head space or bolt face

Discussion in 'Gunsmithing' started by cva54, Nov 1, 2008.

  1. cva54

    cva54 Well-Known Member

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    can some one explain head space to a green horn I am trying to make a vary accurate .06 all ready did tirger job and glass bed it up to sight ring about 2" of barrle it is a rem 721/700 were do U all think I should go next?
     
  2. KRP

    KRP Well-Known Member

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    Head space is the measurement from the bolt face to the datum line on the shoulder of the cartridge.

    How accurate is the rifle now and what would you like it to be? If you don't handload that is the place to start. My 721 '06 will shoot about 1.5 MOA, that's the best I've been able to get from it. It's 50 years old with who knows how many rounds through it and probably wasn't always given the best care. It still kills things though which is the important part. I've got another one that will get a completer workover one of these days(trued, new barrel, stock, trigger, etc.). What you do next really depends on what you want from the rifle and how much you would like to spend getting it.
     

  3. kraigwy

    kraigwy Well-Known Member

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    Head space measuring varies with the type of case. Bottle neck cases headspace on the shoulder. Rimmed cases on the rim. Belted cases headspace on the belt. Straight wall cases headspace on the mouth of the case. As with any rule there are exceptions. An example, 30-30s normally, being a rimmed case head spaces on the rim, but in the TC, it headspaces on the shoulder.

    Most of the guns I've built were target guns and had rather tight chambers. I cut the chamber on a lathe until the bolt lacks about 1/8 of an inch of closing. Then by hand until it closes firmly.

    I think if I was gonna build a straight hunting rifle, I'd loosen it up a bit but still just bearly accepting the Go Gage.
     
  4. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    Here is a tib bit from a rifle shooter magazine article by Patrick Sweeney.

    "In simple terms, headspace is the dimension of the chamber of your rifle, the gap between the face of the bolt and the stopping surface for the cartridge. To be precise, it is the distance between the face of the bolt and the datum line, which is a circle of stated diameter, along the slope of the shoulder of the cartridge.


    On a rimless cartridge such as the .308, the stopping surface is the shoulder. On a rimmed cartridge like the .30-30 or .303 British, the headspace is the gap for the rim. On a belted magnum, headspace is the gap for the belt. Since not every factory rifle or cartridge can be made to exact dimensions, with perhaps the best custom rifles being one exception, headspace is deemed to be correct if it is within a certain range."

    Here is a link to the entire article. Measuring Headspace

    If this is a factory rifle you could have the lugs lapped and the barrel cleaned and bore scoped for any unforseen problems.
     
  5. cva54

    cva54 Well-Known Member

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    thanks for the info right now the moa is 1 3/4 at 89 y range finder didnt have room for a 100 yes it is a hunting rifle but here is my prob I am a mechanic deisel auto heavy equipment and so on ben doing it for 26 years so I got the mind set that any thing factory made CAN be tweaked to a lot better so would getting the bolt worked on or getting a costom bolt help me out accuracy. Trying to keep up to my buddy wiyh a 700 7mm rem mag I know but if I could pull off a 3" groop at 200 Y I would be happyer than a goffer in soft dirt I dont think that is to far out the relm thanksgun)
     
  6. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    If 1 3/4" groups is the best it will do at 89 yards there is something probably wrong. The barrel may be bad, I would clean it to remove all the powder fouling and copper and then have it bore scoped. Check the crown do you see any dings or knicks, if so this could be part of the problem also. Try a different scope, you may have a scope that's not holding zero. Is the bedding stress free? Is the stock a plastic synthetic type? These types of stocks aren't usually worth even bedding as they flex so much. Are you shooting factory loads or hand loads. With some factory loads in a factory gun if you can get 1" at a hundred yards your doing OK. A new bolt more than likely isn't going to fix whatever is wrong, plus you would then have to have the headspace set. There is only so much tweaking you can do a factory rifle. Depending on what level of accuracy your looking for you might want to consider taking it to a reputable gunsmith to have it looked at. You'd be amazed at the difference puting a custom barrel on would do if done right.
     
  7. cva54

    cva54 Well-Known Member

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    think thats what I needed IT IS what it is. So a bolt aint going to do s#%t. Yes I can see a nick at the muzzle looking through it ( what about a 30 deg. or so bevel cut in it ) so if iam going to rebarle it what about going to 270 win or 7mm rem mag and yes I do use a good gun smith there in morris town MN do U know them? By the way just droped a doe with it yesterday it was a unfair shot 25 yards hart shot yyyyyyyyyyyyaaaaaaaaaaaaa
     
  8. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    You could have it re-crowned, that nick probably isn't helping anything, or you could have it re-barreled. A 270 Win will fit with no bolt face alterations. You can do a 7mm Mag but the bolt face will need to be opened up to a mag and a sako extractor installed. If your going to install a new barrel that's the time to have the action blueprinted. I don't know who your gunsmith is in MN but if your comfortable with his work than by all means that who I'd use.
     
  9. cva54

    cva54 Well-Known Member

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    the gun smith I have been using is ahalmans in s. MN has any 1 heard of them what I here thay are the best ( i think ) around here thats were gander mountan and other so called gun stors send there stuff is this right realy thinking about the 7mm mag the only prob I see with it is were is the bullet going to go after leaving a deer how far will it go who will it hit what I am looking for is long range 300 y ? with all the ballistcs of 30 cal and vary accutare HELP
     
  10. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    It's hard to say how far the bullet will go aftre it exits a deer. It would depend on what the bullet struck, bone or in between ribs, was it perfectly broadside or did the bullet strike it quartering toward or away. If the furthest your planning on shooting is 300 yards you wouldn't have to go to a magnum unless you wanted. Most any 30 cal. with good bullets is capable of taking deer size game at 300 yards.
     
  11. cva54

    cva54 Well-Known Member

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    just got back form deer hunting up here in MN rifle season thinking about it all cal. that is . This what I came up with . start with bow opener sep 13th went up to the canda border 6 miles south spent 4 day there didnt see a think just tracks . Came home 2 day lator went down to river bottoms in the AM 20 min. from home set up a stand in just the tree no stand 20 foot up came back in PM 3:00 4:45 8 point with a kisser walked out 35 yards boulbe lun pass througt droped in 20 yards away . Rifle opener nov. 8th back up north not as far doe walks out behind me 20 yards to the right I am right handed ( wished id had a 44 mag then black hawk that is ) so it walked behind me when it came around I pulled up (slowly) sighted in stoped and thought I should have my bow well that did happen didnt know it at the time after it drpoed another 20 yards away gutting it I did a perfick hart shot it exploaded and took out the front left 1/4 (I always do that gess I dont like tracking) went up 2nt week end sitting there just thinking and looking pulled out range finder a lot. trying to find a 300 yard shot up here is dam hard unless dad has a farm mine dont so 7.62X63 will do just fine so there that. Now how accurate do I want to get well lets just say with my bow a mathews that is decked out vary nice all up to date 2008 60 yards 5" circle dam neer every time 40 on down I am getting tired of buying arrows so I gess with my 721 in 30.06 looking at 2" at 200 that not to mutch to ask for the only prob I see is getting it done before i a wheel chair or. Most likley go with recrowned barrle and a new stock starting to go back to a wood stock Uall know what I mean wow ben doing this 1 for a while