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Inconsistent neck tension

gearguywb

Gunny Sergeant
Full Member
Minuteman
  • Mar 17, 2018
    830
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    Loading 6.5 CM with 140 Hornady.

    FL Redding sizing die.
    Then run the brass through a Sinclair Expander die.
    Bullet seating with LE Wilson seating die and a KM arbor press.

    Issue is that I am getting far too many pieces of brass that take way too much pressure to seat the bullet. I have some Hornady and Prime brass. All of it is 2x fired at most. Annealed prior to re-sizing.

    Looking at the Brownells site (Sinclair) but I do not see any other options for a different size expander mandrel.

    About to load some 300 WM and I am afraid of hitting the same issues.

    Suggestions?

    Thanks!
     
    I have very consistent neck tension using a Lee Collet die.
    On my bolt gun
    Shoot
    Anneal
    Clean
    De-Prime, Redding full length sizing die bumping shoulders .002.
    Run thru Lee collet die
    Clean
    Prime
    dump powder
    Seat
    Shoot
    Repeat

    6.5 AR10
    Shoot
    Anneal
    Clean
    De-Prime, Redding full length sizing die
    Run thru Lee collet die
    Clean
    Prime
    dump powder
    Seat
    Shoot
    Repeat

    I do not neck turn, all my bullet seating pressure is very consistent.
    Anneal every other reload, Lapua Brass, 135 ATips in bolt gun, 140 ELD’s in my gasser, both 6.5 CM
     
    Just went downstairs to do some measuring. I needed a break after last night!

    Took several pieces of brass that were re-sized, ran through the Sinclair expander, etc. Put the necks into the dial calipers and rotated the brass. It was very apparent that they were not "round". No question that there were high and low spots.

    Baffled....
     
    Is your bullet seated deep enough that the bullets bearing surface is at the neck shoulder junction.

    Seating them about .10 off the lands. Groups are pretty good about .4 for 5, just very inconsistent pressure to seat the bullets. Some are taking so much pressure that it moves the arbor press.
     
    Did you understand my question?
    Is the bullet seated deep enough that the bearing surface of the bullet gets pushed into where the neck and shoulder meet.
     
    Did you understand my question?
    Is the bullet seated deep enough that the bearing surface of the bullet gets pushed into where the neck and shoulder meet.

    Took me a minute to realize what you were asking (I will blame it on not enough coffee yet). It is pretty close to the neck shoulder junction.

    I don't think that is the issue. Getting the bullets started takes too much pressure even in the beginning of the bullet seating stroke.
     
    A Lee Collet die will give you good consistent neck tension and very uniform.
    I have ran some stubborn cases through the Collet die and then through the Redding neck sizing die with a .289 neck bushing and back through the Collet. All my seating on a Dillon 750 requires the same hint of pressure and very smooth throughout the seating process.
     
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    So you are resizing using a fl die without the expander button on the die then you are pushing a expander mandrel into the neck.
    Correct ?

    Are you properly chamfering the necks? No way should the necks be out of round, what are the measurements for the out of round necks.
     
    Just went downstairs to do some measuring. I needed a break after last night!

    Took several pieces of brass that were re-sized, ran through the Sinclair expander, etc. Put the necks into the dial calipers and rotated the brass. It was very apparent that they were not "round". No question that there were high and low spots.

    Baffled....
    It helps to have numbers. What were the high and low numbers for your neck OD after the mandrel? What is the actual diameter of your mandrel? Did this problem just start and everything was fine before?

    If you have a piece of brass with varying neck wall thickness, and you push it over a mandrel, you push those defects to the outside of the neck. Not baffling at all the neck OD would vary, but the amount matters. What are the neck diameters post sizing, and then post mandrel? What neck bushing if any?

    Maybe I misread, but are you mixing brass brass makes within the batch?

    Your problem is something simple. Mandrel mismarked and undersized, insufficient or shoddy inside neck chamfer, mixing brass makes and expecting the same results, lube conditions, galled necks, etc
     
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    Loading 6.5 CM with 140 Hornady.

    FL Redding sizing die.
    Then run the brass through a Sinclair Expander die.
    Bullet seating with LE Wilson seating die and a KM arbor press.

    Issue is that I am getting far too many pieces of brass that take way too much pressure to seat the bullet. I have some Hornady and Prime brass. All of it is 2x fired at most. Annealed prior to re-sizing.

    Looking at the Brownells site (Sinclair) but I do not see any other options for a different size expander mandrel.

    About to load some 300 WM and I am afraid of hitting the same issues.

    Suggestions?

    Thanks!


    You're going to be hard pressed getting consistency using different brass. Hornady and Prime (Peterson, I'm assuming)

    Are you chamfer/deburring?

    Also, how are you annealing? Flame or induction? Either way, 2 different brands of brass will anneal at different times.

    Have you tried, say, 10 or 20 pieces of the same brand brass and making sure everything is the same (brass length, times fired, etc.). Not being condescending, but, one can't expect consistent results with inconsistent prep work.

    As far as different size mandrels. I turn my own mandrels to suit the neck tension I want. But, I have a lathe, too. If you don't, I'm sure a local machine shop will turn one for you.
     
    Outside diameter

    You need to use something like a pin gauge and verify they are all the same neck tension. If they are, it’s a friction issue and you need to use lube or graphite.

    If you use a gauge pin and you’re getting different neck tension, then it’s probably a inconsistent spring back issue.
     
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    You're going to be hard pressed getting consistency using different brass. Hornady and Prime (Peterson, I'm assuming)

    Are you chamfer/deburring?

    Also, how are you annealing? Flame or induction? Either way, 2 different brands of brass will anneal at different times.

    Have you tried, say, 10 or 20 pieces of the same brand brass and making sure everything is the same (brass length, times fired, etc.). Not being condescending, but, one can't expect consistent results with inconsistent prep work.

    As far as different size mandrels. I turn my own mandrels to suit the neck tension I want. But, I have a lathe, too. If you don't, I'm sure a local machine shop will turn one for you.


    My Process:
    Make sure brass is pretty clean
    Anneal with Annealeez
    FL size/deprime
    Trim with Giraud
    Run through Sinclair expander (E26)
    Hand Prime
    Powder drop
    Bullet seating with Wilson seater

    I have tried limiting to one type of brass. This has been ongoing but seems to be worse now (or I am just more aware of it. This brass is Prime, once fired
     
    E26 is the Sinclair Stainless expander, so lubrication is absolutely a must to prevent galling. In my experience even dry lube isn't enough, I would suggest you upgrade to at least their TiN Coated mandrels or use a q-tip to apply wet lube to the inside of the neck.

    I thought someone else mentioned it, but are you using a FL die with the button removed? You may be over sizing the necks and creating too much tension, even with the expander die. FL dies typically way oversize neck brass. Either expand the necks twice, or upgrade to a bushing die.

    Third, I chamfer prior to seating and I usually give a healthy chamfer. Use a VLD chamfer tool as well. I also keep dry lube on the necks to smooth out bullet seating. If I don't have enough chamfer I can feel it during seating and will typically ring the bullet nose.
     
    A Lee Collet die will give you good consistent neck tension and very uniform.
    I have ran some stubborn cases through the Collet die and then through the Redding neck sizing die with a .289 neck bushing and back through the Collet. All my seating on a Dillon 750 requires the same hint of pressure and very smooth throughout the seating process.

    THIS! Beat me to it. Was just going to recommend trying a Lee Collet die. OP, the collet die neck-sizes the case around a mandrel, and de-primes all in one stroke. And the way it's designed, you don't even have to lube the case. And they're inexpensive as well. The interior dimension of your case neck (which creates your neck tension) will be very nearly the same for every case. Much more consistent than traditional dies.
     
    So do you just use the collet in place of any FL or bushing die?
    Works fine in a CoAx press?

    Yes. In place of FL or bushing dies. As far as the Coax press, I don't have personal experience with one. I don't see why it wouldn't work, but perhaps someone who's used one on a Coax could chime in.

    One thing, after several (3 or 4) firings, you may need to run your brass through a body die to bump the shoulder back a bit. For that operation, you would need to lube the cases. When I do that, I run them through the Lee Collet die first (I'm loading on a Dillon 550B so I prime the case on the upstroke), then the body die, then charge the case, then seat the bullet. Used a Lee Classic Cast single-stage press with the same operations before switching over to the Dillon.
     
    So do you just use the collet in place of any FL or bushing die?
    Works fine in a CoAx press?

    I’d still run them through a die and FL/bump shoulder. Just add the collet die step in instead of mandrel in your process. Not FL sizing us asking for trouble unless you only shoot leisurely at the range
     
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    The more I think about this....I may try to run a piece of brass through the sizer without trimming. I wonder if the Giraud could be cutting off center....


    IME the Giraud only cuts brass 'off center' is if the brass is off center (i.e. runout). If I see unevenness in the chamfer, it is an indicator that something else is wrong before that in the chain. I notice a difference in the consistencies of the chamfer with different dies.

    Also, like Pvt Donut said - if your lube isn't right or consistent, it can be screwing with your necks.

    I'd start at the beginning and either check your sizing or annealing. Try some that aren't annealed maybe.

    Edited for typo.
     
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    Thanks guys. I am FL sizing with the button in place. Also using that to deprime. I will try a few different option tonight or in the morning.

    Going to try a few cases without running them through the Giraud and will also see if I can remove the button (not sure but I think that needs to be in place to de-prime.
     
    So, you’re using button and an mandrel?

    Yes. So I guess this will put me in the lead for "Dumb question of the day", but if you take the button off, how are you de-priming? Using some type of die that does not use a button to hold the decapping pin?

    I must be old....For a million years I just used a FL sizing die and a bullet seating die......
     
    I use a dedicated decapping die on my progressive as the first step of my process. Mostly because its a dirty step that I like to keep separate from everything else. It also allows me to get into the primer pockets when tumbling.

    There's also hand decapping. Frankford

    Or some dies have an undersized cap for a removable pin, in place of the expander.
     
    Yes. So I guess this will put me in the lead for "Dumb question of the day", but if you take the button off, how are you de-priming? Using some type of die that does not use a button to hold the decapping pin?

    I must be old....For a million years I just used a FL sizing die and a bullet seating die......

    A lot of times a die will come with a decapping pin with and a decapping pin without the expander ball.

    If you want to keep depriming and sizing in same step, I’d get a pin holder without the expander.
     
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    I used to use just a standard stainless Sinclair expander mandrel and lube. While I was getting way better than not using the expander mandrel, tension consistency it still could be better as I was getting one very so often that would feel slightly too easy or feel to stiff. Listened to a MDS podcast with Scott Satterlee about how lube can create some inconsistencies with the inability to control how much is used from case to case. Switched to a 21st century black nitride turning arbor to not have to lube and I can say the 100 I loaded up with it I felt that it definitely made a difference. Could have been in my head as I don’t have a way to measure the applied seating pressure, but even if it wasn’t better for that I’m still digging not lubing my neck lol

    FWIW I’m also using 6.5cm with Hornady 140 ELD.
    I dry media tumble then use a lee decapping die.
    Size/.002 shoulder bump with a FL Redding typeS with the expander ball and decapping pin removed and a .288 TiNi bushing.
    Trim if necessary and debur.
    Run through expander die.
    Seat using Redding competition seater.

    If you want different sizes you can use turning mandrels/arbors and those are .002 under bullet diameter. Standard expander mandrels are .001 under bullet diameter. With my Lapua brass the turning arbor for 21st gives me .0025 neck tension with spring back. K&M makes “custom grind” stainless .0005 mandrels and you have to use their die. I’m sure if they don’t BN coat them they can help you find someone that will.
     
    I am pretty happy with them so far , but the last time I was able to shoot the 140 hornady was a while ago now and they did loose 90 + fps from previous uses . It is still my go to pinking ammofor 6.5 creedmoor mostly for the cost . A little re zeroing and they shot about the same as they did before though I only got off 7 rounds before the owner of the range got out there to tell me they were closed down for that pesky corona virus darn it . still the two that hit the 600 yard steel looked nice 5 on paper were also pretty good . Before they shot just as well as the prime 130's or the140 berger group size wise , they did have higher sd's I just take it as its factory ammo not as precise as hand loaded ammo could have just been a not so good batch who knows . ( they just don't care as much) :eek::eek::eek::cry:
     
    So I tried an experiment this morning. I took 20 rounds that I fired this past week. Wiped them off, ran them through the FL sizer with expander in place. Primed, powder drop, and seated bullets.

    Out of those 20, 2 were horribly difficult to seat. One so much so that you couldn't seat the bullet. I pulled the bullet and ran the neck thou the rial calipers (outside dimension) and there is a significant "warp" , around 2-3 thousands.

    Once I figure out how to upload a video I will
     
    So I tried an experiment this morning. I took 20 rounds that I fired this past week. Wiped them off, ran them through the FL sizer with expander in place. Primed, powder drop, and seated bullets.

    Out of those 20, 2 were horribly difficult to seat. One so much so that you couldn't seat the bullet. I pulled the bullet and ran the neck thou the rial calipers (outside dimension) and there is a significant "warp" , around 2-3 thousands.

    Once I figure out how to upload a video I will

    Get a set of gauge pins, using calipers on the outside is just adding confusion to equation not clarity.

    I had to heavily modify my Giruad trimmer as the centerline of cutter head and centerline of the cartridge holder were no where near co-axial. Long story, lotta frustration but corrected now.
    I've also noticed that Hornady vs Prime brass has different neck thickness which changes how the cutter does the inside / outside chamfer.
    Picture of case mouth, how much chamfer is present would be helpful.

    Have you measured hard to start bullets to verify that the bullet diameter isn't slightly large or that at bulge at BT / bearing surface junction is present? I've seen plenty of oddities on bullets that cause issues.
     
    Regular full length.
    usually folks use a special micrometer to measure their neck wall thickness match that with a proper sized bushing(or a xustom honed die) and a proper sized mandrel to match ans get the desired neck tension.
    it spunds like you have factory die smooshing down brass to what the fuck ever it is leaving you trying to force the bullet in.
     
    I’m guess I’m confused how you’re getting that much difference using a mandrel other than your madrel die is bored crooked or something. Does your mandrel free float or do you have it set screwed down tight?

    Edit: just saw the video. Angle is funny. Is that .001-.002 variation?
     
    I’m guess I’m confused how you’re getting that much difference using a mandrel other than your madrel die is bored crooked or something. Does your mandrel free float or do you have it set screwed down tight?

    Edit: just saw the video. Angle is funny. Is that .001-.002 variation?

    Yes.

    Im not sure either, thats why I'm baffled. I bit the bullet (no pun intended) and ordered a carbide expander mandrel.

    Yes, the mandrel is floating due to the o-ring in the cap
     
    Yes.
    Im not sure either, thats why I'm baffled. I bit the bullet (no pun intended) and ordered a carbide expander mandrel.
    Yes, the mandrel is floating due to the o-ring in the cap

    I think the mandrels are great for getting neck tension correct, however I'm a huge proponent of pin gages like a few others on this thread have mentioned.

    Especially if you're working with new brass, or you're not annealing, OR if you're hand annealing and you wanna check your process. Either way its good piece of mind to check your brass BEFORE you seat it and find out your neck tension isn't right.

    Since pin gages aren't exactly a common firearm world tool, I posted some pictures below for you. I got mine from McMaster Carr, which is where I usually get anything that Lowes doesn't carry. I would recommend getting a few sizes per caliber so you check and set tension to what you want.

    I grabbed some new brass for my 6.5cm that hasn't had the neck tension set and tried to run my 0.261 pin gage through the mouths. The first case it does not go in freely. The second picture perfectly slides in. So one case has 3 thou neck tension currently and the other has more than 3 thou... ended up being just shy of 4 at the moment. The goal would be that your mandrel sets them all to the same thing but if they start off different they may also have different spring back, resulting in dissimilar neck tension in the end.
     

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    Yes.

    Im not sure either, thats why I'm baffled. I bit the bullet (no pun intended) and ordered a carbide expander mandrel.

    Yes, the mandrel is floating due to the o-ring in the cap
    Yea I don’t know man lol. Other than maybe trying a different sizer and see if the neck area is out of whack in your current die, but I would think that would effect all your cases not just a few. Ever thought about marking those particular cases and see if it’s the same ones every time? (I’m reaching here I know lol) I know I saw a Facebook video of Scott Satterlee and his progressive reloading process and if the brass has been sitting around at all before powder and bullet he runs the mandrel through again just before powder and seating.

    Im not an expert in metallurgy but if inconsistent spring back was the issue I would think it would still have a “round” neck. If thats truly the issue I would invest in some better brass.
     
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    Since pin gages aren't exactly a common firearm world tool, I posted some pictures below for you. I got mine from McMaster Carr, which is where I usually get anything that Lowes doesn't carry. I would recommend getting a few sizes per caliber so you check and set tension to what you want.

    I'm assuming you use the "GO" gauge's, correct?