Case trimming? Confused

[wildfowler.250]

Folks, anyone with more wisdom than myself care to explain this one.

Why is there a difference between in this instance, Nosler textbook 6.5x55 case length of 2.165 and the viht app which suggests trim the case to 2.157”?

I appreciate the case will expand when fired. But don’t fully understand why the app recommends trimming to a shorter length than the original case?

Thanks!

 

[Jagged77]

2.155” is the trim to length, 2.165” is the max case length. Viht have rounded out 54.74mm to 54.8mm or 2.157”

Irrespective the best thing to do is find the max case length of your chamber if possible and trim to that. Or pick a number under the max length and stick to it.

 

[Sniper308]

I always trim to the length that the case started at new

 

[User00056]

I just use the Lee calibre-specific trim dies and don't worry about measuring. A couple of quick spins and it's done

 

[Tikkat1x]

i always trim to min case level, then wait till its a couple of thou of max then trim it again,

 

[Stalker-of-the-deer]

Personaly I trim every firing back to min length. Just makes everything consistent and with my rcbs case trimmer 2 its dead easy with the power attachment

 

[Dalua]

I always trim to the length that the case started at new

Gosh - do you scratch the relevant length into each case? Sounds very labour-intensive!

 

[Sniper308]

Gosh - do you scratch the relevant length into each case? Sounds very labour-intensive!

Of course not. Lapua brass has always been consistent for me

 

[Ronin]

Measure a sample of new unfired cases and pick the shortest

Trim to that length

Trimming cases assists consistancy of pressure internally and bullet release

All aiding to increased accuracy (providing end user does their bit)

 

[Muir]

Ive made 7-08 cases from military.308 and had them .025"short. As long as they were the same length there was no problem.-Muir

 

[enfieldspares]

The next question is when the time comes to do this is do you trim AFTER firing but BEFORE resizing? Or after resizing? My advise is always trim after resizing.

 

[Motard]

Me after resizing, although I pay the most attention to minimize shoulder bump, cases are always coming out longer grom a FL dies. you can skip that if only collet resizing, especially with the Lee collet die.

 

[Stalker-of-the-deer]

Fl resize, trim de bur and chamfer then into the cleaner for an hour or two

Case prep done

 

[wildfowler.250]

Cheers gents! Yes I thought the case length as per the textbook would be what you trim to but viht app wanted to trim shorter than this and I couldn’t understand it.

I suppose as long as everything is consistent it should be okay but there does seem to be a bit of variety on here too

 

[enfieldspares]

I remember the RCBS "X Die" that was supposed to eliminate the need to trim cases. I never seem to have seen a review of them.

 

[Border]

I remember the RCBS "X Die" that was supposed to eliminate the need to trim cases. I never seem to have seen a review of them.

I did and the conclusion was that it wasn't worth the hassle. From memory there was an internal "lip/groove" in the die that was supposed to stop brass being displaced. Apparently all this did after a few loadings were to give doughnuts and chambering problems from the review that I read 20+ yrs ago.

 

[enfieldspares]

I did and the conclusion was that it wasn't worth the hassle. From memory there was an internal "lip/groove" in the die that was supposed to stop brass being displaced. Apparently all this did after a few loadings were to give doughnuts and chambering problems from the review that I read 20+ yrs ago.

Thank you for taking the time to reply. I did wonder if they were the better mousetrap they were supposed to be. Hope it is of use to others also.