sizing dies and neck diameter

M

mbessey

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I posted this as a reply in my other thread but re posted so It can get as many eyes on it as possible and its kind of a more specific question/different one.

ok here is a revelation i had on the way to work,
I am using forster "benchrest" dies, by chance i was going to load some barnes x bullets up and try them out, I found that the forster F/L sizing die only size the case necks to .337" (which turned out to be the same size as the X bullets, i guess they undersize them a thou because they are solid copper and it may help reduce pressure spikes) and i am going to say that is not very tight (the X bullets could be pulled out of the cases by hand), and maybe just fine for benchrest where i think they only use single shot rifles and its not going to need to be crimped or have to be overly tight in the case neck, so is it possible that when i load up 3 or 5 rounds into my Mag and shoot them one at a time, that the recoil (mind you there is a brake on this thing and it only feels like a 308 or so..) is greatly affecting the seating depth of the rounds in the mag still and giving me unpredictable points of impact? since even .337 is not much grip on a .338 bullet?? maybe I should get a redding neck sizing die?
unless all dies size necks to 1 thou under bullet diameter??
m
 
The diameter of the sized neck is not determined by the die, it is the expander button that regulates this diameter. The only exception is when you turn necks and the die is incapable of sizing down the neck, this is not an issue with factory brass (assuming you are using factory brass). If you wabt to increase the friction between your bullet and the case just chuck up your expander assembly in adrill and run some fine emery paper over it, take a .001 off and this will solve your looseness prolem. Go slow and measure often, dont take off too much, also be aware that other bullets will be harder to seat also. A spare std. expander button might be handy!
bigbull
 
ok i guess what i really want to know is this possibly an issue of benchrest dies making the bullets too loose in the necks and move around in the cases on recoil?
i personaly dont want to take the precision machined tolerances of the expander button and put it in a chuck and give it the precision emery paper machine job ;)
im willing to buy another neck sizer die from a different manufacturer perhaps redding would be made to different tolerances for other kinds of shooting than benchrest and may be a bit tighter on the neck?
 
mbessey said:
ok i guess what i really want to know is this possibly an issue of benchrest dies making the bullets too loose in the necks and move around in the cases on recoil?................
im willing to buy another neck sizer die from a different manufacturer perhaps redding would be made to different tolerances for other kinds of shooting than benchrest and may be a bit tighter on the neck?
Click to expand...

You can spend your money any way you like but short of reducing your button's diameter the only other solution is buying a die with a sizing collar and avoid the sizing button all together.
bigbull
 
Besides having bullets in the magazine pushed in during recoil, you may also pull a bullet when extracting a loaded round dumping your powder into the action. Especially if your engaging the lands.

Redding and others make dies for precision shooting that have a interchangable neck bushings which you can order in any size.

You could probably give the rounds a bit of a crimp to tighten up the tension on the bullet.
 
the lapua bullets are seemingly seated pretty tight, it seems to have just been crappy older barns x bullets maybe, i still think its a little loose! but am doing further testing and emailing forster.
 
By now you've probably already checked this out but the recommended method for selecting a bushing for one of Redding's Bushing Style Neck Sizing Dies is to measure the neck diameter of some loaded rounds then subtract .001" from the smallest average diameter. If your average "loaded" neck dia = 0.368 then your die selection would be 0.367. That said, they list em from 0.361 to 0.369 for this calibre, ??

I've ordered one thats 0.365. Should have it by the end of next week.
 
By now you've probably already checked this out but the recommended method for selecting a bushing for one of Redding's Bushing Style Neck Sizing Dies is to measure the neck diameter of some loaded rounds then subtract .001" from the smallest average diameter. If your average "loaded" neck dia = 0.368 then your die selection would be 0.367. That said, they list em from 0.361 to 0.369 for this calibre, ??

I've ordered one thats 0.365. Should have it by the end of next week.
 
By now you've probably already checked this out but the recommended method for selecting a bushing for one of Redding's Bushing Style Neck Sizing Dies is to measure the neck diameter of some loaded rounds then subtract .001" from the smallest average diameter. If your average "loaded" neck dia = 0.368 then your die selection would be 0.367. That said, they list em from 0.361 to 0.369 for this calibre, ??

I've ordered one thats 0.365. Should have it by the end of next week.
 
First off although most dies the neck tension is determined by the inside diameter of the neck of the die. Although the expander button is the last part that touches the brass, due to springback, the amount of sizing on the neck ALSO has a big impact on the finished rounds neck tension.

Dies such as the Redding "bushing dies" allow you to tailor the amount of neck tension by using bushings with inside diameters in .001 increments

Problem with this method is it makes a huge difference what headstamp brass you are using. Even brass from the same manufacturer differs (especially if has been loaded numerous times

For segegrate my brass in groups determined by how many times loaded ( and obviously brand ). The thickness of the neck determines the tension for a given bushing, so if neck thickness varies the tension becomes inconsistent

I have loaded plinker rounds where there is mixed brass. I have had some brass get so little neck sizing that the bullet literaly falls into the case ! ( obviously this brass had very thin necks )

So much for the theory that its the expander ball that determines the neck tension ! Matter of fact the Redding Type S ( the more reasonably priced ) has an expander ball, but he the top of the line Redding Competition bushing dies don't even have an expander ball ( you can put one in if you want )

I run both styles and to reiterate even though I use a carbide expander ( optional on the redding...very cool because you don't have to lube the inside of the neck ) I can vary the amount of tension by changing on the the bushing size

It is very noticable in the amount of force it takes to seat the bullet

I personally like about .002 "tension" on most of my target rounds . More like .003 for semi autos

IF you can spend the $$ the Redding Competition Bushing is the cats ass. It has a floating guide that centers the brass as it enter the die and a micrometer adjustment of how much of the neck you want to size

They come in a kit along with a "body die" and seater with micrometer adjustment ( makes the hornady micrometer seating adjustment look like a joke )
 
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