Cammed and Jambed

Discussion in 'Handloading and Reloading' started by HowieG, Jan 16, 2022.

  1. HowieG

    HowieG Member

    Joined:
    Dec 2, 2020
    Messages:
    1,665
    Location:
    Central New Mexico
    I needed to verify the zero on my Remington Mohawk 600 carbine a couple of days ago. This is a used gun I picked up years ago as a project and I have been messing with it ever since.

    I loaded up a few rounds with 87 grain soft points that I intend to use on Javelina. This gun likes bullets out by the rifling, but I screwed up with my seating die, so these rounds were a couple of thousandths longer. I didn't notice until I was out in the desert and had to cam the bullets into the rifling with bolt ala the benchrest guns. Apparently, this gun really likes that. This group is .75" center to center.

    Obviously a cammed load isn't a hunting load, and this wasn't a multi-round testing session, but I found it interesting. Have any of you experimented with this technique for real?

    243jambed.jpg
     
  2. Blue68f100

    Blue68f100 Member

    Joined:
    May 25, 2011
    Messages:
    7,752
    Location:
    Piney Woods of East Texas
    Doing that increases pressure. What do your primers look like.
     
  3. HowieG

    HowieG Member

    Joined:
    Dec 2, 2020
    Messages:
    1,665
    Location:
    Central New Mexico
    I realize that. My loads are tailored for bullets just short of the rifling and they aren't max anyway. Like I said, this isn't a hunting load and not something I would do as a normal practice since I am not a benchrest competitor. It is interesting though.

    243cam.jpg
     
  4. Armorer 101

    Armorer 101 Member

    Joined:
    Jan 6, 2019
    Messages:
    516
    Location:
    Florida
    Did you not check the seating depth on just one laded cartridge with a magic marker before you loaded up a bunch of these? Come on, that is reloading 101 stuff.
     
  5. HowieG

    HowieG Member

    Joined:
    Dec 2, 2020
    Messages:
    1,665
    Location:
    Central New Mexico
    Who says I loaded up a bunch of these?? I missed that part. Paw through your loading history and let me know if you are perfect. I am sure you aren't unless you just started loading yesterday. Even then, I bet you aren't.

    I loaded up enough to check my zero. It isn't the first time I've loaded these. After the first round, I checked the fired case using my nearly 50 years' experience, and it was fine, so I proceeded with what I needed to do. I corrected the setting on my micrometer seating die after the fact.

    By the way, I don't ever use a magic marker. If I am going to check, I use a micrometer and a bullet comparator. I already know when that particular bullet contacts the rifling in that particular rifle. I actually want this bullet to be up close and personal with the rifling in this gun.

    Another thing I do, if I am going hunting, is run every single round of my carry ammunition through my rifle to make sure there are no problems with the brass or anything else. I don't bother doing that if I am doing benchwork.
     
    Show Me and dh1633pm like this.
  6. dh1633pm
    • Contributing Member

    dh1633pm Contributing Member

    Joined:
    Apr 28, 2009
    Messages:
    3,868
    Location:
    Central New York
    Never used a sharpie in all my years. Just use the OAL from the manual.
     
    Show Me likes this.
  7. 243winxb

    243winxb Member

    Joined:
    Jul 7, 2004
    Messages:
    12,994
    Location:
    Hopewell Big Woods
    Nice group.

    This centers the round in the chamber & gives better starting pressures. Better for accuracy, till a loaded round needs removed. Light neck tension, pulled the bullet, letting IMR4350 laying in my action.

    My 243 Win Mohawk likes Redding type S fl bushing die. I size 1/2 of the necks, to center rounds.
     
    Demi-human and HowieG like this.
  8. HowieG

    HowieG Member

    Joined:
    Dec 2, 2020
    Messages:
    1,665
    Location:
    Central New Mexico
    I actually removed a chambered round for a test and it came out okay. Just enough rifling engagement for me to feel it when I closed the bolt. A very good point, though, on why you don't want to do this kind of thing with hunting ammo. You might actually need to remove the round.

    I guess if you think you have a long round, you could raise your muzzle up some and slowly extract the case.
     
    Demi-human, AJC1 and 243winxb like this.
  9. AJC1

    AJC1 Member

    Joined:
    Jan 14, 2020
    Messages:
    6,386
    Location:
    Memphis
    I need to do this on my lead cast rounds for 308 but I got the mold after it already got cold. Havent fired a rifle in months. The rcbs casting manual says ti limit jump.
     
    Demi-human likes this.
  10. Demi-human

    Demi-human Member

    Joined:
    Dec 8, 2016
    Messages:
    5,182
    Location:
    The Haymarsh, MI (Aka, Paradise.)
    That is how I load for my Savage M12.
    From a test ran .020” out of to .020” into the lead I found that .000-.010” into the lands shoots smallest.
    And because of my lighter neck tension anything past .016” into the leads will soft seat to 1.916” on my comparator.
    The bullet, for all intents, is jammed firmly into the rifling. It still extracts without pulling the bullet, but being a target rifle I don’t usually have to.
    On a hunting rifle I would just try it first. It may not need to jam as hard as one would think to get an accuracy improvement.
     
  11. edwardware

    edwardware Member

    Joined:
    Feb 23, 2010
    Messages:
    4,009
    I wouldn't give up on that quite yet. You might be able to enjoy the benefits of jamming the bullet on chambering with very little force, low enough to extract consistently.
     
    Demi-human likes this.
  12. MEHavey

    MEHavey Member

    Joined:
    Jul 27, 2010
    Messages:
    4,033
    Location:
    virginia
    Given the extreme camming leverage of a bolt action, you would likely not even feel such engagement.

    That said, engagement is not necessarily bad at all, if the engagement. . .
    - Is light enough to just leave marks on a "sooted" bullet
    - Is carefully controlled to remain at that light level and not truly "jam hard"
    - Is the result of load work-up
     
    Demi-human likes this.
  13. jmorris

    jmorris Member

    Joined:
    Sep 30, 2005
    Messages:
    19,496
    I have played with OAL quite a bit. As noted it can change pressures, I have also seen the technique straighten bullets that were crooked. You could measure for this with a runout fixture.

    As a rule I don’t like loading ammunition that will not eject without help from the bore end. So if the load likes the increase of operating pressure, I’d seat slightly less for clearance and work up the load to compensate and see how it likes it.
     
  14. swg1

    swg1 Member

    Joined:
    Feb 15, 2020
    Messages:
    445
    I’ve inadvertently done it with some 45-70 in a Ruger No1. While the extractor looks kinda wimpy on that rifle, it is more than capable of pulling a four hundred grain bullet from the case and covering the bench in 3031 upon ejection as I recall. Been awhile.

    I’ve used a sharpie many times as well when reloading for a number of uses.
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice