New barrel headspace question

[mtang45]

Folks I'm screwing my new Shilen barrel into my Savage action and since this is my first Savage build I have a couple of questions.

1) When setting headspace is it best to have as tight a chamber as possible, or just a hair (.001") over minimum?
2) When checking headspace should the bolt head be stripped or assembled?


Thanks!

[Browningguy]

The instruction say to strip the bolt head, but I did mine last week without stripping and it seemed to work out ok. Headspace depends a little on your use, for a hunting gun you probably don't want it set to tight, but for my target rifle I set it to minimum. Using a go gauge I screwed in the barrel until I felt it touch, then backed off maybe 1/8 turn. With a piece of tape on the back of the go gauge the bolt will barely start down before stopping. I tested it with 3 different factory loaded rounds and all chamber, but you can feel a little resistance starting as the bolt bottoms out.

[mtang45]

The instruction say to strip the bolt head, but I did mine last week without stripping and it seemed to work out ok. Headspace depends a little on your use, for a hunting gun you probably don't want it set to tight, but for my target rifle I set it to minimum. Using a go gauge I screwed in the barrel until I felt it touch, then backed off maybe 1/8 turn. With a piece of tape on the back of the go gauge the bolt will barely start down before stopping. I tested it with 3 different factory loaded rounds and all chamber, but you can feel a little resistance starting as the bolt bottoms out.


Thanks for the advise. This rifle is a 308 and a go gauge is 1.630. I have a 1.631 gauge that I have used on setting headspace on 308 semi-auto rifles because it eliminates the need for figuring in "setback" of the locking shoulder to get proper headspace. I'm guessing that your backing the barrel off 1/8th turn is the same as adding a thousandth to the minimum gauge dimension.

[Skunce]

Backing off an eigth turn adds about .006" headspace.

[mtang45]

Backing off an eigth turn adds about .006" headspace.


WOW that would definitely be too much.

[stangfish]

Idealy you want .001/.002 float in the cartridge, or as close as you can go without effecting the bolt tension when closing. This is more important on your factory ammo or reloads than where the gage sets you. You could set it in the middle and still have a tight bolt. If I'm not mistaken the standard is .002 max on belted cartridges and up to .004 on standard cartridges. Someone correct me if I am wrong.

[geargrinder]

Putting it in perspective. An 8th of a turn is 45 degrees.

I usually set headspace with a piece of sized brass. I'll get it all snugged up by hand. Then I'll get my fine tip sharpie and put two dots next to each other, one on the nut, one on the barrel. Then I have a good reference for how much I'm backing my barrel out.

[mtang45]

I'm a little shocked. I just pulled my Savage F/TR out of the safe to measure its headspace and started in on adding .002 tape to the back of my 1.631 gauge. Two pieces of tape were snug but the bolt still closed with little effort. Three pieces and the bolt would not close at all. That means my factory rifle (which shoots great BTW) is .005 over minimum or 1.635

Is this a normal condition for Savage?

[stangfish]

I'm a little shocked. I just pulled my Savage F/TR out of the safe to measure its headspace and started in on adding .002 tape to the back of my 1.631 gauge. Two pieces of tape were snug but the bolt still closed with little effort. Three pieces and the bolt would not close at all. That means my factory rifle (which shoots great BTW) is .005 over minimum or 1.635

Is this a normal condition for Savage?


did some research.....006 is industry max.

[bigedp51]

The British Enfield at maximum headspace of .074 with American commercial cases can have as much as .016 head clearance or "air space" between the bolt face and the rear of the case. With a head space setting of .067 or SAAMI NO-GO you can have .009 head clearance.

The reason I'm telling you this is because of the manufacturing tolerances of your reloading dies + - and the manufacturing tolerances of your cases + - if you set your headspace too tight your reloading die might not push the shoulder back enough to chamber the case in your rifle. Even if your long on headspace by seating your bullets long when fire forming your cases by jambing the bullets hard into the rifling this will hold your cases against the bolt face and prevent stretching.

One sliver of brass, a little unburnt powder, moisture that freezes in your chamber and you may not be able to chamber a cartridge in your "tight chamber".

From the opposite perspective the last batch of Remington .243 case I purchased had cases that did not meet minimum cartridge headspace standards and were .012 shorter than minimum headspace. You also have tools for the proper resizing of your cases and measuring your cases.

Its a plus or minus world so don't cut yourself short on headspace. The shell holder below is .003 shorter than normal to make up for a rifle thats has the headspace set just .001 below minimum headspace.

http://i122.photobucket.com/albums/o254/bigedp51/IMGP6943.jpg

If your a little long on headspace the headspace shims or the shell holders below can be used to control cartridge headspace.

http://i122.photobucket.com/albums/o254/bigedp51/7-17-201054719PM.jpg

http://i122.photobucket.com/albums/o254/bigedp51/7-17-201054345PM.jpg

"BUT" there are some forms of excess headspace that "NO ONE" should have to put up with.

http://i122.photobucket.com/albums/o254/bigedp51/10_foambeer_lgl.jpg

[stangfish]

Great information Big. What would you suggest as the max airspace for his application?

[bigedp51]

stangfish

I have to answer your question with "it depends what type shooting you are doing and your reloading ability" And ability means what reloading tools you have as far as headspace gages and tools to measure "cartridge headspace". What this boils down to is the type shooting you are going to be doing, hunting or competitive shooting.

There is nothing wrong with setting your headspace right at Minimum or GO "BUT" you may have to tweak your reloading gear like I did by making the shell holder shorter and keep the case .002 shorter than chamber headspace.

The average person can keep headspace anywhere within SAAMI limits for that caliber, if your striving for the utmost accuracy then a custom barrel/chamber and "tight" headspace would be your answer. Just remember scotch tape isn't calibrated and it isn't a precision measuring instrument. And resizing dies have plus and minus manufacturing tolerances, just for grins and giggles and to play around with I have three differently manufactures of .243 dies and each one sizes the case differently. (headspace and diameter)

Bottom line, the tighter you set your headspace the "less" margin for error you have and the need for quality gages to measure your work increases. I'm retired and have nothing to do and all day to do it, so I can be as fussy as I want to with my cases.

I collect the British Enfield rifle and and during WWI the chamber was enlarged in length and diameter to make room for the mud of the battlefield (mud of Flanders fields) When reloading for the Enfield chamber you have to remember when your chamber your cartridge case, its like parking a Volkswagen in a blimp hangar and your going to have to "compensate".

[mtang45]

Big,

Thanks for the info. I have been reloading for a number of years, but never have ventured into all the various ways of eliminating variation. Resize, check case length, trim when necessary, measure distance from bolt face to lands, experiment with different projectiles, seating depths, and powders. That pretty much encompasses the extent of my reloading. Obviously there is MUCH more to learn and play with. I am accuracy obsessed, just need the time and knowledge.

PS, that last pic is certainly a problem that I would PO'd about if I had excessive headspace! ;D

[lal357]

this is ineresting reading before i did mine i tried it out on my lrpv in 223 i put in the go guage bolt closed put one piece of tape and no go .so when i head spaced my Mcgowen barrel in 223 i turned it until it just touched tightened nut down then added piece of tape and no go . this is also the way i'll be done my shilen 308 barrel when the bolt head get here today.

[stangfish]

stangfish

There is nothing wrong with setting your headspace right at Minimum or GO "BUT" you may have to tweak your reloading gear like I did by making the shell holder shorter and keep the case .002 shorter than chamber headspace.

The average person can keep headspace anywhere within SAAMI limits for that caliber, if your striving for the utmost accuracy then a custom barrel/chamber and "tight" headspace would be your answer. Just remember scotch tape isn't calibrated and it isn't a precision measuring instrument. And resizing dies have plus and minus manufacturing tolerances, just for grins and giggles and to play around with I have three differently manufactures of .243 dies and each one sizes the case differently. (headspace and diameter)

Bottom line, the tighter you set your headspace the "less" margin for error you have and the need for quality gages to measure your work increases. I'm retired and have nothing to do and all day to do it, so I can be as fussy as I want to with my cases.


Big, That is the meat and potatoes. You are a valuable asset here. I, like the others are glad you chimmed in.