Trimming necked rifle cases

[DIYguy]

I have two case trimmers, one being the Hornady hand crank and the other the Dillon RT1500. Both of these are true over all case length trimmers that go off the case base to neck for total length. When my Hornady case prep machine died a while back I replaced it with a Frankford Platinum case prep machine which includes a trimmer.

The last time I trimmed my Lapua 308 brass I used the Hornady crank trimmer. Besides being phsically painful on the hand when needing to trim a couple hundred cases I ended up with a rolled lip on the case mouths from not getting a clean trim. I'm thinking of setting up the Frankford machine to trim the 308s again but wondering about the fact that the Frankford indexes off the shoulder of the case when trimming. How accurate are the exact total lengths of the cases when indexing off the shoulder? Any surprises with this style of trimmer? These are for precision loads so picky about accurate numbers.

 

[Steel head]

I use the Frankfort trimmer on my cases happily.
If your sizing your brass accurately you can trim accurately with it.
A couple thou if variance does absolutely nothing
My 7 saum brass has 15 loadings on it now and I’ve trimmed it once and it does plenty well past a mile.
People way over think reloading.

 

[DIYguy]

Fifteen loads and trimmed once? I get about two or three fires and I'm long enough to need trimming.
Sure would be easier on the hand to use the Frankford. The Dillon is so much work to set up has to be a major job to make the time worth while.
Good to know you like the Frankford

 

[straightshooter1]

The last time I trimmed my Lapua 308 brass I used the Hornady crank trimmer. Besides being phsically painful on the hand when needing to trim a couple hundred cases I ended up with a rolled lip on the case mouths from not getting a clean trim. I'm thinking of setting up the Frankford machine to trim the 308s again but wondering about the fact that the Frankford indexes off the shoulder of the case when trimming. How accurate are the exact total lengths of the cases when indexing off the shoulder? Any surprises with this style of trimmer? These are for precision loads so picky about accurate numbers.

I use a Giraud trimmer that indexes off of the shoulder and much prefer this as it gives me very consistent neck size where indexing of the case base does not do near as well. Consistence case volume is important to me so I want very consistent head space as measured of the shoulder datum. And having consistent contact surface between the neck and bullet is also important to me, so consistent neck dimensions are important to that end.
So, for "precision", I feel going off the shoulder is the best way . . . just have be sure your getting a consistent shoulder bump when sizing.

 

[DIYguy]

Dido on the shoulder bump. Learned that one the hard way. When I finally received my 308 and started loading for that gun I did the typical sizing die set up with the all the way to shell plate, 1/8 turn extra and check with case gage. Once the cases passed the gage test ran over (150) cases, primed etc. Afterwards discovered the die was bumping my shoulders WAY farther back than needed. Ended up having to form fire all those cases to get them back to size.

 

[Steel head]

Fifteen loads and trimmed once? I get about two or three fires and I'm long enough to need trimming.
Sure would be easier on the hand to use the Frankford. The Dillon is so much work to set up has to be a major job to make the time worth while.
Good to know you like the Frankford

I minimally full length size and neck size so brass growth is very minimal.

 

[Simonsza1]

I agree with straightshooter1. I was taught reloading back in the day that the proper way to trim is off the shoulder. I use a CTS trimmer and gauge for every caliber I reload for. They are great trimmers for going off the shoulder.