Reloading question

Mtslackcountry

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May 14, 2015
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I'll start by saying I'm a new reloader and sometimes make things more complex than needed...

I'm reloading for a 7mm rem mag. So belted case.


I have a redding competition shell holder set and hornady headyspace gauge and have set out to only bump the shoulder .002. I fire formed some hornady brass and figured out the right shellholder to get the .002 bump and thought I was golden.

That was until I measued the once fired brass compared to 2x fired brass using the headspace gauge. The 2x fired brass measured .002 longer than the 1x brass. Resizing both they bump .002 but the 2x fired brass is always longer by .002.

To complicate this further in my mind. I has some once fired in same gun FC brass that when I resize using same shell holder the shoulder does not move at all but ends up about the same measurement as the once fired resized hornady brass.

So is it ok/normal that the 2x fired headspace measures longer than 1x after both were resized? (Both bump .002, the 2x brass is longer from base of case to shoulder by .002)

Is it ok /normal that the FC brass shoulder did not move when resizing with same shell holder/die setup as my other brass?

I'm confused as hell.... Should I continue to use same she'll holder and size away and not worry about the difference as long as shoulder is bumped? Should I sell all my stuff before I blow my gun up?

I watched a video broz made on bumping the shoulder and it seemed like once you got the right shell holder you were good to go.

Please help...
 

luke moffat

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You are bumping the shoulder back sure...but the neck grows with firing. Which is why a case trimmer can be needed after X amount of firings. I personally wouldn't sweat .002" total brass length so long as the shoulders are the same, but I am not a gnats ass reloader either. :)
 
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Mtslackcountry

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You are bumping the shoulder back sure...but the neck grows with firing. Which is why a case trimmer can be needed after X amount of firings. I personally wouldn't sweat .002" total brass length so long as the shoulders are the same, but I am not a gnats ass reloader either. :)

That's my problem I'm measuring from base to shoulder NOT total length. My 1x vs 2x brass is different by .002 in base to shoulder length. Also the other once fired FC brass doesn't bump but is about the same as once fired Hornsby. So basically 2x fired is not resizing to same as 1x fired as far as shoulder to base measurement goes.
 

Muttly

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When you close the bolt on the sized brass of either brand, are you feeling the same amount of resistance?
 

GKPrice

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When you close the bolt on the sized brass of either brand, are you feeling the same amount of resistance?

what rifle are you using ? I've found FC brass to be quite soft and "stretchy" - like Muttly says, is the bolt sticky to close ?
 

16Bore

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7mm Mag stretches like a mofo. I headspaced off the shoulder, FL sizing die. VIrgin brass is supper sloppy out of the gate.
 

rayporter

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as noted above brass stretches differently and you must have it tight in the chamber.


i would fire a case at least 3 times with just neck sizing if i could. this way you know the case has stretched to the chamber. then measure for a bump back. the bolt should have a little resistance after 3 or 4 firings.

the case has to fill the chamber before you measure for your bump or you are going to bump too much. if the case is 2 thou short of filling the chamber and you bump 2 thou you are now essentially bumping 4 thou as an example.

i also like to remove the firing pin to get a feel for the brass as i check it in the chamber.
 
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Mtslackcountry

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Fellas,
Thanks for the responses!

Gun is a Rbros 7mm rem mag. Defiance action.

Ok this is making sense. So my once fired brass has not stretched enough to fill the chamber and my 2x fired brass really hasn't eighter. Both of these are pretty easy to close the bolt with the firing pin removed.

When I was using 1x fired brass to determine how much to bump my bolt had little resistance. (since the brass had not filled the chamber completely? ) so I used the thinnest shell which bumped shoulder .002 when full length resizing. ( this was bumping it too much because brass had not stretched to its ideal length?)

So since I am using the shellholder that does the least amount of shoulder bumping and I am bumping too much what are my options here? Set the die so that the shellholder doesn't contact it as firm? (less cam over)
 

16Bore

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Remember that the shoulder is going to slightly push forward when you FL size, then get bumped back. For giggles, measure the shoulder of once fired, then start in small increments turning the die in (mark the neck with a sharpie) and measure along the way. Interesting to see what's moving where. Doesn't hurt to feel it in the chamber along the way either.

Belted cases baffled me at first, until I monkeyed with it enough to see what was happening. Yeah, it headspaces off the belt initially, but once I sorted ignored that and treated it like everything else I.E. shoulder, it kinda came together.
 

16Bore

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And good on you for using the headspace insert. I don't know how people load without one.
 

LaHunter

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I have a 7mm mag and I use the Redding Competition Shell Holders.
When you get ready to size more brass, try the shell holder that allows the least amount of shoulder bump. This is the one with the tallest 'rim' on it in the set. Make sure your shell holder is making solid contact with your die when at the top of the stroke of your press.

Check these sized brass for fit and easy bolt closing in your rifle. I want zero resistance when closing my bolt on my sized brass, just like I was closing on an empty chamber.

I do this every time I resize brass, just to make sure they all fit properly. If after 4 or 5 firings, if you start feeling some resistance when closing the bolt on your sized brass, you can always increase the shoulder bump by changing shell holders.
 

KD32

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Jul 2, 2016
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Mtslackcountry,
I would check out the forums on accurateshooter.com, there are some really knowledgeable guys on there when it comes to reloading.
 
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Mtslackcountry

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Thanks for the info guys! I got it figured out. What threw me off was the brass takes a couple firings to fully fill the chamber.
 
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