bottleneck rifle case being resized. As stated above the case lengthens base to shoulder as it is compressed in the die. The last few thousandths the die contacts the shoulder of the case and pushes it backwards decreasing the base to shoulder length. As the brass is further compressed at the shoulder the neck of the case increases in length.

Bottom line, when the brass is compressed by the resizing die the brass can only move in one direction and that is "upward".

Or as Catshooter once posted, as the jeans compress the models bottom it causes the upper part of the body to move and increase in size.
(really, just keep watching, they just keep getting bigger and bigger) ;D

 

[CatShooter]

Good morning Ed...

I'm glad you stole some of my artwork - now I don't feel guilty about stealin' all of your artwork.

God, she makes me breath funny

 

[bigedp51]

Good morning Ed...

I'm glad you stole some of my artwork - now I don't feel guilty about stealin' all of your artwork.

God, she makes me breath funny

I don't have that problem Catshooter, my wife sprinkles saltpeter on my Corn Flakes every morning. :

And she caught me posting "YOUR" bouncy photo. :'(

My wife doesn't believe I got the photo from "YOU" and thinks I'm lying, she said what kind of decent human being would call themselfs "Catshooter". ;D

 

[Barlow]

Forget the belt, size them to set the shoulder back. Barlow

 

[Erik Cortina]

Forget the belt, size them to set the shoulder back. Barlow

This statement makes no sense. What are you talking about?

Oh, the brass! I remember now. After bigedp51 posted that picture, I forgot what we were talking about!

 

[mattlewis]

I have thoroughly examined the illustration, and haven't noticed any shoulder problem. For that matter, I haven't noticed a shoulder at all. But I will continue to study.

 

[Rtheurer]

Some times it takes more than one firing to fully expand brass to max out the brass to the chamber size....