Case Neck Trimming, correct procedure
- Thread starter DennisH
- Start date
This is what I do:-
a) Decap, using a Lee Universal decapping die. (I will not chance introducing crud into my Redding die)
b) Clean cases using wet s/s
c) Anneal, using a gas jobbie (I can't afford an electric version)
d) Resize using a Redding bushing die.
e) Trim using a Wilson
a) Decap, using a Lee Universal decapping die. (I will not chance introducing crud into my Redding die)
b) Clean cases using wet s/s
c) Anneal, using a gas jobbie (I can't afford an electric version)
d) Resize using a Redding bushing die.
e) Trim using a Wilson
Last edited:
Trimming before sizing won't help you much. Sizing reduces case diameter, cases tend to grow in length during sizing.
I don't shoot BR preferring NRA-style long range stuff so my typical practice is to trim new, sized (308 Palma) brass to 2.005".
After being fired, cleaned, annealed then resized (in that order) I check length & trim if they grow beyond 2.010". Some cases have been fired over fifteen times. My chambers are all cut to 2.025" so there's generous room in there so I probably don't have to trim when I do but I think it helps keep neck tension more consistent.
DennisH
Life Time NRA member
A thought: After firing, the brass is fully "fireformed". All should be "exact" except the neck length! Wouldn't it be wise to trim the brass at this point? Then FL size?
When I trim, 1st I deprime, clean, 3-way trim, which put all of my brass within less than .002 of each other, anneal (at the fireformed state), then FL size! My necks length stays consistent, but some cases do change a little. Sometimes I cull 2 or 3 pieces of brass at this point as they are way off, and don't like change, so their history. This is out of a bunch of 170 pieces.
When I trim, 1st I deprime, clean, 3-way trim, which put all of my brass within less than .002 of each other, anneal (at the fireformed state), then FL size! My necks length stays consistent, but some cases do change a little. Sometimes I cull 2 or 3 pieces of brass at this point as they are way off, and don't like change, so their history. This is out of a bunch of 170 pieces.
47WillysGuy
Gold $$ Contributor
After full sizing.
the entire procedure is different for different rifles.
but as to trimming. at the stage where i am cleaning primer pockets and brushing out necks i examine cases carefully and measure trim length. if they need trimming that is when i do it. if not that is when i chamfer and debur, prime, charge and seat bullets.
as for trimming i want the case resized. i use a pma trimmer that indexes off the shoulder. need all cases consistent. i don't trim often. only when cases are at or exceed max. then i trim the entire batch back about .005. never all the way to trim length.
but as to trimming. at the stage where i am cleaning primer pockets and brushing out necks i examine cases carefully and measure trim length. if they need trimming that is when i do it. if not that is when i chamfer and debur, prime, charge and seat bullets.
as for trimming i want the case resized. i use a pma trimmer that indexes off the shoulder. need all cases consistent. i don't trim often. only when cases are at or exceed max. then i trim the entire batch back about .005. never all the way to trim length.
The .243 Win. case, is a real "STINKER" as, it,.. grows, GROWS and grows, some more !!
I threw out, my Expander Ball, to obtain, GOOD, Neck concentricity and I'm now, getting, .002 TIR or, less, "run-out" ! I ground down the old, expander ball, to fit THROUGH the Neck without,.. expanding/ touching the case neck,.. to de-prime cases.
Found out that, I couldn't trim, after sizing, as Neck dia., was NOW, too small, to fit over, trimmer pilot,.. So, I trim BEFORE sizing, to 2.025 then, they STRETCH after sizing about, .010 to finish out at, about 2.035,.. which is, the minimum case length. No wonder so many shooter praise,.. the 6mm SLR and .243 Ackley ! Probably going to send my Tikka in, to get re-chambered to 6 SLR as I hate trimming EVERY shot !!!
I threw out, my Expander Ball, to obtain, GOOD, Neck concentricity and I'm now, getting, .002 TIR or, less, "run-out" ! I ground down the old, expander ball, to fit THROUGH the Neck without,.. expanding/ touching the case neck,.. to de-prime cases.
Found out that, I couldn't trim, after sizing, as Neck dia., was NOW, too small, to fit over, trimmer pilot,.. So, I trim BEFORE sizing, to 2.025 then, they STRETCH after sizing about, .010 to finish out at, about 2.035,.. which is, the minimum case length. No wonder so many shooter praise,.. the 6mm SLR and .243 Ackley ! Probably going to send my Tikka in, to get re-chambered to 6 SLR as I hate trimming EVERY shot !!!
Shynloco
You can lead a horse to water, but ........
DennisH,
During the FL process, your casings may well stretch and therefore the lengths of the necks may vary. Now if you only Neck Size, then you won't get that variance in Neck length that FL resizing may cause. So you can trim your casings after Neck Resizing only. Personally, I FL resize and then check the case length for uniformity after every firing. Also, if you are going to Anneal, FL AFTER you anneal your brass. Just my .02 worth.
Alex
nmkid
Gold $$ Contributor
Nothing an expander mandrel couldn't fix.
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