Grinding a FL sizing die?

[Wannashootit]

Noticed that the bolt was a bit stiff to close while using our first round of reloads (Rem. 700, .223). So, bought all the gauges- headspace, OAL, and bullet comparator.

I found out that the Hornady FL sizing die is sizing the brass to around .003 more than the fire-formed brass. I called Hornady and he commented that it must be a really short-chambered gun (more on that in a minute), and offered to take .005 off the bottom of the die if I sent it back to them.

Anyone DIY this? The grinding itself doesn't seem difficult, but keeping the base completely flat and true may be easier said than done. Then again, I'm not sure that's even critical because the die would just seat to the longest spot (?).If I take off too much I can always adjust the die upwards. Any tips for grinding this correctly? Or, should I just send it back to Hornady?

Why doesn't a sizing die take the brass back to unfired (or nearly so) dimensions?

Also...
I was VERY surprised to find that the chamber is much shorter than I anticipated. I had been told here before that seating to the lands on a 700 probably couldn't happen anyway because the OAL would be too long to fit in the mag. Nope...

A 52 gr. Nosler match hp was touching the lands at an OAL of 2.25! The 60 gr. Hornday hp, because of it's more "pointed"(?)shape, didn't hit the rifling until 2.32.

Now the other question... I've got some of the Noslers seated to 2.26- with some a bit more to 2.263 due to inconsistency in the seating die. So, I'm jamming the round .05-.053 into the rifling. Is that enough to be concerned about pressures? I can always shoot them in my mini- it's got a full .1 more to the rifling.

As always, any and all advice appreciated, and thanks in advance!

 

[IRISHCYCLONE]

Re: Grinding a FL sizing die?

FYI Die steel is EXTREMELY hard I have taken some off but we did it in a lathe. Personally i would send it to hornady and let them screw it up.... lol

 

[ChrisGarrett]

Re: Grinding a FL sizing die?

I took ~.004" off a Redding SB body die and it went fine. Used my Dremel tool with the round grinding wheel and just pressed the die's bottom onto the top of the wheel, that way, to keep things even.

It took about 20-30 min, but it worked.

Chris

 

[bohem]

Re: Grinding a FL sizing die?

I've trimed 7 WSM neck dies into 7/300 WSM and 7 SAUM length dies. I cut them on the lathe with carbide insert tooling, it came out very nicely.

Unless you have a lathe to do it yourself I'd just send it back to Hornady and let them do it right.

 

[9H_Cracka]

Re: Grinding a FL sizing die?

Hand it to a gunsmith/machinist with a lathe and have him do it the right way by facing the bottom of the die.

 

[427Cobra]

Re: Grinding a FL sizing die?

So you are cammed over and the shoulder is still not set back correct, you stated that the brass is .003 longer after resizing, are you measuring that with a headspace gage or just OAL of the brass?

 

[JuniperEyes]

Re: Grinding a FL sizing die?

Remove the material from the top of your shell holder

Also, shell holder heights vary quite a bit, even from same mfg.

 

[Wannashootit]

Re: Grinding a FL sizing die?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">So you are cammed over and the shoulder is still not set back correct, you stated that the brass is .003 longer after resizing, are you measuring that with a headspace gage or just OAL of the brass? </div></div>

Yes, cammed over and checked with a (Stoney Point)headspace gauge.
New brass (Win.) measured 1.457-1.461
Fire-sized is 1.463-1.465
Sized is 1.467

Fire-sized brass from my Mini is 1.47.

9H- good idea, I'll try to find someone local that can do it quickly rather than wait for the turnaround from Hornady.

Thanks, guys.

 

[jmtyndall]

Re: Grinding a FL sizing die?

This thread caught my attention because I was trying to set up my Forster die to bump my shoulder .003" and I can't seem to get it to. Seems that screwed all the way in and camming the press, I get .000"-.002". On a hornady head space gauge I'm showing 1.451" for fireds brass, 1.451" for fired/sized, and 1.450" for Unfired new brass. I also have a lee sizing die I use for my AR15 reloads, and the shoulder after sizing in that is 1.455"!..is my chamber REALLY this small too?!

 

[former naval person]

Re: Grinding a FL sizing die?

Yes. But Forster will make it good. Send the die and 3 fired cases and they will fix it.

 

[jmtyndall]

Re: Grinding a FL sizing die?

Is it going to be expensive? If so, is there a way to double check before I shell out?

 

[Sandbogg]

Re: Grinding a FL sizing die?

I took a few thousandths off my RCBS 223 sie with an air die grinder and a course green 3m roloc sanding pad. Came out great and works perfect.

 

[davidlbeaty]

Re: Grinding a FL sizing die?

A full lenth sizer die is designed to bump shoulders a limited amount. If a reloader is not paying attention they can increase the headspace too much, so the manufacturers only build a limited amount of bump into a die. Usually when brass is getting difficult to eject it is because there is over pressurization and the cases are stretching. The first thing to fix is the cause of the over pressurization.

First step would be to trim your brass to the dimmension in the reloading book. 2.005 for a .308, then you can move onto resizing the case. Set up the die as the manufacturer recommends and resize a case. Put it into your gun and see if the bolt will close with just a slight amount of pressure. About 1 pound of pressure. If the bolt will not close and you have no more adjustment on your die, then you will need to bump the shoulder back further by modifying your die. That will require you to chuck it in a lathe and using a carbide cutter remove about .030 from the bottom.

To properly bump the shoulders for your gun, you need to remove the firing pin. Without the die in place run one of your cases all the way up on your press and then begin screwing the die down until it just touches the case. Move the handle up and screw the die down 1/8 of a turn. Run the case back into the die and then insert it into your chamber. If the bolt is still too hard to close you must bump the case a little more. Continue with this 1/8 turn process until the bolt will close with a pound of pressure. Once you get there, put the case back into your press and engage the case in the die. Lock down the ring on your die and you are now ready to run the rest of the cases.

A word of caution here is that you are after a zero headspace so go slowly in bumping the shoulder back. If you have the proper powder and quantity, then your cases should fire form to your chamber and will not require bumping shoulders every time you reload. BE CAREFUL!

Precison shooters want the bullet as close to the lands as possible. Most factory guns are set up with a lot of clearance so they will chamber anybodies ammo. If the barrell has been set back and you can adjust the clearance between your loads and the lands you will need to find what is the most accurate place for you. A few large magnum rifles must have a little clearance between the bullet and lands to keep over pressurization from creating problems. Hope that helps.

 

[Wannashootit]

Re: Grinding a FL sizing die?

I can certainly understand a manuf. being cautious in that regard.
But my sizing die only comes within .01 (larger) of new factory brass I measured. Not enough to chamber the re-sized brass without resistance from the bolt. I would think it would be safe enough to size back to factory specs, or at least very close to that.

 

[Sandbogg]

Re: Grinding a FL sizing die?

I guess I am cheap(and impatient), It costs more than the die is worth to send it to somebody with a lathe and a carbide cutter. I have loaded five gallons of 223 on my die since I ground it down a couple thousandths and have not had a single failure to chamber(had them about 5% of the time before grinding).Like the guy above said it did not take much to get the clearance I needed, just a little love went a long way.

BTW my ammo is for a match grade ar 15.

 

[Fuzzball]

Re: Grinding a FL sizing die?

Actually, 3 thou isn't very much, it's only the thickness of a sheet of paper. But, if it's long by that much it will be difficult to chamber so take it off yourself and be done with it.

You can "cam-over" a press without a case inserted in the die, what counts is the way they fit when cam-over occurs. Insert a case, size as you normally do, leave the ram fully up and look under the die to insure you don't have a gap to the shell holder. If you do, turn the die down to close it. If you don't, shorten the die.


"...keeping the base completely flat and true may be easier said than done. Then again, I'm not sure that's even critical because the die would just seat to the longest spot (?)"

Correct in both instances. The die is case hardened so a file won't touch it but a grinding wheel or power sander will. You can visually keep things plenty square by watching the removal pattern as it grows, keep it consistant all the way around and it will remain very square.


"If I take off too much I can always adjust the die upwards."

Also correct.


"Any tips for grinding this correctly?"

You would first remove out the decap pin and then use your caliper to measure the full body length of the die. Carefully remove a tad all around and measure, repeat until you have removed what ever your goal is.

You do NOT need to push shoulders back from the fired length, they have already shrunk back a thou or two from the chamber length.

 

[rg1]

Re: Grinding a FL sizing die?

Much easier to just sand or grind the shellholder. You can just use a sheet of sandpaper laid on a flat surface and move the shellholder back and forth rotating it in your fingers as you work. Will take a little while but is cheap and can be done at home. By the way, the distance from the top of the shellholder to the shelf that the case head sits on is supposed to be .125". They do vary. Or you could sand half off the shellholder and half from the bottom of the die.

 

[Wannashootit]

Re: Grinding a FL sizing die?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">
You do NOT need to push shoulders back from the fired length, they have already shrunk back a thou or two from the chamber length. </div></div>

Thanks for the reply.

This last part above is interesting. I thought it was sop to resize to .002 less than the fire-sized length?
What you say makes sense though, the brass is going obviously going to shrink back somewhat from it's maximum expanded size once it fills the chamber.

So you're saying to FL size to the same dimension as the fire-sized?

 

[Fuzzball]

Re: Grinding a FL sizing die?

"So you're saying to FL size to the same dimension as the fire-sized?"

Well, that's what I've done ever since I got my first case shoulder length gage years ago. There are some strong opinions otherwise but for the life of me I don't understand why. We can easily re-chamber a spent case, why a case resized to the same shoulder length is supposed to be more difficult to chamber escapes me. And my rifles.

It is worth mentioning that not all fired cases will expand/contract or size/expand the same. I frequently find a span of maybe 3 thou variation in shoulder length from cases in the same box. I deal with that by finding the longest fired lenght and, knowing it's still a thou or two shorter than the chamber, I size so the longest resized length is equal to no more than the max fired length. With that, they work fine and last a long time without trimming too.

 

[Wannashootit]

Re: Grinding a FL sizing die?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">Actually, 3 thou isn't very much, it's only the thickness of a sheet of paper. But, if it's long by that much it will be difficult to chamber so take it off yourself and be done with it.

You can "cam-over" a press without a case inserted in the die, what counts is the way they fit when cam-over occurs. Insert a case, size as you normally do, leave the ram fully up and look under the die to insure you don't have a gap to the shell holder. </div></div>

Quick update and a "thank you" for the suggestions.
As I mentioned, I screwed the die down until it contacted the shell plate with the press cammed over...I would have thought that would eliminate any gap, right?

Since I couldn't really see well under the die, I thought about what you said about a piece of paper being the thickness I was looking to eliminate. Tore off a small piece of paper, and with a flashlight, tried to insert it under the edge of the die...

To my surprise- it slid right under...

I removed the die from the bushing, screwed it down 1/4 turn, and sized a case. It definitely took some increased pressure to cam the press fully over; but not <span style="font-style: italic">too</span> much. The case came out right around the size of brand new brass! Problem solved. I then backed it off a bit until I got exactly what I needed.

So, it wasn't the die after all. Just needed a bit of pressure/resistance to be sure the die was REALLY pressed down hard onto the shellplate. Lightly touching it, as the directions indicated, just didn't get her done...

Thanks again, Fuzzball!