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Thread: What's the best way to neck expand 5.7x28?

  1. #1
    Boolit Buddy tiger762's Avatar
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    What's the best way to neck expand 5.7x28?

    What's the best existing die that can be reused for our purposes of opening up the neck inside diameter? Have tried a Lyman 28cal neck expander but it assumes that the neck being expanded is already close to 28cal. Have tried a Lee universal. It flares the neck but does not open the neck up making the brass be a straight wall, which is ideally what we want.

    Interested in first-hand anecdotes of what die to purchase. Thanks in advance!

  2. #2
    Boolit Master
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    You should probably anneal the necks first, going from 22 to 28 is a big step. You should probably do it in as many steps as possible like, first .243, .257, .277 and then .284 if you have those die sets. Alternately you could just fire form them. Replace the primer, charge with a small charge of fast powder cover with filler like cream of wheat and plug the case mouth with a slug of wax or bullet lube. The fireforming approach needs and extractor that has a strong grip on the rim.

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  3. #3
    Boolit Master

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    You might find an old unloved 7mm TCU die.
    Many of them came with a tapered expander ball so you could just size .223 up.
    Use gently, rammin' and jammin' splits a lot of necks.
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  4. #4
    Boolit Master

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    I use the Sinclair neck expanders usually used for neck turning. You just get one die body plus whatever size expander you need. I usually set up two presses side by side, one with a 30 cal expander and another with a 243 or 257 expander for those cases with dented mouths. I lose 3or4 out of every hundred by splitting the case mouth but they are usually the dented ones. Might as well cull the defective ones right away.

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  5. #5
    Boolit Buddy Littlewolf's Avatar
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    the case neck expanding ive done isnt with 5.7x28 but it's still the same method. first start with an expander ball of the same caliber as the parent case, then replace expander ball with the next caliber up ie .244 but the trick is having the expander ball just inside the shoulder and the die body backed out just enough to not push the neck shut. then repeat with a .257 expander ball then .266 , then .277 , then .311. using the size die for 5.7x28 in this manner will keep the case straight while the neck is being opened. this is the method i use to open 223 into 300B/O

  6. #6
    Boolit Master
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    Someone already touched on annealing the case necks. There may be a factor that I don't think has ever come into neck annealing processes. The following is from Wikipedia. I'm not sure that it applies to all 5.7x28 cases but I know that the one batch of that stuff that got off the range turned a funny color when I processed it for sale.

    "FN's 5.7×28mm cartridge cases are covered with a special polymer coating for easier extraction with the PS90 carbine due to the high chamber pressures and lack of case tapering.[32] In addition, this coating ensures proper feeding and function in the magazines.[32]"

    You probably already know this, if not it might be something to be aware of.
    Literacy should not be considered optional in computer based communication.

  7. #7
    Boolit Buddy


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    It does apply to all 5.7 x 28 cases. SS pins make short work of it though, or if you anneal in an oven, it burns off in the process.
    Zbench

  8. #8
    Boolit Master Pee Wee's Avatar
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    Quote Originally Posted by tiger762 View Post
    What's the best existing die that can be reused for our purposes of opening up the neck inside diameter? Have tried a Lyman 28cal neck expander but it assumes that the neck being expanded is already close to 28cal. Have tried a Lee universal. It flares the neck but does not open the neck up making the brass be a straight wall, which is ideally what we want.

    Interested in first-hand anecdotes of what die to purchase. Thanks in advance!
    We use BT Sniper swage dies. The expander die takes them out to .311 I believe, you can probably get just the expander die from him.
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  9. #9
    In Remembrance

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    I guess it begs the question: What are you doing with the cases?
    If you are reloading them, then your usual full length resizing die should work fine. Be sure to use plenty of resizing lube, but be extremely careful to NOT get any on the neck or shoulder.
    If, on the other hand (because you posed the question in the Swaging area), you are swaging open the neck to get a core inside (to turn the case into a jacket for a rifle bullet), then PeeWee is right. The neck expander from BT Sniper works perfectly. You have to be careful to not overly expand the neck though. To attempt to expand it to full case diameter will cause the shoulder to collapse, and overwork the brass, causing a split when you are case forming. You want to expand it JUST ENOUGH to slide a core in, nothing more than that.

    I have processed maybe 6,000+ of these cases as bullet jackets for 308 (168 grain) and 300 blackout (150 grain). The ONLY annealing that I do is AFTER the neck expanding (annealing before neck expanding can cause the shoulder to collapse, not good), to burn the plastic off the outside. Next operation is to SS pin tumble to get burned residue off. I have found that a combination of SS pins and ceramic pins makes a faster job of it.
    They then go to core stuffing, and finally to point forming. My bullet swaging lube is approx 75% anhydrous lanolin (Randy Rat supplies the best lanolin), with Militec-1 mixed in. I use a special stirrer that I made from a large paper clip to do the mixing of the two.

    My die set for this 5.8 X 28 FN to .308" diameter bullets was made by BT Sniper, and is awesome.


    Quote Originally Posted by tiger762 View Post
    What's the best existing die that can be reused for our purposes of opening up the neck inside diameter? Have tried a Lyman 28cal neck expander but it assumes that the neck being expanded is already close to 28cal. Have tried a Lee universal. It flares the neck but does not open the neck up making the brass be a straight wall, which is ideally what we want.

    Interested in first-hand anecdotes of what die to purchase. Thanks in advance!


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  10. #10
    Boolit Buddy
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    I own an expander die from BT sniper but have wondered about using the neck expanding tools for K&N. I have neck expanders in smaller sizes like 22, 6mm, 25, and 30 from K&N, for smaller sizes they are ~$13 for the mandrel and $12 for the adapter, looks like custom sizes are $28.
    The only downfall I see with the K&N is that they have a longer taper, if that should be shortened that make that a very affordable alternative. The dies use a small hex screw to secure the mandral but the screw really shouldn't see much pressure as it presses against the adapter.

  11. #11
    Boolit Master



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    Old Thread - But:

    I have used two different "Processes":

    (a) Use a RCBS Shellholder No.45 to hold the 5.7 x 28 case. Then, expand using the 7x57 expander button of the 7x57 resizing die. I cycle the ram to the top; turn the die down until the button touches the case mouth. Lift the handle to drop the ram, turn the die down 1/4 turn - cycle the ram, turn the die down an additional 1/4 turn, cycle the ram - repeat until the 7x57 die has expanded the mouth to below the case shoulder. (Prep all 5.7x28 cases on hand this way) - Then..... repeat the previous steps using a 308 Winchester resizing die set. You are once again turning 1/4 turn - cycle 1/4 turn - cycle, etc.. until the case mouth has been expanded to below the old shoulder. Then size the 5.7x28 cases in your appropriate dies for making .308 Bullets.

    Using this method I loose about 5% of the cases to Split Mouths.

    Alternate method:
    (b) Use a RCBS Shellholder No.45 to hold the 5.7 x 28 case. Then, expand using the .308 Winchester expander button of the 308 Winchester resizing die set. I cycle the ram to the top; turn the die down until the button touches the case mouth. Lift the handle to drop the ram, turn the die down 1/8 turn - cycle the ram, turn the die down an additional 1/8 turn, cycle the ram - repeat until the 8x57 die has expanded the mouth to below the case shoulder. (Prep all 5.7x28 cases on hand this way) - Then size the 5.7x28 cases in your appropriate dies for making .308 Bullets.

    Using this method I loose about 5% of the cases. Mostly they are a result of Shoulder Collapse, but a few with Split Mouths.


    After removing the shoulder as described in (a) or (b) above I make my .308 jackets from 5.7 x 28 cases by running them through a Corbin 9mm to .308 die swaging set. After this step I anneal each jacket to a "White Glow" using a propane torch. Let them Cool and then clean them in ultra sound cleaner with Dish Soap and Lemi-Shine. I then create boat tails on the "Jackets" by running them through my Corbin BT-1 die for making RBT bullets. After creating the Boat Tail Jackets; I then load them with the appropriate weight lead core (~ 115 Grains) and run them through the Corbin BT-1 die to seat the cores. Then through the BT-2 die and finally finish the bullet in the 8S Nose forming dies. This results in a 175 Grain Boat Tail (Semi-RBT actually - quite a bit of Brass on the base so a full RBT is not accomplished).

    Accuracy seems to be slightly less than what I get when making same RBT 175 grain 308 using 5/16 copper tubing. Difference is a 5/16 Copper Jacket costs me about 9 cents to make. The 5.7x28 converted to a 308 jacket is free when I find them at the range; and about 5 cents or less when I buy 5.7 x28 (shipped).
    Mustang

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check