Rem 700 bolt lift

Discussion in 'Gun Project Questions & Gunsmithing' started by Dr.Lee, Jan 30, 2014.

  1. Dr.Lee

    Dr.Lee

    Joined:
    Jan 3, 2011
    Messages:
    42
    the rifle is a well built 6 br 600 yd gun. In the interest of lightening bolt lift someone suggested cutting the firing pin spring.
    What will the reduced force do to accuracy ? Other than polishing which has already been done, what other ways can you reduce 700 bolt lift effort.
    thanks
    Lee
     
  2. WayneShaw

    WayneShaw

    Joined:
    Dec 2, 2005
    Messages:
    419
    Really? Timing?

    Without the influence of a fired round in the chamber, cocking the firing pin is where bolt lift comes into play. A heavy spring certainly has the most effect, the cocking ramp, cocking piece, bolt handle length has some too. You can cut or replace the spring with a lighter one, but at some point, ignition will start to suffer.

    BAT's roller on the cocking piece is the best effort to reducing bolt lift, aside from lightening the spring.
     
  3. Dr.Lee

    Dr.Lee

    Joined:
    Jan 3, 2011
    Messages:
    42
    What happened to the first reply referencing the bolt timing ? Was it deleted ? Why ?

    Dr.
     
  4. dmoran

    dmoran Gold $$ Contributor

    Joined:
    Nov 25, 2004
    Messages:
    2,639
    If primary extraction is not timed on cam first, all your mentions points have little meaning.
    Primary extraction timing comes first, then all other aspects like you referred to fallow in line after.

    Good points all the same....
    ---------------------------------------------------------------------------

    Dr.Lee

    Here is a good video on bolt timing and enhancements (by SSG):
    http://www.onetruemedia.com/otm_site/view_shared?p=8b22387aaa58bd1650a1ad&skin_id=601&utm_source=otm&utm_medium=image

    Good Luck
    Donovan Moran
     
  5. WayneShaw

    WayneShaw

    Joined:
    Dec 2, 2005
    Messages:
    419
    You go through 80-90% of bolt lift before primary extraction takes place, cocking the spring.
     
  6. dmoran

    dmoran Gold $$ Contributor

    Joined:
    Nov 25, 2004
    Messages:
    2,639
    On a Rem-700 as the OP is asking, if your not on cam the instance you start lifting the bolt handle, your not in time.
    All cocking and spring depression happens while lifting on cam and traveling across the primary extraction cam.
    When the handle is up, on top of primary, extraction is complete including all firing pin assembly movement.
    2) Pull the bolt back for ejection and loading.
    3) Push the bolt ahead to the top of the cam.
    4) Close the bolt down, back down across the cams.
    5) Pull trigger and repeat.....
    Hence the words: bolt timing
     
  7. jsthntn247

    jsthntn247 Silver $$ Contributor

    Joined:
    Mar 9, 2010
    Messages:
    1,474
    Dan at accutig tiged and timed my bolt. It's smoother than anything I own now.
     
  8. Dans40X

    Dans40X Welder

    Joined:
    Nov 27, 2004
    Messages:
    1,224
    DrLee-
    There are several TIMING issues involved.
    Wayne-
    You're spot on!
    dmoran-
    You need to look at the big picture,'cause a you tube video apparently has you in a state of confusion.
    Firing pin cocking/timing starts as soon as you start rotating the bolt out of battery,primary extraction starts approximately 70 deg later & pin cocking ends at the 90 deg position.
    jsthntn247-
    Brad,glad I could be of service.
     
    dgray and gunsandgunsmithing like this.
  9. dmoran

    dmoran Gold $$ Contributor

    Joined:
    Nov 25, 2004
    Messages:
    2,639
    Dan - tell us how they open when they have poor timing, but with good "firing pin assembly" geometry.
    Like for instance, say the primary is 10-degrees off, how does the bolt lift?
    Excessively hard on top would be my input, no matter what the spring or bolt handle.

    Also , say you have a stiff spring and good timing, how would that compare for "bolt lift" compared to poor timing and a soft spring?

    In closing, as I read Wayne's input, he is saying the firing pin assembly and bolt handle is what matters, and not at all timing of the handle and bolt body.
    For myself, "firing pin assembly" is meaningless until bolt timing is correct on cam and primary, then I agree with Wayne's good pin assembly inputs.
     
  10. X Ring Accuracy

    X Ring Accuracy Site $$ Sponsor

    Joined:
    Feb 11, 2009
    Messages:
    580
    If bolt is timed correctly, a little smudge of grease on the bolt lugs and the extraction ramp on the action helps. If you can, take the bolt should off and a little lube on the firing spring helps.
     
  11. Dans40X

    Dans40X Welder

    Joined:
    Nov 27, 2004
    Messages:
    1,224
    dmoran-
    Referencing an un-molested Remington-
    First off, the proverbial ding/divet & persuant BURR that is pushed up into the bolt handles extraction cam surface is caused by being TIMED into battery/the handles drafted 35* surface is too steep & doesn't match the receivers drafted 35* surface hitting the RH side of the receiver primary extraction cam surface upon pushing the bolt fwd.
    Operational for a field/hunting rifle but not ideal.

    ANY OEM Rem bolt body & handle after "D" prefix serialized receivers(ISS/J Lock) there are several issues that were not performed-cutting operations/cuts manufacturing costs.
    1.Bolt bodies were not cut under the handle for bolt lock safeties.
    2.Bolt handles are not tempered.
    Current "G" & "RR" bolt handles have been redesigned into a "SHORT CAM" as I refer to them to eliminate the dreaded ding/burr.
    Current OEM Rem bolt handles are JUNK to say the least.

    Firing Pin Timing-
    OEM Rem & 90% of the Custom CLONES are timed identically w/ bolt in battery.
    (hint-if the manufacturer fabs his own bolts/handles/shrouds is the exception)
    All other custom clones are -you guessed it -monkey see monkey do.

    The Rem is cock on open-
    Rocket Science is commencing here-they are also COCK on CLOSED unless modified.
    Until being modified,depending on how you cycle the bolt will change trigger pull in excess of 3/4 Lb & I don't care whose trigger group is installed or who molested it.

    Installing a lighter firing pin w/ heavier spring to ensure ignition is a marketing scam & makes for even tougher bolt manipulation.

    Of the hundred or so personal Remington in my possession,none have broken a firing pin & needed to be replaced w/ aftermarket units.
    Springs replaced-yes,as steel relaxes & takes to memory.

    When bolt handles & firing pins are properly LOCATED & TIMED bolt manipulation can & is accomplished with TWO fingers.
     
  12. WayneShaw

    WayneShaw

    Joined:
    Dec 2, 2005
    Messages:
    419
    I'm not sure how the Remington extraction surfaces came to be, but they ain't pretty. To me, they don't make sense, the surfaces don't match, they are angled, etc. Give me a custom where the cam is SQUARE with the bolt, the bolt handle is SQUARE with the bolt, the angles MATCH, what's not to like? The bolt comes up, they mate nice and snug, and the bolt comes back.
     
  13. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

    Joined:
    Feb 4, 2007
    Messages:
    1,845
    Yep, some of the customs just have a radius on the handle, where it meets the cam on the action. If the two mating sufaces were PERFECT, the mating cams would be fine...but there is no such thing as perfect...just lesser degrees of f'd up.--Mike Ezell
     
  14. WayneShaw

    WayneShaw

    Joined:
    Dec 2, 2005
    Messages:
    419
    I agree, they are all not made equal. BATs and Bordens are great. For some reason Farley used the same stupid Remington style. A Panda has a steel rubbing surface, but the root of the bolt handle mashes down after use.
     
  15. X Ring Accuracy

    X Ring Accuracy Site $$ Sponsor

    Joined:
    Feb 11, 2009
    Messages:
    580
    Hence my advice for some lube on the primary extractor on the action. They will chew themselves up working. Not anything to consider, just my experience.
     
  16. snowshoe

    snowshoe

    Joined:
    Nov 15, 2009
    Messages:
    13
     
  17. Will Henry

    Will Henry

    Joined:
    Dec 8, 2013
    Messages:
    63
    Did not realise just to what extent bolt lift was related to rocket science until reading this thread. From the viewpoint of one who is just an old gunsmith, bolt lift is influence by three things: the spring rate, the cocking cam finish and hardness, and the extraction cam (if cases are sticking at all). To reduce the effort required to cock the rifle, hardening and polishing the cocking cam will do wonders; especially on a 700. Heat with oxy-acetylene torch with a slightly carburizing flame until it is bright red then quench in oil. Use a small, intense heat and don't dawdle. Polish with a felt bob and jeweller's rouge in a Dremel or by hand with 600 grit or finer wet or dry paper.
    As far as the extraction is concerned. The handle can be re-located and the base of the handle re-shaped to maximise primary extraction. One of the better repairs I made involved the insertion of a hardened pin at the bolt handle base to provide the contact point between the bolt and receiver. I once made a roller insert which worked very smoothly but I didn't really like it because I don't like the addition of moving parts. WH
     
  18. BoydAllen

    BoydAllen Gold $$ Contributor

    Joined:
    Jun 13, 2005
    Messages:
    6,320
    What we may be dealing with is different definitions of cock on close. What I mean when I use the term is that as the bolt is closed, not far off of the top of the handle's stroke the cocking piece makes contact with the top lever of the trigger before the flats on the back of the lugs have started to overlap the surfaces in the actions lug abutments that are perpendicular to the bolt center line. When this happens the leading edges of the lugs are still on the closing cams and in order for the bolt closure to be completed the firing pin spring must be compressed as to the point where the edges of the lugs clear their closing cams and start across the flat parts of the abutments.
    As the bolt handle's down stroke starts I first feel the effort that comes from the spring having to be compressed slightly as the cocking piece is moved out of the indexing notch just past the top of the cocking cam, and then I will feel a second resistance began when the cocking piece contacts the trigger's top lever if the lugs are not yet on the main surface of their abutments in the front receiver ring of the action. From that point until they reach their engagement surfaces, I am compressing the firing pin spring. Many custom actions have trigger hangers that make some provision for moving the trigger fore and aft in the action so that the trigger contact point can be adjusted. The problem with this approach is that it also has an effect on the length that the firing pin falls. The only way to get around this seems to me to be altering parts, namely the cocking cam and the firing pin. To restore lost cocking travel the cam notch can be deepened slightly extending the cam length at its bottom, but for this to be utilized the shoulder of the pin must be thinned a corresponding amount on its front surface, and to keep the protrusion the same the tip of the pin should also be shortened. Finally, although I do some of my own work, I am most emphatically NOT a gunsmith. This is just my take on the issue. Feel free to comment, criticize, and correct.
     

Share This Page