Case trimming?

[T3_tinker]

I'm sure this has been covered in the past but say all of my cases are under max case length. Is there much need to trim them all to the exact same length? I know uniformity is best but does anyone have any real world experience of it making much difference? And if so I assume I should always be trimming to the same length as the shortest case? Thanks 

[Gandy]

In reality it probably makes little difference but I trim to the shortest length so they are all the same. 

[MarinePMI]

I'd say that it's more important that the cases aren't too long, more so than all the same length.

That being said, I trim them to all be the same length.  A Giraud case trimmmer makes short work of the task and ensures consistency.

[miki]

As long as they are not a huge amount shorter (2mm say) then it shouldn't (as @Gandysaid) be much if any difference, it depends upon if that difference is cumlative. Are the cases the same volume, is the the COAL the same, is the neck tension the same etc

With the same load does the MV change between the longer and the shorter case and by how much. Are you aiming for less than 1MOA over 600yds or 1MOA @ 100yds. Longer than SAAMi and i'd trim them to length, a few thou shorter wont effect stalking or varmint shooting IME

[KABOOM]

6 hours ago, miki said:

As long as they are not a huge amount shorter (2mm say) then it shouldn't (as @Gandysaid) be much if any difference, it depends upon if that difference is cumlative. Are the cases the same volume, is the the COAL the same, is the neck tension the same etc

With the same load does the MV change between the longer and the shorter case and by how much. Are you aiming for less than 1MOA over 600yds or 1MOA @ 100yds. Longer than SAAMi and i'd trim them to length, a few thou shorter wont effect stalking or varmint shooting IME

A consistent length will contribute to accuracy. Cases that are too long can jam in the lead of rifling resulting in pressure spikes. C.O.A.L has nothing to do with neck length unless your neck is so short you must seat ever deeper just to use the case in question. This is why I try to avoid setting the shoulder back unless its becoming hard to chamber, cases stretch in the resize die. I have noticed less neck growth by not setting the shoulder back. All my brass goes in the trimmer in any event, many times I wont remove any material or a slightly visible cut.

[No i deer]

The cases will soon stretch..

2 or 3 thousanths on firing and around the same resizing them..

[miki]

7 hours ago, KABOOM said:

A consistent length will contribute to accuracy. Cases that are too long can jam in the lead of rifling resulting in pressure spikes. C.O.A.L has nothing to do with neck length unless your neck is so short you must seat ever deeper just to use the case in question. This is why I try to avoid setting the shoulder back unless its becoming hard to chamber, cases stretch in the resize die. I have noticed less neck growth by not setting the shoulder back. All my brass goes in the trimmer in any event, many times I wont remove any material or a slightly visible cut.

I perhaps disn't explain myself correctly although I can't see where I said that the length of the cartridge was directly related to neck length. A consistent dimensioned cartridge will offer a consistent resistance to the bullet as it leaves the neck. If the cases are the same volume and the COAL constant then the bullet is seated to the same depth and the 'release drag' is the same so with a matching charge the pressure will be the same and the bullet will enter the lands at the same moment at the same speed. It will leave the barrel at the same point of the wave and arrive at the point of aim subject only to the perturbations of the atmosphere. Nirvana (not the band, the idealism).

If the neck is longer than SAANi - trim it back. A few thou shorter wont effect stalking or varmint shooting IME . It depends what the OP is trying to acieve ... less than 1MOA over 600yds or 1MOA @ 100yds.

If the later (1 MOA @ 100) then as long as the case is not longer than SAAMi or significantly shorter (2 - 3mm) then it will make little to no difference to your required accuracy. If its longer 'trim it' if it's (a lot) shorter 'bin it'. If, on the other hand, you are searching to target at distances of 600M or greater (K02M for example) then getting everything perfectly matched to the chamber and timed to the harmonics in your rifle is a must.

[KABOOM]

6 hours ago, miki said:

I perhaps disn't explain myself correctly although I can't see where I said that the length of the cartridge was directly related to neck length. A consistent dimensioned cartridge will offer a consistent resistance to the bullet as it leaves the neck. If the cases are the same volume and the COAL constant then the bullet is seated to the same depth and the 'release drag' is the same so with a matching charge the pressure will be the same and the bullet will enter the lands at the same moment at the same speed. It will leave the barrel at the same point of the wave and arrive at the point of aim subject only to the perturbations of the atmosphere. Nirvana (not the band, the idealism).

If the neck is longer than SAANi - trim it back. A few thou shorter wont effect stalking or varmint shooting IME . It depends what the OP is trying to acieve ... less than 1MOA over 600yds or 1MOA @ 100yds.

If the later (1 MOA @ 100) then as long as the case is not longer than SAAMi or significantly shorter (2 - 3mm) then it will make little to no difference to your required accuracy. If its longer 'trim it' if it's (a lot) shorter 'bin it'. If, on the other hand, you are searching to target at distances of 600M or greater (K02M for example) then getting everything perfectly matched to the chamber and timed to the harmonics in your rifle is a must.

Quite possible I didn't quite grasp your context regarding c.o.a.l, best regards.

[geek]

On 4/27/2020 at 6:40 PM, Gandy said:

In reality it probably makes little difference but I trim to the shortest length so they are all the same. 

Me too.