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Thread: Bolt Close/Lift Tension Question

  1. #1
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    Bolt Close/Lift Tension Question


    I have a new Savage FCP HS Precision in .308 WIN. I have had it to the range one for break-in and had an issue with a Federal Gold Medal Match 168gr SMK getting stuck in the lands and coming apart and ending my day early.

    I just started reloading and used the Hornady Overall Length Gauge and a Bullet Comparator to measure the exact distances to the lands. I figured I would start my load development with the bullet seated 0.010" off the lands. I can adjust closer/further after I find an appropriate charge weight.

    I loaded up a dummy round to these specs and loaded it in my gun. The bolt was noticeably more difficult to close than it is when loading an empty case which was full-length resized to the same dimensions. I certainly wouldn't say it is "hard" to close, but it requires more pressure for sure (both close and open). Is this normal? I am using Lapua brass which I know has a reputation for being a little thicker than some other brands but wouldn't expect a factory barrel to be so tight that the case neck thickness would make a notable difference.

    If this is normal I am not all that concerned but wanted to make sure this couldn't indicate a problem I am not thinking of. I guess my only concern is if with the already slightly increased bolt lift will I notice a heavy bolt lift caused by an excessive load.

    I'm new to reloading so figured it was best to ask the question but certainly could be hyper-sensitive since I am still getting comfortable with the gun/reloading.

  2. #2
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    I've had new brass be a little tight in the beginning, but once fired or fire formed to the barrel it ran without issue. This was with aftermarket barrels as I haven't really played with factory barrels much.

  3. #3
    Basic Member Robinhood's Avatar
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    If the bullet touches the lands there will be a definite increase in bolt lift/close effort.

  4. #4
    Basic Member Steelhead's Avatar
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    Does a lapua case chamber normally without bullet?
    if so double check seating depth and then compare a fired case neck diameter to a loaded case neck.

  5. #5
    LongRange
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    What steelhead said and also look at the bullet you seated in the dummy round if it did go into the lands you should be able to see some marks in the bullet from the rifling.

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    I will redo everything again tomorrow and take pictures. The unforced case with no bullet seated chambers easily. Once I seat the bullet is when I notice the stiffness. I started with it being seated at what I measured to be 0.010" short of the lands (2.2350" base to ogive). When I noticed the bolt was stiff I seated the bullet deeper in increments of 0.005" until I got to 2.2000" which should be 0.045" off the lands.

    I will redo everything tomorrow and post an update. I will need to pay closer attention to any markings on the bullet but even if I find some I don't know how to explain the difference. I will also measure the before/after neck diameter.

  7. #7
    Basic Member Robinhood's Avatar
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    You never said if moving the bullet changed the effort required to close the bolt.
    Last edited by Robinhood; 12-21-2014 at 12:32 AM.

  8. #8
    LongRange
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    what Robinhood said...did the deeper seating change anything? if not when you redo everything and rechamber the round open and close the bolt a few times on the round and check the neck and shoulder of the case before and after for any marks.

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    Sorry I left that detail out. The bolt close didn't get any easier with closing the bolt.

    I ran some checks today and measured the dimensions at each step. Nothing jumped out at me as to the cause of the stiff bolt closing and no setup generated a bolt close which was "easy". I am wondering if this is just normal for my gun or if throat erosion will take care of this as the gun gets broken in further (gun currently has 25 round through it).

    Summary:
    - Took fire formed Winchester (1) and full length resized new Lapua (2) and once fired Winchester (3)
    - Checked bolt close on three empty cases -
    --- Once fired full length closed stiff, throw away (unsure why this would happen since it loaded easily before full length resize)
    --- Full length sized Lapua and fire formed Winchester closed easily
    - Neck size fire formed Winchester - bolt still closed easily
    - Seat two 168 SMK which have identical dimensions (+/- 0.0005)
    - Seated to approx 0.010" short of lands (desired length 2.2350")
    --- Winchester - bolt close stiff
    --- Lapua - bolt close slightly stiffer
    - Opening and closing bolt made little difference (but some)
    - Seated bullet deeper (approx 0.0500" short of lands)
    - Winchester and Lapua- bolt close stiff

    See dimensions of all steps below. I didn't see anything that would indicate that the stiff bolt close was the result of something measuring in excess.



    I inspected the rounds after having loaded and unloaded then several times.
    - Winchester - No significant markings of note
    - Lapua
    --- There is a mark that runs laterally across the bullet slightly forward of the neck. This occurs in the same place regardless of seating depth
    --- There are some minor markings on the case neck which run from front to back.
    --- There is a mark that runs laterally that runs along the datum of the shoulder








  10. #10
    Basic Member Robinhood's Avatar
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    It looks like you are using a Forster dies. That confuses me because it also looks like you are using a Lee collet die. This is a shot in the dark but if you are using a lee you are not set up correctly and are bulging the transition of the body to the shoulder. If you are not using a lee and are using the forster how far off the shell holder are you to the bottom of the die?

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    Quote Originally Posted by Robinhood View Post
    It looks like you are using a Forster dies. That confuses me because it also looks like you are using a Lee collet die. This is a shot in the dark but if you are using a lee you are not set up correctly and are bulging the transition of the body to the shoulder. If you are not using a lee and are using the forster how far off the shell holder are you to the bottom of the die?
    I have a Forster full length and seating dies and Lee Collet for neck sizing. I set the Lee Collet die up per the instructions which was touching the shell holder plus 1 turn when the ram was up. The Forster full length was set up roughing the shell holder plus 1/4 or 1/2 turn as I recall.

    In my test I full length sized the Lapua but only neck sized the Winchester since it was the only fire formed I had.

    For both rounds the brass chambered easily until I seated a bullet, stiff with bullet seated (at various lengths), and then easily again after I pulled the bullet.

    I really appreciate the input and am not discounting any possibility. Just trying to provide all the info that could be helpful to someone more experienced than I am.

  12. #12
    gotcha
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    It sounds to me that you need to re-visit your method of establishing seating depth. Try this: Seat a bullet at the distance you established as touching the lands. Then abrade the bullet w/ steel wool or abrasive pad to remove all of the shine. Chamber the round and lightly bump the bolt at the rear of the action with the heal of your hand. Do not attempt to close the bolt with the bolt handle. Remove the round and inspect the bullet looking for shiny impressions made by the lands and leade on the bullet surface. If you have obvious marks on the bullet surface let us know and we can advise as how to properly establish bullet seating depth.

  13. #13
    gotcha
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    A 2nd thought. I ran into this same problem with a .223 Rem. Bolt gun. The culprit was the diameter of the free bore. It was actually smaller than the diameter of the bullet. In effect "0" free-bore. Changing to another bullet Mfg. solved the problem. Try seating a bullet so the bearing surface is slightly below the neck then chamber. If resistance disappears this could be your problem.

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    Quote Originally Posted by gotcha View Post
    A 2nd thought. I ran into this same problem with a .223 Rem. Bolt gun. The culprit was the diameter of the free bore. It was actually smaller than the diameter of the bullet. In effect "0" free-bore. Changing to another bullet Mfg. solved the problem. Try seating a bullet so the bearing surface is slightly below the neck then chamber. If resistance disappears this could be your problem.
    What would the "solution" be to that scenario? Uses different bullet until throat erosion opens up the free bore enough that it isn't tight? Just shoot it and watch for pressure signs as I work up the charges? Send it back to Savage? I hate to send it back because the first group I shot after breaking in looked pretty promising.

  15. #15
    Basic Member Robinhood's Avatar
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    Is it possible you set up the seating die incorrectly. I put a piece of prepped brass in the shell holder and raise it to the top of the stroke. I then screw the seater die down, with the seater adjustment screw way out, till it stops. Then I back off a 1/4 turn. I then adjust my seater plug to the right depth. I say this because it looks like you shoulder is bulging. You could be compressing the neck into the shoulder. Just a hunch. I set my Collet die up the same way. Don't ask how these lessons were learned.

  16. #16
    gotcha
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    Hawk, Not to be a smarty pants but try the 2nd thought 1st. This will prove or dis-prove my hunch. Also give the free-bore a THOROUGH cleaning with a bronze brush and copper solvent to remove any potential build up of jacket/powder material constricting the free-bore. ........ If you can chamber a round with light to no resistance when bearing surface is below neck mouth but can't when bearing surface is above neck you've identified the problem. ...... Hang in there. We're still waiting to see neck dimensions sized vs. bullet seated....... Also, some don't realize that F/L sizing can actually push shoulder forward resulting in tight chambering. If you find this to be true simply adjust the die downward until bolt closes with light resistance.
    Last edited by gotcha; 12-21-2014 at 10:01 PM.

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    Quote Originally Posted by Robinhood View Post
    Is it possible you set up the seating die incorrectly. I put a piece of prepped brass in the shell holder and raise it to the top of the stroke. I then screw the seater die down, with the seater adjustment screw way out, till it stops. Then I back off a 1/4 turn. I then adjust my seater plug to the right depth. I say this because it looks like you shoulder is bulging. You could be compressing the neck into the shoulder. Just a hunch. I set my Collet die up the same way. Don't ask how these lessons were learned.
    I will certainly check that next time I have the chance. I setup the die by raising the ram, screwing the die down until it stopped, backed off 1/2 turn and locked the lock-nut, backed the coarse seater adjustment out several turns and worked it down until I was in the ball park of the desired length, lock down the coarse adjustment, fine tune with micrometer adjustments.

    Pardon my ignorance but if it was an issue with the shoulder then why would I not experience similar tension when closing the bolt on the same casing after bulling the bullet?

  18. #18
    Basic Member Robinhood's Avatar
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    Pardon my ignorance but if it was an issue with the shoulder then why would I not experience similar tension when closing the bolt on the same casing after bulling the bullet?
    If you mentioned that you were pulling the bullet I missed it and I am barking up the wrong tree. The rub marks on the shoulder indicated a problem. You did mention that you pulled a bullet from a factory loaded cartridge in your first post. Sounds like a throat problem as well. You loaded your ammo to .050 shorter than mag length and still had issues. The lack of physical evidence on the projectile from dragging in the lands led me to look at the case. Following the progress it is obvious that you have some technical ability. I think you are close to figuring it out.

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    Quote Originally Posted by gotcha View Post
    Hawk, Not to be a smarty pants but try the 2nd thought 1st. This will prove or dis-prove my hunch. Also give the free-bore a THOROUGH cleaning with a bronze brush and copper solvent to remove any potential build up of jacket/powder material constricting the free-bore. ........ If you can chamber a round with light to no resistance when bearing surface is below neck mouth but can't when bearing surface is above neck you've identified the problem. ...... Hang in there. We're still waiting to see neck dimensions sized vs. bullet seated....... Also, some don't realize that F/L sizing can actually push shoulder forward resulting in tight chambering. If you find this to be true simply adjust the die downward until bolt closes with light resistance.
    Gocha,

    Thanks for taking the time to reply to my thread. I was looking on my phone and missed one of your posts (the one about steel wooling the bullet) and wanted to make sure my question about the "solution" to the undersized freebore didn't come across as anything but a sincere question.

    Could you please clarify what you mean by "try the 2nd through 1st". I assume this means seat a bullet with the bearing surface completely below the neck and then try the steel wood test to measure the lands? I will do both as soon as I can find an hour or so to get back to the garage and do some more experimenting.

  20. #20
    Basic Member short round's Avatar
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    Quote Originally Posted by Robinhood View Post
    It looks like you are using a Forster dies. That confuses me because it also looks like you are using a Lee collet die. This is a shot in the dark but if you are using a lee you are not set up correctly and are bulging the transition of the body to the shoulder. If you are not using a lee and are using the forster how far off the shell holder are you to the bottom of the die?
    I agree, measure body to shoulder diameter on sized case, seat bullet & measure again, if measured on seated case is larger, either die needs adjusted or inside of case mouth chamfered

  21. #21
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    Quote Originally Posted by gotcha View Post
    Hawk, Not to be a smarty pants but try the 2nd thought 1st. This will prove or dis-prove my hunch. Also give the free-bore a THOROUGH cleaning with a bronze brush and copper solvent to remove any potential build up of jacket/powder material constricting the free-bore. ........ If you can chamber a round with light to no resistance when bearing surface is below neck mouth but can't when bearing surface is above neck you've identified the problem. .....
    I agree with you, its a bullet-freebore issue, not a brass issue.

    For both rounds the brass chambered easily until I seated a bullet, stiff with bullet seated (at various lengths), and then easily again after I pulled the bullet.
    It would also explain ....
    I have had it to the range one for break-in and had an issue with a Federal Gold Medal Match 168gr SMK getting stuck in the lands and coming apart and ending my day early.
    He should thoroughly clean the chamber first then try it. If the problem still exists then a chamber cast should be made to measure the freebore diameter of the cast vs the bullet shank diameter(s).

    Bill
    Each morning eat a live green toad, it will be the worst thing you'll have face all day.

  22. #22
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    BillPA, Thanks for clarifying. I have some more input but will wait 'til Hawk can perform the "bearing surface above and below the case mouth" test............. Hawk, No need to dull bullet surface for test that Bill & I outlined. But do look for circular impression around the circumference of bullet caused by a too tight free-bore. Good luck!

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    Well my duck hunt got cancelled so I had some time to work in the garage tonight to try out some of the things that everyone was kind enough to take the time to suggest.

    I did a thorough cleaning of the bore and chamber until it was spotless.

    I checked the distance from the head to shoulder datum both with and without a bullet seated and there was no measurable difference in the length that would indicate that I am compressing the shoulder with the seating die.

    I continued to seat the bullet down until the entire bearing surface was below the case mount and the bolt closed easily (2.0620" base to ogive). The markings on the bullet are from seating depths longer than the one shown. Whatever is making the marking appears to be the same cause of the stiff bolt closing.



    I then pulled the bullet and tried to determine at what point the bolt stiffness disappeared (2.0785"). At 2.0875" the first bolt close is a little stiff but subsequent closings gets easier. I would say this one is right on the edge of where the problem is starting

    I then loaded another round at 0.010" short of where I measured the lands to be and steel wooded the bullet. I played around a little with seating depth but nothing extreme. I am getting a mark on the top side of the projectile that covers just under 90-degrees. I believe there may be a burr in the chamber that is rubbing against the bullet and once the extractor grabs the bullet it is twisting the bullet along the burr and causing it to score around circumference of the bullet as I close the bolt and causing the stiffness. Not until I get the bearing surface below the neck to I avoid the contact.





    Even seated fairly deep the relation of the marking on the bullet and the case neck remains the same





    I also tried a 165gr Hornady A-Max in addition to the 168gr Sierra Match King which I have done most of my testing on but haven't done extensive measuring to know the exact point where an A-Max hits the lands. I didn't get the scoring (or any other clear marking) on the A-Max but the stiffness was still there.

    What I don't know now is what the proper next step is. I suppose I need to order a casting kit and make a cast of my chamber so I can measure things. Are the casts accurate to within 0.01" or do they expand/contract enough that the measurement won't be accurate enough for my needs. I also plan to call Savage to talk to someone in their technical support department. I called today but they needed the serial number which I didn't have at the time. I fear their default answer is going to be to send it back and they will end up drilling out or replacing a barrel that I believe is quite accurate. If that ends up being the only solution then I suppose that's what I will have to do.

    How long does throat erosion take to erode a few thousandths? The gun has only 25 rounds through it. Would getting another 75-100 rounds down the barrel with a reasonably light load potentially solve my problem? Thanks to everyone for suggestions so far and I appreciate your continued help.

  24. #24
    dcloco
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    Blacken the bullet with a sharpie, let the ink dry. This will help to see more of what may be going on.

    Is the bullet only being marked at one spot in the throat?

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    Quote Originally Posted by dcloco View Post
    Blacken the bullet with a sharpie, let the ink dry. This will help to see more of what may be going on.

    Is the bullet only being marked at one spot in the throat?
    I first pressed the round into the chamber without closing the bolt. There were not markings. I then did the same and closed the bolt. The only marking is the same line that runs along the circumference of the bullet just above the neck which is in the pictures above as well. No other markings that indicate contact is being made on any other point on the bullet when chambered (did it twice to be sure).


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