how many times until a case trim?
 

OK, I read the case length thread sticky'd above, but since I am new to reloading I still have a question.

after the first firing of my loads the case has stretched about .008. I assume this is now fire formed to my chamber correct? (supersonic load)

approximately how many times can I reload this case before I should trim it back to factory, specs?

after how many loadings should I re-size the case?

here are some pics of my fired cases, how do the primers look as compared to unfired case? (super sonic loading) 20.5 G of H110 under a 110 G Vmax from a 10.5" barrel AR15, Pistol length gas tube.
http://i684.photobucket.com/albums/v...1/P1050617.jpg
http://i684.photobucket.com/albums/v...1/P1050623.jpg
http://i684.photobucket.com/albums/v...1/P1050619.jpg

thanks.

Trim length is usually .010 shorter than max case length. So if your trim length is 1.355, trim them when they hit 1.365. Keep you subs and supers separate. For instance, use Winchester brass for subs and Remington for your supers. It will help you keep track of your brass. The subs will not have to be trimmed as much.

If shot from an AR, brass needs to be completely full length sized every time at the increased risk of failure to feed correctly, stuck cases and at worst...slam fire.

Neck sizing only applies to bolt actions.

As for trim length...the subs don't need it as often because of case stretch but are much more sensitive to neck tension variances, so I trim to 1.355" every time but especially if using a Lee Factory Crimp die. Changes in length directly effect neck tension when the FCD's are used.

Your primers look like they are flattening but the test will be how they feel trying to press in a new primer after sizing. If they are loose, then your pressures are definitely too high.

Lastly...I'm assuming you have an adjustable gas block to lessen the pressure of shooting hyper-sonic through a pistol length gas system?

Trim when they reach length stated by Allycat. some brass moves more than other so measure it. Commercial /as aposed to milserp.brand a to brand b...Sme of those primers look alittle flat in the photos. Military brass tends to be thicker , wich means less interior room so a powder charge can reach high pressure that would be fine with comercial brass.
Enjoy and be safe ....I love loading for this calliber. Its very easy on brass,:grin:

I do, but I also was having issues with this as no matter the load, or adjustment, I was not getting lock back on an empty mag and was having periodic cycling issues, I have a thread on this in the other 300 category (rifles and pistols)on this web board. I am having the gas port up sized to .125 and gas block realigned again.