You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Trim it
- Thread starter Tlewis81
- Start date
JeepHammer
Moderator
Depends on your case sizing abilities.
'Trim It' is about like all the other flat faced cutters on the market,
You still have to champfer inside and usually outside once the mouth is cut to length.
The 'Trim It II' has a 'V' shaped cutter that trims to length, champfers/Deburrs in one step.
The reason I say it depends on your resizing capabilities is the 'Trim It' is a datum point index, datum point being on the neck down shoulder.
Head Space is determined from datum point on the shoulder to the head stamp end of the case.
If the head space is correct, and dead on, then the cutter will index off the shoulder/datum point and give you VERY accurate cuts since its almost infinately adjustable.
The 'Got Ya' here is stuff like 'Spring Back' of different brands of cases, or different hardness of cases that don't all headspace size exactly the same...
If the sizing die gives you (+/-) 0.002" or 0.003" difference in cases, that's going to carry over into the necks since the datum point on the shoulder isn't in exactly the correct spot.
Personally, I use the crap out of my 'Trim-It II' and its the closest thing to exact I've found yet without hand lapping the cases...
When aim processing cases I double size die in a progressive machine, meaning I run through two sizing dies,
One to decap and NOT squeeze the neck, get the shoulder back where it belongs,
The next die finalizes the shoulder/headspace, supports the shoulder while the neck gets sized.
VERY accurate headspaced cases this way, so the trimmer works exceptionally well...
(Some people 'Double Tap' the body of the case in a single die before pulling the sizer ball through the neck,
But this leaves the shoulder unsupported in a common die)
Anyway, its up to you,
One tip, you *Might* consider honing out the neck of the die so it doesn't undersized and work harden the neck,
Only push the brass back where it will be 'Gently' sized by the sizer ball,
This keeps the crush, opening by the sizer ball from moving your shoulder around in common dies and gives you more accurate headspacing with common dies...
'Trim It' is about like all the other flat faced cutters on the market,
You still have to champfer inside and usually outside once the mouth is cut to length.
The 'Trim It II' has a 'V' shaped cutter that trims to length, champfers/Deburrs in one step.
The reason I say it depends on your resizing capabilities is the 'Trim It' is a datum point index, datum point being on the neck down shoulder.
Head Space is determined from datum point on the shoulder to the head stamp end of the case.
If the head space is correct, and dead on, then the cutter will index off the shoulder/datum point and give you VERY accurate cuts since its almost infinately adjustable.
The 'Got Ya' here is stuff like 'Spring Back' of different brands of cases, or different hardness of cases that don't all headspace size exactly the same...
If the sizing die gives you (+/-) 0.002" or 0.003" difference in cases, that's going to carry over into the necks since the datum point on the shoulder isn't in exactly the correct spot.
Personally, I use the crap out of my 'Trim-It II' and its the closest thing to exact I've found yet without hand lapping the cases...
When aim processing cases I double size die in a progressive machine, meaning I run through two sizing dies,
One to decap and NOT squeeze the neck, get the shoulder back where it belongs,
The next die finalizes the shoulder/headspace, supports the shoulder while the neck gets sized.
VERY accurate headspaced cases this way, so the trimmer works exceptionally well...
(Some people 'Double Tap' the body of the case in a single die before pulling the sizer ball through the neck,
But this leaves the shoulder unsupported in a common die)
Anyway, its up to you,
One tip, you *Might* consider honing out the neck of the die so it doesn't undersized and work harden the neck,
Only push the brass back where it will be 'Gently' sized by the sizer ball,
This keeps the crush, opening by the sizer ball from moving your shoulder around in common dies and gives you more accurate headspacing with common dies...
JeepHammer
Moderator
Start with a brass bolt, small enough to fit in the neck of the die,
Cut a slot in it and use polishing cloth in the slot,
Turn with a LOW SPEED hand drill.
*IF* your sizing ball makes cases the bullets more or less fall into,
And you would like a little more neck tension,
Simply remove the decapping rod/expanding ball,
Tape the threads, spin in a drill, use honing cloth to take a little off the outside of the ball.
When you get the neck tension you are looking for, STOP!
Believe it or not, just a second or two can make a big difference when you get close...
Then measure the thickness of the neck wall... X2 + the diameter of the ball.
This *Should* be what you are shooting for...
If you don't have gauges to reach up into the die,
GO SLOWLY!
Take a little out, then size a brass WITHOUT the rod/expander,
See if the ball plus two case neck thicknesses is there,
STOP A LITTLE SHORT, you want the neck a little undersized so the ball can expand it.
Trial & error without a bore gauge set...
*IF* you go a little large, don't sweat it, not all case neck thicknesses are the same, I have dies set up for military brass, forign brass, and my favorite, Winchester brass.
Cut a slot in it and use polishing cloth in the slot,
Turn with a LOW SPEED hand drill.
*IF* your sizing ball makes cases the bullets more or less fall into,
And you would like a little more neck tension,
Simply remove the decapping rod/expanding ball,
Tape the threads, spin in a drill, use honing cloth to take a little off the outside of the ball.
When you get the neck tension you are looking for, STOP!
Believe it or not, just a second or two can make a big difference when you get close...
Then measure the thickness of the neck wall... X2 + the diameter of the ball.
This *Should* be what you are shooting for...
If you don't have gauges to reach up into the die,
GO SLOWLY!
Take a little out, then size a brass WITHOUT the rod/expander,
See if the ball plus two case neck thicknesses is there,
STOP A LITTLE SHORT, you want the neck a little undersized so the ball can expand it.
Trial & error without a bore gauge set...
*IF* you go a little large, don't sweat it, not all case neck thicknesses are the same, I have dies set up for military brass, forign brass, and my favorite, Winchester brass.
JeepHammer
Moderator
Help yourself, I check this about every other day.
JeepHammer
Moderator
What I can't stress enough is getting that shoulder/datum point back where it belongs.
Most guys start with a case length gauge that completely ignores the datum point/head space,
They crank the sizing die down until the brass chambers easily,
Which usually produces a 'Short' (Head Space) brass,
But since it fits in the length gauge or caliper, they are off to the races with it sloping around in the chamber...
If you want to make 'Proper' brass, a datum point adapter on your caliper is mandatory (luckily its cheap to make or buy) so you crank out proper headspace length brass to the datum point,
THEN you use a trimmer to get case length.
What I like about datum point trimmers is,
Some of my rifles have a little longer than SAAMI headspacing,
I set up dies for those rifles to crank out matching brass,
But I don't have to mess with trimmers since virtually all cases from datum point to mouth are the same length in the chambers.
When I'm cranking out 'Range' ammo, everything gets punched SAAMI,
Trimmed to SAAMI or slightly under, and trimming/champerfing takes about 1 second each, no blocking/locking in a trimmer, then trimming, then inside champfer, then outside champfer...
Everything in 1 second & done. A serious time saver if you load any kind of volume at all!
$135 for the Trim It II and $30 hand drill beats $500 for the motor included bench model.
I get the drills with a 'Collar' right behind the chuck, intended for a band clamp handle, makes a great mounting boss...
With a $350 difference and mounting of my choosing, I'm inclined to put my own motor on it...
Most guys start with a case length gauge that completely ignores the datum point/head space,
They crank the sizing die down until the brass chambers easily,
Which usually produces a 'Short' (Head Space) brass,
But since it fits in the length gauge or caliper, they are off to the races with it sloping around in the chamber...
If you want to make 'Proper' brass, a datum point adapter on your caliper is mandatory (luckily its cheap to make or buy) so you crank out proper headspace length brass to the datum point,
THEN you use a trimmer to get case length.
What I like about datum point trimmers is,
Some of my rifles have a little longer than SAAMI headspacing,
I set up dies for those rifles to crank out matching brass,
But I don't have to mess with trimmers since virtually all cases from datum point to mouth are the same length in the chambers.
When I'm cranking out 'Range' ammo, everything gets punched SAAMI,
Trimmed to SAAMI or slightly under, and trimming/champerfing takes about 1 second each, no blocking/locking in a trimmer, then trimming, then inside champfer, then outside champfer...
Everything in 1 second & done. A serious time saver if you load any kind of volume at all!
$135 for the Trim It II and $30 hand drill beats $500 for the motor included bench model.
I get the drills with a 'Collar' right behind the chuck, intended for a band clamp handle, makes a great mounting boss...
With a $350 difference and mounting of my choosing, I'm inclined to put my own motor on it...
JeepHammer
After trimming the case to the datum point , do you check it in your stripped bolt ( I'm shooting bolt action ) to get that slight resistance against the bolt face. My problem is my fired brass is wider, making my brass shorter after firing. Just love the idea of trimming the brass back to the datum point, that's using the case trimmer. You made me feel like an A H for not thinking of it . Again, learned something new today. I ordered a Go gauge 1.630 hoping it would be the same reading on my other gages , but just added to the confusion. Your post would have saved me money. Your getting to be my Hero. Thanks again , Chris
After trimming the case to the datum point , do you check it in your stripped bolt ( I'm shooting bolt action ) to get that slight resistance against the bolt face. My problem is my fired brass is wider, making my brass shorter after firing. Just love the idea of trimming the brass back to the datum point, that's using the case trimmer. You made me feel like an A H for not thinking of it . Again, learned something new today. I ordered a Go gauge 1.630 hoping it would be the same reading on my other gages , but just added to the confusion. Your post would have saved me money. Your getting to be my Hero. Thanks again , Chris
JeepHammer
Moderator
Some guys have 'Long' chambers, usually the guy at the factory getting lazy and hogging too much out...
That's why I recommend spending $1.50 on 'Plasti-Gauge' and using it between bolt face and brass.
Plasti-Gauge will give you a good idea if you are getting any clearance between bolt face and brass (0.0005" or less is optimum).
It's very cheap & fast way to set your sizing die up,
And having a slight gap keeps you from wearing bolt locking lugs away having the bolt size the brass for headspace.
Jamming the bolt closed is always a bad idea, as you wear bolt locking lugs the headspace increases, adding another variable into the mix...
Stick the Plasti-Gauge to the head stamp on the brass,
Use as slick of moly lube as you can find on the bolt face,
GENTLY chamber the brass,
Have a look at the Plasti-Gauge using the crush guide on the Plasti-Gauge package, and it will tell you what you have for headspace.
Not crushed enough, crank the die down a little or use a 'Feeler Gauge' between brass and shell holder.
Crushed too much, back the die off a little...
For 'Newbies' this is a very economical way to determine head space and produce brass that fits ONE particular rifle,
Without expensive, complicated head space gauges.
One thing I see all the time,
Common digital calipers are only capable of 0.005" accuracy.
The last digit on 3rd number behind the decimal point will be a 0 or a 5.
1/2 thousandth is all they are capable of, so any measurement can be up to 0.005" off.
SO...
When someone 'Says' they have 'Exactly' the third digit behind the decimil point, I'm always skeptical...
I prefer NOT to have my brass 0.005" off one way or the other,
So I often use analog (dial face) caliper of good quality.
A high accuracy caliper is worth the money since its not specific to just one caliber or function...
Its a general tool you will use for about everything...
Most guys get confused with dial calipers, so they buy direct read digital.
You *Can* get a digital caliper for reasonable cost that has the 4th digit that is 0 or 5, and 5/10,000 off is acceptable for most home built ammo with no issues.
To be quite frank about it, I'm OCD and I shoot bench rifles,
So EXACT was a way of life,
But I've also found out the ammo is mostly more accurate than the shooter/rifle.
If you are lucky, Or you work long & hard (not lucky) you can usually find that 'Accuracy Node', that nearly perfect load that works nearly perfectly with ONE specific rifle... The result is a hyper accurate combo,
Then you have ZERO excuses for missing, its all on you!
That's why I recommend spending $1.50 on 'Plasti-Gauge' and using it between bolt face and brass.
Plasti-Gauge will give you a good idea if you are getting any clearance between bolt face and brass (0.0005" or less is optimum).
It's very cheap & fast way to set your sizing die up,
And having a slight gap keeps you from wearing bolt locking lugs away having the bolt size the brass for headspace.
Jamming the bolt closed is always a bad idea, as you wear bolt locking lugs the headspace increases, adding another variable into the mix...
Stick the Plasti-Gauge to the head stamp on the brass,
Use as slick of moly lube as you can find on the bolt face,
GENTLY chamber the brass,
Have a look at the Plasti-Gauge using the crush guide on the Plasti-Gauge package, and it will tell you what you have for headspace.
Not crushed enough, crank the die down a little or use a 'Feeler Gauge' between brass and shell holder.
Crushed too much, back the die off a little...
For 'Newbies' this is a very economical way to determine head space and produce brass that fits ONE particular rifle,
Without expensive, complicated head space gauges.
One thing I see all the time,
Common digital calipers are only capable of 0.005" accuracy.
The last digit on 3rd number behind the decimal point will be a 0 or a 5.
1/2 thousandth is all they are capable of, so any measurement can be up to 0.005" off.
SO...
When someone 'Says' they have 'Exactly' the third digit behind the decimil point, I'm always skeptical...
I prefer NOT to have my brass 0.005" off one way or the other,
So I often use analog (dial face) caliper of good quality.
A high accuracy caliper is worth the money since its not specific to just one caliber or function...
Its a general tool you will use for about everything...
Most guys get confused with dial calipers, so they buy direct read digital.
You *Can* get a digital caliper for reasonable cost that has the 4th digit that is 0 or 5, and 5/10,000 off is acceptable for most home built ammo with no issues.
To be quite frank about it, I'm OCD and I shoot bench rifles,
So EXACT was a way of life,
But I've also found out the ammo is mostly more accurate than the shooter/rifle.
If you are lucky, Or you work long & hard (not lucky) you can usually find that 'Accuracy Node', that nearly perfect load that works nearly perfectly with ONE specific rifle... The result is a hyper accurate combo,
Then you have ZERO excuses for missing, its all on you!
JeepHammer
Moderator
Once you settle on a caliper,
Then order or make a 0.330"datum point adapter that clamps on the caliper jaw.
Since they usually run under $20 and are easy to use, its not a big deal to have one for each caliber you want to accuracy load.
Once you get brass coming out of the die, using 'Plasti-Gauge' to verify the brass in the chamber,
The caliper & datum point adapter will tell you what you have for chamber length in inches.
Now you have a quick way to verify your brass is coming out of the die correctly.
Then its off to trimming for length...
Trimming from the datum point, which you KNOW is correct for your rifle,
You are off to the races!
In bolt rifles, I don't use a 'Crimp' most times.
I simply reduce the size of the sizer ball to produce the neck tension to withstand recoil & chambering.
I will NOT use roll or taper crimp on bolt guns intended for hyper accuracy.
Since roll or taper crimps push directly down on the case mouth, they move the shoulder angle & datum point.
The collet 'Factory Crimp' dies support the shoulder and fingers crimp from the sides instead of pushing down, they will effect headspace the least or not at all.
Again, for heavy recoil rifles, some crimping might be needed, and 'Factory Crimp' dies are cheap enough to own one for every accuracy caliber you load.
I simply use a little more neck tension on .308 Win rifles, crimps aren't needed, and cases last longer without splits from crimp overworking the brass.
Then order or make a 0.330"datum point adapter that clamps on the caliper jaw.
Since they usually run under $20 and are easy to use, its not a big deal to have one for each caliber you want to accuracy load.
Once you get brass coming out of the die, using 'Plasti-Gauge' to verify the brass in the chamber,
The caliper & datum point adapter will tell you what you have for chamber length in inches.
Now you have a quick way to verify your brass is coming out of the die correctly.
Then its off to trimming for length...
Trimming from the datum point, which you KNOW is correct for your rifle,
You are off to the races!
In bolt rifles, I don't use a 'Crimp' most times.
I simply reduce the size of the sizer ball to produce the neck tension to withstand recoil & chambering.
I will NOT use roll or taper crimp on bolt guns intended for hyper accuracy.
Since roll or taper crimps push directly down on the case mouth, they move the shoulder angle & datum point.
The collet 'Factory Crimp' dies support the shoulder and fingers crimp from the sides instead of pushing down, they will effect headspace the least or not at all.
Again, for heavy recoil rifles, some crimping might be needed, and 'Factory Crimp' dies are cheap enough to own one for every accuracy caliber you load.
I simply use a little more neck tension on .308 Win rifles, crimps aren't needed, and cases last longer without splits from crimp overworking the brass.