Is case resizing always necessary?

Tim

Tim

Checked Out
Staff member
2A Bourbon Hound 2024
2A Bourbon Hound OG
Charter Life Member
Benefactor
Vendor
Multi-Factor Enabled
Joined
Dec 17, 2016
Messages
16,462
Location
A Glass Cage of Emotion
Rating - 100%
85   0   0
The brass coming out of my bolt gun fits perfectly in a Wilson case guage. Why resize it?

If so....why?
 
If you start getting sticky cases or heavy bolt lift then full sizing usually fixes that too.
 
A word of caution, don't just use your Wilson case gauge to determine whether or not to size, especially if you have a precision barrel. Wilson gauges are to SAAMI specs, usually midpoint or maximum, but chambers may be cut in the lower part of the spec. This will result in cases running nicely through the Wilson gauge and not running well in the rifle.

It is always a good idea to verify several of the cases in your chamber if they pass the Wilson case gauge.
 
  • Like
Reactions: Tim
Neck tension.
On the cheap get a Lee collet neck sizer.
Or spend a bunch of money on a bushing die from someone else.


Sent from my SM-G360V using Tapatalk
 
Beef15 said:
Neck tension.
On the cheap get a Lee collet neck sizer.
Or spend a bunch of money on a bushing die from someone else.


Sent from my SM-G360V using Tapatalk
Click to expand...


I've been looking at the Hornady and Redding bushing dies. How do you know which bushing to get? A few thousandths over/under or right at nominal caliber (.264)?
 
Read the manufacturers literature for bushing size. Something along the line of measuring the neck of a loaded round (make note of brass and bullet for future references) and subtract 1 or 2 thousandths to determine bushing size.
Weak rounds may not expand the brass enough to need resizing. I had a few weak rounds that had soot from the mouth to about 1/3 down the case (not enough pressire to expand the neck to create a seal). The brass didnt need to be resized.....the neck still had plenty of tension and fit the chamber just fine.
 
The general formula for neck sizing bushing selection is:

(case neck thickness x 2 + bullet diameter) - 0.002 or 0.003.

The negative two or three thousandths is your neck tension. I strongly suggest a micrometer over calipers to measure case neck thickness as the curve of the case neck combined with human error may impact the reading on a caliper by a thousandth or more. That error get doubled in the formula.
 
Charlie R said:
The general formula for neck sizing bushing selection is:

(case neck thickness x 2 + bullet diameter) - 0.002 or 0.003.

The negative two or three thousandths is your neck tension. I strongly suggest a micrometer over calipers to measure case neck thickness as the curve of the case neck combined with human error may impact the reading on a caliper by a thousandth or more. That error get doubled in the formula.
Click to expand...

That's why calipers have a knife edge.... Tim, sounds like you're running some quality brass if it comes back like you say it does. What brand??
 
Bailey Boat said:
That's why calipers have a knife edge.... Tim, sounds like you're running some quality brass if it comes back like you say it does. What brand??
Click to expand...


Hornady
 
Last edited:
Bailey Boat said:
That's why calipers have a knife edge.... Tim, sounds like you're running some quality brass if it comes back like you say it does. What brand??
Click to expand...

The knife edge is for measuring distance to holes. Suppose to measure as close as you can to the sliding bar. On cheap calipers the "fingers" can deflect open causing wrong or inconsistent measurement.
 
you should be using a micrometer for case neck. Similar to this.

star769micx350.jpg
 
Djstorm100 said:
The knife edge is for measuring distance to holes. Suppose to measure as close as you can to the sliding bar. On cheap calipers the "fingers" can deflect open causing wrong or inconsistent measurement.
Click to expand...

I think you're confusing the knife edge on the anvil with the knife edge on the spine used for measuring interior diameters...
 
Bailey Boat said:
I think you're confusing the knife edge on the anvil with the knife edge on the spine used for measuring interior diameters...
Click to expand...

No sir. Referring to E. knife edge for measuring in holes (or similar surfaces that are concave in one dimension) or where access is limited.
RjEEO.jpg
 
True, True......... It's easy to fudge up caliper numbers. Quality..... I dunno at the moment. I have a pair of Brown and Sharp calipers I paid good money for 20+ years ago and they are still in calibration. I have purchased a pair of Frankford Arsenal calipers to keep in the range bag ( a whopping $20) and so far they are in spec with my B&S calipers. Time will tell if they last.
 
Tim said:
The brass coming out of my bolt gun fits perfectly in a Wilson case guage. Why resize it?
Click to expand...
Tim, As the case enters the die, the decapping pin with its expander ball enters the case. When the brass seats fully into the die the case mouth is down sized and brought into perfect concentricity. The as the case exits the die, the expander ball sizes the case mouth to a few thousandths less than your projectile diameter readying it for bullet seating.
 
Tim said:
The brass coming out of my bolt gun fits perfectly in a Wilson case guage. Why resize it?

If so....why?
Click to expand...

Simple. Pick up the spent cartridge and put it back in the gun and close the bolt. I bet you can't do it. :p
 
Tim said:
The brass coming out of my bolt gun fits perfectly in a Wilson case guage. Why resize it?

If so....why?
Click to expand...

From the Wilson website:
Note: Does not measure body diameters. This gage is intended to be used with fired cases to determine a basis for full length sizing and trimming.
Click to expand...

Use the Wilson case gage to measure a fired case to determine how much to set the shoulder back (headspace).

http://www.lewilson.com/casegage.html

There are chamber style case gages that will check a case to SAAMI spec, such as the Sheridan gages.

http://www.sheridanengineering.com/index-1.htm
 
  • Like
Reactions: Tim
Toprudder said:
Use the Wilson case gage to measure a fired case to determine how much to set the shoulder back (headspace).

http://www.lewilson.com/casegage.html
Click to expand...

Exactly how I understood the Wilson gage to work.

So...back to my original question. If my FIRED cases check out via the Wilson gage with respect to headspace and overall length, then there's no need to full length resize. A neck sizing is all that's needed.
 
Last edited:
In my experience, I don't have a problem neck sizing only, any brass I fire in my bolt gun, as long as I use the same brass in the same gun.
You shouldn't either as long as the neck hasn't grown out of tolerance. Then trim and continue. It should help with accuracy as well as case longevity.
 
Tim said:
Exactly how I understood the Wilson gage to work.

So...back to my original question. If my FIRED cases check out via the Wilson gage with respect to headspace and overall length, then there's no need to full length resize. A neck sizing is all that's needed.
Click to expand...

Sorry, I wasn't sure I understood the question.

I don't consider myself an expert, but if the head does not stick above the end of the gage, then it falls inside the SAAMI spec - for headspace only. I agree with @mechdriver that as long as you are loading it for the same rifle, then neck sizing is all you need. You might still want to drop it back in the gage to make sure it does not need to be trimmed.
 
Tim said:
Exactly how I understood the Wilson gage to work.

So...back to my original question. If my FIRED cases check out via the Wilson gage with respect to headspace and overall length, then there's no need to full length resize. A neck sizing is all that's needed.
Click to expand...

That's all I would do for a bolt gun. If you're not confident..... load an uncharged round and see if it chambers/feeds. If so..... rock on.

Just my .02 Some dies are hard on the brass... I had a RCBS neck sizing die that put too much tension on the neck, and I felt like the expander ball was doing more hard than good. Bushing dies are awesome.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom