Re-barrel Model 75 IV .270 Win S/S?

Discussion in 'Sako 75, 85 and A7' started by mwchoclabs, Jan 15, 2015.

  1. mwchoclabs

    mwchoclabs Member

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    1st goal
    I am looking to replace the original .270Win barrel with a factory replacement.
    Is it possible to get a factory replacement barrel in the USA?


    2nd goal
    Which gunsmith would you use to procure a replacement barrel? I guess that they would be providing the dimensions and thread specifications to a barrel manufacturer. Then they would get the blank with the bore completed and ream the chamber or some combination of these procedures?

    Thanks to all!
     

  2. paulsonconstruction

    paulsonconstruction Sako-addicted

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    It is highly unlikely you will find a factory barrel for your 75.
    You could either order a blank with the bore size, twist, & contour you want & have a competent gunsmith thread, chamber, headspace, cut to length, crown, etc. & fit it to your action or send it to the barrel maker of your choice & have them install it. Some barrel makers provide only their standard contours & some will custom contour to match your factory barrel exactly. It's not a simple "plug & go" procedure & who does it & how well it is done affect how your rifle will shoot. If you are not familiar with rebarreling I recommend you send it to a barrel maker.
    Curious what is wrong with the barrel you have?
     
  3. mwchoclabs

    mwchoclabs Member

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    Thank you for sharing the details. Yes re-barreling requires the application of some precision metal working for accurate results. I am hoping that Accuflite will be able to provide the replacement barrel as they are probably the largest SAKO dealer/gunsmith in the US. There is nothing wrong with the current barrel EXCEPT that almost 20 years ago I allowed a gunsmith to cut brake ports near the muzzle and it is too loud to shoot with anyone near, esp. off to the side. I am also hoping that this email helps to identify any additional gunsmiths who are experienced with working on SAKO rifles. If the cost estimates result near the same as replacing the entire rifle, then I may just keep it like it is.
     
  4. paulsonconstruction

    paulsonconstruction Sako-addicted

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    A quality barrel will cost $250 to $300 from most of the barrel companies. Fitting it to your rifle will be about that amount, so a first class rebarrel will be $500 to $700 depending on what you do & how you do it. If you cut the ports off your existing barrel (I'm guessing two inches or less) you will only lose about 100 fps or so & it would cost less than $100. Just something to consider. Finding a good competent smith to do barrel work can be the most difficult part depending on where you live. I've had the best luck sending my barreled actions to Shilen or Pac-Nor & have them do the barrel install. Always a first class job!!!! Sakos are no different than any other rifle with regard to rebarreling & it doesn't take any more skill or knowledge to perform the task.
    Good luck whatever you decide.
     
  5. mwchoclabs

    mwchoclabs Member

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    Hawkeye,

    A SAKO Model 75 with a 20.25in length barrel is something worth considering and a very good suggestion on your part. I do admit that my OP read a little like I implied that working on a SAKO action was somewhat mysterious or out of bounds for a good gunsmith to be able to accomplish.

    What I did not communicate is that I have previously had my TRG-S rebarreled from .300WinMag to a Shilen .300WbyMag. About a year ago I was speaking to a representative at KRG about their Whiskey chassis system for the M995 action and he explained to me that the thread specs used on the tenon of the barrel was not common to most lathes used in the USA. And it is the cost of getting your lathe set up to do a one of or low volume barrel thread was prohibitive to most gunsmiths. I now wish that I had kept the dimensions that he shared with me for the M995 barrel. He also suggested that most US gunsmiths would not know the actual thread specifications and dimensions for SAKO barrels nor probably where to get that information.

    I do have a couple of questions for you, since the ports do extend back from the crown about 1.75 inches, and obviously these ports are rapidly dissipating hot gunpowder gasses, then have I not already lost the ability for those escaped gasses to continue accelerating the bullet?

    I have never shot this rifle through a chronograph prior to having the barrel ported so I cannot compare before and after muzzle velocity. It now seems to me that a 20.25 inch .270Win barrel might actually be creating as much or more muzzle blast as what I have now? With all of this thought process going on, it has dawned on me that I need to break out my chronograph and capture a few numbers.

    And another great point that you make is to contact the barrel makers and see if they would use the existing barrel as a guide then re-barrel the action as they would also be able to provide the proper head space calibrations.

    Thanks for provoking my thoughts!
     
  6. m995

    m995 Well-Known Member

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    The tenon specs. being metric , don't matter for lathe work. Most modern lathes will cut metric threads ( if they are used on the 75 series actions) . The threads on the 995 action are definitely metric , just under 1.0625". Most tenon specs. are on the sloppy side to account for debris & lack of maintenance.

    As for the porting, You could talk to a local machine shop about making a split gas block to cover the ports, they don't look pretty but you will retain your full barrel length
     
  7. mwchoclabs

    mwchoclabs Member

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    m995,

    Thank you for the corrections re: lathe capability, I obviously am neither a gunsmith nor machinist. I misunderstood someone telling me that the the rate of spin relative to the travel of tool required to make these metric threads required the late to need a different set of gears installed. Oh well I am sure that there are so many different configurations possible for any number of models of lathes that he may have been speaking about his particular machine.

    I happened to work in and around the Williamsport area in the late summer and fall of 2010. Our company had a nice home leased on the east bank of Pine Creek, about 6 miles north of Jersey Village, that I stayed at for a while. Your idea about about the split gas block is interesting. It lead me to consider that if I do go ahead with the shorter barrel that i might consider have thread cut into the muzzle. Then I could consider a broad range of muzzle devices some of which would include flash suppressor styles as there are some which would direct the blast totally forward. I have seen test showing that some of these devices actually lower the sound level as measured at the shooters ear as compared to a bare muzzle.

    Do you know if a barrel with ports actually does halt the acceleration of the bullet when the hot gasses begin to exit through the ports? I'm beginning to think that I already have the effective muzzle velocity of a 20.25in barrel.

    Thanks
     
  8. paulsonconstruction

    paulsonconstruction Sako-addicted

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    I've chronographed a lot of loads in a lot of different cartridges & I think you will find the difference between a 22" & a 20.25" barrel is pretty inconsequential. As your ports are reducing velocity some to start with the difference is even less. Bullberry barrel makers has some data on their site showing velocity changes as they cut an inch off a barrel from 26" to 14". It shows how little difference a 26" is from a 20" & makes one wonder what all the concern & fuss shooters express over such minute changes is all about. The big differences in velocity don't show up until you get near 18" & are quite drastic from 18" to 14". Your gun will be a tiny bit louder than a non-ported 22" barrel if you cut it, but definitely less loud than it is now & you need hearing protection anyway. I cut a 30-06 from 24" to 20" & only lost 125 fps with a 180 grain bullet. Last moose I shot didn't notice the difference.
     
  9. mwchoclabs

    mwchoclabs Member

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    1+ on hearing protection, late to the game on that but wear it every time I shoot for exception of hunting. I have not yet gotten used to the electronic earphones I have while hunting. Perhaps the solution would be to step up to the electronic in the ear design?

    I do believe that for all practical purposes my range during hunting will not suffer from the shorter barrel. So the hearing protection issue is more relevant than a small decrease in MV. In fact there may be an improvement in accuracy as the shorter barrel might develop a smaller barrel whip amplitude.
     

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