Head space

[bigedp51]

airaddict

Below is the SAAMI drawing for chamber dimensions for the .308 Winchester.

The drawing below shows a minimum chamber headspace of 1.630 and a maximum of 1.640 (GO and Field Max)

http://i122.photobucket.com/albums/o254/bigedp51/308-ajpg.jpg

Below are the SAAMI drawing for cartridges manufacturing tolerances, "PLEASE" notice that the maximum cartridge length is 1.634 and that is .004 "LONGER" than the GO gage at 1.630. The last batch of new unfired .308 cases I purchased were from 1.628 to 1.623 so during manufacture they try and keep the cartridges below or shorter than minimum headspace.

http://i122.photobucket.com/albums/o254/bigedp51/308-bjpg.jpg

The GO gage is 1.630 and the NO-GO gage is 1.634 therefore even .001 to .002 over GO or 1.630 will ensure any cartridge case will chamber, "AND" you still can fireform your case to a perfect fit to your chamber. If you set your headspace too tight you run the chance your full length resizing dies will not resize your cases small enough or push your shoulder back .002 under your rifles headspace setting.

My Stevens 200 came from the factory at plus .002 over the GO gage (1.632) and I see "NOTHING" wrong with this headspace setting.

[Terry Balding]

I have done both successfully. I have sized brass in my full length sizing die and set a barrel with it. Put two layers of scotch tape on the end of the case after setting. If the bolt closes it's too loose, if not it's OK. I use the same procedure with a go gauge. Two layers of tape = .002

Terry

[DutchH]

Hello....I'm in the process of installing a bull barrel on my Savage 110 .30-06 and need a little advice. I've read all the replies concerning setting head space and have a set of Foster head space gauges. But no one mentions removing the ejector pin during the head space setting. I'm sure that it needs to be done,yet not positive. Can anyone set me straight on this and if it's required how difficult is the ejector locking pin to remove ?...Thanks for the assistance,Dutch

[DutchH]

Hello....I'm in the process of installing a bull barrel on my Savage 110 .30-06 and need a little advice. I've read all the replies concerning setting head space and have a set of Foster head space gauges. But no one mentions removing the ejector pin during the head space setting. I'm sure that it needs to be done,yet not positive. Can anyone set me straight on this and if it's required how difficult is the ejector locking pin to remove ?...Thanks for the assistance,Dutch

I guess after 10 days with no reply I shouldn't expect one.....For any,such as myself,who are replacing a Savage barrel for the first time let me offer what I did on removing the ejector pin. I took a spent shell case which was fired previously from the gun I was putting a bull barrel on and slipped it under the extractor. Then as I pressed it into aligment with the bolt face it took tension off of the ejector lock pin. I then laid the bolt face onto a thin piece of hard wood to allow room for it to tap out while still holding pressure on the spent case. I took a very small punch and with a few taps had the locking pin out. By slowly releasing the pressure on the spent shell case tension was released on the ejector which easily dropped out. I put it back in by just reversing the removal order. While it was out and with my bolt reassembled I checked with my no-go and go guages to assure the barrel was set with the correct headspace. After a day at the range all fired cases show no pressure points and the gun chambers great. Beings this was the first barrel I've ever replaced I was worried I may encounter problems,but it is a very simple procedure even for a novice as myself......

[sha-ul]

If it makes you feel better, remove the ejector, after doing it a couple times on one of my rifles, it goes pretty easy, the hard part is finding a punch small enough. (fwiw my Redding die had a spare decapping pin that tapped out the retaining pin quite nicely)

[DutchH]

If it makes you feel better, remove the ejector, after doing it a couple times on one of my rifles, it goes pretty easy, the hard part is finding a punch small enough. (fwiw my Redding die had a spare decapping pin that tapped out the retaining pin quite nicely)

I appreciate both of your replies. For a punch I took a small stainless steel metal screw and filed off the threads plus flattened the pointed end. Put a drop of Kroil oil into the locking pin recess and after a short while it punched out with little effort. I put the modified screw into my tool kit for further barrel changes such as a 26" bull barrel on my Model 10FP .308........

[Hammer]

.


Mere casual speculation without any actual attempt to use or serious thought given nor check of accuracy, numbers, or arithmetic…



Savage barrels have 20 threads per inch.

One complete turn of the barrel moves headspace 0.050 inches.

1/25th of a turn moves headspace about 0.002 inches.

Some think that industry headspace tolerance is normally 0.004 inches.

If we were to put 25 dots or marks engraved (punched) uniformly spaced around the barrel just beyond where the barrel nut goes, we would have a built in headspace gauge. (Just like a UniqueTek converted Dillon powder measure.)

We could turn the barrel in tight against any factory or handloaded cartridge we wanted to shoot, and then back off one dot for 0.002 inch headspace.

This would allow variation in cartridge sizing (headspace) without giving us excessive barrel headspace.

If 25 dots are too many for us to handle, 12 dots would produce 0.0042 inches or right at maximum tolerance. (The circumference of a Savage barrel is 3.3 inches.)

Any gunsmith with the most primitive lathe could easily put the dots on the barrel.

Aftermarket manufacturers of Savage ready-to-install barrels could put marks on barrel for us.

Takes longer to explain than to do.

If this will really work, am sure many smart people have already done it.



[Derived from August 2011 Precision Shooting article “You Too Can Have a Switch Barrel Rifle”, by Josh Benin, pages 13 – 25.]

.

[devildogandboy]

i retired about 18 months ago and decided i needed a hobby to keep me busy. being i have always been into firearms since i was 10 years old i decided i wanted to build a rifle on my own, well i had to start somewhere so i bought a rifle basically complete minus the barrel which is fine, it gave me a place to start. i then bought a barrel and waited for the go and no-go guages to arrive, in the mean time i got impatient and started reading here about headspace. i read all 6 pages of what i consider pretty informative information and i decided to try biged's(bigedp51) approach to headspacing as it seemed to just make sense to me. after following his input and checking everything twice it seemed to be perfect and i was happy and confident. going to take it out in 2 days on Saturday to the range and see what happens.
day after i get it all together i get guages from ups delevery. just out of curiosity i check the go guage and it works just fine. next i check the no-go guage and the bolt will not close! this is the same results i got with "biged's" info.
i believe i have learned a lot from this site and i am grateful to all you members who have given input to this site, allowing people like myself to learn the basics to building and maintaining our firearms.
Special thanks to "bigedp51" !

[mstarling]

OK Guys,

I have a bit of an unusual situation.

I need to pull the Douglas installed Douglas barrel on my 110 to ship it out to be threaded for a can. The headspace was checked several times to make sure it's OK.

I have fired cases on once fired new Winchester brass from this rifle (or will have when I shoot some specifically for this). Headspace is fine.

Why cannot I use a fired case from this rifle to reinstall the barrel on this rifle? I do not have gauges and hate to spend $54 plus shipping on them for a single use.

Thanks!

Mike

[johnp034]

Awesome site! First timer here, and just learned enough info on head spacing to satisfy my curiosity. Thanks so much,

JohnP

[thomae]

Awesome site! First timer here, and just learned enough info on head spacing to satisfy my curiosity. Thanks so much,

JohnP


JohnP:
Welcome to the forum. New members are always welcome and appreciated.
It is a great site with lots of good stuff. If you spring for a paid membership, it is even better with classifieds, etc...
Go to the very top of the page and click on "Membership Info." All will be explained. IMHO, it is well worth the $1.00 per month to join.

[jeffm]

Here is a site that rents the guages for $5 plus shipping. http://www.reamerrentals.com/SearchResults.asp?Cat=26

[joe0121]

On the Savage website they say they use a minimum headspace gauge. Where do I find one of those? I used a Forster go gauge when putting my .260 barrel on my 12 action. I closed the bolt with the go gauge, then screwed the barrel in until contact was made, then just because I am new at this and wasn't sure what to do, I screwed the barrel back out until I felt no resistance while opening and closing the bolt. I tightened the nut, then chambered a once fired case that I had FL sized. It was hard to close the bolt. So what do I do now? I am guessing it shouldn't be difficult to close the bolt if the head space is correct.


FWIW

This is a method I found on Snipers hide and works very well.

Place the Go gauge in the barrel, place the barrel in the action and close the bolt. Tighten down the barrel till the go gauge contacts the bolt face. Open the bolt. Screw the Barrel 1/2 turn in close the bolt. Do this until bolt closure becomes difficult. Buck off 1/4 Turn untill the bolt closes with no resistance. this should set your head space good and tight. Double check the the no go to make sure the bolt wont close.

I have read where you have to remove the firing pin and extractor but I know of several people who haven't gone through all that with excellent results.

[243LPR]

I use an action wrench in a vise,letting the barrel unsupported. I tighten the nut with go gage in place but barrel still rotates enough to lock up the action and can't open bolt.What can I do to stop the barrel from rotating while tightening the nut?

[hotbrass]

Hold on to the barrel.

[243LPR]

With what? Tried a strap wrench and still turns.

[barrel-nut]

Barrel vise or wooden blocks in a bench vise.

[Blue Avenger]

that or plan for the turn by backing off some.

[243LPR]

As mentioned above,the action is already being held in the vise so putting the barrel in a vise is out.Like suggested I just anticipated the turn and that seemed to work. Fired for the first time today and all seems good.

[andrewst35]

What about using the RCBS case mic and Redding competition shellholder kit?