Brass trimming and using Collet die

viper12161 · February 7, 2017, 11:35 AM

So I am new to reloading rifle cartridges. I have some factory Remington brass that was fired in my Savage bolt, so I am going the neck sizing vs full length route. I de-primed and ran them through the Lee Collet die last night. According to the instructions that came with the die set, I I should feel primer pop out and then need to apply approx 25 lbs of pressure to the size portion. There really wasn't much resistance after the primer popped....only the very last inch or so of travel on the handle. Is that normal or do I not have it set up right? Not sure what I am supposed to be looking for after it's done.

For trimming I know max length is 2.015 and trim to is 2.005. So does that mean I trim all my brass to the 2.005 number? What if it's shorter than that already? (not sure if they are, just figured I would ask now)

Thanks!
Dave

**Unclenick** · February 7, 2017, 05:50 PM

Dave,

Yes, the primer pops just before the end of the stroke range. The 25 lb number is approximate, as different presses have different linkages with different resulting mechanical advantage. The bottom line is that you want the case neck about one to two thousandths of an inch smaller after sizing than it was when it had a bullet in it. If you didn't think to measure that before shooting the ammo initially, you can check its outside diameter now and then again after seating a bullet. You should see that much difference. If you get less, you may want to apply more force.

The Lee Collet Die has a learning curve for most folks, but you do develop a feel for it. Some folks don't try, instead figuring out how far to screw the die into the press so that it completes correct sizing when the press handle reaches its stops (all Lee presses have them and don't cam over as some older press designs do; I'm assuming you are using a Lee press here). Here's an example of someone who has a Forster Co-ax press (also has over-travel stops) set up this way.

Note that if you load to full normal pressures the case will gradually grow with each firing to fill the chamber too tightly. If it gets to where you detect some resistance on loading, the cases need to be run through a full length sizing die once before you go back to neck seating again. It's common for folks who are neck sizing-only to go to the FL die once every five loads or so.

The standard SAAMI spec for a .308 Winchester case is 2.015 -0.020 inches. That means 1.995-2.015 is the range. 2.005" just happens to be the middle of the range, giving you the most room for trimming error either side of center. Most home trimming tools are more consistent than ±0.010", so you choose to use something shorter if you want. That said, if you aren't full length sizing most of the time, you may never need to trim again. Neck sizing doesn't grow case length after initial trimming. Case length grows when a full length die sets the case shoulder length back and the excess brass flows into the neck.

nhyrum · February 8, 2017, 01:46 AM

I, personally trim all my brass to the max length. But yes, you generally trim to the "trim to"length.

Also... Take what unclenick as if it were from "the good book" he knows his stuff

Sent from my SM-G920V using Tapatalk

viper12161 · February 8, 2017, 09:04 AM

Thanks so much!! So as long as the case is under the 2.015 max, I don't need to trim them? Or should I trim down to 2.005 for consistency with each round? I know this seems to be a 50/50 split on trim or not to trim.

February 7, 2017, 11:35 AM	#1
viper12161 Member Join Date: December 4, 2016 Posts: 36	Brass trimming and using Collet die So I am new to reloading rifle cartridges. I have some factory Remington brass that was fired in my Savage bolt, so I am going the neck sizing vs full length route. I de-primed and ran them through the Lee Collet die last night. According to the instructions that came with the die set, I I should feel primer pop out and then need to apply approx 25 lbs of pressure to the size portion. There really wasn't much resistance after the primer popped....only the very last inch or so of travel on the handle. Is that normal or do I not have it set up right? Not sure what I am supposed to be looking for after it's done. For trimming I know max length is 2.015 and trim to is 2.005. So does that mean I trim all my brass to the 2.005 number? What if it's shorter than that already? (not sure if they are, just figured I would ask now) Thanks! Dave

February 7, 2017, 05:50 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Dave, Yes, the primer pops just before the end of the stroke range. The 25 lb number is approximate, as different presses have different linkages with different resulting mechanical advantage. The bottom line is that you want the case neck about one to two thousandths of an inch smaller after sizing than it was when it had a bullet in it. If you didn't think to measure that before shooting the ammo initially, you can check its outside diameter now and then again after seating a bullet. You should see that much difference. If you get less, you may want to apply more force. The Lee Collet Die has a learning curve for most folks, but you do develop a feel for it. Some folks don't try, instead figuring out how far to screw the die into the press so that it completes correct sizing when the press handle reaches its stops (all Lee presses have them and don't cam over as some older press designs do; I'm assuming you are using a Lee press here). Here's an example of someone who has a Forster Co-ax press (also has over-travel stops) set up this way. Note that if you load to full normal pressures the case will gradually grow with each firing to fill the chamber too tightly. If it gets to where you detect some resistance on loading, the cases need to be run through a full length sizing die once before you go back to neck seating again. It's common for folks who are neck sizing-only to go to the FL die once every five loads or so. The standard SAAMI spec for a .308 Winchester case is 2.015 -0.020 inches. That means 1.995-2.015 is the range. 2.005" just happens to be the middle of the range, giving you the most room for trimming error either side of center. Most home trimming tools are more consistent than ±0.010", so you choose to use something shorter if you want. That said, if you aren't full length sizing most of the time, you may never need to trim again. Neck sizing doesn't grow case length after initial trimming. Case length grows when a full length die sets the case shoulder length back and the excess brass flows into the neck. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 8, 2017, 01:46 AM	#3
nhyrum Senior Member Join Date: March 9, 2016 Posts: 588	I, personally trim all my brass to the max length. But yes, you generally trim to the "trim to"length. Also... Take what unclenick as if it were from "the good book" he knows his stuff Sent from my SM-G920V using Tapatalk

February 8, 2017, 09:04 AM	#4
viper12161 Member Join Date: December 4, 2016 Posts: 36	Thanks so much!! So as long as the case is under the 2.015 max, I don't need to trim them? Or should I trim down to 2.005 for consistency with each round? I know this seems to be a 50/50 split on trim or not to trim.