Headspace Help Please!

[Hschweers]

Weatherby Vanguard .223
Unfired factory new Norma brass (primed from factory)
Varget
69 BTHP SMK

Headspace (base to shoulder using hornady comparator A) on the new brass is pretty uniform 1.460”. After seating a bullet, it grows to 1.468” and no longer chambers.

To prep brass I neck sized, chamfered, and deburred. Brass came primed. Just charge and seat and it ~should~ chamber/fire. Why is my base to shoulder growing with seating, and how do I combat this?

I seated a dumby bullet to confirm lands. No powder. This one did not grow and chambers. I am not compressed. I’m at book minimum 24.0 grains for these first loads.

Please help! Thanks

 

[freddyG]

Color the neck and shoulder of the brass with a sharpie, and it will show you what to do next.

 

[Axlrod]

Is the bullet hard to seat? Sometimes on new brass I have had the case bulge a bit right before the shoulder. Needed some dry neck lube.
Measure the case body right before the shoulder and compare to new brass. You can usually see the bulge if that is the problem.

 

[blkqi]

What seating die? Does it also crimp?

 

[Vern400]

Your neck tension could be high enough to deform the case. Actually it's not neck tension, it's the amount of interference fit between the neck and the bullet. Try a dry lube inside the neck and if that's not enough get a neck mandrel that's about 0.002 under your bullet diameter. That may open the case mouths more gently.

That's the downside of high neck angles, very square shouldered cases. You can actually pooch out the wall of the case inserting the bullet. The Ackley angles are about the steepest that are consistently successful. Just as one example, the 30-06 ain't new shiny or cool, but you'll never have this situation with one because of the shallow shoulder angle as compared to more modern cartridges.

 

[Hschweers]

Is the bullet hard to seat? Sometimes on new brass I have had the case bulge a bit right before the shoulder. Needed some dry neck lube.
Measure the case body right before the shoulder and compare to new brass. You can usually see the bulge if that is the problem.

New brass is 0.354”. 2 of the problem loaded rounds are 0.355”, but 1 is still 0.354”. The primary dimension that’s grown is base to shoulder

Edit: bullet doesn’t feel exceptionally hard to seat

 

[Hschweers]

What seating die? Does it also crimp?

RCBS type A FL set with seater. 11101 part number. Per the RCBS website, it does have a roll crimp

 

[Hschweers]

Color the neck and shoulder of the brass with a sharpie, and it will show you what to do next.

Small little ring right at the shoulder. Not sure how to interpret that

 

[Hschweers]

Your neck tension could be high enough to deform the case. Actually it's not neck tension, it's the amount of interference fit between the neck and the bullet. Try a dry lube inside the neck and if that's not enough get a neck mandrel that's about 0.002 under your bullet diameter. That may open the case mouths more gently.

That's the downside of high neck angles, very square shouldered cases. You can actually pooch out the wall of the case inserting the bullet. The Ackley angles are about the steepest that are consistently successful. Just as one example, the 30-06 ain't new shiny or cool, but you'll never have this situation with one because of the shallow shoulder angle as compared to more modern cartridges.

All I have is some imperial sizing wax. Put some on a Q tip and did one quick swirl inside the neck after charging and seated. Same issue.
Sized necks are reading 0.2225”, bullets are 0.2235” - one thousandth interference

 

[SamsonMan22]

The neck and shoulder both look bulged in the picture. Looks like the neck is sized down way too much, are you using an expander ball or mandrel when sizing? Measure the outside of the neck after sizing and measure the neck on the loaded round so see how much you are sizing the neck.

 

[shtrbc]

As another diagnostic tool, I would full length resize the case without a de-capping pin in place. Use your normal lube process. Make sure you are bumping the shoulder back .001-.002". Repeat the seating process with your powder charge in place. See if the end result is the same. As mentioned earlier, some type of lube on the bullet or neck may be to your advantage.

 

[Hschweers]

The neck and shoulder both look bulged in the picture. Looks like the neck is sized down way too much, are you using an expander ball or mandrel when sizing? Measure the outside of the neck after sizing and measure the neck on the loaded round so see how much you are sizing the neck.

Factory new: 0.2435” OD
Neck sized: 0.2430” OD
Bullet seated: 0.2470” OD

Expander ball in the die. Whatever the die came with is what I’m using - no extra steps. Neck size with RCBS 11130 and seat.

 

[Hschweers]

The main issue I’m trying to chase only happened in the charged rounds. The dummy round I made with no powder did not grow the base to shoulder dimension and chambers perfectly. When I add powder, base to shoulder grows and no longer chambers

 

[blkqi]

RCBS type A FL set with seater. 11101 part number. Per the RCBS website, it does have a roll crimp

Setup the die so that the crimp isn't touched. IIRC about 1 full turn out. That will eliminate one important variable.

 

[packer58]

Looking at your pics,

The neck and shoulder both look bulged in the picture. Looks like the neck is sized down way too much, are you using an expander ball or mandrel when sizing? Measure the outside of the neck after sizing and measure the neck on the loaded round so see how much you are sizing the neck.

You beat me to the punch, it does to me also. looks to me that the necks are undersized .....

 

[blkqi]

It looks like the necks are undersized, but could also be that the bullet is getting deformed by interference from the roll crimp. You likely do not need a crimp on these anyway, so I would get that out of the picture.

 

[Hschweers]

As another diagnostic tool, I would full length resize the case without a de-capping pin in place. Use your normal lube process. Make sure you are bumping the shoulder back .001-.002". Repeat the seating process with your powder charge in place. See if the end result is the same. As mentioned earlier, some type of lube on the bullet or neck may be to your advantage.

Full length size factory new brass?

 

[Hschweers]

It looks like the necks are undersized, but could also be that the bullet is getting deformed by interference from the roll crimp. You likely do not need a crimp on these anyway, so I would get that out of the picture.

Can I remove the crimp from that die? I don’t want to crimp. This is for a bolt gun

 

[blkqi]

Can I remove the crimp from that die? I don’t want to crimp. This is for a bolt gun

No - it is a shoulder in the die body. Just set it up so that your case does not touch the shoulder.

 

[Pickettpuncher]

back your seater die out a full turn, it looks like you’re trying crimp way before your bullet gets set.