Which method? (barrel and action blocks)

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by daveosok, May 21, 2002.

  1. daveosok

    daveosok Guest

    I just recieved my PACNOR barrel. It is 40 inches long and 1.7 inches in dia. One question I've had is that the Nesika action I want has 1/16 - 18 TPI which seems to be a bit on the small side when compared to the diameter of the barrel. I am wondering if it shouldnt be more proportional to the dia of the barrel.
    Should I use a combination of a barrel/action block and clamp both items within this block?
    This would ease my mind about the thread dia issue and support the area where the most stress is going to occur.
    I would like to compete one day at Willamsport but do not have the regulations for what class I would be in.
    The barrel weighs in at 26 pounds the action is another 60.0 oz (3.75 lbs), the scope base and rings will sit a top of the barrel/action block and will add appx. 3 lbs to the weight, stock will be about another 8 to 10 pounds with all of the adjustments ie. LOP, and 3-way butt plate. The total weight with scope will be inbetween 40 to 45 pounds.
    What class will that put me in?
    The scope will be a U.S. Optics SN-3 MkIV 3.8-22X with a 40 mm tube and 80 mm obj the MkIII is the only one they list a weigh of and it's 21.0 oz's.
    Let me know your thoughts on using a barrel/action clamp block for both items.
     
  2. Steve Shelp

    Steve Shelp Well-Known Member

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    Dave,
    I've been down this road and continueing down it in a different direction because of what I learned. The harmonic patterns produced by that long barrel hanging on an action only isn't the way to go in my opinion without putting alot of taper on it to reduce muzzle weight.
    Here's my example... In my 1,000yd Heavy Gun Class rifle (which is the class you would be in based on the info you gave above) I used the big BAT 2"x10" action which uses 1 1/4" dia x 1 3/4" long tenon threads and supported a Lilja 32" long uptaper 1.850" diameter barrel without a block. I shot this configuration for 2 1/2yrs in BR competition this way and had the barrel setback this winter and a slight taper put on the barrel which is now 30 1/4" long and man what a difference. This thing is showing more potential now then it ever had. Now you are talking a 40" barrel with less diameter and less length tenon threads holding it. To me it's a no brainer to go with a barrel block in your situation. Plus your going to have to add weight to the butt section to counterbalance that rifle with a 40" barrel on it in order to shoot it halfway decent. My old barrel configuration shot good for score but it just wouldn't group 10 shots that tight, day in and day out to keep up with the 6.5s and 30s for group. But that is changing with this difference configuration.

    Hope this helps,
    Steve

    [ 05-21-2002: Message edited by: Steve Shelp ]
     

  3. Nicholas

    Nicholas Well-Known Member

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    That's great to hear that the Yogi is starting to perform for you. What kind of groups are you getting from it now?

    By the way as far as they taper you put on your barrel, what is the muzzle thinkness?
     
  4. daveosok

    daveosok Guest

    Steve.

    The stock will have an integral bedding block to include the action and a section of the barrel.
    How much of the barrel would you support with it being 40 inches long? Say 7 inches of barrel block and a complete action block?
    That would be about a 15 inch long bedding block and block clamp.
    How many screws should be used and what size?
    This top clamp block will have an integral picatinny style rail on it for use with all the popular ring styles with the picatinny rail. I wish I could post a drawing of it using AutoCAD, I have drawn it up and will be making the top clamp block out of Ti, and the bottom-bedding block will also be Ti with heil-coils in the threaded holes.

    I took an idea from the Grizzly 50 cal and have used the butt of the stock to house the action to give the gun a shorter length. This will place the scope more over the barrel than the action. I have designed a new trigger and have used cantilever system to manipulate the trigger to obtain a 13 ½ in LOP at the trigger shoe. The OAL of the rifle will be app. 54 inches a common length for guns with 30-34 in barrels.
     
  5. daveosok

    daveosok Guest

    That is interesting, you said they shorten up and allow a small space between the throat and the case when fired? Are you using fireformed and neck sized case only?
    Do you turn your necks?
    How or will, you solve this problem?
    have you tried any of the new Rutumbo powder yet?
    The nesika action is 1.7 in dia, the barrel is 1.7 in dia (+/-.005), hopefully they will meet up and ill use Ti devcon to bridge the gap if their is any. If the barrel is smaller I will probably go ahead and grind it betweeen centers until the action matches the barrel. If its the other way around the barrel being bigger I will probably turn the first 10 inches forward of the chamber to match the action dia and then blend the diff at the 10 in mark. I will try and email you with the drawing tonight.
    My orginal question about the thread dia of the action being ok hasnt really been addressed as to whether or not that thread dia is sufficent for my application.
     
  6. Steve Shelp

    Steve Shelp Well-Known Member

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    SR90,
    We're getting there. Nothing spectacular yet due to very bad conditions in the last 3 matches, but I've got 2 relay wins in that period with it and the 3rd target was very competitive. Last Saturday my group was 14" but it was all left/right because we had big time switches in the wind. The up/down was in the 5-6" range of the 14" group though. Would've won the shoot-off if I hadn't had a problem chambering round #6. I think I jammed the bullet back into the case some. I had a 20" group in the shoot-off. 9 shots were in 9-10" with one straight down just about a 1/4" from the bottom of the paper for the 20" overall. But that's why we measure all 10 shots. 15" won the relay and his was a lot wider than my 9 shots. It was very bad conditions. We've got a 2 day match in up in VA this weekend. Hope to have some good conditions to see what it will really do.
    I did shoot a 4 1/2" group at the NC club a couple of weeks ago just testing it though.

    Dave,
    I've got ACAD R14 on my home PC (use to be a draftsman) if you want to email your drawing to me. I've got a few questions on the action and barrel block setup that I would like to see first and go from there. We did an experiement 15yrs ago with a bedded action and barrel channel that didn't work very well. But your going further with the complete block also. Not looking to steal any secrets, but have some concerns with blocking the action and barrel at the same time that your drawing may answer.

    FYI: remember our discussion a couple of weeks ago about carbon buildup in the throat area and keeping after it......?? guess what got me at the next match! Just a little humbling. It wasn't in the rifling/throat area, it was actually in the chamber neck area so bad that I couldn't chamber a round after my 4th sighter round. Another wildcat lesson learned with the cases shortening after firing, leaving an small exposed area of the chamber just ripe for carbon buildup. Took a lot of aggresive cleaning to get it out. It never showed in years past due to my using H1000 for the last 2 years which is a lot cleaner in my book. Started back with R25 in this new chamber. It took 163 rds to buildup so a round couldn't be chambered. Thought you would get a kick out of that.

    Steve
     
  7. Steve Shelp

    Steve Shelp Well-Known Member

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    Hey Dave,
    See my comments below your questions.

    That is interesting, you said they shorten up and allow a small space between the throat and the case when fired?
    This brass (which is typically when a blowing shoulder out) shortens up .025-.030" on the first firing. This creates a little bit of exposed neck area from the 2nd firing on. I never had this problem before until coming back and using R25 starting this spring. It slowly built up enough until a round wouldn't chamber. Essentially the same symptoms of having a case that is too long for a chamber and needs trimming.
    I used H1000 almost exclusively until I had it rechambered and then R25 came alive, so I started using it again. R25 is known for some carbon build up in certain larger chamerings.

    Are you using fireformed and neck sized case only? Do you turn your necks?
    yes it's fireformed in my chamber, but as mentioned above it shortens up on the first firing only. Yes, it is a tight neck and the necks are turned for .0015" overall clearance.

    How or will, you solve this problem?
    The "problem" is that when moving a shoulder forward in any case forming it will shorten up somewhat. Now that I'm aware of the R25 carbon buildup issue, I'll simply make sure I concentrate on this area with a brush and carbon cleaner to keep it out of there. Or go back to H1000. But this R25 is working so good I hate to change.
    I can't just get a shorter reamer because then you would have to trim the case to get them into the new shorter chamber and the case will still shorten up the same .030" from that point. So I'll end up with the same .030" gap, it will jsut be in a shorter chamber.

    have you tried any of the new Rutumbo powder yet?
    no I haven't. haven't heard back any reports on it yet either. Hear anything yourself?

    The Nesika action is 1.7 in dia, the barrel is 1.7 in dia (+/-.005), hopefully they will meet up and ill use Ti devcon to bridge the gap if their is any. If the barrel is smaller I will probably go ahead and grind it betweeen centers until the action matches the barrel. If its the other way around the barrel being bigger I will probably turn the first 10 inches forward of the chamber to match the action dia and then blend the diff at the 10 in mark.
    ok. that gives me a good picture of what you have in mind. I don't think you will need to go that far if you just block the barrel only and leave the action diameter as is and free flaot it off the back. Numerous guys have floated Rem 700 actions off from the back of blocked 30->40" barrels and don't have a problem. The Remington tenon threads are 1 1/6" dia I beleive and that action is 1.350 dia. So if it doesn't give a problem with a 1.350" dia Remington the bigger Nesika 1.7" dia is even better. That's another advantage of a blocked barrel, is you don't need all of that meat in the action. As a matter of fact some guys prefer the light Remington for this application because of less weigh and just epoxy a magazine follower into the bottom of the action. This should save you a lot of machining time/work. Plus then your action will be original, in case you ever wanted to use it for another project or sell it. Just thinking out loud.

    [B}I will try and email you with the drawing tonight. [/B]
    I'll be home tonight but will be leaving before dawn and returning late on Sunday for a match up in VA. If I don't hear from you tonight, I'll respond when I get back.

    My orginal question about the thread dia of the action being ok hasnt really been addressed as to whether or not that thread dia is sufficent for my application. you should be jsut fine by blocking the barrel only as mentioned above.
    I see your from middle Georgia. I would like to extend an invitation to come up to NC 1,000yd club on June 15th (our next match) and I'll introduce you to fellas that have current barrel blocked rifles and you can talk with them a see their setups first hand if that would help you. Let me know.

    good luck on your project no matter what you decide to do.

    Steve
     
  8. daveosok

    daveosok Guest

    Thanks Steve. I will be clamping both the barrel and action. This rifle will resemble a regular rifle as much as possible with respects to looks. I sent you the drawing by way of my email at work so it will show up as a military email. I have designed the stock to and will be using wood where I can because I liek the feel of wood over synth or al stocks.
    Have fuin at your shoot, I wont be able to make the June 15th as my mother is coming into town that day from Ohio.
    Thanks for the invite however and maybe one day I will get up round that area maybe even bring my 7 mm STW up for a couple of shoots or soemthing.
    Dave.
     
  9. Steve Shelp

    Steve Shelp Well-Known Member

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    Dave,
    Never recieved the drawing, but I've got a good mental picture of what you want now anyway.
    I like wood also!! Ya can't beat it.

    As for matches the next one after that is June 29th, then one in July, Aug, and Sept to close out the season. Plus the club will be hosting the IBS National Championship match Labor Day weekend also. So we're there most every month from Feb. through Sept. Bring up the STW and have at it. Got a couple of hot 7mm Rem Mag's right now in both Factory and LG classes.

    Talk to you later!
    Steve