Resizing question?

[williaada]

Have been reloading for just over a year and am slowing getting things figured out. The one thing I am having issues with is some of my brass not fitting in the chamber after sizing. I set my resizing dies to 0.002 bump, having said this I have about a 3% rate where the new load will not chamber. Has anyone run into this before, or a more likely explanation is I missed resizing the fired brass and made up a load. What are other people’s experiences with this.

 

[A382DWDZQ]

If you missed resizing, your bullet would just fall into the case unless your doing body and neck in separate steps. Try and find out what it’s hanging up on and that will lead you to what you need to adjust.

 

[Koda_]

A correctly set up die bumping .002" will always feed, but if your not annealing your brass the hardened temper might spring back more than .002" and you will get some that wont fit the chamber. Measure the datums of 10 bumped cases and if they vary more than .002" you might need to evaluate your setup process.

 

[Vern400]

Your harder brass can push back even 0.001 less and not fit. Shoulders get harder with successive firings until or unless you anneal. I've seen it too.

 

[Pickettpuncher]

At what point are you figuring out if they’ll load or not. If it’s loaded brass, your seating die could be low enough to contact the longest brass and swelling out the shoulder enough to not fit. And you won’t hardly see it. I would look at the length of the cases. Those pieces might need trimmed. I don’t think the annealing is an issue if your brass has a shot or two on it. I know guys that have shot brass 10 times or more, never annealed anything, and they fit fine. What you’re not telling us is caliber. I once bought some 308 brass and sized them all, ready to go. Got to the range and some wouldn’t fit. Ended having to run them thru a small base die. If it’s new brass or brass already been fired in your gun, that shouldn’t be an issue. What gauges do you have to measure brass with. Do you have the Hornady headspace gauges to measure set back? What’s your measurements?

 

[blkqi]

Do the problem loads have the correct headspace?

 

[Weldor]

Do you use a case gage?

 

[TaperPin]

The chamber has a size +/- a tolerance. The sizing die has a desired size +/- a tolerance. The angles of the shoulder in the chamber and die will never be exactly the same. Usually they work together, but a sizing die can squeeze in the sides of the shoulder, which pushes the entire shoulder and neck up. Then the die contacts the shoulder and pushes it back. If the outer diameter of the shoulder and outer face of the shoulder are squeezed at the same time, but the shoulder/neck junction is free to move, the inner part of the shoulder is squished up, yet the case measurement, which is usually on the outer portion of the shoulder, reads ok.

If you smoke the cartridges that won’t chamber it would show interference where they are contacting the chamber.

Essentially, I’m guessing your case measurement is over estimating the pushback of the entire shoulder and you just need to add a little more so they can reliably feed. If 3% of cases are doing this, I’d bet if a .001” shim were placed on the bolt face many more, maybe most of the cartridges also wouldn’t chamber.

 

[B23]

1) Are you measuring every piece you size with a bump gauge to know for certain you're actually bumping the shoulder back 2 thou?

2) Is your resizing process setup to where you are getting any amount of cam over on your press?

3) Are you keeping your brass separated by how many times it's been fired or do you have it all mixed together?

 

[ropeup79]

At what point are you figuring out if they’ll load or not. If it’s loaded brass, your seating die could be low enough to contact the longest brass and swelling out the shoulder enough to not fit. And you won’t hardly see it. I would look at the length of the cases. Those pieces might need trimmed. I don’t think the annealing is an issue if your brass has a shot or two on it. I know guys that have shot brass 10 times or more, never annealed anything, and they fit fine. What you’re not telling us is caliber. I once bought some 308 brass and sized them all, ready to go. Got to the range and some wouldn’t fit. Ended having to run them thru a small base die. If it’s new brass or brass already been fired in your gun, that shouldn’t be an issue. What gauges do you have to measure brass with. Do you have the Hornady headspace gauges to measure set back? What’s your measurements?

I had this happen with my 270 WSM when I first started loading for it. Seating die was screwed too far in an created a barely noticeable bulge at body/shoulder junction. They would not chamber. My fix was to remove decapping rod from sizing die carefully bump cartridge until it would chamber.

 

[Andouille]

I'm having a similar issue of rounds not chambering in my 300 WSM, but to a larger magnitude. I have to full length resize rounds with 0.010 shoulder bump to get them to chamber with a couple thou clearance. This means I'm having to excessively resize my brass. For example, can take a once-fired case at 1.773 that just barely chambers, then FL resize to 1.770 and it will not chamber at all- hard bolt stop. The resizing in my FL Hornady Custom die (expander ball removed) causes a bulge in the shoulder that effectively makes the cartridge "longer" as far as chamber fit goes, so I have to resize to 1.766 to accommodate the shoulder bump plus a little clearance.

Here's some base to shoulder measurements on 2x fired brass to clarify the issue:
1.775 longest fired length, doesn't chamber.
1.773 average fired length chambers (tight)
1.771 shortest fired length chambers with 1 layer scotch tape (I should be shooting for this length).
1.768 longest FL resized round case that chambers (tight bolt)
1.766 longest FL resized round that chambers with 1 layer scotch tape (~1.7675")
Brass annealed prior to resizing. Trim length checked (still well below max).
And for reference, new Norma brass is 1.765"

I've sharpied the shoulders of fired and re-sized rounds, then spun them in a Wilson Case gauge and the buldged shoulder is evident on the resized round, whereas the fired round just shows a thin mark at the base of the neck/shoulder junction. I'm using Hornady custom dies and #35 shell holder.

I'm at a loss as to how to change my die setting to achieve 0.002-0.003 shoulder bump from 1.773 to have a cartridge that chambers with a few thou clearance to spare. Does anyone have any insight on whether I can bump only 0.002" with my FL die without affecting shoulder shape?

 

[Pickettpuncher]

I'm having a similar issue of rounds not chambering in my 300 WSM, but to a larger magnitude. I have to full length resize rounds with 0.010 shoulder bump to get them to chamber with a couple thou clearance. This means I'm having to excessively resize my brass. For example, can take a once-fired case at 1.773 that just barely chambers, then FL resize to 1.770 and it will not chamber at all- hard bolt stop. The resizing in my FL Hornady Custom die causes a bulge in the shoulder that effectively makes the cartridge "longer" as far as chamber fit goes, so I have to resize to 1.766 to accommodate the shoulder bump plus a little clearance.

Here's some measurements on 2x fired brass to clarify the issue:
1.775 longest fired length, doesn't chamber.
1.773 average fired length chambers (tight)
1.771 shortest fired length chambers with 1 layer scotch tape (I should be shooting for this length).
1.768 longest FL resized round case that chambers (tight bolt)
1.766 longest FL resized round that chambers with 1 layer scotch tape (~1.7675")

I've sharpied the shoulders of fired and re-sized rounds, then spun them in a Wilson Case gauge and the buldged shoulder is evident on the resized round, whereas the fired round just shows a thin mark at the base of the neck/shoulder junction. I'm using Hornady custom dies and #35 shell holder.

I'm at a loss as to how to change my die setting to achieve 0.002-0.003 shoulder bump from 1.773 to have a cartridge that chambers with a few thou clearance to spare. Does anyone have any insight on whether I can bump only 0.002" with my FL die without affecting shoulder shape?

Is the 1.773 measurement off the shoulder or from base to mouth

 

[Andouille]

Is the 1.773 measurement off the shoulder or from base to mouth

Base to shoulder measured with Hornady comparator. I've also measured total cartridge lengths and I'm still 0.005-0.0015 under SAAMI max 2.100 and well below the measured max trim for my rifle of 2.123," so that eliminates trim length as the chambering issue. I've measured 20+ fired cartridges a similar number of resized, and at least that many scotch-tape clearance tests, so I'm very confident in the precision of the measurements. What I'm not confident in is my understanding of my resizing die!

 

[Pickettpuncher]

Base to shoulder measured with Hornady comparator. I've also measured total cartridge lengths and I'm still 0.005-0.0015 under SAAMI max 2.100 and well below the measured max trim for my rifle of 2.123," so that eliminates trim length as the chambering issue. I've measured 20+ fired cartridges a similar number of resized, and at least that many scotch-tape clearance tests, so I'm very confident in the precision of the measurements. What I'm not confident in is my understanding of my resizing die!

What sizing die are you using? I would mark the case head and see if your die isn’t sizing enough lower on the case body

 

[Andouille]

What sizing die are you using? I would mark the case head and see if your die isn’t sizing enough lower on the case body

Hornady Custom full length with expander ball removed and #35 shellholder. The case is completely inside the die body with the press ram cammed up, so the body is resized within a few thousands of the bottom of the case head. With no cartridge in, the shellholder hits the bottom of the die right before full cam-over- this is where I ended up to achieve the chamber-able length, but definitely seems tighter than Hornady's instructions of "barely touching" to achieve SAAMI min size.

 

[Pickettpuncher]

Hornady Custom full length with #35 shellholder. The case is completely inside the die body with the press ram cammed up, so the body is resized within a few thousands of the bottom of the case head. With no cartridge in, the shellholder hits the bottom of the die right before full cam-over- this is where I ended up to achieve the chamber-able length.

Just because it’s in there doesn’t mean it’s sizing. You could have a bad die. I don’t necessarily think that’s the case tho. The bulge isn’t making sense to me in your case. Gonna think on it

 

[Andouille]

Just because it’s in there doesn’t mean it’s sizing. You could have a bad die. I don’t necessarily think that’s the case tho. The bulge isn’t making sense to me in your case. Gonna think on it

The case body is definitely getting sized and fits in my rifle chamber and Wilson chamber gauge. I cleaned the die and ran a couple 2x fired cases, bumping them to 1.772 which should chamber, but definitely don't. The shoulder is being "rounded" by the die, losing the fire-formed flat shoulder surface, and I can feel an increase in handle pressure on the press when the neck/shoulder are being resized. A case resized less than 0.005-ish no longer fits in the Wilson case gauge (how ironic) due to the shoulder rounding.

Could it be that my annealed Norma brass is soft and the neck is being pushed downwards as the shell enters that section of the die?

I have ordered a Lee collet neck sizing die for the shells that still chamber (with clearance) after firing, and a Lee full length die to check my sanity. That former will at least keep me going with some reloads.
I'll give Hornady a call tomorrow about my custom FL die.

 

[Jason Snyder]

I anneal my Hornady brass every time in my 6.5 and have never experienced this. I’d call Hornady and see if they’ll send you a new sizing die.

 

[TaperPin]

For the 300 Win short mag:
The only way a bulge can happen is if the die is a little larger in diameter at the shoulder than the chamber. It could be a chamber on the smaller side, or a die on the larger side, or the combination. Unusually small chambers happen when a well intentioned gunsmith hand sharpens a chamber reamer and takes off too much - that can also change the angle of the shoulder. Not knowing anything else other than what you’ve told us, I’d assume your barrel was chambered by a solo gunsmith if it is in fact undersized.

Mass produced dies are more consistent now than they ever have been, but human error in the setup of any machining operation, CNC or not, will cause off sizes. Dies that are too small overall won’t pass an inspection, but slightly oversized diameter of the shoulder may not get detected.

It would bug me and I’d figure out if the chamber needs to be chased with a properly sized reamer or the die needs to replaced. However, I don’t think it‘s over working the brass - the part of the brass that would fail is the web above the case head, as long as some portion of the shoulder, either inner near the neck, or outer, keeps the base from developing more than a few thousandths of headspace. If you were getting splits at the shoulder it would be different.

 

[Andouille]

For the 300 Win short mag:
Not knowing anything else other than what you’ve told us, I’d assume your barrel was chambered by a solo gunsmith if it is in fact undersized.

Thank you for your explanation, I'm guessing it's either user error on the press or a bad die. I have a factory Tikka 300 WSM barrel that I installed myself and that might marginally affect headspacing, but shouldn't affect the shoulder geometry. The chamber is a little tight on factory Federal ammo with 0.001 or less clearance (scotch tape test) before firing.

Even if I don't get over-worked brass, I'm still unsatisfied with having to bump 0.010" to make chamber-able brass and re-fire-forming my shoulder each time; that somewhat defeats the purpose of reloading.