Sizing Belted Magnums

[4xforfun]

I have this die.....It works great.....I do not use it every time, only when regular FL sizing is not enough.

When I set up my FL die, I take my firing pin assy and ejector out of my bolt. I then set up my die to bump THE SHOLDER just enough so that the bolt closes about 1/2 way with gravity and just a light push to close it the rest of the way. I figured I get about a .001 bump on the shoulder. Once I find this setting, I lock up my die and throw away the key....it will NEVER change. I NEVER headspace on the belt.

If you are hunting "dangerous game" and are not smart enough to run EACH AND EVERY LOADED ROUND through your rifle BEFORE you go afield..well..lets just say that there is a good reason for the rule of natural selection!!!

Just my .02

 

[wapiti25]

size your brass so it fits your gun and have a good time. I have used the shoulder sizing for 30 yrs in three cals and it works. make that 4 cals, 7mm Rem, 338 Win, 300 Win, and 300 H&H.

 

[bigedp51]

The only difference between a rimmed case, a belted case and a standard bottle neck case is the distance from the bolt face to the datum point. And all three type cases can headspace off the shoulder of the case to control head clearance using shoulder bump..

 

[savagedasher]

Thanks just what I said But if you see what was ask None of addressed it. Larry

 

[swampshooter]

After reloading my belted magnum cases 5 or more times they are hard to chamber, even when the shoulder is bumped back as much as .003". Using Innovative Technologies collet sizing die they are then easy to chamber when the shoulder is only bumped back .002". I'm not going to argue theory with anyone, but their die works. Resizing dies do not resize all the way to the belt. This area expands and makes it hard to chamber the cartridges. The Innovative Technologies die resizes all the way to the belt. My cases fired 10 times now chamber as easily as they did when brand new.

 

[bigedp51]

Thanks just what I said But if you see what was ask None of addressed it. Larry

I answered your question, and you were moving your lips when you read it and missed it.

"ONE MORE TIME"............you fire form the case.

Now I have a question for you............

How did this case get from this.

To this?

Do you see the little round silver doohickey with the dent in it above?

 

[savagedasher]

Swampshooter answered the question that was ask. You busted all of us.

Larry

 

[swampshooter]

Sorry, didn't intend to bust anybody.

 

[BoydAllen]

One of the variables in all of this is the design of the chamber. On factory .300 Wby chamers, I have seen the shoulder of new brass blown forward .021. I have seen the same thing on other factory belted chambers. This may be the source of the problem. If the die is set to only slightly bump the shoulder of fired brass, the back of the die that sizes the part of the case that is just in front of the belt, may end up too far forward of the belt, and leave a band unsized, that will eventually cause the tightness, that is alleviated by the collet die. On the other hand, working from sized cases from a particular die, set to size as near the front of the belt as possible, to come up with dimensions for a matching chamber reamer that cuts a chamber that is a good match for the die, much of this problem can be avoided.

 

[bigedp51]

It saddens me greatly to say this but swampshooter and all the other belted magnum owners here are all completely and totally wrong.

Any of the older people here who have read anything written by Jack O'Conner should know that the .270 Winchester is the worlds best non-belted magnum.

And in second place is the British .303 that has killed more African game than any other caliber........

Belted Magnums.................Balderdash!

 

[swampshooter]

I reload for five different belted magnum cartridges. All but one have factory barrels. They all benefit from the use of the Innovative Technologies die.

In theory if the barrel chamber and dies were a perfect match the Innovative Technologies collet sizing die would be unnecessary. But that is not the case in the real world. My 300/8mm Mag has a Shilen barrel, the chamber is cut with a custom chamber reamer from JGS. The dies are special order from Redding. This rifle still needs the Innovative Tech collet die. If I had had dies custom made with the same chamber reamer maybe it wouldn't be necessary. But that is not the case.

The good thing about this die is that it works for all belted magnums that are based on the 375 H&H case. I'm able to use the same Innovative Technologies Collet Resizing Die on all of my belted magnum cartridges. 7RM. 300/8mm, 338WM, 375 Weatherby, 458 WM.

 

[Area Man]

Wow. Lot's of info on loading belted magnums, with moving graphics and everything. Thanks so much. I learned a lot and will looking to apply it in the future. For now, I'll not buy the die, set my sizing dies as recommended, and if I determine in the future that I might be having chambering problems due to the bulge problem, I'll know what to do.

I'm not shooting anything more dangerous than paper.

 

[243winxb]

Old thread warning.

One of the variables in all of this is the design of the chamber. On factory .300 Wby chamers, I have seen the shoulder of new brass blown forward .021. I have seen the same thing on other factory belted chambers. This may be the source of the problem. If the die is set to only slightly bump the shoulder of fired brass, the back of the die that sizes the part of the case that is just in front of the belt, may end up too far forward of the belt, and leave a band unsized, that will eventually cause the tightness, that is alleviated by the collet die. On the other hand, working from sized cases from a particular die, set to size as near the front of the belt as possible, to come up with dimensions for a matching chamber reamer that cuts a chamber that is a good match for the die, much of this problem can be avoided.

When full length sizing, headspacing (head clearance) a belted magnum off the shoulder, the area in front of the belt may become unsupported in the chamber on firing. Brass will bulge.

 

[gman47564]

its my understanding that when you screw a belted barrel on you set the head space with the belt... then as you fire brass through it you size the brass from the shoulder .. so fired case gets the shoulder bumped back .001 or .002.. my 300 win mag go gauge has no shoulder on it... head space is set initially with the belt... brass is doing fine after 10 cycles sized with a redding body die and a lcd for neck tension... my .02 cents...

 

[Dgd6mm]

You can search the archives for information under catshooter and get the skinny on belted magnums.