tight bolt close

3

308Loader

New member
So, I've been loading for 2 different .308's, one rem 700p and one savage mod 10-t sr. On this last load cycle, I am having a hard / tight bolt closure on the Savage. On the Rem things are smooth like normal. So, I did some measuring:

Tools: Hornady caliper, Hornady comparator to ogive, and Hornady comparator to shoulder datum. Wilson case gauge.

First, I dropped them in the case gauge thinking I might have not sized fully. all fit flush with the gauge.

Then I took a Fed GMM 168 HPBT from a factory box, cycled it through the savage, bolt closes like normal. measured the round from base to ogive = 2.222. Measured from base to shoulder datum = 1.654.

Then measured my loaded rounds base to shoulder 1.662 (average of 5 cases 1.663 to 1.661 max to min) then base to ogive = 2.196 (again average of 5, 2196max - 2.195min one oddball 2.199)

Conclusion, both completed rounds measure tip to tail 2.800, base to ogive my loads are shorter by .0255 (probably not the issue) from shoulder to base my loads are longer by .008 (could this be the issue?).

I've used this same die-lock ring- press bushing- lee press combo before with the Savage and had no trouble. Case trim is 2.005-2.006 well in spec. I’m a little confused.

Fired cases measure from shoulder to base = 1.665 in the savage. extraction is smooth. Using 2 headstamp's FC and Hornady. both range brass and both once fired, both measure same.
 
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Get out a sharpie and draw a couple of lines down the cartridge from the base of the case to tip of the bullet and you should be able to figure out where it's rubbing pretty quickly.
 
308Loader
Remingtons have more free bore then Savages . Here's what I do . I full size only , when sizing my fired cases , I use a stripped bolt only the housing . You can feel the case size down to zero case head space then size down to .001bolt will have no resistance . I measure the zero case , I record that measurement . The with that case I seat a bullet long test in chamber , size down untill round closes with very little resistance on bolt closure , record that measurement . You from there can size your cases with zero on up headspace ,same with ogive setting. Both rifles have different headspace an head to ogive measurements . Stripping a Savage bolt may be more difficult , Remington is simple. I use the RCBS Precision Mic for both , great tool.
 
308Loader,

Yes, the extra 0.008" is the problem. When you resize, the sizing die first narrows the case as the sides make contact with the die first. This squeezes the case out longer. You then have to push it against the shoulder hard enough to form the shoulder back. This flows the extra brass into the neck, which is why necks often need trimming after resizing and not before.

What you want to do is take a flashlight and when one of your cases is all the way up in the die, look for a crack of light between the mouth of the die and the shell holder that is due to the sizing force actually stretching the press frame a little. Back the ram down and turn the die in and check again and repeat until that crack of light is gone. Your cases should then lose the extra length. Figure about a ninth of a turn deeper.

With a small base die, both the squeezing that first lengthens the case and the press stretching force are greater than with a standard sizing die.
 
First, I dropped them in the case gauge thinking I might have not sized fully. all fit flush with the gauge.
Click to expand...

If I sized a case to return it to minimum length I would expect the case to be .004" shorter than a go-gage length chamber; if I measured a case and found it to fit my Wilson case gage flush with the end of the gage I would consider the case to be the same length as a go-gage length chamber.

If your case was flush with the end of the Wilson case gage after sizing you failed to size the case. If that happened to me I would determine if the die made it to the shell holder when I raised the ram. In the perfect world and the case gets sized when the ram is raised there will be no gap between the shell holder and bottom of the die.

F. Guffey
 
Then measured my loaded rounds base to shoulder 1.662 (average of 5 cases 1.663 to 1.661 max to min) then base to ogive = 2.196 (again average of 5, 2196max - 2.195min one oddball 2.199)

Conclusion, both completed rounds measure tip to tail 2.800, base to ogive my loads are shorter by .0255 (probably not the issue) from shoulder to base my loads are longer by .008 (could this be the issue?).

I've used this same die-lock ring- press bushing- lee press combo before with the Savage and had no trouble. Case trim is 2.005-2.006 well in spec. I’m a little confused.

Fired cases measure from shoulder to base = 1.665 in the savage. extraction is smooth. Using 2 headstamp's FC and Hornady. both range brass and both once fired, both measure same.
Click to expand...


In the quote above I copied a lot of stuff/details that could be repetitive.

If you are using Hornady tools that are datum based forget accuracy. The tool you are using is a comparator, the datum has a radius meaning the reloader must learn to zero the tool first. And then there is that thing with measuring before and again after.

F. Guffey
 
Dog… “Get out a sharpie and draw a couple of lines.” assuming the sharpie rubs off in the right spot, on my to do list.

CW… “I use a stripped bolt only the housing.” Safety thing? No powder or primer same? “You can feel the case size down to zero” more questions on this.

Nick… “Yes, the extra 0.008" is the problem.” What I figured… “I've used this same die-lock ring- press bushing- lee press combo before with the Savage” is my confusion.

I get that the Savage – Remington – and the Wilson have different sizes / chamber cuts. (guffy). What once worked ok, now is not. Hence the question and the measuring.
” the datum has a radius meaning the reloader must learn to zero the tool first.” Hu? In the case of a comparator how can one zero? It is a comparison. “And then there is that thing with measuring before and again after.” Did that as you pointed out.

Would have expected the case gauge to be SAMMI min-ish. When loading for two Win .308’s. I guess I should load and segregate brass for each rifle. What I’ve loaded to the case gauge and suggested OAL I thought would be fine and is. Don’t get me wrong, everything I shot = 1” @ 100y +/-. Thanks for the reply’s all. Now I have created a bigger problem for myself, installing a rock chucker supreme to replace my Lee classic… talk to you all soon about that.

Again, thanks for the reply’s. I’ve been at this for only a couple of years. I know that what I know is only enough to be dangerous, I haven’t gone all the way down the rabbit hole (YET!). By trade I have been in offset lithography, and HFC communications. Both require attention to detail, so I feel I might be able understand this. Like the afore mentioned trades, there is not a school for this sort of thing that I know of. I just have you all
 
308Loader:
Dog… “Get out a sharpie and draw a couple of lines.” assuming the sharpie rubs off in the right spot, on my to do list.

CW… “I use a stripped bolt only the housing.” Safety thing? No powder or primer same? “You can feel the case size down to zero” more questions on this.

Nick… “Yes, the extra 0.008" is the problem.” What I figured… “I've used this same die-lock ring- press bushing- lee press combo before with the Savage” is my confusion.

I get that the Savage – Remington – and the Wilson have different sizes / chamber cuts. (guffy). What once worked ok, now is not. Hence the question and the measuring.
” the datum has a radius meaning the reloader must learn to zero the tool first.” Hu? In the case of a comparator how can one zero? It is a comparison. “And then there is that thing with measuring before and again after.” Did that as you pointed out.

Would have expected the case gauge to be SAMMI min-ish. When loading for two Win .308’s. I guess I should load and segregate brass for each rifle. What I’ve loaded to the case gauge and suggested OAL I thought would be fine and is. Don’t get me wrong, everything I shot = 1” @ 100y +/-. Thanks for the reply’s all. Now I have created a bigger problem for myself, installing a rock chucker supreme to replace my Lee classic… talk to you all soon about that.

Again, thanks for the reply’s. I’ve been at this for only a couple of years. I know that what I know is only enough to be dangerous, I haven’t gone all the way down the rabbit hole (YET!). By trade I have been in offset lithography, and HFC communications. Both require attention to detail, so I feel I might be able understand this. Like the afore mentioned trades, there is not a school for this sort of thing that I know of. I just have you all
Click to expand...
While a rehash and starting from the beginning this is a MAXIMUM CARTRIDGE / MINIMUM CHAMBER 308 Winchester drawing from our friends at SAAMI. Now if we assume that either of your rifle chambers meet those drawing specifications then any cartridge meeting those specifications will chamber and function.

We need to keep in mind that the Hornady® Lock-N-Load® Headspace Gauge system is, as Mr. Guffy and others point out is a comparator type system. That means most of the numbers you mentioned in your first post are just references they are not actual case dimensions which is why they are not close to the dimensions in the link. The Maximum cartridge dimension from base to shoulder datum (where the OD of the shoulder crosses through 0.400" is 1.634" -0.007". The problem with the Hornady gauge is the bushings (.330", .350", .375", .400" and .420") have a machined radius on the holes and are not sharp corner breaks. Most I have seen and used normally measure low but you are coming up with some large numbers. Here is what I am getting at with pictures.

I zero a digital caliper:
Hornady%20CG1.png


I attach the case gauge:
Hornady%20CG2.png


I zero the digital caliper:
Hornady%20CG3.png


Now rather than measure a case I will measure a known value actual chamber headspace gauge with a known 1.630" dimension base to shoulder datum.
Hornady%20CG4.png


Note the reading is 1.624" using a known 1.630" gauge so my reading is actually -0.006". I will now measure a known 1.634" chamber headspace gauge.
Hornady%20CG5.png


My reading has increased 0.004" as expected (1.624" to 1.628") but I am still 0.006" below my actual gauge. The cause of the error is again, the bushing is not very exact as to a 0.004" corner break. I zeroed off the large flat on my bushing but my hole where I meet the datum on the shoulder is not a true 0.004" diameter. However, the gauge did accurately measure the difference between my first headspace gauge and my second as 0.004" which is actually what the gauge is supposed to do.

So the idea of doing this is to fire a case and measure the fired case. Now resize the case and measure again. The idea being I can resize my case for a measurement about 0.002" less than where I started. As long as the system is linear you have a good working "comparator" allowing an accurate comparison of before and after.

Real numbers, most factory ammunition, I get cartridges around 1.629" to 1.630". My Federal Gold Medal Match comes in right about 1.630". If you want real numbers and accurate numbers I suggest the RCBS Precision Mic or buy a 308 Headspace GO gauge which should be a 1.630" gauge and set up your Hornady gauge off that gauge.

My experience has also been when using good dies, correctly adjusted, my resized brass comes out right around 1.630" when full length resizing 308 Winchester, unless I intentionally set my die higher off my shell holder. When sized to a true 1.630" the cases should chamber and function in any 308 chamber meeting SAAMI specifications.

Finally and before I forget, the images are mine and if anyone wants them feel free to download them for your own use. The images are also linked to a domain which I own.

Ron
 
Without segregation between cases fired in the two guns, and with multiple loadings (work hardening of the brass) your results may not be unexpected. Especially if you are using the same sizing die setting for both guns (and the shellholder doesn't touch, or very nearly touch, the sizing die when sizing the cases).
 
"Mr. Guffy and others point out is a comparator type system. That means most of the numbers you mentioned in your first post are just references they are not actual case dimensions which is why they are not close to the dimensions in the link."

yes, I understand that. after installing both devices to the caliper it was zeroed.

"and the shell holder doesn't touch, or very nearly touch, the sizing die when sizing the cases"

No crack of light between shell holder and die base here.

I'm installing the new rock chucker tonight, witch means all of the dies will be reset. I will try again and see what happens. It just struck me as odd that what once worked fine suddenly didn't. I used the same setup to load for the new savage 3-4 times with no issue, this time it didn't. Thought I might be overlooking something. What really sucks about all of this is the 800 rounds that were sized, some of witch will be resized when I'm done segregating / allotting brass for each rifle. Thanks for the reply's all.
 
Let us know how the press works out. I have to agree that nothing should have changed but something did. Anyway, please do follow up. After sizing several try the brass for form, fit and function in each rifle and see what you get.

Ron
 
308Loader said:
"No crack of light between shell holder and die base here..
Click to expand...
Just to reiterate, there should be little or no light when actually sizing a case. Depending on press flex and wear, there can be several thousandths more clearance between die and shellholder when loaded with an unsized case versus no case in the press.
 
I go about it differently than some...

General chambers (Sloppy) a case gauge will get you there 99% of the time.

'Tight' (in or about SAAMI specification) you will need a gauge cut the same as your chamber for it to be efficient.
Example: Your case gauge works fine for your Remington, which is probably older than the current crop of super tight chamber rifles..

1. Rim/Lower Case Bloat.
Rim get hammered out oversize, bolt has to resize rim, tight bolt.
Rim gets deformed by extractor/ejector (and sometimes by shell holder) and does not get restored by top down sizing dies.

2. The die simply can't reach down below the case holder rim to size out the lower bloat.
Exactly ZERO top down dies will remove lower case bloat, which presents as hard to lock bolt, bloat being last thing to enter the chamber.

3. Datum Line Length,
Distance from head stamp surface to Datum line on case shoulder.
The Datum length is the measurement that fits into Chamber Head Space.

4. Shoulder Angle.
An alarming number of dies (and chambers) do NOT have the correct shoulder angle to produce properly sized brass.

5. Neck diameter & length.
This one should be self explanatory.
 
Just to reiterate, there should be little or no light when actually sizing a case. Depending on press flex and wear,
Click to expand...

And then? There is the case; the case can have more resistance to sizing than the press can overcome. To Increases the presses ability to overcome the cases ability to resist sizing I lower the die and or shim the case head up and off the deck of the shell holder. I know, that sounds like a conflict; because I use the same procedure to size cases for short chambers but the procedure does not work if the case has too much resistance to sizing.

Again, I have long chambers, when sizing cases for long chambers I adjust the die off the shell holder with a feeler gage. I have one 30/06 chamber that requires the die be adjusted off the shell holder .014" to get the magic .002" clearance. The chamber is .016" longer than a minimum length chamber from the shoulder of the chamber to the bolt face; that is .011"lomher than a go-gage length chamber.

F. Guffey
 
Originally Posted by 308Loader View Post
"No crack of light between shell holder and die base here..
Click to expand...

Crack of light; I had a chance to purchases a light gage, I thumbed through the users manual and turned it down; instead I purchased a Pratt and Whitney electronic gage that was close to useless because it started at .000005". I removed the electronics and then installed I dial indicator. And now? It is one smooth running dial indicator stand.

Crack of light and or a sliver of light? I use a feeler gage to measure the gap between the top of the shell holder and bottom of the die.

F. Guffey
 
JeepHammer, thank you for the more constructive thought on the whole issue.

Ron, I will let you know what I figured out, thanks for the input.

Guffy, what in the F is a light gauge. I work with fiber optics, we have light meters to quantify inferred light levels, no gauges. Also how did you install a dial indicator? "the case can have more resistance to sizing than the press can overcome." that was kind of what I was thinking. These cases were donated to my by a friend who fired then once through his ar10. I small base sized them, my Lee press was creaking and flexing more than normal. But as stated before, the first 3-4 batches of 100 worked out just fine.

New press is in, and I have reworked the mounting system on my bench. I have a chunk of 2x10 mounted to my bench at a 45 degree angle so that I can work from both sides of it. One side has the single stage and the other has the 4 hole turret for pistol rounds. the previous 2x10 had a crown to it that I think added to the flexing. new 2x10 is perfectly straight, a little shorter, and is anchored better.
 
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So now that it is crystal clear to me that I need to size different for both rifles. the process for die set up is:

Measure fired case shoulder to head with comparator. assuming the fired case has sized itself to the chamber.

Subtract .02 and size to that for each individual rifle by moving die up or down.

Seems dumb to ask because I've read about it 1000 times in various places, but the only dumb question I know of is the one never asked. This might have been the first question I asked in my first post here 4 years ago.
 
Subtract .02 and size to that for each individual rifle by moving die up or down.
Click to expand...

If loading for a specific rifle you only want to reduce the head to shoulder datum measurement by about 0.002" not 0.020" but I figure that was a typo.

Adjusting the die to give a head to shoulder datum difference of 0.002" should extend brass life as when resizing you work the brass less. Using the die per the instructions, running it down to the shell holder and then 1/8 to 1/4 turn will resize the brass so it should fire in any standard chamber. So you have a choice.

Ron
 
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