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puzzled on case resizing and neck setback.

wayno1

wayno1

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Mar 1, 2013
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Northern Peoples Republic of Illinois
Rifle: Rem700 PSS .308
Reloading brass from this rifle.
Using a Whidden FL die, it's a modified die that doesn't cram the brass back to starting size like some FL dies, but does a 'moderate FL resize.
Directions say to use a shoulder bump gauge to set the shoulder back about.002-.003 if reusing brass fired in that rifle.

My 'pickle': 1 FC match .308 cartridge case 1x fired.
Bump gauge shows 1.612 so it would seem to set the die so the shoulder bumps back .002-.003. ie 1.609-1.610.
The shoulder diameter just below the shoulder shows .455.
Does that sound right?

Next have about 150 .308 FC match cases fired from a different .308 Rem 700 measured with the shoulder bump gauge showing 1.620. Apparently a little different chamber than mine.
When I FL re size these cases (did 4 so far) am showing 1.586 on the shoulder bump gauge. The case diameter after FL resize shows .451/.452
Does that sound right?

Am I nitpicking? Should I just FL resize all the cases from the other rifle, trim to 2.005 (suggestion was 2.007) and start loading, shooting and then using the shoulder bump gauge to set the dies so it gives a .002/.003 shoulder setback?

Die set: Whidden FL resize, Forster Micro seating die.
HAve all the primer pocket reamer, deburring tools, neck chamfer, etc to work from.
Was decent at this 25 years ago - relearning - but never ran into the 'bump gauge' use before this.

Thanks very much for any help - or reference to other threads..... did a search and found lots of things to read, but stuck on this issue.

Wayne
 
I think you are confusing the terms "neck" and "shoulder". The neck is at the top a has a dia. of about 0.340 on a fired case. The shoulder is the 40 deg angled section and you measure from the base to a section on the shoulder which is 0.400" in Dia. in order to measure headspace of the chamber. This should be around 1.635 for a 308 so what is measuring 1.610.
 
Hmmm. This may be a problem with the bump gauge that came with the Whidden die. It looks like the gauge opening touches the neck of the fired case too far down on the sloped part (shoulder).
1.612 is what the base to the sopt on the sloped part that the gauge touches. I may have to get another shoulder bump gauge from sinclair that hits the 'right spot'.
Thank you,

Wayne
 
I use a Hornady .400 bump gauge insert for my 308 reloading. When I zero it using a set of digital calipers, I get a reading of 1.613" for fired cases out of my custom chambered 308 and my SR-25. Cases fired out of my Remington 40XBKS measure 1.616" with the gauge. When I measure fired cases from an M-1A or some other 308, I will get measurements around 1.620-22". For my different rifles, I use a set of Skip's die shims to adjust for the different rifles.


When I took a 308 1.630" headspace gauge and measured it (the shoulder) with the .400" Hornady bump gauge, I got a reading of 1.611". My point is some gauges aren't going to give you a reading of 1.630" minimum headspace gauge SAAMI spec. My Hornady gauge with the 1.613" fired cases reading shows snug chambers on two of my rifles.

I also happen to use a Sinclair bump gauge. It will give different number readouts from the Hornady gauge, but the numbers will be consistent with the amount of shoulder bump.

I don't know why you're getting measurements of 1.586" on your resized cases with your gauge, unless you have the die set too far down. 1.586" is a pretty far set back for the shoulder bump from the 1.612" of your fired cases. My redding F/L die maxes out on the shell holder at about 1.610" on the Hornady gauge (which is very near the SAAMI minimum).

EDIT: I found a photo of the Whidden bump gauge and it seems to be very similar to the Hornady gauge. I will bet the I. D. of your Whidden gauge is .400", which is the proper SAAMI measurement off of the .308 Winchester case.
 
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To understand the problem you are having it is important to understand exactly how headspace on the 308 is measured....The distance from the bolt face to a point in the chamber where the shoulder measures .400 is the point where you measure the rifles headspace. If you take a tube of metal that has a .400" hole in it and set it over the shoulder of a case, where that .400" inside diameter "circle" hits the shoulder is called the datum line. From the datum line, where ever it is on the case shoulder, to the base or head of the case is the case length as far as headspace is concerned. In this instance forget about trim to length, it's not what we are talking about...we are talking about making the case fit in the chamber.
If you are using a set of dial calipers with an attachment like the Stoney Point gauge where it has a .400 I.D. tube and you check it with a headspace gauge it should read 1.630 minimum with a go gauge. It should read 1.635 with a no go headspace gauge. If checking cases they will stretch when fired. Not much in a bolt gun, maybe .002-.003 but usually around .008 in a semi auto like a Garand or M-14. If you are trying to set the cases to just under {.001"} what the rifles headspace is then you really need to know exactly what the rifle is set to. Bottom line...if you measure fired cases with the proper gear and get less than 1.630 something is wrong somewhere. Might be the gauge, might be the rifle and then again it might be the brass has been sized way too small. It is important to find out which one because brass cases that are way to small means excess headspace and that is very dangerous. Hard to believe it is a rifle chambered that short{1.609"}??? ...how would even the most inept gunsmith set the chamber size that small??? There is no headspace gauge I know of that would be that small to allow a bolt to close when checking it. Brass that has been sized that small can be saved but you have to load it with the bullet set way out to touch the lands so it is held back against the bolt face when fired. Then they will fireform back out where they belong and can now be properly sized. Under no circumstances should anyone load and attemp to fire brass cases that measure 1.612" in a 308.
 
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I usually fill in one of these data sheets on every match rifle chamber. Helps me keep track of all the dimensions when setting up dies.
 

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MSIEBERT: Thanks very much for the reply and your time!

Thanks for checking on the Whidden gauge. Got it with his FL sizing die that is supposed to 'mildly' resize the brass, and not be as tough as FL resizing for an autoloader.
Have a Rem 700 PSS and it's pretty tight.

The bump gage sits VERY low on the shoulder, like 90% toward the case wall. In checking my guns once fired Federal Gold Match .308 brass, it showed 1.612.

The lower bump resulted from me screwing down the FL die on some brass was fired from another remington so went back and did some remeasuring now that I know the bump gauge isn't messed up.

Re zeroed the gauge and took measurements.
1) Pulled a bullet on a fed GM match .308. Checked the unfired case with the bump gauge. Measures 1.611.
2) Measured the 1x fired fed GM Match case that is 1x fired. Measures 1.618
3) measured the 1x fired cases I had re sized before to fit a Dillon cartridge gauge - they average 1.608
4) the cases I bought that are 1x fired from another gun show 1.625 - so a little looser chamber.
5) I need to back that FL die off before I wreck any more cases - luckily it was only 3 that I backed the shoulder off to the 1.586....
will start with the die a lot higher and work the shoulders to something reasonable.

--------------------------

I had started working up some loads 10 years ago and used an RCBS micrometer gauge and found the lands. Was seating the bullets farther out.
Contrast- the fed .308 GM match with 168g BTHP SMK is 2.799 OAL
and the rounds I was working up loading had an OAL of 2.917 just touching or .001 off the lands - lost the notes so will have to pull the bullets and start over again.

Again, thanks for the input - my main confusion was how the Whidden bump gauge was working.
 
Waste_knot: thanks for the data sheet. will download and use it.
And thanks for your explanation, it got things started and I understand better with your input, and the subsequent ones as well. I have a bunch to learn. Thanks for helping!

Wayne
 
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wayno1 said:
Hmmm. This may be a problem with the bump gauge that came with the Whidden die. It looks like the gauge opening touches the neck of the fired case too far down on the sloped part (shoulder).
1.612 is what the base to the sopt on the sloped part that the gauge touches. I may have to get another shoulder bump gauge from sinclair that hits the 'right spot'.
Thank you,

Wayne
Click to expand...

Wayne, I have the Sinclair bump guage, and when I zero it out on my calipers and then measure a fired 308 case from my gas gun, it usually measures around 1.516". I believe the Sinclair gage measures to the shoulder and not the datum line of the case. Anyone else want to confirm this?
 
I also use the Sinclair bump gauge in 308 along with a Hornady bump gauge. When I zero out my Sinclair gauge with a digital caliper, I get a reading of 1.561" on a 1.630" 308 Winchester go gauge. My fired cases from my tight chambered rifles measure 1.563". My readings are a little different than yours, but they still are able to show the amount of bump. I don't know why I'm not getting readings in the same ballpark when we're using the same gauge. My Hornady .400" gauge insert gets a reading of 1.611" on a 1.630" go headspace gauge. I don't know why it doesn't read 1.630". I may buy another Hornady.400" insert and see if I get a different reading from it, but like i said, the gauges do read the amount of bump they are just different numbers. What it comes down to is getting a reading and bumping -.001-.002" from the fired cases for a bolt gun and -.003"-.005" for a gas gun.

Some other reloaders on this forum have also reported the Sinclair gauge to be a little finicky. My Hornady gauge with the .400" bore is a little more consistent than the Sinclair.

Sometimes, what I do is to zero the caliper out on fired cases from the same rifle. I can then resize and measure the bump and see a reading of -.002" or whatever it is and adjust the die accordingly. That's why I like using a digital caliper. It give you some flexibility measuring. You just have to take several readings when you zero it to be sure it isn't drifting.
 
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Sorry Flight, slight case of dyslexia. I meant to say my cases measure 1.5615" using my Mitutoyo caliper which measures to 4 decimal places. Sorry for the confusion.
 
The reason you are not getting the 1.630" dimension for the "GO GAGE" using the Hornady 0.400" insert is
that there is a chamfer in the mouth of the tool. Every insert may be different depending on the depth that
chamfer has been cut. Your "GO Gage" is accurate it's just your not adding that difference from the tool face
to the chamfer cut depth (or the actual .400" datum). See below.

hornady1.jpghornady2.jpg

Terry
 
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Also, here is a video I did awhile back on how I set up my FL Dies. Please note that I do use the
Skip's Circular shims underneath my dies. However, for quick checking the feeler gages work well also.
There is varying opinions if using the shim will add run out, mine opinion is if your press is correct the only
force is staight up. Also, my dies are not cammed over thus I am not putting stress into the die itself.
i can only speak for what comes out of my press and they come out with minimal run out.



Terry
 
Suasponte said:
The reason you are not getting the 1.630" dimension for the "GO GAGE" use the Hornady 0.400" insert is
that there is a chamfer in the mouth of the tool. Every insert may be different depending on the depth that
chamfer has been cut. Your "GO Gage" is accurate it just you not adding that difference from the tool face
to the chamfer cut depth (or the actual .400" datum). See below.

View attachment 2830View attachment 2831

Terry
Click to expand...

That makes sense. It seems I have a .019" chamfer on my tool. Thanks for the diagram, I haven't seen that diagram before. I bought the tool when it was still "Stoney Point". Many years ago, I used the Wilson style drop in case gauges. While they helped greatly in setting up dies, the newer gauges are so nice since you can read numbers off of the datum line. It makes a big difference when you're setting up your die on a precision rifle. I see Forster just brought out a new bump gauge this year, similar to the Hornady, but it is self contained.

http://www.forsterproducts.com/store.asp?pid=37195&catid=19938
 
You have not seen that diagram as I just sketched it up in Autocad. ;)

May have to order up on of those gages, Thanks for the link.

Terry
 
I made one with a 0.400 bore and found it measured this Go-gauge kind of short so I bored the next one 0.396 and it's on the money.
Could someone measure the true bore dia. of the tool and post it.
 

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There's a better way . . . .

Rather than make your handloads fit according to somebody's go gauge . . . . that "should" (but might not) represent your particular chamber; why not make your handloads fit YOUR chamber perfectly? Take a look at the Digital Headspace Gauge. It gets calibrated to one of your fired cases. Your 50,000 PSI chamber pressure makes your fired case as close as any chamber casting, and it doesn't matter if your cases are fired once or ten times.

The Digital Headspace Gauge displays the shoulder clearance that your handloads have in YOUR particular chamber. It shows the correct die shim to use in order to get a -.001" shoulder bump in your bolt gun, and about -.003" in a gas gun. There are no special bushings required. It works on all different calibers, and it doesn't require datum information, cartridge drawings, or a collection of caliber specific go/no-go gauges.

Most shooters would be surprised to see the actual shoulder clearance that their handloads have in their chamber.
 
waste_knot said:
I made one with a 0.400 bore and found it measured this Go-gauge kind of short so I bored the next one 0.396 and it's on the money.
Could someone measure the true bore dia. of the tool and post it.
Click to expand...

The true bore diameter on the Hornady/ Stoney Pointe Headspace gage for .308 is .400"

Terry
 
Innovative:

That is exactly what we are doing, Sizing our cases down based on the fired base dimension.
However, the question was asked why the Stoney Pointe and Hornday gage readings was not
at the listed 1.630" dimension for the "GO gage". The following post was a explanation of why
your not getting that reading when you are zeroing out to the face of the tool.

Terry
 
I don't trust these case measuring tools to give a true HS measurement.

When setting a die for ammo to fit any rifle, I zero my caliper on a HS gage and compare sized cases to it, ensuring I'm a thou or two under.

When setting a die for ammo for a specific rifle, I zero my caliper on a few fired (from the rifle in question), decapped cases, and ensure I'm a thou or two under.

That's it.
 
Ongoing saga-
Have been down and out with the flu....

Pulled the bullets on 30 some FC match .308 1x fired cases I had resized -before- the match FL die, using Dillon's.

Did the bump case case measurement and got 1.608.

Given that I got 1.611 measurment on an unfired case are these 1.608 cases useable?

Thanks!

Wayne
 
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If I'm understanding you correctly, fired cases in your rifle measure 1.612". Your resized cases in your last post measure 1.608" of shoulder bump. That is a difference of .004".

I would shoot the cases and measure them after you shoot (remember to decap them before measuring. A fired primer in the case can give you a false reading) and then set your F/L sizing die to bump the shoulder no more than .002".

Be aware that the amount of shoulder bump can change or differ when using different brass, brass that has been work hardened and may need annealing and using a different type and the amount of sizing lubricant.
 
Thanks - so the ones measuring 1.608 are shootable?

Worse problem now. I have a bunch (100) of unprimed new brass from 10-12 years ago (all federal) that before I knew what I was doing, FL resized and bumped the shoulder back during FL resize (duh) and trimmed all to 2.005 OAL
With a new unfired case from a fed GMM .308 measuring 1.611, these cases measure 1.604. The length is correct 2.005 but is the shoulder too far back on these to use?

PS - will try decapping only and then measure the brass. Good point on the primer removal.
Thanks!

Wayne
 
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wayno1 said:
Worse problem now. I have a bunch (100) of unprimed new brass from 10-12 years ago (all federal) that before I knew what I was doing, FL resized and bumped the shoulder back during FL resize (duh) and trimmed all to 2.005 OAL
With a new unfired case from a fed GMM .308 measuring 1.611, these cases measure 1.604. The length is correct 2.005 but is the shoulder too far back on these to use?
Click to expand...


With those 100 cases, rather than scrapping them, Load up 10 rounds with a mild load and shoot them. Then check the headspace/shoulder with your gauge after you shoot them. Remember to deprime them before measuring. Firing them once if the shoulders aren't bumped too far back should be okay as long as they don't get stretched too much. Then be sure to bump them back only .002" from then on.

I don't know how you've bumped the shoulders of those cases below the SAAMI minimum since all of my various 308 F/L dies even the small base dies (RCBS Small base, Forster National match and Redding) will barely resize/ bump the shoulders to get me near SAAMI minimum. Usually the only way to get below minimum is to shave off a shell holder or grind metal off the base of the die.
 
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Would it be a reasonable thing to see if those cases will chamber to the point where the extractor engages the rim of the case?
If not I don't think they would be safe to load and shoot.
Someone suggested seating the bullets longer in the case so it would be touching the lands, ergo making the extractor engage. Either that or dump the cases vs set up a dangerous situation?

Thanks!
 
You wrote your gauge measurements on new cases gauge @ 1.611". Your old resized cases measure 1.604". That is .007" difference. If you think it will be dangerous to shoot them, then don't.
 
I found that my "Excedrin Headache" got a lot better when I realized that MY rifle wasn't like anyone else's rifle. Rather than try and keep track of all the "readings" I just have a fired case that was "Molded" to my chamber. I check fired cases periodically and find that they all are within a thou or so of my "reference case".

I then use a Stoney-Point/Hornady headspace measuring tool to set my die for shoulder "bump". Since my dies are set in quick change bushings it's merely a matter of rechecking periodically to see that they are still in adjustment.

As far as "gauges" go, it's tough to beat the rifle. After all, regardless of what the tools and gauges say, if it won't fit the rifle chamber then what good were all those tools?

Sometimes measuring, measuring, and data collection can cause a disease called "Paralysis by Analysis".
 
Wow
I,m all about keeping it simple

Find a case that is hard to chamber, pert easy to feel

stuff in FL die and turn it down 1/4 turn until it chambers with ease

Done
tighten down lock ring on FL die and forget it

make it as hard or as simple as you want
 
LOL! That's a great idea!

Just finished with the basic sizing settup. What was -supposed- to be spec was hard to seat in the rifle.
I did it the way you suggested and I had to bump the shoulder back another .004 from where I started to get an easier close on the bolt and still engage the extractor. It's still a new gun and apparently has a tight chamber....

I had done this before with about 100 cartridges and was worried they were too short - now I find they are just right for this gun.

Thanks for the suggestion and the help!

Wayne
 
Wayne, I am going to do some measuring to check my work, but the master reloader who i took a course from told me an easy way to get your die really close for a Rem700. Pull the bolt out of the rifle. Hold the cocking lug on the bottom of the bolt either in a vise, or I just do it by hand, on the edge of my bench, but it a hardwood bench. Anyway, pull the bolt to cause the "Button" on the end of the bolt to come out a little. You will find a groove there. Place a penny in the groove, and you can then unscrew the bolt sections, taking the firing pin out. Then, place the bolt back in the gun, and slowly size a case until the bolt will close without "any" strain. You will be very, very close to your chamber size. I did this when I first started, and I have had very good success with the brass.
 
Sniper Uncle said:
Wayne, I am going to do some measuring to check my work, but the master reloader who i took a course from told me an easy way to get your die really close for a Rem700. Pull the bolt out of the rifle. Hold the cocking lug on the bottom of the bolt either in a vise, or I just do it by hand, on the edge of my bench, but it a hardwood bench. Anyway, pull the bolt to cause the "Button" on the end of the bolt to come out a little. You will find a groove there. Place a penny in the groove, and you can then unscrew the bolt sections, taking the firing pin out. Then, place the bolt back in the gun, and slowly size a case until the bolt will close without "any" strain. You will be very, very close to your chamber size. I did this when I first started, and I have had very good success with the brass.
Click to expand...

This is a good way to do it. Using the rifle as a gauge is the traditional way to get your reloads to size properly. All of this posting I did with Wayno1 was to help him use the gauge that came with his dies, which he was asking about. Once you have a number using the gauge on brass fired in your rifle, you can now just go with the number and you don't have to pull out the rifle every time you want to check shoulder bump. You can if you want, but the gauges do make it easier.

On my rifle, I know a shoulder bump reading of 1.613" will easily chamber. I can go up to a reading of 1.615" or so for a snug press fit. The gauge can also tell you when it's time to anneal or when when using other brands of brass that don't resize or spring back the same as the brass you used for your initial die set up.
 
FLIGHT762 said:
This is a good way to do it. Using the rifle as a gauge is the traditional way to get your reloads to size properly. All of this posting I did with Wayno1 was to help him use the gauge that came with his dies, which he was asking about. Once you have a number using the gauge on brass fired in your rifle, you can now just go with the number and you don't have to pull out the rifle every time you want to check shoulder bump. You can if you want, but the gauges do make it easier.

On my rifle, I know a shoulder bump reading of 1.613" will easily chamber. I can go up to a reading of 1.615" or so for a snug press fit. The gauge can also tell you when it's time to anneal or when when using other brands of brass that don't resize or spring back the same as the brass you used for your initial die set up.
Click to expand...

That is understood, and appreciated. What tool do you use to check these measurements? I am slowly getting my measurement tools purchased. I have the inserts for chamber measurement for actual case neck length "room," the tool for bullet seating depth, the inserts for the comparator, but my comparator got lost in shipping, and the replacement is on back-order. Do I need other tools to check the shoulder "bump?" And if so, what is it called?
Thanks,
 
I use the Hornady headspace gauge that attaches to their comparator body. The comparator body can also be used with their comparator inserts to measure bullet measurements from the ogive.

http://www.midwayusa.com/product/47...-headspace-gage-5-bushing-set-with-comparator

I also use the Sinclair bump gauge which also happens to fit into the Hornady comparator body. After using both gauges, I believe the Hornady set is a good value. The 5 bushings it comes with can measure scores of cartridge calibers.

It's also not a bad idea to also have a Wilson style drop in gauge for a quick check on fired and resized cases. I use the Dillon ones for .223,308 and 30/06. Some guys prefer the J P Enterprise drop in gauges for 223 and 308. They report they are made to closer tolerances for match chambers.

http://www.jprifles.com/1.5.1.2_maint.php
 
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