belted magnum go / no go gauge

[DUSTY NOGGIN]

there is not a specific cartridge like other go/no go gauges , reading about and found 7rm , 300wm & 338wm all same height

im working with a 7mm rem mag

saami cartridge drawings
.220 (-.008)
chamber drawings
.220 - .227

is there any benefit to keeping it tight in these tolerances (at .220 ) so when you expand your brass you actually get 2 headspacing points , one at belt and one at shoulder datum ?? i figure eventually all brass will match that anyway but would only really be headspacing on the shoulder

my reasoning would be the pin pushing idea , whether or not it happens i dont know , but if you could keep that headspace at the belt held tight as possible it would certainly fire form out the shoulder to match , on the first firing

is there really a difference in brass makes of .008 ??? to the belt

 

[EddieHarren]

In the past 20 years, of installing belted magnum barrels on rifles, I've seen great variations in belt dimensions from all of the factory ammo makers. I always advise my customers to set their dies according to belt thickness.
The ideal situation is to set the headspace to place the shoulder .002" off the chamber when resizing brass.

 

[J E Custom]

I recommend setting the headspace for the belt at .002 to .003 and after firing the first time, headspace off the shoulder to save the brass life and better fit the chamber.

With the variances in belt thicknesses, it would be hard to use both the belt and the shoulder for headspace.

On dangerous game cartridges, I recommend setting the headspace at .003 every time so feeding would not be an issue at the worst time.

Just the way I do it

J E CUSTOM

 

[EddieHarren]

I recommend setting the headspace for the belt at .002 to .003 and after firing the first time, headspace off the shoulder to save the brass life and better fit the chamber.

With the variances in belt thicknesses, it would be hard to use both the belt and the shoulder for headspace.

On dangerous game cartridges, I recommend setting the headspace at .003 every time so feeding would not be an issue at the worst time.

Just the way I do it

J E CUSTOM

I would hate to have to set the headspace to the shoulder and the belt due to the variances that I mentioned earlier.
JE, I know we are talking about the same thing I'm just not wording it correctly.

 

[J E Custom]

We are on the same page. I hope I said it right.

Set the head space using the belt first, and then after fire forming
size only enough to chamber the round, This way head space is based on the shoulder from then on.

The exception would be on a dangerous game rifle where the case should be full length sized and the belt head space maintained for safety. (more important not to end up that green stuff between an Elephants toes, than to increase brass life ).

J E CUSTOM

 

[DUSTY NOGGIN]

dangerous paper , is about all this gun has in store for it ... i appreciate your help guys

ups is supposed to be visiting on friday , hella excited to finally give this rifle some hope

 

[Gregg C]

I believe this question to be relevant to the thread. If not please move to its proper location.
I got a belted mag built as a semi custom, 338-378 Wby. The Smith only asked for one round for fitting. All of my brass at that time was brand new, onlyfull length sized. When I eventually got the rifle done and in my possesion, the bolt wouldn't close easily on more than half of my brass. Some of it was a real struggle. In my ignorance, I forced it closed and shot anyway. Resizing did not help. I must have guessed rite, as lapping the lugs did help, and I soldiered on and got a lot of loads out of that brass. My question, hope fully relevant to this thread, is ; can a belted mag chamber be cut so close as to nearly eliminate neck sizing ? If I back my FL sizer off, the brass won't chamber. That is, the shellholder MUST at least touch the die, or it will not close without undue force on the bolt. Am I off base here ? If it's pertinent, I reloaded those 18 times. Thanks.
Gregg