Go Back   Alberta Outdoorsmen Forum > Main Category > Guns & Ammo Discussion

Reply
 
Thread Tools Display Modes
  #1  
Old 12-15-2018, 09:06 PM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default 7mm-08 headspace measurement

Does anyone have the printed headspace length measurement for the 7mm-08 case? I bought the hornady headspace comparator and it is not mentioned in my nosler reloading book. Thanks
Reply With Quote
  #2  
Old 12-15-2018, 10:22 PM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

What is it you are trying to accomplish?
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #3  
Old 12-15-2018, 10:33 PM
warriorboy10 warriorboy10 is offline
 
Join Date: Jun 2007
Posts: 1,047
Default

You have the comparator! Do you have the 7mm-08 modified case and bullet seating depth gauge? That is what is needed, then you figure out your exact headspace using your bullet with the bullet jump that you want.
You want the headspace for that particular chamber and can be different for different types of the bullets ogive.
Reply With Quote
  #4  
Old 12-15-2018, 11:02 PM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default

I'm fitting my cases so they snug up in my chamber and want to see where I am compared to the specs.
Reply With Quote
  #5  
Old 12-16-2018, 08:01 AM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

Just out of curiosity?
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #6  
Old 12-16-2018, 08:13 AM
Dick284's Avatar
Dick284 Dick284 is online now
 
Join Date: May 2007
Location: Dreadful Valley
Posts: 14,585
Default

Quote:
Originally Posted by Savage Bacon View Post
I'm fitting my cases so they snug up in my chamber and want to see where I am compared to the specs.
Its admirable that you are curious as to where your rifles headspace is set, but let’s face it the exercise is pretty much pointless, as the headspace is what it is, unless you want to set your barrel back, and re do the headspace.

After your first firing your brass is set to your rifles headspace.

Determine your headspace and set your dies to manage your brass accordingly.
__________________


There are no absolutes
Reply With Quote
  #7  
Old 12-16-2018, 09:05 AM
qwert qwert is offline
 
Join Date: Jan 2012
Posts: 2,443
Default

Quote:
Originally Posted by Savage Bacon View Post
Does anyone have the printed headspace length measurement for the 7mm-08 case? I bought the hornady headspace comparator and it is not mentioned in my nosler reloading book. Thanks
https://saami.org/technical-informat...ami-standards/

https://saami.org/wp-content/uploads...-SAAMI_CFR.pdf
see page 50

The SAAMI 7-08R datum dia is .400", and case base to datum dimension = 1.634 (+.000-.007").
The .007" allowable spec tolerance is a LOT larger than typically recommended case shoulder bump for best accuracy and case life.
Practically, I agree with post #6. as suggested procedure can best manage SAAMI allowable chamber variation.

Headspace comparators are very useful to provide a 'relative' measurement, but IMHE are not accurate enough to properly measure 'absolute' head-space. A proper solid head-space GO gauge is much more accurate, and can be used to calibrate a comparator, and measure an actual chamber.

The Hornady comparator bushings have a square SAAMI datum sized shoulder, and can measure CBTD directly, but they are soft aluminum and can easily lose accuracy.
The Sinclair case bushings have a bevel matching the shoulder angle, and are made of much harder material.
IMHE, both require calibration against a solid GO gauge if an 'absolute' measurement is required, but for reloading purposes a 'relative' measurement is more useful, as we need to fit the resized case to the actual chamber, and not the spec dimension.

Good Luck, YMMV.
Reply With Quote
  #8  
Old 12-16-2018, 10:40 AM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default

Thanks qwert. My once fired cases all measure between 1.619 and 1.621. With the majority being 1.620. Shorter than the 1.634 - .007 spec. I guess I will leave the shoulders alone and recheck after they are twice fired. I know the saami spec is not perfectly dead on to "my" chamber. I just wanted to see where I am in comparison to that number. Yes just out of curiosity. Thanks again
Reply With Quote
  #9  
Old 12-16-2018, 12:11 PM
303carbine 303carbine is offline
 
Join Date: Aug 2008
Location: Vancouver Island ,BC
Posts: 714
Default

Quote:
Originally Posted by Savage Bacon View Post
I'm fitting my cases so they snug up in my chamber and want to see where I am compared to the specs.

Most chambers are going to be a bit different, fire forming and neck sizing for your rifle is the best way to go.
Reply With Quote
  #10  
Old 12-16-2018, 12:58 PM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default

So should I now write down my 1.620 and always come back to this measurement? It's hard to tell when the bolt starts to get some resistance because it cocks on bolt close. These cases will only be used in this rifle.
Reply With Quote
  #11  
Old 12-16-2018, 01:04 PM
qwert qwert is offline
 
Join Date: Jan 2012
Posts: 2,443
Default

Quote:
Originally Posted by Savage Bacon View Post
Thanks qwert. My once fired cases all measure between 1.619 and 1.621. With the majority being 1.620. Shorter than the 1.634 - .007 spec. I guess I will leave the shoulders alone and recheck after they are twice fired. I know the saami spec is not perfectly dead on to "my" chamber. I just wanted to see where I am in comparison to that number. Yes just out of curiosity. Thanks again
IMHO, your ‘curiosity’ is a worthwhile exercise, well worth the time and effort of self-training. All new tools require familiarization to learn their individual peculiarities, accuracy, and usefulness, many tools perform very well in ‘off label’ usage and intended market. Once familiar with the abilities and achievable accuracy, results of other use will be easier to evaluate.

I do suggest you obtain a quality, solid, .08Win head-space GO gauge; it will gauge all the .08Win family.
Use it to calibrate your comparator & bushing, and accurately measure your individual chamber using various thickness tape applied to the base of the gauge. (IMHO, this is more accurate than the 2 gauge GO/NO GO procedure, which is more suitable for a production environment)

Compare your measured chamber with a case before and after fire-forming in your chamber, the difference is (probably) ‘spring-back’ which can vary with case hardness and other factors.
Then use the comparator to set your sizing die adjustment to partially resize the case for desired shoulder bump & fit in your chamber, (expect similar case ‘spring-back’ to occur).
Log your results for future use and comparison.

Good Luck, YMMV.
Reply With Quote
  #12  
Old 12-16-2018, 01:22 PM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default

The GO gauge is next on my list. Thanks again for your help. I'm loging all of the measurements and will start comparing after they're fired again. I agree that my experience will benefit from doing the extra work now so I definitely don't mind being particular and going the extra mile. It is a learning experience trying to tune this thing in that's for sure.
Reply With Quote
  #13  
Old 12-16-2018, 01:32 PM
qwert qwert is offline
 
Join Date: Jan 2012
Posts: 2,443
Default

Quote:
Originally Posted by Savage Bacon View Post
The GO gauge is next on my list. Thanks again for your help. I'm loging all of the measurements and will start comparing after they're fired again. I agree that my experience will benefit from doing the extra work now so I definitely don't mind being particular and going the extra mile. It is a learning experience trying to tune this thing in that's for sure.
Welcome to the affliction.

IMHO, use of proper measuring tools facilitates consistency & repeat-ability, which are the fundamentals of precision.

Good Luck, YMMV
Reply With Quote
  #14  
Old 12-16-2018, 01:40 PM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

Quote:
Originally Posted by 303carbine View Post
Most chambers are going to be a bit different, fire forming and neck sizing for your rifle is the best way to go.
No, it isn’t. FL resizing while in control of headspace is.
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #15  
Old 12-16-2018, 01:51 PM
Full Curl Earl Full Curl Earl is offline
 
Join Date: Jun 2007
Location: Northern Alberta
Posts: 1,704
Default Agree

I agree. But this thread will go sideways if we open that up. Lol
QUOTE=303carbine;3894267]Most chambers are going to be a bit different, fire forming and neck sizing for your rifle is the best way to go.[/QUOTE]
Reply With Quote
  #16  
Old 12-16-2018, 02:36 PM
qwert qwert is offline
 
Join Date: Jan 2012
Posts: 2,443
Default

Quote:
Originally Posted by Savage Bacon View Post
Thanks qwert. My once fired cases all measure between 1.619 and 1.621. With the majority being 1.620. Shorter than the 1.634 - .007 spec.
snip
Your comparator may be returning a lower than expected result due to the size or shape of the datum contact edge of the bushing.
If it is not perfectly square (or over spec diameter) it will under-report, and illustrates the possible inaccuracy of using an un-calibrated comparator.

Good Luck, YMMV.
Reply With Quote
  #17  
Old 12-16-2018, 03:13 PM
Savage Bacon's Avatar
Savage Bacon Savage Bacon is offline
 
Join Date: Oct 2017
Location: Calgary-Red Deer area
Posts: 3,205
Default

Do I calibrate it with the GO gauge and find my comparators zero from the GO gauges spec?
Reply With Quote
  #18  
Old 12-16-2018, 05:14 PM
qwert qwert is offline
 
Join Date: Jan 2012
Posts: 2,443
Default

Quote:
Originally Posted by Savage Bacon View Post
Do I calibrate it with the GO gauge and find my comparators zero from the GO gauges spec?
There are several possible procedures and methods, but the solid GO gauge provides a way to measure the comparator indicated error, which can then be added to or subtracted from indicated to obtain true value.

Alternatively, it may be possible to zero @ the value of the indicated error and true value read directly, without requiring further calculation.

Caution, it is easy to get + & - values confused.

Good Luck, YMMV.
Reply With Quote
  #19  
Old 12-16-2018, 05:33 PM
Nyksta Nyksta is offline
 
Join Date: Dec 2014
Location: Calgary
Posts: 1,543
Default

Quote:
Originally Posted by chuck View Post
No, it isn’t. FL resizing while in control of headspace is.
I agree. Neck sizing only works a couple times before needing a full length size, and now you have a new situation for your load. Full length sizing keeps it consistent.
Reply With Quote
  #20  
Old 12-16-2018, 09:20 PM
303carbine 303carbine is offline
 
Join Date: Aug 2008
Location: Vancouver Island ,BC
Posts: 714
Default

Quote:
Originally Posted by Nyksta View Post
I agree. Neck sizing only works a couple times before needing a full length size, and now you have a new situation for your load. Full length sizing keeps it consistent.
Neck sizing has always worked best for me, about every five firings, I will FL and anneal the brass.
Reply With Quote
  #21  
Old 12-16-2018, 10:13 PM
REMINGTON JIM REMINGTON JIM is offline
 
Join Date: Apr 2010
Location: Kamloops BC
Posts: 270
Default

Quote:
Originally Posted by chuck View Post
No, it isn’t. FL resizing while in control of headspace is.
Why you say that Chuck ? don't like Neck sizing only ? Can you Explain ? RJ
__________________
The 284 WIN - is the Original Short Magnum !
Reply With Quote
  #22  
Old 12-16-2018, 10:15 PM
REMINGTON JIM REMINGTON JIM is offline
 
Join Date: Apr 2010
Location: Kamloops BC
Posts: 270
Default

Quote:
Originally Posted by Nyksta View Post
I agree. Neck sizing only works a couple times before needing a full length size, and now you have a new situation for your load. Full length sizing keeps it consistent.
Not ALWAYS It depends on how HOT ? PRESSURE your loads are ! RJ
__________________
The 284 WIN - is the Original Short Magnum !
Reply With Quote
  #23  
Old 12-17-2018, 06:33 AM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

Quote:
Originally Posted by REMINGTON JIM View Post
Why you say that Chuck ? don't like Neck sizing only ? Can you Explain ? RJ
It’s simple. Neck sizing provides no advantages in accuracy, it messed with consistency, and creates issues with chambering and extraction.
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #24  
Old 12-17-2018, 06:46 AM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

A quick search found this. Start watching at 11:20.

https://youtu.be/ZrTKhVPPi34
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #25  
Old 12-17-2018, 08:24 AM
DLab DLab is offline
Shooting Xs
 
Join Date: Sep 2009
Location: Medicine Hat
Posts: 836
Default

Quote:
Originally Posted by chuck View Post
It’s simple. Neck sizing provides no advantages in accuracy, it messed with consistency, and creates issues with chambering and extraction.
Yup, my opinion also,from my own experience with NS only.
I FL size ,button or bushing dies depending on the cartridge.
Reply With Quote
  #26  
Old 12-17-2018, 12:09 PM
lclund1946 lclund1946 is offline
Banned
 
Join Date: Apr 2010
Location: Rimbey, AB
Posts: 671
Default

]
Quote:
Originally Posted by REMINGTON JIM View Post
Not ALWAYS It depends on how HOT ? PRESSURE your loads are ! RJ
It is true that it depends on pressure that your load is loaded to. I loaded for the 7mm08 for many years by fire forming Remington brass with a load using Varget and a Speer 110 HP. I needed the extra case capacity of a Neck Sized case and had a couple of very accurate loads using this method. The secret is to work up the fire forming load so that the brass does not stretch past 0.4703" or Saami MAX CARTRIDGE DIMENSION at the 0.200" Datum line. Preferably the pressures of the fire forming load should be 0.001" under that, like most factory loads, as a FL die will likely just barely size the Base datum if you decide to FL size.

If you neck size then your load should be developed with only enough pressure as to not exceed the Saami Max Cartridge dimension of 0.4703" and then that dimension will not increase with subsequent firings as there will be at least 0.001" clearance at the base datum. The pressures will likely be low enough that there is good spring back at the shoulder as well. You may never have to FL size the brass.


As Chuck pointed out the preferred method is FL sizing as described in the video. If you FL size it is possible that brass will not be fully, fireformed to the Shoulder Datum at 0.400", on Factory rounds or properly designed fire forming load. Set your FL die by running it to the shell holder and back out one turn then size a brass and see if it will re chamber. If it does then reload and fire again and FL with die set out. If it does not fit back in then screw the die down in 1/8-1/4 turn increments until the bolt closes on it. Removing the Firing pin and Plunger Extractor help in getting this fine tuned. Once the bolt closes snugly, on the FL sized round, you can use your comparator to record the HS dimension for your rifle. It can then be used to get whatever HS clearance you want which I believe need be no more than 0.001". Your initial load, developed on the first FL sized case, may or may not require further tweaking but you are good to go for many firings on whatever brass you choose.
Reply With Quote
  #27  
Old 12-17-2018, 05:02 PM
303carbine 303carbine is offline
 
Join Date: Aug 2008
Location: Vancouver Island ,BC
Posts: 714
Default

Quote:
Originally Posted by chuck View Post
No, it isn’t. FL resizing while in control of headspace is.
Neck sized brass will give the best fit for the rifle it was fired from, headspace should be perfect after a trim if needed.
Reply With Quote
  #28  
Old 12-17-2018, 06:13 PM
warriorboy10 warriorboy10 is offline
 
Join Date: Jun 2007
Posts: 1,047
Default

Quote:
Originally Posted by chuck View Post
It’s simple. Neck sizing provides no advantages in accuracy, it messed with consistency, and creates issues with chambering and extraction.
Agreed!

These are the facts, not an opinion!
Reply With Quote
  #29  
Old 12-17-2018, 06:21 PM
Pathfinder76 Pathfinder76 is online now
 
Join Date: May 2007
Posts: 15,768
Default

Quote:
Originally Posted by 303carbine View Post
Neck sized brass will give the best fit for the rifle it was fired from, headspace should be perfect after a trim if needed.
No thanks.
__________________
“I love it when clients bring Berger bullets. It means I get to kill the bear.”

-Billy Molls
Reply With Quote
  #30  
Old 12-17-2018, 08:04 PM
REMINGTON JIM REMINGTON JIM is offline
 
Join Date: Apr 2010
Location: Kamloops BC
Posts: 270
Default

Quote:
Originally Posted by 303carbine View Post
Neck sized brass will give the best fit for the rifle it was fired from, headspace should be perfect after a trim if needed.
YUP Then when u load and fire it only the neck expands - Its actually A simple concept ! RJ
__________________
The 284 WIN - is the Original Short Magnum !
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 07:44 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.