Looking for advice on buying a case trimmer.

[theunrulychef]

IMHO, their dies are set up incorrectly or they're not using full length dies.

I'm no expert on all trimmers on the market, but I thought all trimmers index off the shoulder. Are there trimmers that index off the base? I'm only personally familiar with the Trimit, which indexes off the shoulder.

For consistency of trim length, indexing off the shoulder depends on consistent and precise shoulder setback when resizing. Resizing, in turn, indexes the shoulder off the base.

The point is, it's a two-step process, and if resizing to the shoulder is inconsistent, trimming as indexed to the shoulder only repeats the error. There is no inherent advantage (for consistent OAL) to indexing off the shoulder if resizing is not accurate.

The reason I press this point is I've talked at the range with three different guys using .223 reloads that jammed their rifles, in some instances deforming the case in the process. They insisted the cases had all been trimmed, but simply holding the cases side by side revealed variation in shoulder setback and, consequently, OAL.

[Hawk]

I'm no expert on all trimmers on the market, but I thought all trimmers index off the shoulder. Are there trimmers that index off the base? I'm only personally familiar with the Trimit, which indexes off the shoulder.

For consistency of trim length, indexing off the shoulder depends on consistent and precise shoulder setback when resizing. Resizing, in turn, indexes the shoulder off the base.

The point is, it's a two-step process, and if resizing to the shoulder is inconsistent, trimming as indexed to the shoulder only repeats the error. There is no inherent advantage (for consistent OAL) to indexing off the shoulder if resizing is not accurate.

The reason I press this point is I've talked at the range with three different guys using .223 reloads that jammed their rifles, in some instances deforming the case in the process. They insisted the cases had all been trimmed, but simply holding the cases side by side revealed variation in shoulder setback and, consequently, OAL.

Trimmers can index two ways, off the base (head), or off the shoulder. Most of the old style trimmers indexed off the base. Only in the past (maybe 5-7 years) have these new style trimmers that index off the shoulder have come out.

Not all shooters/re-loader's know what they are doing when it comes to reloading. If they set up their presses and dies correctly and trim using the shoulder as the index they will never have an issue with OAL. I've been doing it this way for all my AR's for about 7 years and well over 10K rounds now and never had a case jam or crush due to excessive OAL. I typically only trim once in the life of the case. I use a case gauge to determine if a spent case needs trimmed or not.

Case Gauge: https://www.amazon.com/Dillon-Precis.../dp/B0039OETOM

[SteveWag]

The solution to your problem is easy and cheap. DON'T TRIM BRASS!! Trimming is a waste of time and the need to trim is usually related to bad resizing practice. While neck sizing is nice and I recommend it, when using semi-auto OR more than one firearm, full length and SAMMI dimensions must be retained. Case length has NOTHING to do with cartridge OAL or head space. Uniform case length may be required when crimping, otherwise the longer cases may be over crimped or otherwise deformed. SO STOP CRIMPING!! .223/5.56 do not need crimped. Stay away from AR15.COM and other sites where "experts" are posting. Good Luck!
Steve

[theunrulychef]

[Remington788]

The solution to your problem is easy and cheap. DON'T TRIM BRASS!! Trimming is a waste of time and the need to trim is usually related to bad resizing practice. While neck sizing is nice and I recommend it, when using semi-auto OR more than one firearm, full length and SAMMI dimensions must be retained. Case length has NOTHING to do with cartridge OAL or head space. Uniform case length may be required when crimping, otherwise the longer cases may be over crimped or otherwise deformed. SO STOP CRIMPING!! .223/5.56 do not need crimped. Stay away from AR15.COM and other sites where "experts" are posting. Good Luck!
Steve

Huh?

[Delkal]

Bottle necked rifle cartridges must be trimmed occasionally. Or the longer case will not chamber or the neck will jam the bullet in tight giving higher pressures. It will happen.

Most standard / low velocity pistol cartridges don't need trimming (at least thats what I do). They usually neck split or get lost before you have any problems clambering them

[markshere2]

The solution to your problem is easy and cheap. DON'T TRIM BRASS!! Trimming is a waste of time and the need to trim is usually related to bad resizing practice. While neck sizing is nice and I recommend it, when using semi-auto OR more than one firearm, full length and SAMMI dimensions must be retained. Case length has NOTHING to do with cartridge OAL or head space. Uniform case length may be required when crimping, otherwise the longer cases may be over crimped or otherwise deformed. SO STOP CRIMPING!! .223/5.56 do not need crimped. Stay away from AR15.COM and other sites where "experts" are posting. Good Luck!
Steve

No. NO. and NOOOO!!!
You are wrong.

[Tacgunner]

Handloader Magazine covered this topic a few issues back. But, they were talking about straight-walled pistol brass. On that, they said no need to trim after the initial case length being checked.

Been reloading .223/5.56 ammo since the '70s, only check the case length about every 3 or 4 reloadings of the same brass. With a new batch, I check the case length and trim if needed (using old style hand trimmer). Crimping? No, I've tried it a few times and got inconsistent velocities and point of zero changes. If crimping, you need to ensure all your brass is 100% same length and same brand (wall thickness at neck), then ensure your crimping die is adjusted properly for that batch you are reloading. Too much hassle & headache for me.

[SteveWag]

Tacgunner has hit the nail on the head in regards to crimping! As to the chance of overly long brass "self crimping" when the brass meets the rifling, shoot the rifle (after all we are talking about bottle necked cartridges, and not 7.62x25 or SIG Sauer 38's, so it must be a rifle) a 200 times and the rifling will move (BE moved) ahead enough so that the chance of that happening will disappear. For 5.56 or Wylde chambered rifles this is already taken in to consideration.
Steve

[frankski]

Tacgunner has hit the nail on the head in regards to crimping! As to the chance of overly long brass "self crimping" when the brass meets the rifling, shoot the rifle (after all we are talking about bottle necked cartridges, and not 7.62x25 or SIG Sauer 38's, so it must be a rifle) a 200 times and the rifling will move (BE moved) ahead enough so that the chance of that happening will disappear. For 5.56 or Wylde chambered rifles this is already taken in to consideration.
Steve

Or are these your conclusions based on personal observation, or can you kindly cite verifiable sources for this?

As my teachers said, back when teaching was a profession, show your work.