Brass Length on Belted Magnums?

How important is brass length on belted magnum cartridges? I understand the headspacing is controlled from the belt to the bolt face instead of the shoulder/rim so as long as COAL is consistent, I should be in the same position off the lands. Does brass length matter that much? (Assuming bolt closes with little effort and no extraction issues.) Just curious because I haven't been trimming my cases on my 300 WinMag reloads. I've been just neck resizing these and am expecting I have been bumping the shoulder back a bit, in the process, although I haven't measured for this. Not noticing any case stretch after 4/5 reloads?

I trim all my cases with a LEE trimmer. This keeps all cases the same length, thus ensuring consistent neck tension.

Just the way I do it :-)

saami says MAX 2.620...i use to trim mine to 2.610...i wouldnt let them get much longer than saami max.

I believe that a long neck could jam into the leade and put a "crimp" on the bullet resulting in a hhigh-pressure issue. Worth checking every 2-3 reloads and trimming as necessary.

Well, I went ahead and got a Lee Case Trimmer. It used the specific case guage thingy to trim all your brass to the same length. The problem I forsee with the Lee system is it's not adjustable!?! Well I've run into variable case capacities with the 300 win mag pretty fiercely. I'm wondering how consistent the case lengths will be with different brass? I'm assuming different head widths/ internal case dimensions will throw the measurements off since it uses a dowel inserted into the primer pocket as a guage? I hope I haven't wasted my money on this thing!

Quote:

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Originally Posted by FreqRideR

since it uses a dowel inserted into the primer pocket as a guage?

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Haven't used the Lee myself and can't tell from the image - does the pilot actually reference off the case, or does it reference to the shellholder?

I have the Wilson case trimmer. Love it. Holds case by body and uses case head as reference point. Also super adjustable and accurate with the micrometer adjuster.

I asked the same question, Hair_Boxer and then I saw your post. The guage's pin rests on the caseholder assembly, not inside the case, so OALs remain constant. Seems only logical. :)

The inside case length gauges work ok as long as ya clean the burrs from the flash holes first and neck size. WW brass seems to be the worst for this.

An exact trim length for a specific chamber can easily be obtained by using the caliber specific gauges sold by Sinclair and no doubt others.
Its an inexpensive very simple device that is installed into a modified case and then chambered. Its best to keep a proper length case for
future referrance for each cartridge you load for. Simply put the proper length case in the trimmer and make adjustments to the trimmer
off the gauge. A good lathe type trimmer such as a Forster or others will last several lifetimes. A decent caliper is the best tool for measuring
the case length as well as the oal of the finished round.

Quote:

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Originally Posted by FreqRideR

Well, I went ahead and got a Lee Case Trimmer. It used the specific case guage thingy to trim all your brass to the same length. The problem I forsee with the Lee system is it's not adjustable!?! Well I've run into variable case capacities with the 300 win mag pretty fiercely. I'm wondering how consistent the case lengths will be with different brass? I'm assuming different head widths/ internal case dimensions will throw the measurements off since it uses a dowel inserted into the primer pocket as a guage? I hope I haven't wasted my money on this thing!

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Lee trims to minimum length, which is irrelevant to usable case capacity. With a bullet seated, the neck isn't part of the capacity the powder has to work with, so if there is more or less doesn't affect it in any meaningful way.