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Forster - shoulder bump not enough

JL6.5

PrrrressssBANG
Minuteman
  • Sep 13, 2020
    56
    13
    SoCal Desert
    Just about to reload my first batch of once fired brass (Hornady Match). Since it is my first time, I am being extremely methodical and precise. My fired cases measure 1.5330” using a Forster datum dial. When I setup my Forster FL sizing die on my Forster Co-Ax press, it will only size down to 1.5315” (1.5 thousandths) before the die is bottoming out on the shell holder and the cam over is very hard/nearly impossible. At this point the die is bottomed out and cannot size any further.

    Seems like shaving a.001-.002 off the bottom of the die would be the logical answer (that or sending the die and a fired case to Forster and let them figure it out).

    However I’d like to employ the opinions of others who are more experienced on this issue than I and hopefully correct this seemingly easy issue myself.

    Educated/sound advice would be greatly appreciated. Thx guys.
     
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    I use the Redding Competition Shellholder Set and make the bump adjustments with the shellholder, not the die ram depth. Had the same issue trying to do this with the die vs. the shellholder. That's my advice.
     
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    Two choices : Remove material from bottom of die , or remove material from top of shell holder.
     
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    Should have mentioned that I’m using a Forster Co-Ax press. No shell holder.

    So,…..what’s the best way to shave a die without access to a lathe? File, sand, polish?
     
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    I had the same issue with my Mighty Armory die where I couldn’t size the case w/the shoulder bump I wanted so they took off .002” from the die. No problems achieving the desired bump now. I also use a CoAx.
     
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    Can you close the bolt on the sized cases easily?
    Good question.......if he can , there's no problem with his setup.

    @ O P..........I seen material removed from die by holding it against the side of a " cutoff wheel " .......crude ,yes ,but it works when only a tad needs removing
     
    1) I run the same amount of bump because it's all I can get. If you can close your bolt just fine like I can I wouldn't worry about it.

    2) However, I wouldn't doubt it if you sized all your brass again it will take another 0.005 - 0.001" off if you really just want the number to be 0.002
     
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    So,…..what’s the best way to shave a die without access to a lathe? File, sand, polish?
    Easy answer is to let forster know they made the die too long.

    The "proper" way Ive heard about is to put a piece of sand paper down on a piece of glass for a really flat surface and to run the die bottom over it in figure 8s to try and keep it even when its sanding it off. Seems like it would take forever.
     
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    6.5CM ? Not so long ago they announced that there was a bad batch in circulation that had this issue. Send it back in.
     
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    How is it an issue?
    Good question. I’m interested in this answer also.

    To the OP, I’ll reiterate what some have said. If it fits in the chamber and bolt closes easily, forget about that extra 0.0005” and shoot it already. I’d actually prefer that over 0.002” anyway if it was consistent and I often end up with just that amount.

    Two things that you should know. First off, it’s extremely unlikely that your calipers are capable of accuracy to less than 0.0005” anyway. I’d bet on it in fact, unless you paid much more than $200US for them. Second, bench rest shooters would never want to bump the shoulder back more than 0.001” and typically prefer neck size only for very specific reasons.

    You are worrying about a thing that doesn’t matter. It’s not uncommon with first time loaders, so don’t take it personally.
     
    First off, it’s extremely unlikely that your calipers are capable of accuracy to less than 0.0005” anyway. I’d bet on it in fact, unless you paid much more than $200US for them.
    This!! I always thought this was bull****, but then I upgraded my $30 amazon calipers w/ 0.0005 resolution to mitutoyo. The amazon ones were off by a whole 0.0015"!!! There was a very very small air gap at the top of the calipers you could barely see at the right angle.
     
    Good question. I’m interested in this answer also.

    To the OP, I’ll reiterate what some have said. If it fits in the chamber and bolt closes easily, forget about that extra 0.0005” and shoot it already. I’d actually prefer that over 0.002” anyway if it was consistent and I often end up with just that amount.

    Two things that you should know. First off, it’s extremely unlikely that your calipers are capable of accuracy to less than 0.0005” anyway. I’d bet on it in fact, unless you paid much more than $200US for them. Second, bench rest shooters would never want to bump the shoulder back more than 0.001” and typically prefer neck size only for very specific reasons.

    You are worrying about a thing that doesn’t matter. It’s not uncommon with first time loaders, so don’t take it personally.
    Good info. Thank you. Not taking anything personal here. Hard to learn anything if I can’t take some constructive criticism.
    My main reason for wanting a full .002” bump is I shoot in the SoCal desert and we have A LOT of blowing sand and dust. I plan to shoot PRS style matches where it is very possible to get this type of debris in my chamber so I figure the extra clearance could only help. Maybe I’m being over cautious. Just trying to follow the advice of some other respectable pro shooters.
    Also, for what it’s worth, I’m using Mitutoyo 500-196-30 AOS calipers. They aren’t quite $200, but they aren’t cheap and I know a lot of people use them. They are pretty darn accurate and repeatable (enough for what we are doing anyway. All that said Im guessing that once I test the sized case in my chamber it’s probably going to to be just fine. Thanks for your input. Much appreciated 🙏🏻.
     
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    For those interested, my comment above about accuracy was not meant to be a slight or exaggeration. It’s just a simple fact of repeatable accuracy. I have those same calipers and here’s the actual accuracy expectation from the mitutoyo website:

    BF4EECBF-98B9-442A-910E-207A8FA0C714.jpeg


    Thus, my comment on not worrying about what that ten thousandths digit is telling you. Just because the digit displays does not mean that’s the level of accuracy you are getting.
     
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    If it freely chambers, shoot it. If not contact Forester. Life is simple until you look for ways to complicate it.
     
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    Easy answer is to let forster know they made the die too long.

    The "proper" way Ive heard about is to put a piece of sand paper down on a piece of glass for a really flat surface and to run the die bottom over it in figure 8s to try and keep it even when its sanding it off. Seems like it would take forever.
    Had this problem with my 7mm Niedner Mauser. Put an extra shell holder in my drill press using a bolt and nut through the primer hole. Checked table for square to arbor. Wet and dry paper on table. Lowered shell holder sanding and checking size until my bolt closed easily.....
     
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    For those interested, my comment above about accuracy was not meant to be a slight or exaggeration. It’s just a simple fact of repeatable accuracy. I have those same calipers and here’s the actual accuracy expectation from the mitutoyo website:

    View attachment 7630949

    Thus, my comment on not worrying about what that ten thousandths digit is telling you. Just because the digit displays does not mean that’s the level of accuracy you are getting.

    They make certified dial calipers that are as accurate as a micrometer. Starrett also. Cost more but if you want to be sure that’s how you go about it.
     
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    They make certified dial calipers that are as accurate as a micrometer. Starrett also. Cost more but if you want to be sure that’s how you go about it.
    Show me a caliper that is accurate to ±.00005in
     
    Should have mentioned that I’m using a Forster Co-Ax press. No shell holder.

    So,…..what’s the best way to shave a die without access to a lathe? File, sand, polish?
    I had the same issue and no lathe. I found a grinding wheel for a drill that was about 1.5 inches in diameter. I chucked in my drill press, held the bare die body with a bug pair of pliers and then lowered the drill press head till the grinding wheel touched the die. Takes some force and time to grind what you need off stp often and check.

    David
     
    slide a shim stock/ feeler gauge beneath head of case and on deck of shell holder, (effectively raising case in shell holder), and readjust die for desired bump.... I have a piece of .002" feeler gauge taped to my press, use it all the time.... if the die is already too long, Redding Competition Shell Holders won't help....
     
    I had the same issue with a Forster 6BR full-length sizer in my Co-ax press and I returned it to them for neck honing. They ground off the end of the die when they honed the neck and I had no issues after that.
     
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    Same as grizz here. Have them neck hone it when you send it in for shortening.
     
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    I had the same issue with a Forster 6BR full-length sizer in my Co-ax press and I returned it to them for neck honing. They ground off the end of the die when they honed the neck and I had no issues after that.

    Thanks grizzaws. Curious though (since I know nothing about it). What exactly does the neck honing accomplish? Is it just extra polishing of the neck or does it actually changing the dimension? If so, how is it beneficial?
     
    Thanks grizzaws. Curious though (since I know nothing about it). What exactly does the neck honing accomplish? Is it just extra polishing of the neck or does it actually changing the dimension? If so, how is it beneficial?
    Changing the dimension. If you size the neck diameter down more than necessary just to open it back up then all you are doing is “overworking” your brass. So you adjust/hone it to only size down just as much as you feel is necessary.
    Warning: making it size the minimum on one type of brass may not be enough on another and it’s a one way operation.
     
    Changing the dimension. If you size the neck diameter down more than necessary just to open it back up then all you are doing is “overworking” your brass. So you adjust/hone it to only size down just as much as you feel is necessary.
    Warning: making it size the minimum on one type of brass may not be enough on another and it’s a one way operation.
    What he said
     
    I know this is an old thread, but I am having the same problem with my new Forster 6.5 Creedmoor full length sizer die.

    I can't get a .002 bump even at full cam over. I can close the bolt, but I am getting some resistance compared to factory Hornady 140 ELD-M. I think this is the reason I am getting pressure signs early in the form of some primer cratering and ejector marks. Rifle is an MPA PMR Pro which is known to have a tight chamber anyway.

    Based on this thread, I will call Forster tommorow to see what they recommend. I would prefer not to do any adjustments on my end. It sounds like having them shorthen the die and hone the neck to match my fired brass is the ticket.
     
    I can't get a .002 bump even at full cam over. I can close the bolt, but I am getting some resistance compared to factory Hornady 140 ELD-M. I think this is the reason I am getting pressure signs early in the form of some primer cratering and ejector marks. Rifle is an MPA PMR Pro which is known to have a tight chamber anyway.

    No, that is not why you’re getting pressure signs. A tight fit in the chamber does not cause those pressure signs.
     
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    No, that is not why you’re getting pressure signs. A tight fit in the chamber does not cause those pressure signs.
    I know I am off the lands, so the slight resistance on the bolt must be the brass. Accuracy was outstanding, but I saw those minor pressure signs at a much lower load than my other 6.5 CM. I was using standard Hornady Custom Dies previously and never had any issues getting and shooting a .002 shoulder bump in that chamber. I guess it just reinforces that every barrel is different and to always work up loads.