Case neck trimming questions

Dultimatpredator

Dultimatpredator

Well-known member
As a common practice I have ALWAYS trimmed my case necks to minimum suggested length per my RCBS given specs after every firing for the last 20 years that I’ve reloaded.

I thought about it the other day and wondered how much it really matters for consistency since my bullets are always seated farther into the case way past the neck area. I mean realistically the bullet is still going to be seated at the same Seating depth into my case whether my case neck measurements vary or not. I would think as long as my neck measurements are between minimum and maximum recommend lengths my groups would stay the same as if they were all trimmed to the same length...or will pressures vary?

I always find a load that will shoot a nice little cloverleaf when I ladder test as long as I do my part. I don’t know if trimming my case necks is a factor in this though?

I realize that if a case neck varies in length it could cause more or less neck tension.

Has anyone tested trimmed cases VS various lengths VS groupings?

Thoughts?
 
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In my humble opinion, trimming that often is a waste of time and brass. Granted......some cartridges stretch more than others. I would only trim when cases start to exceed maximum lengths. As long as the lengths don't vary too much, from one to another, in the same batch, then your consistency should be there. I never trim til I have to and most of my rifles shoot little bug holes.
 
I shoot a lot of military brass and am amazed at how many far exceed the standard maximum case length. After each sizing I recheck case length and trim accordingly. Too long of a case can jam the case mouth into the throat of the barrel and put extra grip onto the bullets. Once fired commercial brass is much less likely to be overly long. The difference between maximum case length and trim to length is pretty small so as long as the cases are within those parameters I doubt you could see a difference in group size due to neck length. The variable work hardening of the case neck from repeated sizing is likely to have more of an effect on neck tension and therefore group size.
 
I find it easier to just trim them every time than measure, my trimmers are all set so I have no adjusting to do, most are not the collet type so just stick them in crank and they are done. it takes longer to dial a calipers or mic. I have one trimmer set up for 20 Practical, 223, 6x45 and another for 204R , 22-204, 6mm-204 and 25-204, these are Wilsons. For my 222 Rem, 22-250 and 6.5 Grendel are Lee quick trims set up in a old four station turret press along with a bullet pulling die. The oddball stuff, low volume are Lee shell holders and shaft type cutters 7x57R, 35 Whelen, 250 Sav. and for the really oddball stuff I still have a couple of collet Reddings set up for the 5.6x52R and 6.5x58R, I need to find another for the 5.6x50R but I might be able to mod a Lee 220 Swift for it.

I sit with a whole tray of trimmed brass and watch TV with my wife, chamfer, clean primer pockets and prime. She gets some face time that would otherwise be spent in the shop and everyone is happy.
 
I used to hate trimming cases. For me, it was about as much fun as having my fingernails pulled out. Then I bought a Little Crow WFT2 case trimmer and I don't mind trimming cases all the time now.
 
I use an RCBS trimmer that was included in my rockchucker master kit back in 00’. I bought a drill attachment to run it with.

I do have a lot of cases that were given to me and are shorter than minimum spec that I need to shoot just to get them to stretch.
 
Most hunting rifles will not show consistent group differences between cases at minimum trim length or maximum length. But I think having batches the same length is important, especially if crimping. I normally random check a few when I see some over maximum length I will set up to trim, but I do not trim to minimum. This may change since I just finished a 22-250 that is chambered to minimum SAAMI and very short freebore.
 
Federal brass and Nosler brass both come short in .223 REM. Around 1.742-1.745 ish.

That used to irritate me until i realized i was trimming much, much less. My best groups ever have been with Federal premium brass.

After plinking with Federal M193 or M855 i have to trim an amazing amount the first go round. It is a ton of work. Even with a Little Crow WFT. Still you have to chamfer and de-burr.

I use the Lyman case prep station for that. I am very thankful for electricity.

One time i forgot to trim a small batch for load development. I think the case lengths were 1.765'ish. I went way hot with TAC and Barnes 70gr TSX.

Luckily there were no problems.

I am guessing with a tight tolerance bolt gun i would have been popping primers.

I trim to 1.750 as the load manual says with LC brass.
 
My opinion on trimming cases is what are you expecting. Plinking, hunting, target shooting.
I try and trim every time. You will get the same case length for bullet release. It all makes some sort of difference in the scheme of things. Just how much depends on how picky you are with your accuracy.
 
And especially if you are crimping then most deff need to trim everything. Not so much for the lee factory crimp die but anything else it’s a must
 
Originally Posted By: hm1996Originally Posted By: AWSI find it easier to just trim them every time than measure
^^^^^using the Lee trimmer, shell holder driven with cordless drill. Individual case length gauges available for each particular case. Much faster than measuring each individual case, then trimming.

Regards,
hm





thats pretty much been my method since is witched to the lee power quick trim system as well. i generally refer to it as a 3-in-1 process, but as you point out its actually 4-in-1 when you count the sizing check along with trim, chamfer and deburr.

these days if i add a new caliber to the bench, the quick trim die is an automatic part of the caliber setup
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they seem to produces a reasonably consistent end result. you do have to fiddle with the spring tension for the chamfer/deburr but thats an easy modification by changing which ball bearing is in there. i use a airsoft bb for the thinner neck brass (223/300 blk, etc) and the standard one for thicker stuff (308, 30-06, etc)
 
Catshooter made mention a few yrs ago as to how overly long the neck area of an average factory chamber is cut and that trimming to sammi specs is "shooting yourself in the foot" with those chambers as you are not allowing the neck to grow to match the chamber, allowing full bullet purchase in the neck out at cut chamber length. He was adamant about MEASURING each chamber for cut neck length and trimming brass only when it approached the true cut length....makes sense to me.
 
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Catshooter’s method would require dedicated brass for each rifle/chamber length. That would be a hassle if you had multiple rifles of the same caliber.
 
I trim to a round number near or at max length every time. I used to trim to minimum until I realized Catshooter had a good point. Might as well trim long, but I'm too lazy to actually measure my chambers.

It's faster to just trim them all vs measuring all and then trimming the ones that need it.

Trimming probably doesn't matter most of the time in most guns, but I do it anyways for consistency. And devices like the WFT make the chore fast and easy.
 
Originally Posted By: JMetteMike B what tool could you use to measure your neck length in the chamber? Just curious


I've been using these for a long time. Since before Sinclair had a website, ha-ha!

Chamber%20Length%20Gage.gif.jpg


I haven't trimmed a working case in twenty years.

- DAA
 
most if not all of my trimming is for the purpose of squaring up the necks and getting consistent length. At most I think I trim my 22-250's about every 4th or 5th firing. Any more than that is simply unnecessary.
 


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