All about Headspace - I'm not sure where I stand here?

[milboltnut]

I reloaded good ammo for almost 45 years before I heard the term HS or bump related to sizing brass.

case life again.... and the standard rifle that only shoots 1 inch at 100 yards really can't be improved on handloading. And what is your definition of good ammo?

 

[wkdickinson]

Actually I believe you may be misunderstanding what they mean. Stripping the bolt is probably the best way but once you know the feel I find it not necessary.

I want the bolt to close tight with resistance on a fired piece of brass. That way I know the brass is fully fireformed

I will then take that case and measure base to shoulder datum. Want sized brass 1 to 2 thousandths shorter.

Take that case and put it in the shell holder. Carefully in tiny increments adjust the sizing die till you get that 1 to 2 thousandths bump. In time you will learn the feel when the die hits the shoulder.

Now chamber that sized piece of brass in your rifle. If it chambers easily put a lock ring on that die and don't mess with it any more. If not you have work to do.

No, I get it. You apparently have a lot better feel than I do. When I have used that method to establish chamber length (which has not been often), I tend to use an approach similar Alex Wheeler's method for "finding the lands" with a bullet. Moving back .001" at a time until the bolt handle "drops", then you know you are approximately -.001". When I've done it that way, I have always used a headspace "GO" gauge, added tape and then measure it with either an RCBS Precision Mic or a Whidden "Shoulder Bump Gauge" on a digital caliper.

The reason I don't use "the feel" method with fired brass is I am not confident that the only resistance you feel is generated by the shoulder of the case hitting the shoulder of the chamber. If that were the case, then there would be no need for full-length resizing. Then I set my sizing die up to "chamber length" -.002", measured with either of the gauges mentioned above. I've also found that since I started to leave the case compressed in the sizing die for 5 seconds, my shoulders are much more consistent.

Not saying it is the right way, but so far it has worked the best for me.

 

[Richard Coody]

No, I get it. You apparently have a lot better feel than I do. When I have used that method to establish chamber length (which has not been often), I tend to use an approach similar Alex Wheeler's method for "finding the lands" with a bullet. Moving back .001" at a time until the bolt handle "drops", then you know you are approximately -.001". When I've done it that way, I have always used a headspace "GO" gauge, added tape and then measure it with either an RCBS Precision Mic or a Whidden "Shoulder Bump Gauge" on a digital caliper.

The reason I don't use "the feel" method with fired brass is I am not confident that the only resistance you feel is generated by the shoulder of the case hitting the shoulder of the chamber. If that were the case, then there would be no need for full-length resizing. Then I set my sizing die up to "chamber length" -.002", measured with either of the gauges mentioned above. I've also found that since I started to leave the case compressed in the sizing die for 5 seconds, my shoulders are much more consistent.

Not saying it is the right way, but so far it has worked the best for me.

The only difference between my method and yours is how you identify when your brass is fully fireformed. Not sure from your reply how you verify that.

 

[STS]

where did you buy your crystal ball from ? You have no idea where the case is headpace wise just "adjusting" your die.

Why don't you enlighten the rest of us as to the importance of knowing what the headspace is on the case? The only thing that matters is the case fit to the chamber, and that fit can be made perfect without any gauge, gadget or any exact dimension. What do you propose to do if the chamber is 1 or 2 or 3 or 4 thousands over minimum headspace? All of those dimensions are within acceptable headspace tolerance. What do you do with your gauge to fit a case to those chambers that you can't do with a simple adjustment of the sizing die to the maximum dimension that will close easily in the chamber? While you're at it, please save me the drama of anymore "crystal ball" statements. It doesn't accomplish anything with regards to clearing up the confusion that inexperienced reloaders have about what should be a very simple aspect of the craft.

 

[milboltnut]

ok I say for the last time..... case life. I'm out

 

[STS]

No disrespect, but your reading comprehension leaves a lot to be desired. Case life can't be improved upon when a case is sized the absolute minimum to correctly fit the chamber. Which is exactly what I described, twice.

 

[milboltnut]

Why don't you enlighten the rest of us as to the importance of knowing what the headspace is on the case? The only thing that matters is the case fit to the chamber, and that fit can be made perfect without any gauge, gadget or any exact dimension. What do you propose to do if the chamber is 1 or 2 or 3 or 4 thousands over minimum headspace? All of those dimensions are within acceptable headspace tolerance. What do you do with your gauge to fit a case to those chambers that you can't do with a simple adjustment of the sizing die to the maximum dimension that will close easily in the chamber? While you're at it, please save me the drama of anymore "crystal ball" statements. It doesn't accomplish anything with regards to clearing up the confusion that inexperienced reloaders have about what should be a very simple aspect of the craft.

To answer ya short and sweet..... consistency is what most handloaders work at. I do anyway. So I guess I'll redact my original statement of case life alone and add consistency. I like to make handloading more interesting than just going through the motions and just picking a bullet, powder, brass and primer. It isn't enough for me anymore and it can be boring and the accuracy can get better. Sorry about the drama, really.

 

[Webster]

case life again.... and the standard rifle that only shoots 1 inch at 100 yards really can't be improved on handloading. And what is your definition of good ammo?

Hard to answer. As the years went by I bought more accurate rifles and improved my bench skills. I had 7mm Rem mag light barrel (about 1972-1982) that would shoot under 1/2" with reloads. My factory Rem BDL heavy barrel varmint rifle (bought in 1969) would shoot 1/2 to 3/4" groups . Good enough to kill GH out to 400 yards. Now I have a 6BR (2009 rebarreled from a 6mm Rem. and a 6BRX (2018) . I have had a bump gauge now for about 3 years, it came free with the Whidden 6BRX dies. Both shoot well under 1/2" for varmint hunting. I cannot remember ever having a problem of any kind reloading ammo as far as sizing. I kind of think of any catridge as a wildcat because it conforms to your chamber. The SAAMI spec is always way bigger than any factory cartridge so factory ammo will fit in any rifle that's manufactured. The factories don't make loaded cases for reloading. I don't shoot competition. I consider myself a GH hunter. I shoot 2-3 times a month at the range. 95% of my shooting is off a bench. I shoot smaller groups than just about anyone at the range that isn't a competitive shooter and they have equipment that cost far beyond what I have. My rifle bought in 1969 is still my main rifle. It's glass bedded, Krieger barrel and a jewell trigger. It still has a 15X Unertl Ulta Varmint scope on it purched about 1975. Also have a Anshutz model 64 22 rim fire. At 50 yds. I shot a 20 round group you could cover with a quarter. That embarised everyone at the 50 yrd. benches.

Have fun. Whatever you enjoy is all that matters. My way of relaxing is to sit in a hayfield with binoculars and finding GH's.

 

[milboltnut]

Nice write up Webster.. factory to custom rifles show the difference in accuracy and consistency. Heavy barrel Remington does pretty good, but the Kreiger/jewel set up does better, and worth handloading for. I had a 09 Argentine with a mystery extra heavy bull barrel .243 that was disappointing. The only way I shot under a half an inch was to jam a bullet into the lands, problem is the primer pockets opened up and I wasn't comfortable with that. I even had a Savage 11 .243 with a McGowen medium contour varmint barrel that the rep from the barrel company said I would be surprised what it would do at 300 yards, heck I wasn't really impressed what it did at 100. All said and done.. here I guess it depends on what your expectations are and choose wisely to fulfill them.

 

[jelenko]

And, recognize that we'll learn more about what we can and want to expect as we experiment. I.e., if I only knew 15 years ago what I know now.

 

[divingin]

The 51.89mm is actually my chamber length...


The fact that I now know my chamber length is 51.89mm... Should I not just use this measurement to establish my shoulder bump? Set up my die in such a way to end with a cartridge length of 51.89mm - 0.05mm = 51.84mm That way, I know I always have a headspace of 0.05mm...

Assuming the first sentence is true, that's just about what I would do. The measurements and numbers are all well and good, but what you are looking for at the end is a loaded round that fits your chamber as close as possible without requiring undue force to close the bolt. Since your neck sized brass still fits, I'd use that as your desired length for full length resizing (or maybe make it a thousandth shorter.) Test fire a couple and make sure that any growth in length doesn't cause a stiff bolt, and call it good.

Some observations I didn't see in the posts (not that I read them all, but still...):

Neck sizing does not alter the base to shoulder case measurement. Any change on brass that is only neck sized happens during firing. If the case becomes hard to chamber due to length, you have to size more than just the neck to get it back to being usable.

Full length sizing (or body sizing if you have something like a Redding body die) is capable of shortening the base to shoulder measurement if adjusted to do so. If the die is not adjusted to shorten the base to shoulder, it will likely lengthen it (due to squeezing the body down radially - that brass has to go somewhere, and it does: into lengthening the brass.) Full length sizing with bump will lengthen the OAL of the case.

Pushing the shoulders too far back will cause the case to stretch on firing; the brass will thin at a spot just above the case web, and will eventually open up. In extreme cases it will separate the case head from the body and neck. Don't do this. A light color ring or arc a little ways up the case is indicative of this thinning.

Last, fired brass that causes bolt problem is usually the base to shoulder length, but it can also be caused by brass that is bulging towards the base of the case. ID your problem area before proceeding to fix a non-existent problem (been there, done that.)

Good luck!

 

[Webster]

Where's Guffey?

For some reason I miss him too. I copied most of his weird statements in a Word document so I could review them once in while. It would be inappropriate to post it. I may be the one that finished him off on the website with my image of a head space gauge that they used years ago to measure a person's skull to determine their mental characteristics. I cannot find the image searhing the website.

 

[gambleone]

For some reason I miss him too. I copied most of his weird statements in a Word document so I could review them once in while. It would be inappropriate to post it. I may be the one that finished him off on the website with my image of a head space gauge that they used years ago to measure a person's skull to determine their mental characteristics. I cannot find the image searhing the website.

Oh no lol

 

[DShortt]

Guffy may have known a lot, but he certainly wasn't able to articulate it clearly.
I certainly don't miss the convoluted posts.
'If you can't explain it simply, you simply don't understand it well enough. '

 

[J_idaho]

I haven’t read everyone’s posts but I’m already tired of reading. I just want to say I question your measurements I’ve never seen .004” variations in new brass.

 

[Wild Bill IV]

To make this even more simple...
Since your once fired cases will still allow your bolt to close easy, and you have that data, you should try and use that data and that longer Lapua sample to establish your chamber size.

Being careful with that long Lapua case, since you only found one where the bolt doesn't want to close, carefully start with your FL die turned out where it has no effect and slowly approach the shoulder to try and catch the first sign of it changing the shoulder datum length.

Also use your chamber to verify that feel as well.

Using the very small changes slowly turn the die in to "bump" that shoulder datum down just the first little bit and chamber again while collecting the measurement data and taking notes. Continue till the dimension has changed just 0.001" - 0.002" (0.0254 - 0.0508 mm) . Along the way you may even find that the shoulder datum dimension climbs before it shrinks. This is not uncommon and depends on several variables including the brass and the chamber size compared to the die.

Once you have bumped that shoulder down as above, keep a record of the value and compare it to the earlier ones where the fired cases were still closing in the chamber without effort. You will eventually see them grow to the value and then get tight till they are bumped down where the bolt first closes easily.

You are just a few cycles short of getting a tight closure on those fired cases. It sometimes takes four or more cycles to establish the chamber size, but it can also happen in just two or three cycles depending on your brass, chamber, pressure, and luck.

ETA: Your concern about expander balls and mandrels also changing the shoulder datum on the case is not wrong. Expander balls being pulled back up can alter the shoulders in instances where there is too much cold working and not enough lube. An expander mandrel is less harsh, but you should also consider using lubrication to minimize the longitudinal force on the neck and shoulder. When done right, and expander mandrel will not significantly affect that shoulder length.

Good Luck and take lots of notes.

Great directions!!!

However, I take a case that has heavy bolt closing pressure and adjust the FL die down until there is light pressure!!! I use Redding dies with the Forester calibration lock rings in my 40 year old Bonanza Co-ax press!!! Lube the case body and neck with Bonanza case lube, turn down one more graduation on the lock ring, resize the case while making sure there is no press loading!! If the press shows loading, re-lube the case again and repeat the process!!! SET AND FORGET with this combination!!! I prefer half a thou to one bump back and have being doing that for 40 years on several different guns!! Cases last a long time doing this because there minimal expansion and stops brass from rolling into the neck with the shoulder tight inside the chamber!! I have never had a doughnut problem in cases fired over 15 times!!! I do break the rule of forums by inside neck reaming!!! Never had problems and accuracy improved by around 30% by reaming!!! I only ream cases that have been fully fire formed!!!

 

[Wild Bill IV]

To make this even more simple...
Since your once fired cases will still allow your bolt to close easy, and you have that data, you should try and use that data and that longer Lapua sample to establish your chamber size.

Being careful with that long Lapua case, since you only found one where the bolt doesn't want to close, carefully start with your FL die turned out where it has no effect and slowly approach the shoulder to try and catch the first sign of it changing the shoulder datum length.

Also use your chamber to verify that feel as well.

Using the very small changes slowly turn the die in to "bump" that shoulder datum down just the first little bit and chamber again while collecting the measurement data and taking notes. Continue till the dimension has changed just 0.001" - 0.002" (0.0254 - 0.0508 mm) . Along the way you may even find that the shoulder datum dimension climbs before it shrinks. This is not uncommon and depends on several variables including the brass and the chamber size compared to the die.

Once you have bumped that shoulder down as above, keep a record of the value and compare it to the earlier ones where the fired cases were still closing in the chamber without effort. You will eventually see them grow to the value and then get tight till they are bumped down where the bolt first closes easily.

You are just a few cycles short of getting a tight closure on those fired cases. It sometimes takes four or more cycles to establish the chamber size, but it can also happen in just two or three cycles depending on your brass, chamber, pressure, and luck.

ETA: Your concern about expander balls and mandrels also changing the shoulder datum on the case is not wrong. Expander balls being pulled back up can alter the shoulders in instances where there is too much cold working and not enough lube. An expander mandrel is less harsh, but you should also consider using lubrication to minimize the longitudinal force on the neck and shoulder. When done right, and expander mandrel will not significantly affect that shoulder length.

Good Luck and take lots of notes.

Great directions!!!

However, I take a case that has heavy bolt closing pressure and adjust the FL die down until there is light pressure!!! I use Redding dies with the Forester calibration lock rings in my 45 year old Bonanza Co-ax press!!! Lube the case body and neck with Bonanza case lube, turn down one more graduation on the lock ring, resize the case while making sure there is no press loading!! If the press shows loading, re-lube the case again and repeat the process!!! SET AND FORGET with this combination!!! I prefer half a thous to one bump back and have being doing that for 45 years on several different guns!! Cases last a long time doing this because there minimal expansion and stops brass from rolling into the neck with the shoulder tight inside the chamber!! I have never had a doughnut problem in cases fired over 15 times!!! I do break the rule of forums by inside neck reaming!!! Never had problems and accuracy improved by around 30% by reaming!!! I only ream cases that have been fully fire formed!!

I prefer the expander and use bushings that sizes the neck down to 0.001 or less than the expander diameter to reduce working the brass!!! One less operation and a time saver at the press!!! I use acetone in the garage to degrease the lube from the inside and outside of the formed cases!!! Dries quickly!! A couple hours in the sun, and they are ready to finish reloading!!!