Lee FL die oversizing cases?

flyboyjake · May 7, 2018, 08:38 PM

I'm getting back into shooting and reloading after a hiatus. I have a bunch of 7mm rem mag brass that I couldn't remember where I left off with, so I just full length sized all 50 in the group. After being meticulous with charge weights and seating depth, I only then decided to measure the shoulders of the cases. On my rcbs precision mic, they come in .018 under the zero mark. Ok my Wilson gauge they are all well under the saami minimum step, and with my calipers and a Hornady gauge kit, they came in at .017 shorter than fired brass. This is not a new die, but I don't think I ever went through this much detail in the past. This seems dangerously excessive... Am I wrong?

I ordered headspace go/no go gauges for my Savage rifle. It has a new barrel and it's possible it wasn't headspaced properly, but the Wilson and rcbs mic are showing pretty significant deviation from saami. Is Lee known for this issue?

5whiskey · May 7, 2018, 08:42 PM

This is function of sizing that you can control. Screw the die out about 1/3 turn them try again. Obviously with brass that's not already been sized too short.

flyboyjake · May 7, 2018, 09:02 PM

I do know this can be controlled, and intended to FL size the cases after firing to just bump the shoulder back a couple thou, but I also thought running the die down to the shell holder was supposed to produce saami spec ammo still? I think what aggravates me most is the time I spent on this lot of ammunition. I'm actually considering headspacing the rifle to accommodate these bullets, then bringing it back out. I'm afraid to shoot any of them as is (had 2 case head separations on 20 test loads sized the same way), and id hate to lose the brass.

For such a relaxing hobby, it sure is frustrating...

flyboyjake · May 8, 2018, 04:29 PM

Is there anything dangerous or otherwise inadvisable to adjusting the headspace of my rifle by screwing the barrel in to accommodate these undersized rounds, then adjusting it back to saami?

5whiskey · May 8, 2018, 09:51 PM

Quote:

Is there anything dangerous or otherwise inadvisable to adjusting the headspace of my rifle by screwing the barrel in to accommodate these undersized rounds, then adjusting it back to saami?

Assuming you have a rifle with adjustable headspace (ala savage and their barrel nut) no there's nothing wrong with it really. But... You will still be left with undersized brass as they will conform to the rifles chamber, which will not be saami spec if you change it to accommodate these rounds.

If salvaging the brass is important i would fire form them by using a low charge of a fast pistol powder and a wax plug in the rifle as it sits. My 2 cents.

5whiskey · May 8, 2018, 09:52 PM

You also could fire form with a light bullet and slightly below min charges... But I still would probably use the wax plug trick to be extra safe.

PA-Joe · May 9, 2018, 05:22 PM

It also depends on the shellholder that you used. The bench height varies by manufacturer.

Mobuck · May 11, 2018, 06:19 AM

"This is not a new die, but I don't think I ever went through this much detail in the past. This seems dangerously excessive... Am I wrong? "

Had this ever been a problem in the past? If not, all you're doing is shortening the life of your cases(which are expendables anyway).

F. Guffey · May 11, 2018, 09:58 AM

Quote:

It also depends on the shellholder that you used. The bench height varies by manufacturer.

There was a time dies came with instructions, C&H out of El Monte, Cal had a counter display box with the instructions on the bottom of the box. It read: (something like) This set of dies was designed to be used with a shell holder with a height of .125". I added the word, 'deck; to the word 'height' to get 'deck height'. All of my shell holders have a deck height of .125" regardless of the manufacturer.

I do have shell holders that do not have a deck height of .125", I separate them because some manufacturers change more for them. Difference? All of my screwed up shell holders were made before 1960.

F. Guffey

**Unclenick** · May 13, 2018, 08:47 PM

Man, I go away for one week and the ability of the crowd to catch a basic problem goes up in smoke!

Flyboyjake,

Your Lee die is working correctly. If you haven't noticed, the 7 mm Rem Mag is a belted cartridge. It is designed to headspace on the belt, so the shoulder is located to be sure the case shoulder making contact with the chamber shoulder does not prevent the belt from making contact with the end of its recess in the back of the chamber. Looking at the SAAMI drawing (download the SAAMI rifle drawings PDF file and open it in Acrobat reader, then in the upper left where the page number is, type in page 56 and hit ENTER), you will note the upper drawing on the page is the cartridge and the lower drawing is the chamber. The dimensions have unilateral tolerances in order that the given numbers represent critical limits explicitly. The critical criterion is that the cartridges always fit into and fire in the chamber. They cannot be too big for it. So the numbers given for the cartridge are maximum values followed by minus numbers that are the tolerance range. Oppositely, the chamber numbers are minimum values with plus tolerance ranges so the chamber can never be too small for cartridges that conform with the standard. The maximum cartridge and minimum chamber values are the tightest possible squeeze fit that will still work. However, manufacturers usually don't give you a dead minimum chamber and don't normally make a maximum cartridge. Usually, new cartridges are made at near minimum values.

The case belt has a minimum distance from the bottom of the case head of 0.212" (0.220"-0.008"). The chamber belt recess has a maximum distance of 0.227" from the breech face. That's a difference of 0.015". The shoulder of a new case then has to be sized so the case can slip at least 0.015" into the chamber before the shoulder of the case touches the shoulder of the chamber. That is what you are seeing in the dimensions your sizing die produces.

So, now you know why belted magnum cases are famous for not lasting through many reloads. Lot's of shoulder stretching forward and sizing back. If you adjust the headspace by turning the barrel closer to the breech, you have to move it no closer than the GO gauge allows to be sure belts on all makes of cases will all fit in your chamber. That will not be enough difference to compensate for all the shoulder gap. You could customize your chamber by shortening it still more until the tallest (from the bottom of the head) belts that you have will just fit, but be aware that any brass or ammunition that you might buy in the future that has higher belts will then not fit. The whole purpose of the GO gauge is to give you the minimum space all belts that are made to the SAAMI standard will fit into. If you try to move the shoulder of the chamber back to bring the chamber shoulder closer to your case shoulder location, you probably won't be able to fit any cases into the chamber; not without the belts jamming to prevent you from closing the bolt on them.

The next question is, can you headspace on the shoulder instead of headspacing on the belt in order to get better case life? Probably. A lot of people do it, but there is a constraint. If you headspace on the shoulder, you cease to run the cases into the sizing die far enough to narrow them back near where the belt stops on the ledge of its recess in the chamber. This is OK unless or until the case fit in the chamber gets too tight for the case width to fit into it easily. At full magnum pressures, this is not an uncommon issue. The same thing happens eventually to all rifle cases that are neck-sized only and fired at high enough pressures to gradually fatten and tighten their fit in the chamber. They just hit a point where full-length resizing has to be done at least once, and then the reloader can go back to neck sizing again until they get hard to fit again, or the belted magnum owner can go back to sizing just far enough to headspace on the shoulder. The complication is if you intend to feed the cartridges from a magazine instead of loading singly, you may then run into an issue with ease of feed in the span of fewer reloading cycles. But there is no reason not to try headspacing on the shoulder to see how it works out for you and your chamber. You just set your sizing die high in the press so it only pushes the shoulder back a couple of thousandths.

If, as can happen in some instances, that shoulder set-back widens the case too much below the shoulder, there is a special collet case narrowing sizing tool for belted magnums that is made by Larry Willis and that narrows them all the way down to the belt. Because the belted magnums are all based on the 300 H&H, the same tool works with them all. However, it is an investment, so you want to try without it first to see if you really need it.

5whiskey · May 13, 2018, 10:08 PM

Quote:

Man, I go away for one week and the ability of the crowd to catch a basic problem goes up in smoke!

UncleNick you're the man... totally didn't catch that he was loading a belted magnum.

I still vote for headspace at the shoulder, but something will have to give by probably the 3rd (MAYBE 4th) firing.

flyboyjake · June 5, 2018, 12:08 AM

Guffey, thanks for that. All my rcbs she'll holders are .125, as are the Lee holders that came with the kit.

Uncle Nick. That's some really good information and I appreciate you taking the time to type it. For some back story, I bought 200 brass cases a few years ago that were once fired, but since it was in someone else's rifle, I just full length sized them all with the anticipation of fire forming later. As I fire form them near max loads, I'm finding signs of case head separations, and one actual separation. I was going to just bump the shoulder .02 after firing, but some if these aren't making it long enough. I reduced the headspace to about .05 under a go gauge and am finding that the belt isn't interfering yet, and the cases are no longer failing. If I knew the dimension of this die back in the day I would not have sized them completely, but alas, they are. I'm not concerned about factory ammo or magazine issues, but I guess I just want to make sure pulling the chamber back to accommodate this really loose brass is ok. I guess after I fire them all I can headspace properly and allow them to grow back to the proper size in increments instead of one big .17" stretch.

Thanks everyone for your help

J.G. Terry · June 5, 2018, 10:55 AM

Shell Holders: I thought that shell holders height is .125 as a standard. I have reports of adjustable shell holder but have never seen such.

Belts: Back in the dark ages we had a P.O. Ackley marked 338 Magnum rifle. We checked the head space. The headspace appeared excessive. Our question was did Ackley make the belt area deeper to un-complicate having the shoulder headspace the round. Could this modification be considered dangerous? Is it a Bubba after the fact best thinking?

Or, should this change never be considered?

May 7, 2018, 08:38 PM	#1
flyboyjake Senior Member Join Date: February 19, 2010 Posts: 135	Lee FL die oversizing cases? I'm getting back into shooting and reloading after a hiatus. I have a bunch of 7mm rem mag brass that I couldn't remember where I left off with, so I just full length sized all 50 in the group. After being meticulous with charge weights and seating depth, I only then decided to measure the shoulders of the cases. On my rcbs precision mic, they come in .018 under the zero mark. Ok my Wilson gauge they are all well under the saami minimum step, and with my calipers and a Hornady gauge kit, they came in at .017 shorter than fired brass. This is not a new die, but I don't think I ever went through this much detail in the past. This seems dangerously excessive... Am I wrong? I ordered headspace go/no go gauges for my Savage rifle. It has a new barrel and it's possible it wasn't headspaced properly, but the Wilson and rcbs mic are showing pretty significant deviation from saami. Is Lee known for this issue?

May 7, 2018, 08:42 PM	#2
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,657	This is function of sizing that you can control. Screw the die out about 1/3 turn them try again. Obviously with brass that's not already been sized too short. __________________ Support the NRA-ILA Auction, ends 03/09/2018 https://thefiringline.com/forums/sho...d.php?t=593946

May 8, 2018, 09:52 PM	#6
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,657	You also could fire form with a light bullet and slightly below min charges... But I still would probably use the wax plug trick to be extra safe. __________________ Support the NRA-ILA Auction, ends 03/09/2018 https://thefiringline.com/forums/sho...d.php?t=593946

May 13, 2018, 08:47 PM	#10
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Man, I go away for one week and the ability of the crowd to catch a basic problem goes up in smoke! Flyboyjake, Your Lee die is working correctly. If you haven't noticed, the 7 mm Rem Mag is a belted cartridge. It is designed to headspace on the belt, so the shoulder is located to be sure the case shoulder making contact with the chamber shoulder does not prevent the belt from making contact with the end of its recess in the back of the chamber. Looking at the SAAMI drawing (download the SAAMI rifle drawings PDF file and open it in Acrobat reader, then in the upper left where the page number is, type in page 56 and hit ENTER), you will note the upper drawing on the page is the cartridge and the lower drawing is the chamber. The dimensions have unilateral tolerances in order that the given numbers represent critical limits explicitly. The critical criterion is that the cartridges always fit into and fire in the chamber. They cannot be too big for it. So the numbers given for the cartridge are maximum values followed by minus numbers that are the tolerance range. Oppositely, the chamber numbers are minimum values with plus tolerance ranges so the chamber can never be too small for cartridges that conform with the standard. The maximum cartridge and minimum chamber values are the tightest possible squeeze fit that will still work. However, manufacturers usually don't give you a dead minimum chamber and don't normally make a maximum cartridge. Usually, new cartridges are made at near minimum values. The case belt has a minimum distance from the bottom of the case head of 0.212" (0.220"-0.008"). The chamber belt recess has a maximum distance of 0.227" from the breech face. That's a difference of 0.015". The shoulder of a new case then has to be sized so the case can slip at least 0.015" into the chamber before the shoulder of the case touches the shoulder of the chamber. That is what you are seeing in the dimensions your sizing die produces. So, now you know why belted magnum cases are famous for not lasting through many reloads. Lot's of shoulder stretching forward and sizing back. If you adjust the headspace by turning the barrel closer to the breech, you have to move it no closer than the GO gauge allows to be sure belts on all makes of cases will all fit in your chamber. That will not be enough difference to compensate for all the shoulder gap. You could customize your chamber by shortening it still more until the tallest (from the bottom of the head) belts that you have will just fit, but be aware that any brass or ammunition that you might buy in the future that has higher belts will then not fit. The whole purpose of the GO gauge is to give you the minimum space all belts that are made to the SAAMI standard will fit into. If you try to move the shoulder of the chamber back to bring the chamber shoulder closer to your case shoulder location, you probably won't be able to fit any cases into the chamber; not without the belts jamming to prevent you from closing the bolt on them. The next question is, can you headspace on the shoulder instead of headspacing on the belt in order to get better case life? Probably. A lot of people do it, but there is a constraint. If you headspace on the shoulder, you cease to run the cases into the sizing die far enough to narrow them back near where the belt stops on the ledge of its recess in the chamber. This is OK unless or until the case fit in the chamber gets too tight for the case width to fit into it easily. At full magnum pressures, this is not an uncommon issue. The same thing happens eventually to all rifle cases that are neck-sized only and fired at high enough pressures to gradually fatten and tighten their fit in the chamber. They just hit a point where full-length resizing has to be done at least once, and then the reloader can go back to neck sizing again until they get hard to fit again, or the belted magnum owner can go back to sizing just far enough to headspace on the shoulder. The complication is if you intend to feed the cartridges from a magazine instead of loading singly, you may then run into an issue with ease of feed in the span of fewer reloading cycles. But there is no reason not to try headspacing on the shoulder to see how it works out for you and your chamber. You just set your sizing die high in the press so it only pushes the shoulder back a couple of thousandths. If, as can happen in some instances, that shoulder set-back widens the case too much below the shoulder, there is a special collet case narrowing sizing tool for belted magnums that is made by Larry Willis and that narrows them all the way down to the belt. Because the belted magnums are all based on the 300 H&H, the same tool works with them all. However, it is an investment, so you want to try without it first to see if you really need it. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

June 5, 2018, 10:55 AM	#13
J.G. Terry Senior Member Join Date: January 24, 2014 Posts: 577	Shell Holders and belts Shell Holders: I thought that shell holders height is .125 as a standard. I have reports of adjustable shell holder but have never seen such. Belts: Back in the dark ages we had a P.O. Ackley marked 338 Magnum rifle. We checked the head space. The headspace appeared excessive. Our question was did Ackley make the belt area deeper to un-complicate having the shoulder headspace the round. Could this modification be considered dangerous? Is it a Bubba after the fact best thinking? Or, should this change never be considered?

May 7, 2018, 09:02 PM	#3
flyboyjake Senior Member Join Date: February 19, 2010 Posts: 135	I do know this can be controlled, and intended to FL size the cases after firing to just bump the shoulder back a couple thou, but I also thought running the die down to the shell holder was supposed to produce saami spec ammo still? I think what aggravates me most is the time I spent on this lot of ammunition. I'm actually considering headspacing the rifle to accommodate these bullets, then bringing it back out. I'm afraid to shoot any of them as is (had 2 case head separations on 20 test loads sized the same way), and id hate to lose the brass. For such a relaxing hobby, it sure is frustrating...

May 8, 2018, 04:29 PM	#4
flyboyjake Senior Member Join Date: February 19, 2010 Posts: 135	Is there anything dangerous or otherwise inadvisable to adjusting the headspace of my rifle by screwing the barrel in to accommodate these undersized rounds, then adjusting it back to saami?

May 9, 2018, 05:22 PM	#7
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	It also depends on the shellholder that you used. The bench height varies by manufacturer.

May 11, 2018, 06:19 AM	#8
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"This is not a new die, but I don't think I ever went through this much detail in the past. This seems dangerously excessive... Am I wrong? " Had this ever been a problem in the past? If not, all you're doing is shortening the life of your cases(which are expendables anyway).

June 5, 2018, 12:08 AM	#12
flyboyjake Senior Member Join Date: February 19, 2010 Posts: 135	Guffey, thanks for that. All my rcbs she'll holders are .125, as are the Lee holders that came with the kit. Uncle Nick. That's some really good information and I appreciate you taking the time to type it. For some back story, I bought 200 brass cases a few years ago that were once fired, but since it was in someone else's rifle, I just full length sized them all with the anticipation of fire forming later. As I fire form them near max loads, I'm finding signs of case head separations, and one actual separation. I was going to just bump the shoulder .02 after firing, but some if these aren't making it long enough. I reduced the headspace to about .05 under a go gauge and am finding that the belt isn't interfering yet, and the cases are no longer failing. If I knew the dimension of this die back in the day I would not have sized them completely, but alas, they are. I'm not concerned about factory ammo or magazine issues, but I guess I just want to make sure pulling the chamber back to accommodate this really loose brass is ok. I guess after I fire them all I can headspace properly and allow them to grow back to the proper size in increments instead of one big .17" stretch. Thanks everyone for your help