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If anything back the die out to size just 2/3 or so of the neck, and that’s just in case some are bentMember since 2011, data lost in last hack attack -
I would check the bullet is going to be held at the tension you want for the type of action it's going to be used in. If it is a semi-auto then you want a firmer grip on the bullet than a bolt gun. For a 6.5mm the consensus is .003" for semi's and .001" for bolt guns. You want more tension for auto's because they get knocked around more in the action.
To check this you measure the OD (Outside Diameter) of the neck of a few of the new empty cases with your calipers. Straight from the box, no sizing. Then seat a bullet and measure the OD again. The difference is how much the bullet is going to be held. Different brands and weights of bullets have slightly different OD's.
If the bullet is not going to be held at all then the necks need to be sized as Ric suggests. The body of the new cases will be fine. If it is going to be held to your satisfaction straight out of the box then you've just saved yourself a stack of unnecessary work (apologies if you now this already).Comment
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Lapuas are gtg , just shot my first 100 all were +- 001" . I used to do that to new brass. Now I just check for length and trim if some need it and shoot . If case necks are bent then run it through a neck sizer or just let the bullet seating straighten it out . It kinda depends on what brand you buy ,Lapuas, Norma , nosler , Peterson , alpha are match grade out of of the box/bag. Your gonna love them . My groups tightened considerably with better brass .Comment
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MR:Originally posted by Mindreader1 View Post
Most people do something before loading new brass because some pieces may have dents in the necks. Neck sizing is the norm but if you have a FL sizing die, it will be fine. Factory brass comes to you undersized so it will chamber in the huge variety of chambers available today. Thus your RCBS FL sizing die won't reduce brass life.
Some advice would be not to get OCD over sizing brass. As long as your die is well made and you use a decent case lube, you won't work harden your brass by sizing.
LR55Comment
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Assuming its good brass I just uniform the neck tension with a Sinclair mandrel.Comment
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You do not need to size new brass and shouldn't, new brass come with the proper headspace dimensions in it from the factory. To run it through a full length sizing die can change that dimension and shorten your brass life. As a previous post said you can run it into the die just far enough to straighten out dented case mouths, but no further.Comment
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This statement could be misleading. Most all hornady and Lapua brass when new are .003”-.007” shorter than your normal chamber. This is to ensure the brass will fit any chamber that was properly cut. If you neck size as suggested to iron out any dented case mouths, you will be fine.Originally posted by Twicepop View PostMember since 2011, data lost in last hack attackComment
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Mindreader,
If you have bent case mouths, I'd run them just far enough into a FL size die to use the expander plug to remove the dent and round the mouth, but not actually size them. However, as others have said, as long as you don't touch the shoulder, FL sizing won't hurt the cases. If concerned, just back out the FL size die 1/2-1 turn; that will size most of the neck and then expand it to the proper diameter without touching the shoulder.
ClarenceComment
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MR:Originally posted by Mindreader1 View Post
Yes. One reason why is because new brass is undersized so it will chamber in a variety of factory chambers. Therefore your full length sizer won't be sizing the body or shoulder of the brass because the brass has not yet been shot in a chamber so it hasn't expanded enough for the sizing die to size down anything yet.
Here is a process.
Remove the decapping rod or screw it into the sizer die but not so much that the expander button protrudes from the base of the die. Best to just remove it for now.
Spray some spray lube into the sizer die since it is new and use a patch to wipe the die out so you can remove any crud in the die from manufacture. Leave a film of the spray lube in the die.
Spray some spray lube onto the brass and a little bit inside the neck of the brass, too.
Insert shell holder and screw the die into the press so the base of the die just touches the shell holder. Then unscrew the die four or five turns.
Put a piece of lubed brass into the shell holder and run it into and out of the sizing die. Then look at the neck of the brass and you will see where the die contacted the neck. Most likely you will see only part of the neck was hit by the sizer die because you didn't have the die screwed all the way down. Screw the die down until you see that almost all the neck has been hit by the die. You have just neck sized.
What I would do after setting the die is to screw the decapping assembly back into the die far enough that the decapping pin itself goes through the flash hole of the brass. This ensures your expander button goes completely through the neck and a little bit into the brass. You do not want that expander button to stop in the neck when you reverse the press handle. It needs to be far enough into the die so the button goes completely through the neck.
Some guys will argue over pulling the expander button back through the neck. I do because once you size down the neck, it needs to be opened up to the right diameter for the bullet.
Now you are ready to run the rest of the brass through the sizer die.
One thing to note is this. New brass is undersized so once you shoot the brass one time, you will need to re-set the sizer die so it does size down the brass and also pushes the shoulder a little bit (bumping the shoulder). Gas guns tend to need the shoulder pushed back after firing so the brass will chamber easily again.
LR55Comment
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lR1955,
Great directions; much better explanation than mine.
ClarenceComment
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I mentioned a few posts up using a Sinclair mandrel. I have been using neck mandrels to uniform neck tension without neck turning. One of the issues with bushing and traditional dies is that if you do not have uniformed neck thickness and annealing you will get variation in neck tension. I stopped using expander balls years ago because I have a hard time controlling runout with them. Your sizing die forces neck variation to the ID of the brass and the mandrel forces it to the OD. I noticed an immediate reduction in SD's. The mandrels can also be used for sizing up wildcats or just ironing out dented necks. This is pertinent to this thread because I find factory new brass to have too much neck tension.
Die Body:
Mandrels:
Here is a good video on it:
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I just ran 100 Starline 6.5 creedmoor brass through my hornady FL die just to see and to straighten out the necks. Necks, shoulder, and body hardly touched the die, but the necks rounded out perfect.Comment
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I think transferring any inconsistencies to the outside of the neck is a great idea. I would however caution against using these expander mandrels in a semi-auto.Originally posted by centerfire View PostI mentioned a few posts up using a Sinclair mandrel. I have been using neck mandrels to uniform neck tension without neck turning. One of the issues with bushing and traditional dies is that if you do not have uniformed neck thickness and annealing you will get variation in neck tension. I stopped using expander balls years ago because I have a hard time controlling runout with them. Your sizing die forces neck variation to the ID of the brass and the mandrel forces it to the OD. I noticed an immediate reduction in SD's. The mandrels can also be used for sizing up wildcats or just ironing out dented necks. This is pertinent to this thread because I find factory new brass to have too much neck tension.
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I have a similar expander mandrel by KM and use it to neck-turn new brass for a 6.5*47 bolt gun. My concern is these mandrels are designed to mimic a bullet so after being forced into the neck to expand it you can then neck-turn your brass with the correct ID as if it held a bullet. If you are using these mandrels for loading however this means the expanded necks will not be holding the bullet with any more than about .001" tension. For a semi you want at least .003" to prevent the bullet flying forward under momentum when being forcefully loaded by either hand or gas cycling, or being pushed back into the case. After using the KM mandrel I can force bullets into the necks and pull them out gain by hand which means they are being held by only about .0005". This is fine idea if using a bolt gun but not for the semi auto action of an AR.
Reading the blurb on the Brownells website it says that the Sinclair neck turning pilot is .002" less than a bullet, and the expander mandrel is .001" bigger. So, .002 - .001 = .001 which is the tension the neck will hold any loaded bullet with if you then use them for loading. Very similar to mine.
What actual measured tension does your brass hold a bullet after it has been through the Sinclair mandrel? Be interesting to see if it matches the blurb.
Just an after-thought...if you wanted to use this idea in a semi you could spin a mandrel in a lathe and turn it down another .002"Last edited by Klem; 01-08-2018, 12:09 AM.Comment
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