Smith & Wesson Forum

Go Back   Smith & Wesson Forum > >


Reply
 
Thread Tools Display Modes
  #1  
Old 06-07-2011, 07:34 PM
Rule3's Avatar
Rule3 Rule3 is offline
Member
Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length  
Join Date: Feb 2008
Location: Florida, NRA CERT RSO
Posts: 17,665
Likes: 7,210
Liked 8,259 Times in 4,039 Posts
Question Case trimming and trim to length vs Max length

When trimming cases, usually rifle not so much straight walled handgun cases. The manuals have a trim to length and of course the max case length.

Why do they have a trim to length of (.01) 1/100th less than the max length?

Say for .223 Rem the max length is 1.760 and the trim is 1.750?

If using the little Lee trimmers I believe they only trim back to the max length.

Is the trim length to allow for "growth" of the case??
__________________
SENT FROM MY WIRED DIAL PHONE
Reply With Quote
The Following User Likes This Post:
  #2  
Old 06-07-2011, 09:31 PM
papajohn428's Avatar
papajohn428 papajohn428 is offline
Member
Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length  
Join Date: May 2004
Location: Coastal Missouri
Posts: 1,875
Likes: 849
Liked 908 Times in 445 Posts
Default

I have NEVER trimmed a straight-walled pistol round. Never will. Don't see it as necessary. By the time they've stretched to the point they need it, they're starting to split, and the primer pockets are getting loose. In the case of the 45ACP, they tend to shorten over time and usage.

My Lee trimmers are factory-set to the "trim-to" length, which always seems to be 0.01" below the maximum allowable length. Most are right, but a few have needed to be adjusted a bit.

The bottlenecked rounds tend to grow longer with each firing, which happens faster with full-power loads. If you trim to the recommended "short" length, you should get about five firings before they need trimming again. A well-known ballistic expert, whose initials were Ed Matunas, used to say that after a fifth trimming, the cases were ready for the scrap heap. I have yet to see a case that lived long enough to need TWO trimmings, let alone five.

But of course, your results may be different.
Reply With Quote
  #3  
Old 06-08-2011, 07:00 AM
Bomberman's Avatar
Bomberman Bomberman is offline
US Veteran
Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length  
Join Date: Dec 2010
Location: Off the beaten path, PA
Posts: 136
Likes: 1
Liked 8 Times in 7 Posts
Default

Quote:
Originally Posted by OCD1 View Post
Is the trim length to allow for "growth" of the case??

Yes, that is exactly why they are trimmed to that length. I, for one, also trim my straight walled handgun cases, but only once. When I first get them I trim them to a set size so that all of my brass is the exact same length. That way I know that I get the same crimp and same bullet seating depth every time. Is it necessary? Probably not but I like knowing all of my components are the same.
__________________
Have .44, will travel
Reply With Quote
  #4  
Old 06-08-2011, 07:10 AM
Leonard's Avatar
Leonard Leonard is online now
Member
Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length  
Join Date: Jul 2008
Location: Ohio
Posts: 775
Likes: 137
Liked 465 Times in 162 Posts
Default

I use the Matunas method on my bottle neck cases and cut the to minimum and uniform length from the start.
__________________
Len
Reply With Quote
  #5  
Old 06-08-2011, 09:22 AM
Missionary Missionary is offline
Member
Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length Case trimming and trim to length vs Max length  
Join Date: May 2009
Location: Arequipa, Peru
Posts: 202
Likes: 0
Liked 2 Times in 2 Posts
Default

Good morning
+1 On the trim to minimum... trimming cases is by far one of my least desirable reloading activities. I do them in batches.. After 4 reloadings check length of some . But I also dedicate brass to weapons and stay away from max loadings which really do not deliver that much more benefit. I generally figure a need for a max load shows the need for a bigger bore.
Reply With Quote
  #6  
Old 06-08-2011, 04:30 PM
Driftwood Johnson Driftwood Johnson is offline
SWCA Member
Case trimming and trim to length vs Max length  
Join Date: Oct 2003
Location: Massachusetts, USA
Posts: 683
Likes: 0
Liked 543 Times in 130 Posts
Default

Howdy

Yes, the idea is to trim to the 'trim to' length. If the cases grow at all, after they pass the Max length, trim to the 'trim to' length again.

Some manuals specify .005 under Max for the trim to length, some specify .010.

Whatever the case, count me as one who has never, ever trimmed a straight cased revolver round. At the pressures I normally shoot at, they simply do not grow at all.
Reply With Quote
Reply

Tags
223, 45acp, crimp, primer

Thread Tools
Display Modes

Posting Rules
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Case Trim Length Mals9 Reloading 26 07-17-2017 03:55 AM
Case length trimming Mikeinkaty Reloading 27 02-03-2017 04:53 PM
Case length trimming-procedure improved oldman10mm Reloading 10 08-20-2016 04:09 PM
223 trim length Magload Reloading 25 06-24-2016 06:39 AM
Trimming 44 Mag to 44 Russian - Case Length? Sieveboy Reloading 7 07-16-2013 10:41 PM

Powered by vBadvanced CMPS v3.2.3
smith-wessonforum.com tested by Norton Internet Security smith-wessonforum.com tested by McAfee Internet Security

All times are GMT -4. The time now is 07:00 AM.


S-W Forum, LLC 2000-2015
Smith-WessonForum.com is not affiliated with Smith & Wesson Holding Corporation (NASDAQ Global Select: SWHC)