Headspace

Something been on your mind that you have always wanted to ask and google is no help. Ask it here!
User avatar
daboone
Founding Member
Founding Member
Posts: 1397
Joined: 30 Nov 2013 21:47
My Press Choice: Single Stage
Location: AZ, TX, HI
Has thanked: 677 times
Been thanked: 787 times

Headspace

Post by daboone »

Not really a question this time but this is an excellent video to start a discussion on a much discussed, questioned and misunderstood subject

One of the most important problems in any technical subject is nomenclature. This is a cut and paste quote that is simplistic but excellent. "Just in case you didn't know, the head of the cartridge is the back end. The front, where the bullet is, is the mouth, while the back, where the markings are, is the head. That's why the markings are called "headstamps". "



[BBvideo 560,340][/BBvideo]
An ignorant person is one who doesn't know what you have just found out.

When setting a job up for myself it must be Idiot Proof as well, as I am a bigger idiot than most people I know, and I prove it to myself everyday.
mikld
Founding Member & Supporter
Founding Member & Supporter
Posts: 674
Joined: 30 Jun 2013 09:30
My Press Choice: Turret
Location: S. Oregun
Has thanked: 203 times
Been thanked: 371 times

Re: Headspace

Post by mikld »

Thanks daboone. This is a good video and explanation of headspace...
User avatar
daboone
Founding Member
Founding Member
Posts: 1397
Joined: 30 Nov 2013 21:47
My Press Choice: Single Stage
Location: AZ, TX, HI
Has thanked: 677 times
Been thanked: 787 times

Re: Headspace

Post by daboone »

mikld wrote:Thanks daboone. This is a good video and explanation of headspace...
As I mentioned the explanation of headspace was a cut and paste. But as Einstein once said (approximately) "If you can't explain it to a 6 year old, you don't understand it.) So it's better I did the cut and paste. :D
An ignorant person is one who doesn't know what you have just found out.

When setting a job up for myself it must be Idiot Proof as well, as I am a bigger idiot than most people I know, and I prove it to myself everyday.
larryw
Founding Member & Supporter
Founding Member & Supporter
Posts: 1123
Joined: 20 Dec 2013 11:09
My Press Choice: Single Stage
Location: Arizona
Location: Arizona
Has thanked: 688 times
Been thanked: 327 times

Re: Headspace

Post by larryw »

Good cut & paste for an old goat :):)
Head space sure does seem to perplex a lot of folks. "Most times" it's not the giant problem
Its maybe out to be but, if it is really bad it can create a very bad & dangerous situation. if it is a problem it can be taken care in several ways.
In extreme cases, unscrew the barrel & recut the chamber, or shim it, or recut the breech face.
Some old rifles like old military Enfields have different size bolt faces you can change out.
Last but not least, my favorite. Get new brass, die form it ( false shoulder method )
Light to med load, fire form, neck size only until they get a bit hard to chamber, then, &
Only then bump the shoulder back just a hair. You now have perfectly, custom fit brass
For one particular firearm, headspace problem gone 80 - 90% of the time.
A day late & A dollar short? Story of my life +guns
horseman
Supporter
Supporter
Posts: 994
Joined: 09 Nov 2015 06:35
My Press Choice: Single Stage
Location: Washington State
Has thanked: 37 times
Been thanked: 274 times

Re: Headspace

Post by horseman »

Pretty good video Dan. Thanks for that. Not to nit-pick because I'm sure the guy doing the video knows way more about the subject than I do but I do question the "you should always just neck size brass fired from your rifle"....kinda thought we had gone "full circle" on that one to where "bump sizing" is now maybe the better thing to do. I'm still a bit up in the air between the two. I like Larry's "how to" also.
User avatar
daboone
Founding Member
Founding Member
Posts: 1397
Joined: 30 Nov 2013 21:47
My Press Choice: Single Stage
Location: AZ, TX, HI
Has thanked: 677 times
Been thanked: 787 times

Re: Headspace

Post by daboone »

I'm just not that interested in sub MOA shooting to get concerned with specialized dies for shoulder setback. For my bolts guns the Lee Collet dies have improved the accuracy of my milsurps. I still full length size after 3 to 4 firings.
However because I'm shooting mostly milsurps it is necessary to understand the possibility of headspace problems. Being able to diagnose a potential problem by fired case examination is a healthy exercise. I keep a "paperclip tool" to check for headcase separation.
Image
An ignorant person is one who doesn't know what you have just found out.

When setting a job up for myself it must be Idiot Proof as well, as I am a bigger idiot than most people I know, and I prove it to myself everyday.
cj8281
250 Shots
250 Shots
Posts: 255
Joined: 03 Jan 2017 10:58
My Press Choice: Turret
Location: Utah
Has thanked: 56 times
Been thanked: 85 times

Re: Headspace

Post by cj8281 »

That is a lot like what my friend explained to me many years ago with my 30-30 when I first started loading for it. The die set that I had was moving the shoulder back on my fired brass a lot. By sizing it that way, I never had an issue with loading or extraction on my lever gun.
horseman
Supporter
Supporter
Posts: 994
Joined: 09 Nov 2015 06:35
My Press Choice: Single Stage
Location: Washington State
Has thanked: 37 times
Been thanked: 274 times

Re: Headspace

Post by horseman »

I'm also not that concerned about "bughole" shooting either Dan. The fact is in these day's when everyone on a shooting forum seem to be able to shoot groups that would make Carlos Hathcock hide his face in shame I'm obviously a really poor shot anyway. "Bumping" the shoulder a couple thou using a standard size die (brass from my rifles) to me is just to make sure the round will chamber easily and not "over work" the brass. Am I missing something here? My limited knowledge has me thinking that using a body die in conjunction with a neck die like the Lee collet die would really be the ticket for the utmost in accuracy, providing "proper" brass prep is done. :?:
larryw
Founding Member & Supporter
Founding Member & Supporter
Posts: 1123
Joined: 20 Dec 2013 11:09
My Press Choice: Single Stage
Location: Arizona
Location: Arizona
Has thanked: 688 times
Been thanked: 327 times

Re: Headspace

Post by larryw »

I agree, like I said, it is "most times" a non issue for us average everyday hunters & shooters.
That is, unless It's so bad that you are getting the bright ring of death with only one or two
trigger pulls. Had an old jungle carbine 303! Factory ammo or landlords with new brass.
One trigger pull brass was done, verified with paperclip tool.
So, unless it's bad, prep load, shoot, repeat...
A day late & A dollar short? Story of my life +guns
User avatar
Ranch Dog
Site Admin
Site Admin
Posts: 6456
Joined: 22 Jun 2013 17:16
My Press Choice: Progressive
Location: Inez, TX
Has thanked: 1616 times
Been thanked: 2850 times

Re: Headspace

Post by Ranch Dog »

Thanks for the topic and video! With my bolt guns, I'm a Pacesetter (full-length sizer) and Collet die sizer as some others. My bolt guns; 30-30 Win, 300 Sav, 308 Win, 7.62x39, 303 British, and 35 Rem seem to require the full length sizing on about a one out of three or four cycle. Most of these rifles are shooting max loads so it is usually three cycles of the brass unless that included incremental loads working up to a max load. I know its time because the bolt is getting a bit stiff seating the cartridge above the web. At that point, worry the adjustment of a full-length sizing die is a mute point because it is the south end of the cartridge that needs the sizing and the seating die is going to need to make shell holder contact (as in Lee's instructions) to correct the issue.

This need to full length resize also determines the cycle that I anneal my brass. That task is done prior to the full-length sizing requirement.

I shoot a huge amount of rimmed cartridges, 18 different ones, and I use what the bolt guns have taught me as to how often I anneal them. Every third cycle seems to work out real good.

If you have a cartridge and wonder just exactly where the headspace measurement is taken, just look for the on the SAAMI cartridge and chamber drawings. Say what? You don't have that drawing? Google "SAAMI cartridge name", download the drawing, and print it out as a reference. Only SAAMI listed cartridges are available, proprietary cartridges are not.
Michael
Image
Post Reply

Return to “Question Of The Month”