Lee PrecisionMidSouth Shooters SupplyTitan ReloadingInline Fabrication
ADvertise hereRotoMetals2Repackbox

Page 1 of 2 12 LastLast
Results 1 to 20 of 35

Thread: .30-06 headspace

  1. #1
    Boolit Mold
    Join Date
    Sep 2020
    Posts
    4

    .30-06 headspace

    Hi folks! First time posting here. Getting ready to reload a bunch of brass for my son's .30-06. Hornady's headspace gauge measures the cases at 2.005. That's a fair bit less than max/min from the saami sheet. These are all fire-formed cases. Am I reading saami correctly? It shows, for the loaded case headspace: 2.0526-00.70, which means the minimum (if I'm reading it correctly is 2.0456. Actually, some of the cases only measure 2.000 and less. Any idea what the problem is here?

  2. #2
    Boolit Master

    Winger Ed.'s Avatar
    Join Date
    May 2007
    Location
    Just outside Gun Barrel City, Texas
    Posts
    3,105
    After I full length size .30-06, or other 'long necks', I trim to just a tiny little bit under the minimum length listed in a loading book.
    For the normal life of the case, I'll never need to trim again.
    If I do, I figure it has stretched so much the web is about ready to split anyway, and throw it away.

    Check out how short the 'grip range' is for the neck of a .300WinMag compared to the .30-06.
    If the .30-06 case is a little short, there's still plenty of neck left to hold the bullet even if the OAL is on the long side.

    It's more important for accuracy that they are all the same length.
    For safety- the big problem would be for cases that are too long.
    Splitting hairs on a few .000s case length for a .30-06 being too short is sort of over thinking it a little.
    Last edited by Winger Ed.; 09-16-2020 at 04:18 PM.
    FAIR WARNING:
    As often as not, I offer sarcasm rather than advice.

    It wasn't playing the blame game, finding fault, and complaining about every little thing that made America great.
    It was God, guns, and guts.

  3. #3
    Boolit Mold
    Join Date
    Sep 2020
    Posts
    4
    I get what you're saying, and the case trim length is good. It's the headspace, that comes under the minimum by .045 or more that I'm questioning.

  4. #4
    Boolit Grand Master



    M-Tecs's Avatar
    Join Date
    Apr 2008
    Location
    Minnesota
    Posts
    6,387
    If you are using the Lock-N-Load® Headspace Comparator https://www.hornady.com/headspace-bushings#!/ that is a comparator only unless used in conjunction with an standard such as an actual headspace gauge. Something like the RCBS Case Mic gives direct readings https://www.rcbs.com/case-prep/measu...n-mic/564.html

    Last edited by M-Tecs; 09-16-2020 at 05:14 PM.
    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
    – Amber Veal

    "The Highest form of ignorance is when your reject something you don't know anything about".
    - Wayne Dyer

  5. #5
    Boolit Master
    Join Date
    Mar 2005
    Posts
    4,583
    The Hornady gauge is chamfered on the edge of the datum bushings. This makes it read a few thousandths small when zeroed on the end of the bushing. So you cannot use the Hornady gauge to measure to the SAAMI dimensions unless you zero the caliper to a SAAMI headspace gauge.

    For easy use of the Hornady gauge measure your once fired case and size all cases so they are a drag fit when the bolt turns down in a bolt gun. If you are loading for a pump, auto loader or a lever gun you need to push the shoulder back .002 to .003 on each and every case. Use your gun for the standard and use the Hornady gauge to compare each sized case to the gun.

    For the most consistent shoulder location size each case slowly
    Then retract the case about 1/2 inch and turn it 120 degrees and size it slowly again. Repeat a third time.

    All the slow repeated sizing does is give the brass time to flow to exactly the same location every time. If you don't believe me just slam through several hundred cases and then measure them with the Hornady gauge. They will be all over the place and some will require you to turn the bolt down with a lot of force.
    EDG

  6. #6
    Boolit Master
    dtknowles's Avatar
    Join Date
    Jan 2010
    Location
    Southeast Louisiana
    Posts
    3,628
    Quote Originally Posted by johnfg View Post
    Hi folks! First time posting here. Getting ready to reload a bunch of brass for my son's .30-06. Hornady's headspace gauge measures the cases at 2.005. That's a fair bit less than max/min from the saami sheet. These are all fire-formed cases. Am I reading saami correctly? It shows, for the loaded case headspace: 2.0526-00.70, which means the minimum (if I'm reading it correctly is 2.0456. Actually, some of the cases only measure 2.000 and less. Any idea what the problem is here?
    Do you have the decimal in the wrong place in the tolerance and what is the the heck with 4 decimal places? Your measuring must be better than mine. I trust maybe half a thou but not the nearest 10 thou. I think your brass is fine but others will tell you how you can make it tighter. Different amounts of lube and different brass stiffness can lead to different amounts of sizing. What press are you using and how do you adjust you sizing die. Did you check a fired round, did you check a factory round. Too little data. How do you know your tool is any good?

    This from an old post. http://castboolits.gunloads.com/arch...p/t-29757.html


    When reading Hatcher's Notebook he gives the headspace for the 30-06 as minimum of 1.942" and the field of 1.950".... Current Forster SAAMI spec gauges are 2.049" GO and 2.058" Field. The difference between the Min/GO and Field is 0.008" for both. It looks to me as if the numbers from Hatcher were to the beginning of the shoulder rather than a mid point of the shoulder. If you subtract the rim thickness of 0.049" the numbers do not match. I have tried the math several different ways and can not come up with something that makes sense to me

    commercial .30'06 and mil .30'06 are measured differently.

    maybe he confused the two, or misspoke on one, or did not know there was a difference.

    saami is 2.0487 min and 2.0587 max.

    moving from 4 to 3 significant digits may have led to part of the problem also.
    Words are weapons sharper than knives - INXS

    The pen is mightier than the sword - Edward Bulwer-Lytton

    The tongue is mightier than the blade - Euripides

  7. #7
    Boolit Master uscra112's Avatar
    Join Date
    Jun 2006
    Location
    Switzerland of Ohio
    Posts
    3,690
    What M-tecs said. Lacking an actual headspace gage, you could use a fresh factory round.

    How do the cases fit your gun? The old dodge of stacking bits of tape onto the base of a case until it causes the bolt to drag on closing is not a bad idea. 'Course that doesn't work to well with a semi-auto.

    If you've got fired cases that are significantly short on the base-to-shoulder dimension, it's very likely that they've been fired with light loads, which can push the shoulder back leaving a dangerous headspace condition. There's ways of salvaging such cases, but .30-06 brass is so plentiful that it's easier to just scrap 'em.
    Last edited by uscra112; 09-17-2020 at 02:35 AM.
    Eleutheromaniac

  8. #8
    Boolit Master
    dtknowles's Avatar
    Join Date
    Jan 2010
    Location
    Southeast Louisiana
    Posts
    3,628
    Factory ammo needs to have shorter headspace than the minimum chamber or it would not fit tight guns. Same with reloading dies or they would leave brass too long for some guns and you would have to grind off the bottom of the dies if your gun had a minimum chamber.

    Tim
    Words are weapons sharper than knives - INXS

    The pen is mightier than the sword - Edward Bulwer-Lytton

    The tongue is mightier than the blade - Euripides

  9. #9
    Boolit Master
    Join Date
    Feb 2008
    Location
    Eureka MT
    Posts
    1,388
    Head space is the distance between the bolt face and the rear of the case when the bolt is closed and the case is pushed all the way to the front of the chamber. Somewhere around .002/.003 is a good number to go for when cutting a new chamber.

    How long your case should be from base to datum line depends on what your actual head space is. If you have fire formed cases from the gun in question, your head space should be .000 to maybe .001. So, size the cases until the neck is sized as close as you can to the shoulder without actually pushing back the shoulder and you will have .000/.001
    Sooner or later you will have to lightly set the shoulder back .001/.002 to keep from having very tight chambering of a loaded round.
    Factory head space is normally in the .002/.006 range but fire forming stretches the case so you end up with very little head space unless you shorten the case with a FL sizer set to stop against the shell holder. I don't care much about my base to datum line distance as a fireformed case fits about as good as you could want and I don't size that good fit from my cases.

  10. #10
    Boolit Mold
    Join Date
    Sep 2020
    Posts
    4
    Lots of good information guys and good ideas. I'm gonna crash, but will give you a bit more info tomorrow. I am using a Hornady LNL single stage with their best dies. However, I've also been using the Lee necksizing collett dies, and their factory crimp die. Not light loads, but usually not max either. Closer to the max than the minimum loads. One other thing I've just started doing for a .270 win and .308 win, both Winchester bolt actions, is using CBTO vs. COAL, and am hoping to improve accuracy. That's all for now. thanks for the interaction!

  11. #11
    Boolit Master
    Join Date
    Sep 2010
    Location
    Australia
    Posts
    1,057
    I load for a 375 Whelen and in the early days had head space problems which I traced to a bad custom die. When I full length size any bottle neck case, I never size it all the way I leave a small amount of the neck at the shoulder unsized, as long as that case is used in the chamber that fire formed it I never have a head space problem, unless of cause I was to load a very reduced load as has been mentioned. Regards Stephen

  12. #12
    Boolit Master Jedman's Avatar
    Join Date
    Nov 2014
    Location
    NW OH Oak Openings Area
    Posts
    742
    Johnfg, If you have the rifle that you are loading the ammo for try just priming a case that has been sized and fire it in the rifle. Then check the primer to see if it is flush or if it is protruding from the bottom of the case. If you have a protruding primer you have excess headspace. No matter what action type the rifle is it should be held close enough that the case can’t move forward enough to allow the primer to blow back against the bolt and remain proud when extracted.
    I am of course talking a empty primed case here.

    Jedman

  13. #13
    Boolit Mold
    Join Date
    Sep 2020
    Posts
    4
    I don't always (usually not) look at SAAMI when I'm reloading, but thought I'd check my 2 .308 Wins, and .270 Win against it. All of them measure *under* the SAAMI minimums. Which I guess just demonstrates that the Hornady headspace gauge is not that accurate. It does however provide consistent measurements for what it is.

  14. #14
    Boolit Grand Master



    M-Tecs's Avatar
    Join Date
    Apr 2008
    Location
    Minnesota
    Posts
    6,387
    Quote Originally Posted by johnfg View Post
    I don't always (usually not) look at SAAMI when I'm reloading, but thought I'd check my 2 .308 Wins, and .270 Win against it. All of them measure *under* the SAAMI minimums. Which I guess just demonstrates that the Hornady headspace gauge is not that accurate. It does however provide consistent measurements for what it is.
    The Hornady Headspace Comparator does exactly what it is claimed to do and it does it very well. Hornady calls it a COMPARATOR for a reason. It was not designed as a direct measurement tool unless used in conjunction with a actual standard like a headspace gauge. If you want direct measurements get a headspace gauge to zero your comparator or get the RCBS case mic. That does give direct measurements.

    https://www.keyence.com/ss/products/...sic/method.jsp

    https://extrudesign.com/comparator-types-uses/
    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
    – Amber Veal

    "The Highest form of ignorance is when your reject something you don't know anything about".
    - Wayne Dyer

  15. #15
    Boolit Master
    dtknowles's Avatar
    Join Date
    Jan 2010
    Location
    Southeast Louisiana
    Posts
    3,628
    Quote Originally Posted by johnfg View Post
    I don't always (usually not) look at SAAMI when I'm reloading, but thought I'd check my 2 .308 Wins, and .270 Win against it. All of them measure *under* the SAAMI minimums. Which I guess just demonstrates that the Hornady headspace gauge is not that accurate. It does however provide consistent measurements for what it is.
    Ammo not custom sized to match your chamber will need to be under SAAMI minimums to work in all guns as some could have a SAAMI minimum chamber.
    Words are weapons sharper than knives - INXS

    The pen is mightier than the sword - Edward Bulwer-Lytton

    The tongue is mightier than the blade - Euripides

  16. #16
    Boolit Master Tripplebeards's Avatar
    Join Date
    Apr 2017
    Location
    WI
    Posts
    3,789
    I measure a few fired cases out my gun I’m loading for with my hornady comparator gauge and then go off that particular measurement to bump back accordingly. To be honest I have just followed RCBS instructions for the last 20 years and turned my FLSD a 1/4” lower after it touches my shell holder. I have had excellent accuracy and long case life in all my rifles doing so. Guess I’ve been lucky all these years. I bought the comparator last year to measure my fired case in a 243 AR10. I wanted to make sure the shoulders were bumped backed. I used ammo I had loaded long for another rifle and stuck one on the chamber. I wanted to make sure I had all my bases covered so I bought the Hornady comparator. It’s come in handy for my 35 Remington 336 in the last couple of months. Another one of my guns that needs close tolerance head spacing for reliable ignition.
    Last edited by Tripplebeards; 09-17-2020 at 11:44 PM.

  17. #17
    Boolit Master
    Join Date
    Sep 2016
    Posts
    1,624
    When I had my 1903A3 barrel replaced I asked the smith if he couldset the headspace with two different bolts. One was a standard 03A3 bolt and the other was a 1903A4 bolt bubba had reground the curved section of the bolt for a low mounted scope. Both bolts headspace perfectly.
    However with the U.S. Model of 1917 one has to remember that the bolt lugs were made using a helix or curved lead in section of the bolt. This gives the bolt tremendous camming power and can cause damage to the chamber when using a headspace guage. Strip the bolt, feed the guage into the chamber and gently close the bolt until you feel it stop.Go no further. The bolt handle should not be in the cutout for the bolt handle. This is for a no-go guage. If it does start looking for a replacement bolt or set the barrel back and rechamber. Frank

  18. #18
    Boolit Master Tripplebeards's Avatar
    Join Date
    Apr 2017
    Location
    WI
    Posts
    3,789
    Quote Originally Posted by samari46 View Post
    When I had my 1903A3 barrel replaced I asked the smith if he couldset the headspace with two different bolts. One was a standard 03A3 bolt and the other was a 1903A4 bolt bubba had reground the curved section of the bolt for a low mounted scope. Both bolts headspace perfectly.
    However with the U.S. Model of 1917 one has to remember that the bolt lugs were made using a helix or curved lead in section of the bolt. This gives the bolt tremendous camming power and can cause damage to the chamber when using a headspace guage. Strip the bolt, feed the guage into the chamber and gently close the bolt until you feel it stop.Go no further. The bolt handle should not be in the cutout for the bolt handle. This is for a no-go guage. If it does start looking for a replacement bolt or set the barrel back and rechamber. Frank

    I bought a bent bolt handle for my now long gone 1903 a few decades ago from cheaper then dirt. I had a Gunsmith check the headspace and it was fine without any modifications. I ground the bend in the bolt lever And polished it. It turned out out really nice. Looked like a modern bolt when I finished.
    Last edited by Tripplebeards; 09-19-2020 at 10:25 AM. Reason: Spelling

  19. #19
    Boolit Master
    Join Date
    Feb 2007
    Location
    South Western NC
    Posts
    2,628
    Sizing to SAAMI specs is fine if you want to duplicate ammo that will fit/work in any chamber. But I only reload ammo for me, not everyone else, so I size my cases to closely fit MY chambers.

    Fired cases not only spring back a thou or so in diameter, they spring back in shoulder length (headspace) too. I size my bottle neck cases to match the fired shoulder length; that gives me a thou or two of slack (headspace) to insure easy chambering. Comparators like Hornady's and RCBS' makes that easy to do and that's all I need to know so I couldn't care less what the exact headspace is.

  20. #20
    Boolit Master
    Join Date
    May 2013
    Location
    Eastern WY
    Posts
    1,055
    For full-length sizing, I uae the Redding Competition Shell holders. They provide repeatable sizing, +.002 Thru +.010, with most full-length sizers. I start with the largest that will chamber easily. You can go up .002 if you want to 'feel' the case against the bolt when the action closes. I shoot Savage 99's , the Redding shell holders allow me to decide for a slight feel for the range and long case life or an 'easier fit when smooth chambering with no resistance is needed. I have the gauges but the Redding Competition shell holders allow more consistent results than turning dies to set the shoulder. I can record the shell holder (+.004, +.008 ?) for a rifle and avoid several dies in the same caliber adjusted for different rifles. Select the proper length shell holder for a rifle with a solid bump against the full length sizing die and get the shoulder where you want it.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check