7.62 NATO Brass for Reloading

Lord Bob · February 20, 2007, 01:08 PM

I have a CZ 550 in 308 that will digest fresh 7.62 cartridges, but the bolt will not close on a reloaded one. I've seated the bullet deeper, and I've trimmed the case down a little, but the reloads still will not allow for a closed bolt. Is there something else here I'm missing, or do I just need to shift over to commercial 308 brass?

TimRB · February 20, 2007, 01:20 PM

308 Winchester and 7.62 NATO, while similar, have different headspace specifications, and it is easily possible for a NATO cartridge to be within spec but still be too long to chamber in a short (but also within spec) 308 chamber. If you google you will find any number of sites that explain the difference in detail.

Tim

kkb · February 20, 2007, 01:43 PM

Sounds like the shoulder is hitting on the chamber. Try nudging your sizing die down a smidge.

Crosshair · February 20, 2007, 02:49 PM

I agree, sounds like a sizing die problem.

Scorch · February 20, 2007, 02:57 PM

It fires new ammo made to milspec but not reloaded ammo? Are you using once-fired brass, or was this fired in your rifle? If once-fired, yes, the shoulder may need to be moved back or the base of the cartridge needs to be resized. If the cartridge was fired in your rifle and cannot be chambered after reloading, look at neck thickness. Military brass is generally thicker, and if you have a tight chamber you could be seeing some neck clearance issues.

Thesenator · February 20, 2007, 08:17 PM

Buy a case guage so you can test your resized brass and set your resizing die properly before you reload a pile of it out of spec. The fifteen bucks for a guage will save you a lot of time and effort pulling out of spec ammo back down to be resized again.
Sounds like you need to bring your sizing die down a bit. I never understood why people don't include a guage as part of their essential tools for reloading. I use one for every caliber I reload.

ciunnc · February 20, 2007, 08:51 PM

Hi there,
My freind recently have similar problem with his .243 (that he just bought and the press that he also just bought and we are both new to rifle reloading), he bought all new brass and after just one firing, after he resized it, the bolt wont close on some brass and on most brass were very tight to lock the bolt down... he then ask me to look at it. i tried resizing it a few times, tried trimming it shorter, try cleaning the brass, etc etc.. after many days of testing and talking to lots of poeple. I had a gut feeling that the die werent sizing the brass enough, he had lee dies, but from all that i have heard about Lee dies were that they more then capable of doing their job. when i checked the sizing die which was adjusted by my friend who followed the instruction that came with the lee die set saying to wind the die down to the point that the die touches the shell holder (when its in the up postion) then back it off 1/4 turn and lock it down....
we were out of idea then so i readjusted the die downward another 2 turns i.e pass the point when the die touches the shell holder when in the up position. and when i resizing a problem case......viola.............it was so slick on closing the bolt, that the bolt handle slip out of my hand........ thats was my experience. so i think your problem is the case are not being resized properly..

**Unclenick** · February 20, 2007, 10:56 PM

Ciunnc,

Your friend read the Lee instructions incorrectly. Go to the Lee web site. They have a video of how to make the die adjustment. They touch the shell holder and go in a quarter turn on a steel press, more on a cast aluminum press, then you run the ram back up to hold the die in place while you tighten the lock nut. 2 turns beyond touchdown is too much and will be hard on the press.

Lord Bob,

Assuming you have adjusted the dies correctly, then, it you fired these cartridges in your gun originally, look for a bent rim or other signs of excess pressure. Assuming that is not the problem, especially if your CZ has a tight chamber, you may need a small base sizing die. Military brass is typically thicker and harder (and has less powder capacity) than commercial cases (especially Winchester cases, which have about 8% more powder room). This means it springs back more after resizing, so it usually doesn't return to size as well. The NATO chamber has .005" longer minimum headspace and has a long throat to accept all the different bullet sizes. I don't know if the CZ is a NATO chamber, as tactical rifles usually are, or if it is commercial? In the latter case, you may want to re-think shooting surplus ammo in it, or at least be checking for bullet touchdown on the lands before you do?

Be sure your sizing die is screwed in far enough that the shell holder comes up firmly against it. It is possible for a standard commercial die on the long side of its specification to narrow a military case, which lengthens it, then fail to push the harder shoulder all the way back. This leaves it with longer headspace than it had after fireforming to your chamber. Annealing the neck and shoulder can help. Running it in and out of your sizing die three or four times will usually take another couple thousandths off the headspace. Getting a small base die will also correct the issue.

If you have a load for a Winchester or other commercial case, be aware it will make more pressure in the smaller capacity military case. and that you should reduce it 10% and work a separate load up carefully in the military case. If you are using once-fired military brass that didn't come out of your gun, it may be very long. NATO chambers have a reject maximum headspace that is about 0.007" longer than SAMMI reject maximum. Such a long case should be rejected except for squib loads, as the web will be stretched very thin near the casehead and will give you casehead separation easily.

February 20, 2007, 01:08 PM	#1
Lord Bob Member Join Date: July 8, 2006 Posts: 16	7.62 NATO Brass for Reloading I have a CZ 550 in 308 that will digest fresh 7.62 cartridges, but the bolt will not close on a reloaded one. I've seated the bullet deeper, and I've trimmed the case down a little, but the reloads still will not allow for a closed bolt. Is there something else here I'm missing, or do I just need to shift over to commercial 308 brass?

February 20, 2007, 02:49 PM	#4
Crosshair Senior Member Join Date: December 16, 2004 Location: Grand Forks, ND Posts: 5,333	I agree, sounds like a sizing die problem. __________________ I don't carry a gun to go looking for trouble, I carry a gun in case trouble finds me.

February 20, 2007, 02:57 PM	#5
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	It fires new ammo made to milspec but not reloaded ammo? Are you using once-fired brass, or was this fired in your rifle? If once-fired, yes, the shoulder may need to be moved back or the base of the cartridge needs to be resized. If the cartridge was fired in your rifle and cannot be chambered after reloading, look at neck thickness. Military brass is generally thicker, and if you have a tight chamber you could be seeing some neck clearance issues. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

February 20, 2007, 08:51 PM	#7
ciunnc Junior Member Join Date: September 13, 2006 Location: Australia Posts: 11	resizing Hi there, My freind recently have similar problem with his .243 (that he just bought and the press that he also just bought and we are both new to rifle reloading), he bought all new brass and after just one firing, after he resized it, the bolt wont close on some brass and on most brass were very tight to lock the bolt down... he then ask me to look at it. i tried resizing it a few times, tried trimming it shorter, try cleaning the brass, etc etc.. after many days of testing and talking to lots of poeple. I had a gut feeling that the die werent sizing the brass enough, he had lee dies, but from all that i have heard about Lee dies were that they more then capable of doing their job. when i checked the sizing die which was adjusted by my friend who followed the instruction that came with the lee die set saying to wind the die down to the point that the die touches the shell holder (when its in the up postion) then back it off 1/4 turn and lock it down.... we were out of idea then so i readjusted the die downward another 2 turns i.e pass the point when the die touches the shell holder when in the up position. and when i resizing a problem case......viola.............it was so slick on closing the bolt, that the bolt handle slip out of my hand........ thats was my experience. so i think your problem is the case are not being resized properly..

February 20, 2007, 10:56 PM	#8
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Ciunnc, Your friend read the Lee instructions incorrectly. Go to the Lee web site. They have a video of how to make the die adjustment. They touch the shell holder and go in a quarter turn on a steel press, more on a cast aluminum press, then you run the ram back up to hold the die in place while you tighten the lock nut. 2 turns beyond touchdown is too much and will be hard on the press. Lord Bob, Assuming you have adjusted the dies correctly, then, it you fired these cartridges in your gun originally, look for a bent rim or other signs of excess pressure. Assuming that is not the problem, especially if your CZ has a tight chamber, you may need a small base sizing die. Military brass is typically thicker and harder (and has less powder capacity) than commercial cases (especially Winchester cases, which have about 8% more powder room). This means it springs back more after resizing, so it usually doesn't return to size as well. The NATO chamber has .005" longer minimum headspace and has a long throat to accept all the different bullet sizes. I don't know if the CZ is a NATO chamber, as tactical rifles usually are, or if it is commercial? In the latter case, you may want to re-think shooting surplus ammo in it, or at least be checking for bullet touchdown on the lands before you do? Be sure your sizing die is screwed in far enough that the shell holder comes up firmly against it. It is possible for a standard commercial die on the long side of its specification to narrow a military case, which lengthens it, then fail to push the harder shoulder all the way back. This leaves it with longer headspace than it had after fireforming to your chamber. Annealing the neck and shoulder can help. Running it in and out of your sizing die three or four times will usually take another couple thousandths off the headspace. Getting a small base die will also correct the issue. If you have a load for a Winchester or other commercial case, be aware it will make more pressure in the smaller capacity military case. and that you should reduce it 10% and work a separate load up carefully in the military case. If you are using once-fired military brass that didn't come out of your gun, it may be very long. NATO chambers have a reject maximum headspace that is about 0.007" longer than SAMMI reject maximum. Such a long case should be rejected except for squib loads, as the web will be stretched very thin near the casehead and will give you casehead separation easily. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 20, 2007, 01:20 PM	#2
TimRB Senior Member Join Date: May 18, 2004 Posts: 1,049	308 Winchester and 7.62 NATO, while similar, have different headspace specifications, and it is easily possible for a NATO cartridge to be within spec but still be too long to chamber in a short (but also within spec) 308 chamber. If you google you will find any number of sites that explain the difference in detail. Tim

February 20, 2007, 01:43 PM	#3
kkb Senior Member Join Date: September 5, 2004 Location: Western Slope, Colorado Posts: 403	Sounds like the shoulder is hitting on the chamber. Try nudging your sizing die down a smidge.

February 20, 2007, 08:17 PM	#6
Thesenator Senior Member Join Date: April 12, 2006 Posts: 126	Buy a case guage so you can test your resized brass and set your resizing die properly before you reload a pile of it out of spec. The fifteen bucks for a guage will save you a lot of time and effort pulling out of spec ammo back down to be resized again. Sounds like you need to bring your sizing die down a bit. I never understood why people don't include a guage as part of their essential tools for reloading. I use one for every caliber I reload.