Head space question

[marchx]

Hi,

I am pretty new to reloading and new to 6BR- got my rifle built a month ago. I measured the head space of my fireformed brass- it's 1.161-1.162. After I FL size the brass using Forster FL die the headspace increased up to 1.164. I measure the headspace using the Hornady tool. Why is it the case?
Moreover, when I FL size my brass I feel significant resistance while closing my bolt. In my other caliber I never came across such thing.

 

[Martin52]

Your die may not be screwed down enough into the press and the cases are actually getting longer as a result. The resistance when chambering is related - probably due to insufficient FL resizing. Do you have a few trash cases that you can experiment with so you don't destroy good brass getting your die set up properly ?

 

[marchx]

This was my assumption, but the FL die is screwed down according to this video

7:10
I will screw it down even more. I hope I should get a 0.002 shoulder bump versus my fireformed brass.

 

[RussellJ]

Hi,

I am pretty new to reloading and new to 6BR- got my rifle built a month ago. I measured the head space of my fireformed brass- it's 1.161-1.162. After I FL size the brass using Forster FL die the headspace increased up to 1.164. I measure the headspace using the Hornady tool. Why is it the case?
Moreover, when I FL size my brass I feel significant resistance while closing my bolt. In my other caliber I never came across such thing.

I have had this same problem in the past, my sizing die was sizing the shoulder-body too much. The brass flowed forward and it caused the same problem that you have, increasing the Headspace. I switched to a different resizing die(same brand and part#) and my problem went away. See below for a easy way to check if your sizing die is not matching your chamber.
Here is page 122 for Tony Boyer's THE BOOK OF RIFLE ACCURACY. I highly recommend reading his book and Mike Ratigan's book EXTREME RIFLE ACCURACY.

 

[LCazador]

You can try screwing the die down closer to the shell holder and see if you can get your .002" bump. With things being as scarce as they are it may not be possible to find another die. Is the shell holder the same brand as your die? If your die is completely down as far as possible and you're still not getting the desired bump it may be necessary to take some metal off the top of the shell holder or change to a different brand shell holder to achieve your desired bump.

 

[JFrank]

Brass flows'..They always seem to grow slightly just before they bump, so don't worry just screw the die down a couple more thousand.

 

[marchx]

I have had this same problem in the past, my sizing die was sizing the shoulder-body too much. The brass flowed forward and it caused the same problem that you have, increasing the Headspace. I switched to a different resizing die(same brand and part#) and my problem went away. See below for a easy way to check if your sizing die is not matching your chamber.
Here is page 122 for Tony Boyer's THE BOOK OF RIFLE ACCURACY. I highly recommend reading his book and Mike Ratigan's book EXTREME RIFLE ACCURACY.

View attachment 1271819

Thank you @RussellJ for this. I see 2 options: (1) I did not screw the die down enough- pretty easy, I will do it and test the shoulder bump. (2) I could have a match chamber below saami spec and if this is a case a should order a custom die (God, no).

 

[Coyotefurharvester]

If you are using the decapper/expander during you sizing step make sure the necks are lubed inside also. This will reduce the "pull" on the case. Set your sizing die without the decapper/expander rod in place.

 

[jepp2]

(2) I could have a match chamber below saami spec and if this is a case a should order a custom die (God, no).

If this is the case, just remove a few thousandths off the top of the shell holder. This will enable the die to move the shoulder back more.

You could also remove a few thousandths off the bottom of your die, but I choose to modify the shell holder since they are not hardened and they are cheap. Just keep that shell holder with that die.

 

[Lefty Trigger]

Is your die touching the shell holder yet, or really close? If not keep turning the die down a smidge at a time checking your brass till the headspace changes.
With my Savage and Remage rifles I like to set my chambers on the long side so I know I have plenty of "die" available for adjustment. I only ever had one rifle that I could not bump headspace back on and it was a Winchester 243. I ended up having the FL sizer die machined down. When I sold the rifle I gave the guy that special die.

 

[RussellJ]

Hi,

I am pretty new to reloading and new to 6BR- got my rifle built a month ago. I measured the head space of my fireformed brass- it's 1.161-1.162. After I FL size the brass using Forster FL die the headspace increased up to 1.164. I measure the headspace using the Hornady tool. Why is it the case?
Moreover, when I FL size my brass I feel significant resistance while closing my bolt. In my other caliber I never came across such thing.

Marchx
When you find the solution please us know. Lots of good replies here on the forum.

 

[Ccrider]

What @SPJ said. I often see .001 or so growth. Never a problem. Just adjust die more to get proper bump and go shoot.

 

[marchx]

Ok, guys. Let's summarize.
My headspace in a fireformed Lapua brass is 1.162. I take out the expander out of my Forster FL die, put some imperial lube on my brass and FL size the brass. I need to use a serious amount of force to do that (although the brass was annealed). After that my headspace is 1.164.

I did screw the die down and had a little holdover as Gavin showed on his youtube video. I am using Co-ax press, so there is no shell holder. You screw the FL die until you feel resistance, and then you screw it down further 1/4 of a turn. That's what I did. Before my die was a little bit to high, so I corrected it.

However (bum!)- no visible effect- I still get 1.164 headspace. Does it make sense to screw it down even further?

Luckily, I have also a Forster bushing bump die. When I size the brass I get consistent 1.160 headspace, so I get exactly 0.002 bump as I want.

I cannot explain why the Forster FL die does not bump the shoulders back.

 

[jelenko]

I need to use a serious amount of force

This doesn't sound right.
I also use a Co-Ax with full length dies with an expander.

I'm sure you've done the drill, but I'd want to check the inside of the die, confirm the pressure relief hole is open and confirm it's not a small base die. That said, I wouldn't expect any of those conditions to require serious force.

 

[Wellington]

I would use something I could get up inside the dies and measure the two for distance to the shoulder. I bet the one is a little longer, and when the bottom end of the die is being squeezed the case has to flow up into the shoulder area. My guess anyways.

 

[Ccrider]

Happens with the Coax and some dies and brass. The holder of the press is hitting the bottom of your die before the case is pushed up into the die far enough to size the shoulder. I usually can find the sweet spot by turning the die too far down to where it is hitting the jaws solidly and then slowly working the die back until the press barely cams over, usually with a bit of force. If the die is not sizing the shoulder at that point, use another press or take some off the bottom of your die if you are equipped to do so.

 

[jelenko]

Ah!

 

[DaveTooley]

Every press has some spring to it under a load. I keep creeping down on the FL die using a single case inserted in the die until I feel the die contact the shoulder. I check push back with the case in the rifle using the bolt, not by numbers. After I get the first one to chamber the way I want I'll check several more before securing the lock ring. Most of the time I need to screw the die in a bit further.

 

[divingin]

Try a feeler gauge under the piece of brass before you start grinding anything. Know what the problem is before you try to fix it.