Loose neck tension

[hvychev77]

Hi all, so i was loading some 300 win mag last night, and started experiencing some issues. I usually will take a loaded round and push it against the side of my bench to make sure that the bullet doesn't set back easily. So, you guessed it, the first round was pushed back relatively easy. The unfortunate thing, is this is brand new Winchester brass. I'm just trying to use it up before purchasing some better brass. I am using Lee FL die, and c.o.l. is 3.340. After noticing the problem, i was concerned that the necksizing/decapping pin was sized incorrectly. I measured it with a mic. at work this morning and it is .3055.

Is this a little too big? Any recommendations? Thanks guys, hvychev77

 

[nastynatesfish]

You need to measure the inside neck diameter of your fired brass and compare your sized brass inside neck diameter. I only run my 7 rem mag .003 smaller for tension, that does it for me. Use a piece of emery cloth and chuck your decapper in a drill and take it down if need be.

 

[nastynatesfish]

You don't want it real tight you'll start spitting necks and building a lot of pressure if you take to much off your decapper pin

 

[Joe's]

What type of bullet are you trying to seat. Check the diameter. .3055 should be enough tension. I'm sure others will chime in.

Joe's

 

[hvychev77]

the bullet i'm using is a Nosler Accubond 180grain. I did measure the bullets last night, and they're all consistently .308. So, i'm kinda at a loss here because i can't honestly tell you that i completely trust it. Is there any other kind of brass you guys would recommend? or any other suggestions?

 

[243winxb]

I usually will take a loaded round and push it against the side of my bench to make sure that the bullet doesn't set back easily. So, you guessed it, the first round was pushed back relatively easy.

Not an accurate testing method. An expander diameter of .3055" will give the correct neck tension, if the FL die is doing its job and adjusted correctly . Measure the case neck before and after seating a bullet. Has the neck expanded .002" or more? If yes, you have enough neck tension. If no, the brass is thin or the FL die is defective.

 

[Captcurt]

Been there, done that.

Heavy,

Sounds like your expander ball is too big. You can check it with a mic or you can take it off of the decapping rod and then resize a case. If you seat a bullet and it has tension, the expander is your problem.

 

[popper]

You DID size that new brass first - right? .3055 is fine. Measure the brass neck WALL thickness. It should be ~.011. If much thinner, you die probably won't downsize the neck enough. Neck OD (sized) - 2 x thickness should be just below .305 for the expander to work. Just size with the expander out. I assume the bullet cylindrical part fills the neck? Some end up with the ogive into the neck which is bad.

 

[hvychev77]

so, what i've done is, i've reset my FL sizing die. I think i was a bit off. This time, i took a fired piece of brass, and using my headspace gauge, i set the shoulder back about .003. Then, i measure the outside of the brass where the bullet sets, then i set an actual bullet and got the same measurement again!! I did not however measure the wall thickness of the brass. So, i guess that's next. I'm kinda at a loss here........I don't think that the neck tension is too awfully loose, it's just that i'm kind of paranoid about that "heat of the moment shot" in case i need to chamber another round, THEN i will be scared to squeeze the trigger. I know i'll be thinking about set back.......Thanks for all the help guys, it's great advice and help. I'm thinkin' i need to get some better brass too.

Popper, yes i absolutely resized the new brass. That's where the problem started. So, i'll measure the wall thickness and report back with my findings......thanks again ya'll.....hvychev77

 

[hvychev77]

so, my wall thickness is .014. just for info.....any more advice guys?

 

[wild willy]

You would not be the first person with a defective FL die.If you size without the expander and your bullets are still loose you need a different die.

 

[rcmodel]

building a lot of pressure if you take to much off your decapper pin

No you won't.
Case neck tension is not even a blip on the radar as far as pressure is concerned.
You can't get too much, because the brass will only stretch so far and still maintain neck tension.

I can't comment on the .014" wall thickness.
But without the expander in place, if sized brass comes out of the die and you seat a bullet in it?

You should need close to 70 pounds of force to move the bullet with hand pressure alone.
And that will hurt your hand when you get old like me!

If it doesn't, either you have thin brass.
Or a over-size / out of spec sizing die.

rc

 

[hvychev77]

o.k. guys, thanks for all the replies and info. here. I've already thought i may need to replace my die. So, i'm gonna see what the local gun shops have here and see where that takes me. thanks again.............hvychev77

 

[popper]

.014 is good. Double that and subtract from neck OD. If greater than the decapper size, yes you need a new die, or send the one you have back to get a good one. Set back in a 300 mag would occur in the mag. You could fire one and measure the ones in the mag, a before and after compare. If you have a 4 rnd mag and get .002 setback for the first shot, expect a max of .008 worst case - last rnd. Is that too much?