What am I doing wrong with sizing brass?

So why did it fit fine in the case gauge after he resized, but not after he seated the bullet? I don't think this is a resizing issue.

BTW, I use a Hornady case gauge on every round I load. Once it is resized, and once I seat the bullet.

OP...Are you running a compressed load? When the loaded round is inserted, does it look like the head is offset in the gauge slightly?
Starting with 63 Gr of RL26. I don't believe this is compressed but I could be mistaken. Load data I got from Berger this morning.
 
So why did it fit fine in the case gauge after he resized, but not after he seated the bullet? I don't think this is a resizing issue.

BTW, I use a Hornady case gauge on every round I load. Once it is resized, and once I seat the bullet.

OP...Are you running a compressed load? When the loaded round is inserted, does it look like the head is offset in the gauge slightly?
Point is, this Hornady Case Guage is not going to to tell any of us a number value of the critical stuff. It fits or it doesn't is all you got.
He may have distorted the shoulder on FL sizing. There could be a handful of other things, particularly in the neck. Got to measure everything, especially to preserve brass and safety of handloads.
 
Neck diameter, especially at neck/shoulder junction, on both empty and bullet seated cases !!!
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You should discontinue use of a 'case gauge' and instead start measuring your actual headspacing.
You should stop FL sizing necks as well.
Not all case gauges are created the same. Because of the discrepancies in the base to shoulder measurement on belted magnums, The Wilson Case Gauge for Magnum cartridges is adjustable so as to accurately resemble your chamber.
 
Starting with 63 Gr of RL26. I don't believe this is compressed but I could be mistaken. Load data I got from Berger this morning.

63 gr is not going to be compressed in a 7 rem mag. So much for that theory - where the bullet seating of a compressed load causes the case walls to expand ever so slightly (like applying an internal hydraulic pressure), thus preventing the case from easily being inserted into the gauge without any wall interference. Happened to me numerous times with compressed loads where the case OD is just below the gauge ID.
 
My guess is the case gauge neck diameter is smaller than your loaded round diameter. I've never used these tools and check my headspace with the Hornady comparators. They're well worth the money. I would check the diameter of a fired case to make sure your loaded rounds have sufficient neck clearance. Ideally you're looking for .004-.006 clearance between a loaded round and you're chamber on a hunting rifle. In a perfect world you can run less, but in a rifle out in the field and in the environments, a little clearance helps.
 
63 gr is not going to be compressed in a 7 rem mag. So much for that theory - where the bullet seating of a compressed load causes the case walls to expand ever so slightly (like applying an internal hydraulic pressure), thus preventing the case from easily being inserted into the gauge without any wall interference. Happened to me numerous times with compressed loads where the case OD is just below the gauge ID.


On to the next issue, can you slightly tap the case head so that the round inserts into the case gauge, or does it seem to have a hard stop?

Hornady brass, and sometimes Remington brass (2-3 per 100) seems to have a slight head offset...where they get hung up in a wall interference fit into the case gauge after resizing. I can usually tap it down fully, but have just gotten in the habit of just discarding the case.

If you are checking every case after resizing, and all is fine, but the problem is occurring after seating the bullet, then that's not the problem. However if you don't check every case after sizing, you could have the bump set right and still not fit in the gauge - only to find out after the round is completed.

That's the reason I added the step to check every case in my case gauge just after resizing, even though I use my Hornady comparator tool to verify every shoulder bump length after resizing. The case gauge is not so much for the shoulder verification, but for other issues like concentricity and to make sure my FL die sizes near the base correctly.
 
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On to the next issue, can you slightly tap the case head so that the round inserts into the case gauge, or does it seem to have a hard stop?

Hornady brass, and sometimes Remington brass seems to have a slight head offset. It gets hung up in a wall interference fit into the case gauge after resizing. I can usually tap it down fully, but then just discard the case. If you are checking every case after resizing, and all is fine, but the problem is occurring after seating the bullet, then that's not the problem. However if you don't check every case after sizing, you could have the bump set right and still not fit in the gauge. Only to find out after the round is completed. That's the reason I added the step to check every case in my gauge just after resizing. Not so much for the shoulder verification, but for other issues like concentricity.
I can slightly get more into the gauge but it still stops as pictured.
 
You seem to have a donut at the case neck/ shoulder junction. This is caused by the flowing of the 1st fired brass to fit the chamber (especially belted magnum). The MINIMUN clearance suggested between the case neck and the chamber neck is 0.003". That donut can grip the bullet tighter than you expected and cause dangerous pressures 'cause the bullet doesn't get released properly. The suggested remedy is to inside neck ream.
That's all I know about it as while I have checked the measurements of the neck as I asked you, and have reamers and such for the job, I have never had to neck ream.
Neck Reaming is only done on FIRED CASES BEFORE SIZING.
Sorry if this doesn't help.
 
My guess is the case gauge neck diameter is smaller than your loaded round diameter. I've never used these tools and check my headspace with the Hornady comparators. They're well worth the money. I would check the diameter of a fired case to make sure your loaded rounds have sufficient neck clearance. Ideally you're looking for .004-.006 clearance between a loaded round and you're chamber on a hunting rifle. In a perfect world you can run less, but in a rifle out in the field and in the environments, a little clearance helps.
Thanks. I primarily only load for hunting.
 

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