Forster Bushing Bump Sizing Dies

Discussion in 'Reloading' started by cross, Mar 12, 2009.

  1. cross

    cross Well-Known Member

    May 30, 2007
    I've read in various places that expander balls/mandrels on standard full length sizing dies can tweek the case mouths and cause a decrease in accuracy.

    I would like to get a set of bushing type dies but don't know how to figure out what size of bushing I need. I'm interested in the Forster Bushing Bump Sizing Dies for my 7mm Rem and the Forster website gives dimensions of the bushings that come with their kit as (.308, .306, .304).

    What do I need to do to determine the size of bushing die that I need?

    Does anyone here recommend the Forster Bushing bump dies or should I be looking at the Lee Collet dies?

    Will the Lee Collet dies give you any shoulder bump and if not, do you recommend hunting with cases that have only been neck sized?


  2. boomtube

    boomtube Well-Known Member

    Oct 8, 2007
    "...should I be looking at the Lee Collet dies?"

    Yep. It doesn't touch the shoulders at all.

    I don't take any ammo hunting until it's been chambered from the magazine, method of sizing doesn't matter. If it feeds and chambers at home it will in the woods.

    Most of my hunting ammo has been collet neck sized.

    The only way to get CONSISTANT neck/bullet tension with a bushing die is to turn the necks to a consistant thickness. Not really worth it for factory rifles and hunting ammo. IMHO.

  3. woods

    woods Well-Known Member

    Jun 4, 2006
    Hey cross

    One thing you need to know about the Forster Bump Die is that it does not size the case body. Now I do not know this because I have one but was wondering if it did so I e-mailed Forster and got a quick and short answer from Dee in customer service. Still concerned I asked her to ask my questions of a tech and got the following reply

    "Dee referred your query to me and here is ,hopefully, the answer to your concern. Your question is important to us. You mentioned that you "were leery of creating a bulge in your case body". Answer: The body of the Bushing Bump die is designed to push the shoulder of the rifle case back only .001" or .002". This is just enough to support the case and to keep the body of the case in good alignment while the neck of the case is being squeezed down to a smaller dimension. If one were to try to push the shoulder back much more than .002" you may develop a problem with case "bulge". Best regards and good shooting, Bob Ruch @ Forster Products Inc."

    What this means is that when your case grows and you need to size the case body then this die will not do it. Unlike the Redding Bushing Dies which will size the case body unless they are the Neck Sizing Bushing Dies. Perhaps you will not have to size the case body but I have found that the case will start to bind after several firings along the case body in most cases.

    The Redding Body Die will push the shoulder back and size the case body (unless you have a minimally sized custom chamber, don't ask me how I know). With the Lee Collet to size the neck with minimal runout and the Redding Body Die to size the case body and push the shoulder back you will have a good set of dies to neck size when you can and push the shoulder back when you need to.

    However, the Lee Collet neck sizer does not give a lot of bullet grip, only .001" to .002". If you can't or don't want to live with that then the Lee Factory Crimp Die is a good solution.
  4. phorwath

    phorwath Well-Known Member

    Apr 4, 2005
    I use a 0.310 and neck bushing in my Redding Bushing-Style Neck Sizer Die - for my 7mm Rem Mags.

    I've not yet come to appreciate the role of the Forster Bump Sizing dies. It seems like it's a specialty die and that other reloading dies will, at times, also be necessary. Like a Redding Body Die or a normal FL resizing die.

    Anyhow, those Forster supplied bushings are all substantially smaller than the neck bushing I use, and I outside neck turn my cases also (this should require a slightly smaller neck bushing compared to cases that haven't been outside neck turned - yet I still get by with the 0.310" bushing).
  5. BountyHunter

    BountyHunter Writers Guild

    Jun 13, 2007
    Most of the time with a magazine gun you will need .002-.004crimp to hold the bullet.

    So start with a loaded round and see what it measures. Lets say a 308 caliber of some type and it measures .339.

    You will get a .001 springback in the neck after you size, so you have to plan for that also.

    So in this case, .339-.001= .338-.002=.336 bushing or .338-.003= .335, giving you a .335 neck bushing.

    I would go .335 and .336 to start and if the bullet slips, go with a .334

    No you understand that they the Forester will not FL size, so plan on using a Redding body die at least every 3 shots or so.

  6. cross

    cross Well-Known Member

    May 30, 2007
    Thank you Boom, Woods, Bounty, and Phorpath for the information!
  7. RockZ

    RockZ Well-Known Member

    Mar 10, 2006
    All of the above is very good advice.
    I use a forster bushing bump die for my custom 6.5wssm.
    It allows very precise control of the neck and headspace dimensions without overworking the case. I ordered the bushing size as outlined above.
    And yes I also use a redding body sizer as well. It is necessary.
    For sizing the inside of the neck for neck turning I use a sinclair mandrel.
    This system provides me with rounds with almost no runout. .0005-.0001.

    I also use the Lee dies for my tactical 308win and they turn out very accurate ammo as well.
    Lee are surprisingly good dies for the price.

    For a factory 7mm Rem , if that is what you have, the Lee dies will work very well for your application. You will get good results without all of the extra effort.
  8. cross

    cross Well-Known Member

    May 30, 2007
    Great info RockZ! Thanks!