Case trimming question

[mzvarner]

This may have been touched already but my google-fu was not able to find it. What are you guys trimming your 308 win and 223/556 cases to? I have a lot of brass and its a PITA trimming every piece each time I FL resize. How short is too short? How does neck trimming effect accuracy? I assume the more you trim the less material meaning less internal surface area to make contact with the bullet thus its easier to launch the projectile?

 

[jkonzal]

I trim to book max length. That way I know my cases are all consistent and so is the amount of neck contacting each bullet. I anneal after every 2nd firing.

 

[Silverbullet2]

308 is 2.005" trim to length. You shouldn't be trimming every time you full length resize. Only a semi auto like an HK-91 or something with violent extraction. Or you should be using Lake City brass that is a little thicker than commercial brass. Just my .02, J

 

[427Cobra]

Trimming sucks when your cranking, get a Giraud Trimmer.

Trimming to book min is ok for non barrel burning calibers like 223/5.56 and 308, but in a barrel burner like 6.5-284 trimming to book min only helps to lessen the amount of useable rounds a barrel will have, Sinclair sells little plugs that go in modified cases, use these chamber length gauges to tell you exactly what your max case length is, trim .010 from the gauge says.

I see a lot of posts about trim length and accuracy, I have not been able to shoot the difference in .005, so get a trimmer that makes quick work of the task, and arm yourself with the tools to tells you exactly what your chamber length is.

 

[flounderv2]

Trimming sucks when your cranking, get a Giraud Trimmer.

Trimming to book min is ok for non barrel burning calibers like 223/5.56 and 308, but in a barrel burner like 6.5-284 trimming to book min only helps to lessen the amount of useable rounds a barrel will have, Sinclair sells little plugs that go in modified cases, use these chamber length gauges to tell you exactly what your max case length is, trim .010 from the gauge says.

I see a lot of posts about trim length and accuracy, I have not been able to shoot the difference in .005, so get a trimmer that makes quick work of the task, and arm yourself with the tools to tells you exactly what your chamber length is.

quoted for truth. just got my Giruad and not sure how i ever lived without it. Easily trim, and chamfer inside and out 300 pieces of brass in 30 min or less..

Sent from my DROID RAZR using Tapatalk 2

 

[Mad_Charlie]

Trimming sucks when your cranking, get a Giraud Trimmer.

Trimming to book min is ok for non barrel burning calibers like 223/5.56 and 308, but in a barrel burner like 6.5-284 trimming to book min only helps to lessen the amount of useable rounds a barrel will have, Sinclair sells little plugs that go in modified cases, use these chamber length gauges to tell you exactly what your max case length is, trim .010 from the gauge says.

I see a lot of posts about trim length and accuracy, I have not been able to shoot the difference in .005, so get a trimmer that makes quick work of the task, and arm yourself with the tools to tells you exactly what your chamber length is.

This ^^ .

I don't like to cut them any shorter than they have to be.

 

[dave300]

427 can you give me a little more info on the modified case plugs at Sinclairs? Thank you!

Trimming sucks when your cranking, get a Giraud Trimmer.

Trimming to book min is ok for non barrel burning calibers like 223/5.56 and 308, but in a barrel burner like 6.5-284 trimming to book min only helps to lessen the amount of useable rounds a barrel will have, Sinclair sells little plugs that go in modified cases, use these chamber length gauges to tell you exactly what your max case length is, trim .010 from the gauge says.

I see a lot of posts about trim length and accuracy, I have not been able to shoot the difference in .005, so get a trimmer that makes quick work of the task, and arm yourself with the tools to tells you exactly what your chamber length is.

 

[427Cobra]

Sinclair Chamber Length Gage | Sinclair Intl

FL size the case for what ever cartridge I checking, drill out the primer pocket with a 3/16 drill bit, and trim .100 off the case neck, insert the plug but not all the way and chamber the modified case with plug, remove and measure, NOTE the chamber be clean to get an accurate measurement, the 3/16 hole in the end of the modified case is for pushing the plug out, I do it 3 times and use the longest reading as my reference, trim back .010, it might a couple firings to get there.

 

[Fuzzball]

First, book 'trim to' length is not a specification. Trimming 10 thou less than the specified max length was a rule of thumb long before people got antsy about wanting everything spoon fed to them to measure.

Second, no one can possibly be certain of what's going on inside a cartridge during firing but it has been considered by ballasticians that the neck wall is probably hard against the chamber before the bullet clears the case mouth. If so, there's precious little difference on target a slight neck length variation (or how truly square the mouth is) could make.

 

[fw707]

Trimming sucks when your cranking, get a Giraud Trimmer.

Trimming to book min is ok for non barrel burning calibers like 223/5.56 and 308, but in a barrel burner like 6.5-284 trimming to book min only helps to lessen the amount of useable rounds a barrel will have, Sinclair sells little plugs that go in modified cases, use these chamber length gauges to tell you exactly what your max case length is, trim .010 from the gauge says.

I see a lot of posts about trim length and accuracy, I have not been able to shoot the difference in .005, so get a trimmer that makes quick work of the task, and arm yourself with the tools to tells you exactly what your chamber length is.

Yes.
I trim .005 under book max every time.
Some calibers barely get chamfered.