Page 1 of 2 12 LastLast
Results 1 to 10 of 18

Thread: Bumping shoulders

  1. #1

    Bumping shoulders

    Hi All,
    Apologies to those who have read or posted about this subject previously , the more I learn regarding reloading, the more questions I have.
    In the persuit of accuracy , in what is fundamentally a long range vermin round , would the collective consider "bumping the shoulders " worthwhile, as against F/L sizing of the brass ?
    I have read numerous posts on this , as is often the case , there appears to be no definitive answer . However I'm interested in what others have experienced .I should clarify I'm referring to partial full length resizing not neck sizing.
    Last edited by MarkT; 26-09-2016 at 20:48.

  2. #2
    A partial full length resize that moves the shoulder back to a predetermined length usually a few thou shorter than the rifles chamber size is both beneficial for accuracy and works the case less.

  3. #3
    FL sizing if the die is set correctly, should only bump the shoulders back between 1 and 3 thou. Mine is set for 1 thou, occasionally giving a zero headspace or 1.5 (never can get it more consistent than that). Providing your loads aren't overly hot, you'll get plenty of reloads even if FL sizing. Just anneal after each firing for consistent neck tension. I've trialled neck sizing V's FL sizing and have come to the conclusion that there's little if any advantage to just neck sizing, but it is a right royal pain if when in the field, a round fails to chamber due to the head having expanded slightly or the shoulders needing bumped. I've lost several critters that way, usually accompanied by some fairly colourful expletives, hence I only neck size for my .223 target rounds. The other cals all get FL sized. Using a chrony and checking ES and SD of the corresponding MVs, in my case anyway, neck tension appears to play a greater role in inconsistencies than how they were sized. Annealing helps. After some posts by Muir on the subject, I have also started (again) to give the Lee factory crimp a try as that reputedly also helps consistency.

  4. #4
    Cheers for the replies,
    Perhaps the first thing I should do is measure the head space set by my F/L die (I've got a gauge),when resizing.
    I take your point regarding being unable to cycle a round in the field, if I can get dust blown into my eyes then it can fowl the chamber .
    I did post the crimping question not so many days ago and received some very compelling replies , Muir has me convinced as well .
    I'm not running an especially hot load , 87grain Vmax over 44.2 grains of RS 62 with the OAL set at 2.7". A little tweeking to do, however anything that may improve a rounds accuracy has to be considered.
    I have no mentor to speak of hence a lot of questions.
    Thanks for the help. Straight lead,

  5. #5
    The rifle chamber is your best gauge for setting up your sizing die.

  6. #6
    Quote Originally Posted by takbok View Post
    The rifle chamber is your best gauge for setting up your sizing die.
    I think we're talking about the same thing , measured difference between a fire formed and a full length sized case.?

  7. #7
    Yes, we're more or less on the same page but I was meaning that you can remove the measuring step and just adjust your die until you get the resized cases to chamber snugly (a small amount of resistance to close bolt).

  8. #8

  9. #9
    Quote Originally Posted by MarkT View Post
    If using that method Mark, best to remove the firing pin from the bolt first. It still pays to use the comparator gauge and check the comparative length to the point at which a fire formed case chambers whilst just feeling resistance when closing the bolt. That gives you "Zero" headspace. You can set the die to that or a thou or two under. However; it's largely academic if you already have a gauge. Once a fire formed is measured (why do some have an aversion to measuring stuff???), you get the same result, but a lot quicker!

  10. #10
    From my point of view it'll be interesting to measure, then I've got that data for the future and a little more knowledge as well.I may be more than a little OCD.
    Since a partial sized case would have different unfired dimensions to a fully sized case would I have to redevelope the load?
    They say there are no stupid answers just stupid questions, apologies if this is the lata.

Similar Threads

  1. bumping the shoulder back
    By drummerboy in forum Ammunition, Reloading & Ballistics
    Replies: 9
    Last Post: 12-09-2015, 14:45
  2. Through the shoulders?
    By Fursty Ferret in forum Deer Stalking General
    Replies: 54
    Last Post: 19-08-2013, 09:55
  3. boning shoulders
    By ruby tuesday in forum Carcass Prep, Butchery & Recipes
    Replies: 6
    Last Post: 13-04-2013, 17:57
  4. Sloppy shoulders
    By Fabnosh in forum Equipment & Accessories
    Replies: 14
    Last Post: 10-01-2011, 22:10
  5. 'Bumping' Deer
    By novice in forum Deer Stalking General
    Replies: 1
    Last Post: 07-05-2008, 20:42

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts