Sanity Check - Is my FL Die too long?

[Dutch260]

Okay gents, hoping someone smarter than me (probably most of you) can help me figure out what is going on with my full length sizing operation.

Tools / Components:
-Forster FL Sizing Die (6.5 Creedmoor) with Decapping rod/Expander ball removed
-21st Century Turning Mandrel
-Lanolin 10:1 homemade case lube
-RCBS Electronic Digital Caliper
-Hornady Headspace Gauge (C .375")
-Bighorn TL3 SA
-Proof CF Chambered by Aaron Roberts

This evening I was running some virgin Lapua brass through the FL sizer just because I'm anal and was just trying to get away from the kids fighting over God knows what. Out of curiosity I got out my Hornady headspace gauge and calipers out and measured the headspace on the virgin brass to collect data for my rifle. Thought it would be good to know how much the headspace grows from Virgin to 1x Fired brass. I then measured 5 random 1x Fired pieces (all deprimed and from same lot) and compared. The results were as follows:

5 Random Virgin Pcs:
- 1.5555 - 1.5565

5 Random Virgin 1x Fired (deprimed):
- 1.556 - 1.557

Overall not much growth but they were mild loads. Or maybe it's just a tight chamber. Well I remember having some extra resistance when closing the bolt on some Factory Federal GMM Bergers (130gr). So I checked the headspace on a few of those 1x Fired cases as well as a loaded round and got the following.

1 Loaded Round / 3 Random 1x Fired (deprimed)
-1.558" - 1.559"

So now I figure, okay I must have a pretty tight chamber really close to Virgin Lapua brass specs......awesome right!? Next I wanted to size the sample pieces of the 1x Fired Lapua brass previously measured and listed above to see where I needed to have my die adjusted for a good .002" shoulder bump.

After re-sizing the 1st 1x Fired case I checked with the Hornady headspace gauge and am now getting 1.559". Odd....So I measured the remaining 4 and got a range of 1.559" - 1.5605". It appears as the headspace measurement I am getting has increased at least .002" *after* running it through the FL sizer.

I checked the resized 1x Fired brass in my chamber with the firing pin assembly removed and sure enough, a good amount of effort to close the bolt with the resized 1x Fired brass. So I can say with confidence that brass with a headspace measurement of > 1.557" chambers with almost no effort to close the bolt. Extra effort to close the bolt begins at 1.558" and up.

At this point I'm not sure what else I can do to bump the shoulder back as I already have the die bottomed out with a solid cam over and I have not gotten any of the brass measuring up to 1.560" to budge.

Is my Forster FL sizing die simply too long and not allowing me to push the shoulder back before bottoming out on the shell holder? Anyone else had an issue like this?

 

[spife7980]

Just for good measure what are the base and shoulder diameters?

And you’re locked up by the die compressing the shell plate completely? Or just hitting the bumpstop nub? If you screw it deeper into the lock ring it will stop short of the bumpstop?

 

[Dutch260]

If I measured correctly this is what I got from 3 pcs of brass that I was working with.

Virgin:
Shoulder Diameter - .457
Case Head Diameter - .468"

Unsized 1x Fired:
Shoulder Diameter - .462
Case Head Diameter - .470

Resized 1x Fired:
Shoulder Diameter - .459
Case Head Diameter - .469"

Yeah I had that sucker bottomed out. I screwed the die in another full turn to where it wouldn't even extend fully much less cam at all and tried to size the resized 1x Fired piece and nothing. The shell holder bottomed out on the bottom surface of the FL die and the headspace didn't change at all.

 

[bax]

random thoughts - this is mostly crazy talk. I am assuming that the die is right but trying to explain what you observe when you close the bolt.

Your chamber is actually shorter than your die. Grind 0.010 off the bottom of the die or take 0.010 off the top of the shellholder. I think that this is probably the real problem but I'm on a roll ...

Insufficient lube: if you don't put enough lube on the base, the brass neck sticks in the die. When you pull the brass down, the neck and shoulder will be stretched out and the case gets longer. Try more lube.

Sufficient lube but case body being squeezed: the fired cases are substantially bigger (diameter, not length) than sized cases. When you force the case into the die, the case body is radially compressed and the extra brass pushes toward the shell holder and the shoulder. You cycle fast so the brass doesn't permanently deform to the die shape. When you remove the case from the die, it assumes the longer shape. When sizing, wait a 10-count after lowering the press handle.

You have an unusually tall shell holder. Grind 0.010 off the shell holder.

The die is shaped differently than the chamber - specifically, the die may assume a larger neck-to-shoulder radius (the transition from neck to shoulder) than the chamber. After sizing, the shoulder is short enough but when you chamber, the sharper chamber transition runs into the more-round case and it is hard to close the bolt. You could test this goofy theory with a chamber cast or by inspecting a fired case.

Trump.

Communists.

Stormy Daniels bank account just got a lot smaller.

 

[spife7980]

Sounds to me like the die is too long, I’d call up forster on the phone and see what they have to say about shortening the die.

Normally I would suggest to trim the shell holder but it’s a coax so that’s not an option bax. Im an idiot and making things up that I didnt actually read, my bad.

 

[Dutch260]

Yeah I am going to call Forster this morning and see what they have to say. If they agree the die is too long then I'll just send it back to them and maybe have them hone the neck for my brass while they have it.

I wish I had a Coax @spife7980 , I'm slumming it with the RCBS Rock Chucker at the moment I guess I left that part out of my original post. Either way, I'd really like to avoid any crude means of trying to turn down the surface on my shell holder with shit I have laying around in my workbench. Fortunately I have 200+ pcs of virgin brass that still need fire forming so I've got some time before I truly need my FL sizer again.

I'll report back after talking to Forster. In the mean time, I'll still welcome any insight from anyone else that has experienced this in the past.

 

[spife7980]

Damn, not sure why that got stuck in my mind, guess I just read forster and misconstrued it.

As for sanding down the shell holder, a piece of sand paper on glass for a smooth even surface, a dab of oil and then sand the top of it down in figure 8s. But if forster will fix it then thats what I would do.

 

[ophious]

I had the exact same thing happen with my .308 Dillon die. No matter how hard I cranked that sucker down it wouldn't bump the shoulder to get my brass in spec. Tried the die in 2 different presses, plenty of lube etc. I called Dillon and they had me send some of my fired brass and my die back to them. Couple of days later the die came back. Now it will bump a little too much if I'm not careful. I've heard of guys shortening their dies some, but I'm a person that if I buy something it should work or I'm sending it back. Could possibly be a manufacturing issue with stacked tolerances allowing for some fluctuation. I'd call the Forster peeps up and get it handled.

 

[Sheldon N]

Forster can shorten the die for you no problem. I've had them shorten dies before, they just chuck it in a lathe and take off however much you ask them to.

 

[lash]

I’ve also had Forster shorten a FL die for me. They didn’t think it was out of spec, but removed some anyway and I was happy with the results.

 

[Dutch260]

Thanks for the input guys! Yeah I just got off the phone with a tech at Forster about an hour ago. After explaining everything we came to the conclusion that it is most likely a really tight chamber and the die is probably too long.

I mailed it back with 5 PC's of 1x fired brass so they can turn the die down accordingly and while they have it I'm having them hone the neck for my Lapua brass.

Fortunately I don't need the die anytime soon with all this virgin brass still needing fire forming. So not a bad time to send it back and kill 2 birds with one shot. This has been my first experience with Forster's CS and I'm nothing but pleased. The tech was super helpful and I was able to call and speak to a real person in just a matter of a few rings.