Trim length, does it make a difference in accuracy???

[Ledd Slinger]

I like K&M's idea of a pilot that extends through the pilot hole, but I think that there angle is a bit steep for the main chamfer. A while back Redding came out with this.
View attachment 1383629

I have a few similar chamfer tools as the Redding and they work well.

The beauty of the K&M tool is that it also has an adjustable stop point that contacts the case mouth to not only control the depth of the cut but also keep it perfectly square to the case mouth so you get a perfectly even depth around the entire circumference. I agree on the cut angle being pretty steep and that’s why I made the comment about not running the tool very deep. Nice thing is you can adjust the stop to cut only the exact depth you desire

 

[JFrank]

I have a few similar chamfer tools as the Redding and they work well.

The beauty of the K&M tool is that it also has an adjustable stop point that contacts the case mouth to not only control the depth of the cut but also keep it perfectly square to the case mouth so you get a perfectly even depth around the entire circumference. I agree on the cut angle being pretty steep and that’s why I made the comment about not running the tool very deep. Nice thing is you can adjust the stop to cut only the exact depth you desire

View attachment 1383648

I would not want another man complementing my TOOL however those are a different mouse trap and something to look into.
Thx
J

 

[10XSHOOTER]

Daggum Lee trimmer case length gauge and shell holder for $5 on a cordless drill and you're golden.

If you can set a lee trimmer up in a drill press. Shell holder in the vice trimmer in the chuck. Straight down on the case, No tipping. You will get very consistant lengths.

 

[Gargoyle]

If you can set a lee trimmer up in a drill press. Shell holder in the vice trimmer in the chuck. Straight down on the case, No tipping. You will get very consistant lengths.

I already get consistent lengths. I can also spell consistent, consistently!

 

[CA_Shooter]

I see the term "square" used often. What exactly is "square"?

 

[mikecr]

When you do trim your cases back (from the chambers end) how many thousands do you shoot for?

I trim when within 5thou clearance, to 5thou.
Depending on the formed cartridge and chamber, this might be soon, or quite a while down the road, or never.

With this tight clearance (once there) I get no neck sooting, no carbon ring formation, low SDs.

 

[BartsBullets]

I trim when within 5thou clearance, to 5thou.
Depending on the formed cartridge and chamber, this might be soon, or quite a while down the road, or never.

With this tight clearance (once there) I get no neck sooting, no carbon ring formation, low SDs.

Edit

I said this wrong. I trim so that I have at least .020 total clearance with lenght. To get that I usually take .010 off of my cases.
Bart

 

[CNC-Dude]

I see the term "square" used often. What exactly is "square"?

Probably meaning case mouth parallel to the base....not at an angle!

 

[CA_Shooter]

Probably meaning case mouth parallel to the base....not at an angle!

That makes sense. I had a trimmer that would cut uneven. Differences up to .002 measured by calipers

 

[Ned Ludd]

I see the term "square" used often. What exactly is "square"?

When referring to the use of a trimmer unit that only trims the brass but doesn't chamfer it, square would mean the [flat] top of the trimmed neck walls are all in the same plane as the base of the case, just as CNC-Dude described. However, if the trimmer unit also chamfers the cases, it could have been intended to mean that the depth/height of the inside chamfer/bevel is uniform all the way around the inside of the case mouth. If the cutter head of a unit that both trims and chamfers is not set correctly for the neck wall thickness of a given brand of brass, a chamfer/inside bevel that is not of uniform depth/height all the way around the inside of the case mouth may result.

 

[Bill Norris]

Edit

I said this wrong. I trim so that I have at least .020 total clearance with lenght. To get that I usually take .010 off of my cases.
Bart

Do you trim this .010 off before fire-forming or afterwards ?

 

[BartsBullets]

Do you trim this .010 off before fire-forming or afterwards ?

After firing forming. My trimmer indexes off the shoulder.

 

[Straightshooter1]

When referring to the use of a trimmer unit that only trims the brass but doesn't chamfer it, square would mean the [flat] top of the trimmed neck walls are all in the same plane as the base of the case, just as CNC-Dude described. However, if the trimmer unit also chamfers the cases, it could have been intended to mean that the depth/height of the inside chamfer/bevel is uniform all the way around the inside of the case mouth. If the cutter head of a unit that both trims and chamfers is not set correctly for the neck wall thickness of a given brand of brass, a chamfer/inside bevel that is not of uniform depth/height all the way around the inside of the case mouth may result.

. . . and variance in neck wall thickness can show up with variance in the chamfer, and can depend on how the neck is sized.

 

[Sleepyhollow]

I'm with Bart on this one I doubt you'll ever shoot the difference. It makes me feel good and know I'm taking another variable out of the equation. No difference then guys who clean pockets or necks. If it works for ya keep shooting. If it doesn't try something else

 

[Raptor]

Thanks for all the replies, guys!! Much appreciated!!

 

[BondJamesBond]

Good info....this topic has been on my mind lately as I want to true up the case mouths a bit but don't really need to trim.
By trueing maybe I mean squaring or a new cut 90 degrees to the neck.
Been measuring lengths to monitor them and trimming maybe 10-20 percent to bring them back to the herd a bit.
Good to know what others are doing.

Larry W

 

[rebs]

FWIW…my brass length varies about .002. I won the 3 Gun at the NBRSA Nationals and just won the Tack Driver. So pretty sure it will be ok.

Bart

congratulations Bart

 

[10XSHOOTER]

I already get consistent lengths. I can also spell consistent, consistently!

OK, I can't spell. But, I can shoot!

 

[freebird22/250]

The main key to reloading is making each component as uniform as possible.

 

[Ledd Slinger]

The main key to reloading is making each component as uniform as you can.

Well now that’s just crazy talk! Lol