Tweaking Sizing and Measuring rifle brass.

[swampratt]

Long read so sit down.
I have some good loads for my 10fp but my brass was not lasting but 7 firings .
I would get case head cracks.

I got to measuring and found i was setting my shoulders back .008" using the instructions that came with the Lee dies. Which states to raise the ram with shell holder in place and screw in the die until it touches the shell holder,, then lower the ram and turn the die in another 1/4-1/3 turn.

What i have found with my gun is that i need to just touch the shell holder and turn maybe 1/32 and call it good.
This way i do not push the shoulder back.

Now my die has been polished with an automotive buffing polish.

What i get with my Lee full length sizing(FLS) die set like this is.
no shoulder set back
.001" smaller at the base of the shell right before the extractor groove.
.004" smaller at the shoulder.
BUT the length of the brass does grow .007" longer than the fired case.
I end up with a .306" neck ID
My fired case measures .312" ID


All that is a lot less brass working than if i twisted the FLS die in further.

Now i took a Lee collet neck sizing die and sized another Lapua fired case.
This die has also been polished a hair.
Case body dimensions stay the same as the fired case.
No shoulder set back .

The neck ID is .307" after sizing.
A note on using this Lee die. I get smoother rounder Necks if i size very easy and then turn the case 1/4 turn and size again I do 4 times sizing on 1 case...Your mileage may vary.

The length of the brass only grew .001-.0015" over the fired case length.

Not overworking the brass like this at all and should last much longer.

NOW Dial calipers are not all created equal.
My son was given a set for free and i was at his house measuring stuff and those were the same .001" resolution as mine but i could not smoothly operate them to make them stop on .001", pretty rough.
Try to stop on .001 and it went to .004 or more.

My dial calipers i can stop easily 1/4 past the .001" line or less and read them. so to me that is .00025"
I have checked them many times with my micrometer and they read on the money..

Good tools and learning how to use them will reward you guys in your quest to reload.

Sometimes there is a bit more to it than slap together a bunch of stuff and off you go.

Hope this helps some of you out there.
Of course i am meticulous and there are many ways to get there.

 

[Blitzfike]

I'm a certified member of the Savage Barrel Nut society, and love the ability to switch barrels and set headspace with the barrel nut. After having built a dozen Savage / Stevens bolt action rifles, I find that the factory goofs every once in a while. I wonder if your rifle is head spaced a tad long from the factory. If we ever get together, remind me to bring the 308 headspace gauge and check it. Good info on the brass growth, beats the expense of an X-Die with the same results. Jim

 

[swampratt]

I have some other measurements that make me think my gun is pretty close .
Brand new Lapua brass out of the box measurements.
Vs firing this same brass 1 time from my gun.

Lapua Length.... 2.008-2.010"
1X fired --------- 2.010"

Width at Lapua shoulder .449-.450"
1X fired------------------- .454"

Length to the middle of the Tapered section right before the neck. My fired brass grew .004" longer

Width at the base before the extractor groove Lapua Virgin Brass .468"
My fired brass grew .003" there for a measurement of------------ .471"

The only thing i think i would like to change if i could is how much the neck expands.
My .243 expands .001" with norma brass and .002" with winchester brass measuring neck ID.
Norma measures .244" iD and winchester fired brass measures .245" ID.

I feel this helps that particular gun achieve it's great accuracy.
Yes i know i could use brass with a thicker neck but then i would need full power loads to expand that thicker neck.
It is what it is.
I hear my 24" barrel hurts my accuracy a bit compared to a 20" even though it is a fat barrel.

A note: Even if you get the brass to not move much after sizing that is in no way a gauge to determine potential accuracy.

A few years ago i tested FLS brass pushing the shoulder back .008" (not knowing i was doing this)
VS neck sized brass...Well the FLS brass grouped 2x tighter than the neck sized brass.

I will say i used the same FLS accuracy load in both and seated the bullet the same OAL.

Now maybe the FLS brass wants more or possibly less powder and maybe a different OAL for the bullet than the FLS brass.

It is a terrible thing but the bright side is you will get to load and shoot more

I have thought about this and i almost think pinching my brass down the way i was doing it left a lot of space between the brass and chamber..When fired this space would act as a shock absorber of sort allowing the case to expand and release the bullet a tad more gently.
I do not know.. just thoughts that swirl around in my head.

I will be neck sizing a bunch of fired Lapua brass and working up a load for it and see if it will out shoot the other way of sizing.