Chamber neck dimention for 6.5-06

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Brewer, Oct 8, 2013.

  1. Brewer

    Brewer Well-Known Member

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    Hi all, I am having Hart rebarrel a rem 700 LA to 6.5-06. I have bought some 30-06 Lapua Brass and was just going to size it with a .270 die and then a 6.5mm-06 FL die. so I have a question about what size I should have them make the neck of the chamber? I have heard that you might want it one or two thousandths bigger if you ware working the brass down instead of up? any comments or suggestions?
    Thanks
     
  2. .284

    .284 Well-Known Member

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    If you're not in too much of a hurry you could size some brass and make a few dummy rounds with whatever bullet you plan to use seated to fit your mag and send them to ptg. They can make you a min spec reamer based off your dummy rounds.
     

  3. Brewer

    Brewer Well-Known Member

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    .284, Thanks for response, I never thought about going from the case to the reamer, only the other way around. it sounds like a really good idea! it also sounds really expensive!! I guess what I was thinking I understood from some other guys was that if you are starting with 25-06 brass or even 270 brass, you might want a different neck size than if you are starting with 30-06 brass because there is going to be more brass in the neck area to ream away. Again, this is my first custom build so I am not very adept here. seems like I have seen different neck sizes on different rifles and wanted to make sure it didn't have to do with the brass you were starting from. if not, I am really interested in knowing why there are different neck sizes for the same cartage/caliber?
     
  4. .284

    .284 Well-Known Member

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    It will cost about 100$ for the ptg if I remember correctly and your gunsmith use 30-06 or similar go no go gauges which I'm sure they will have so you won't need to buy those.

    You may have a thicker neck by sizing down, Im not 100% sure. You will have to trim though. I neck up 25-06 brass and there's no need to trim for a while.

    You could also prep some brass and measure the diameter of a few loaded dummy rounds and compare that to the reamer you were going to use.

    People use tight neck reamers to reduce the possibility of the bullet entering the rifling slightly off centre and to hold the cartridge more aligned with the bore before firing. Unless you're planning to shoot bench rest I wouldn't worry too much about all that though.

    I don't shoot bench though so some else may have a better explanation on tight neck chambers.

    My 6.5-06 does not have a tight neck chamber and its shoots great but if you're going to shoot bench and chase groups by the .1 that may help but that game is outta my league
     
  5. Brewer

    Brewer Well-Known Member

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    That makes sense on the neck size. I suppose it doesn't matter then what the neck size in when they run the reamer in. I was planning to ream the brass because most guys that I have talked to say when you go from the 30 to 26 cal. you will have more brass in there than you want. they also said that if you ream, you will have more contact between the brass and bullet which helps the bullet leave the cartridge straight (if that makes sense?)
     
  6. woods

    woods Well-Known Member

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    I have 3 tight necked custom chambers: 6.5 rem mag, 280AI & 338 RUM

    I don't have to neck up or down since I use brass that is made for these calibers, so my experience may be less applicable

    But I don't understand why you are "reaming" rather than "outside neck turning". Outside neck turning is much easier to control and even though I have the capability to ream, I very seldom do it.

    All of the chambers are tight enough so that I have to do a complete outside turn in order for the case to chamber

    6.5 - .293"
    280AI - .313"
    338RUM - .366"

    In all of them I turn for a chamber clearance of .003" which is tight but enough for hunting purposes

    .293"-.003"=.290"-.264"=.016"/2=.013" per side

    The Remington brass averages .015" or so
     
  7. Brewer

    Brewer Well-Known Member

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    Woods, thanks for the responce. So I am confused. if you wanted to get your outside dimention to a specified measurment, why not have a custom die made? I suppose if you turn the outside, you might eliminate some (or all) runnout? that sounds like a nice bonus. I actually havent done it yet. it takes Hart 10 months to kick out a chambered barrel, So I am still waiting. I bought a Wilson trimmer and a reamer but you think an outside neck turner would be the way to go? can you explain why you went with a tight neck? I dont understand that. should I have my barrel chambered with a tight neck? what would help me know it was the right or wrong decision? Thanks for the help
     
  8. woods

    woods Well-Known Member

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    If you get a custom die, then what happens when you get brass that is thicker or thinner. Essentially your chamber clearance would change.

    A tight neck enables you to outside turn any brass to get the clearance you want. IOW if one box of brass is .015" thick and you have a custom die that gives you .003" clearance, then when you get a box of brass that is .014" thick your neck clearance just increased by .002". Not a big deal but for a control freak it makes a difference.

    IME most brass will have a thick and thin side. General consensus seems to be that if you have a variance of over .002" then discard or set aside for other use. With a tight neck you can do a complete turn (rather than just knock the high spots off). Theoretically then the off center neck will be fireformed by the chamber into alignment with the case body.

    IOW if I were going to order a rebarrel or custom gun (planning on a 243AI soon), I would get a box of brass I intended to use, measure it and make sure that I could do a complete outside neck turn taking of at least .001" and probably .002" all the way around. That way I could be sure I could get to the exact neck clearance I wanted
     
  9. Bullet bumper

    Bullet bumper Well-Known Member

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    OK there is many issues being discussed here and lots of confusion.

    1/ When you form a case down any imperfections or excess brass flows to the inside of the neck so many see inside neck reaming as the best option to get an even wall thickness and straight neck .

    2/ When you expand up it's the opposite as most imperfection flows out so outside neck turning is the best to bring it back to external specs.

    You have not said anything about what you intend to use the gun for as that would determine if you would even want or need a tight neck chamber .

    When you expand up to form a case for a tight neck chamber you have to make sure that the resulting brass thickness can be turned to the diameter you choose .

    So the chamber dimension has to match what the brass can turn to with respect to not going too thin .

    284 has the right idea . Make up a formed case or two the way you think you like and then dummy load the bullet you will mainly use to correct OAL and send that off to get a reamer made to suit .
    You can also decide if you want a tight base chamber , what distance the bullet ogive will be from the lands or even a tighter neck , so you can turn a bit more off the necks if you want . Conserving brass thickness is a good idea but not at the expense of concentricity and straightness .

    You have to decide on the way you will form the case , get the gear to do that and then produce the dummy rounds after that the reamer makers should be able to advise you on the best way to proceed .

    Dies are another issue but if you went Lee collet die for neck size the diameter difference would not be an issue if you can buy one . Failing that a bushing type die.
    If you go standard factory 30-06 base Redding should have a 6.5 - 06 body die to handle that I would think as I have never bought one but if they don't a 25-06 with the neck drilled out a bit more (.008 more ) should do it.

    You will have to work out what you expect the cartridge to do .
    It's a complicated subject with many different side tracks and you picked a hard cartridge to work with. .
     
  10. TOM H

    TOM H Well-Known Member

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    I'd sure be talking to Hart before I order any reamers. A tight neck in 6.5 is normally .290" and Hart has that neck dia for a 6.5x284 chamber listed and they may not list all their TN reamers. Gunsmith normally have good collection of throat reamers varies dia.

    This is listing of tight neck 6.5 from one of the gunsmith that builds some of my rifles

    6.5x47 Lapua .290" Neck ,260 Rem. Ackley .290" Neck, 6.5 Swede .290" neck
    6.5x55 Rogue (37 degree) .290" Neck, 6.5x.257 Roberts AI - .290 Neck
    6.5-06 Ackley .290" Neck, 6.5x.284 Win. - .290" Neck

    I do agree to make up some dummy rd with bullets then talk to Hart and see if you want to go with tight neck or something else. If Hart doesn't have your rifle yet might want to deal with one of the gunsmith on this site.
     
  11. nightowl

    nightowl Member

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    Brewer:

    Just saw this post - if you are still looking for info, I have some experience necking down Lapua .30-'06 brass for a custom 6.5-'06 AI with a .294" nk. If you're still interested send me a PM.
     
  12. Brewer

    Brewer Well-Known Member

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    Thanks for all the replies. so just to clarify, I am planning to use this rifle for hunting at ranges up to where I become comfortable shooting. I would think that would be in the 800-1000 yard range. Having said that, I don't have a good scope yet, so for now I am planning to use my 6.5-22X50 burris Fullfield II. I am assuming that will limit me to about 650 yards. I am thinking within 1 year, I will have the $$ to put an NF 5-22x56 on. Hart has my action. I am sure they will be able to do what I want them to, I just don't know what I want them to do. I probably have a couple of months because they are backed up that far. I guess my question is "what size should I have them ream my chamber neck to?" Again, I am starting with Laupa 30-06 brass (I bought 200 rounds so I am locked in on these). I have a Wilson Case trimmer with a reamer for .264, I have bought a set of plane jane Lee .270 dies, a Hornady .264 neck die and a Hornady .264 bullet seating die. Of course, just because I have a die doesn't mean I have to use it. if I find a better way to do something the die can sit on the shelf and I can buy another one. Thanks for any and all comments.
     
  13. TOM H

    TOM H Well-Known Member

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    What you need to do is call Hart and ask what neck dia they use for the 6.5x06. If you can neck brass down load a bullet as you need to know what the dia is before deciding on neck clearance.

    As to the 200rds of brass it may or may not last you the lifetime of your rifle and if you have a tight neck .290" it doesn't matter who's brass your going to use. If you have something set up for that laupa brass and some unknown reason you can't get anymore that could be a problem.

    When I had 6.5x284 build I had .290" neck I could even use 284 brass beside the Laupa 6.5x284.