NEED HELP - Bullet deformation from neck size

[SBruce]

My F/L die and neck sizing die both size them to .309 which is where it should be.

That's about right, and normal for standard dies. If the brass neck is .014 thick, then that gives you a .281 ID on a .284 bullet. IOW, .003 neck tension on a loaded round. Which is very normal on standard (non bushing) dies.

So, something after the resize process is causing the necks to swedge down more than this (would have to be to get a .279 bullet).

What is the neck OD after fireing a round (before you resize it)?
What is the neck OD after you seat a bullet (before you fire it)?

In my mind, only 3 possibilities exist:

1) Seating die is too small and is squeezing down the necks while the bullet is seated.
2) Chamber of rifle is too small in the neck area and is squeezing down the neck while the round is chambered.
3) Some of the bullets are overly soft or have a void between core and jacket.

That is all I can think of, and they can be measured/checked.

 

[Ackley Man]

Rather than screw around with Redding I am just going to turn the necks just to remove the high spots and uniform the neck walls and then order a Wilson neck die with the proper neck bushing and a Wilson seater die.

I've seen some for sale by owner ads that are expired for Lapua 7mm Remington Mag. brass. Does anyone know when I can purchase some?

 

[SBruce]

You can certainly do that, it would give you less neck tension on a loaded round.

In my experiences, turning necks on a hunting cartridge/rifle is kinda a PITA, and I have my doubts that it is beneficial enough to be worth the effort/time.

Be careful of taking too much off. That will just over work your brass if the gun isn't tight neck chambered. Every time you fire it, the brass neck will expand to fill the chamber neck. If you go from .307 loaded to .315 fired and then back to .305 when resize, that's alot of neck working and on a thinner neck to boot..??

Good Luck

 

[Boss Hoss]

Rather than screw around with Redding I am just going to turn the necks just to remove the high spots and uniform the neck walls and then order a Wilson neck die with the proper neck bushing and a Wilson seater die.

I've seen some for sale by owner ads that are expired for Lapua 7mm Remington Mag. brass. Does anyone know when I can purchase some?

You are looking for something that does not exist.. Forget about that and take the measurements and get the correct bushings AND die. Go forward from there.

 

[Ackley Man]

You are looking for something that does not exist.. Forget about that and take the measurements and get the correct bushings AND die. Go forward from there.

What does not exist?

 

[Gene]

Lapua does not make 7mm Mag brass, but Norma does:

Bruno Shooters Supply: Norma

I agree with Boss Hoss; don't fool around with turning necks. Find out what is wrong. Either have a chamber cast made or call Redding, or both.

 

[Ackley Man]

Lapua does not make 7mm Mag brass, but Norma does:

Bruno Shooters Supply: Norma

I agree with Boss Hoss; don't fool around with turning necks. Find out what is wrong. Either have a chamber cast made or call Redding, or both.

I was afraid Lapua quit making it along with .300 Win Mag. Brunos is not far from me but they are out of stock on the Norma. I'm sure it is available on-line from Midway or someone else. Turning the necks is not a big deal for me but it does cause the necks to be overworked in a factory chamber if you cut off more than the high spots. Good suggestion - I'll switch to Norma or Nosler brass and Wilson dies.

 

[SBruce]

I am inclined to agree. Why throw money at a problem that doesn't really exist. IOW, we don't believe it has anything to do with your brass or your neck sizing operation.

Your brass would have to be very seriously work hardened and extremely tough to swedge down a bullet (even doubtful then, unless the bullets are overly soft)!

Like MikeCR and Boss Hoss also said, take the measurements that we've asked for, and maybe we can help you figure this out, without alot of undue expense and frustration.

A post fired neck OD measurement (of the brass)will kinda tell you what size the chamber neck truely is.
A post loaded (bullet seated) brass neck measurment will tell if it's your seating die.
A chamber cast is also a good idea if you are still having issues after doing some measurements.

Generally, Redding dies are just great. I've never had an issue with redding at all. If you're shooting a standard/factory 700 ADL, it can be kinda pointless to spend alot of money and time on turning necks, setting up precise neck tensions, and buying specialty dies. I've had a few different factory rifles that would shoot 1/2 minute groups at 300 and 400 yds with normal standard dies, and I doubt that an Inline Wilson bushing die would have made those factory tubes and chambers shoot much better than that.

Really, I am only trying to help.

 

[RockZ]

If all of the measurements turn out normal.

I know this sounds like a long shot, but maybe the die is screwed down too much.

It may be possible that you are pushing the case too deep into the seating die causing it to have a crimping effect.

Back the die off alot and screw the seating plug down more and see what happens.

 

[mountainman]

If all of the measurements turn out normal.

I know this sounds like a long shot, but maybe the die is screwed down too much.

It may be possible that you are pushing the case too deep into the seating die causing it to have a crimping effect.

Back the die off alot and screw the seating plug down more and see what happens.

I agree, I think that's your problem as well. let us know.