Trim Length

[Jinx-)]

Reading an article
Precision Hand Loading for Long Range-Chapter One: Brass Sort & PrepBy Tres MonCeret

in the part where he talks about Trim to Length
Precision Hand Loading For Long Range-Chapter One: Brass Sort & Prep
the Sinclair Chamber Length Gage was used to determine the chamber length
Case Gauges & Headspace Tools - Sinclair Chamber Length Gage

Then Tres recommend to "trim your brass just short of this measurement instead of "book trim to" specs."
the part I don't get it, how short is short, do I need to be few thousands or hundreds off from the max?

Thank you.

 

[Jinx-)]

Upps I will ask Tres directly

 

[Jinx-)]

no response yet from Tres, but I'll go ahead and ask you guys I trim 0.005" shorter them actual chamber length do you think I should cut lower or not?

 

[GNERGY]

I usually trim .015

Tarey

 

[Jinx-)]

Is there a proven rule to go by when it comes to triming, maybe some formula something I can plug in to get best optimal length for my brass to fit in my chamber?

 

[Gene]

It is not a good idea to use factory or SAMMI spec lengths, as the end of the loaded case could contact the end of the barrel chamber, depending on how it was cut. This could cause pressures to skyrocket, not a good thing. For that reason, most reloaders trim between .010" and .020" below the SAMMI lengths. There is no good reason to do otherwise.

 

[trueblue]

trim 0.020 off

 

[Jinx-)]

All right then, lets try .223 as an example, with Sinclair tool it measured 1.775" as my chamber max, SAMMI has trim length 1.750" when 1.760" is max, so trim is 0.010" from max, so should I also cut 0.010" to 1.765 or 0.020" to 1.755"?