"Rebounding" NATO 7.62 brass???

[budlight]

with military brass i always anneal before sizing, you just dont know what chamber or how sloppy the chamber was on the weapon it was shot out of.
i have used plenty of LC and WCC over the years and annealing first was the ticket.

This is the real answer! Above anneal before sizing

But, H&K 91 & FN's are the worst. It leaves small lines on the neck.... I have the RCBS machine to inside and outside turn/true the case necks.

The internal case volume is less than say commercial 308. So you might have to drop listed powder amounts

M-60 was the name of the belt fed 7.62X51 that we had in the military

 

[Teri Anne]

I have a question about some of the NATO 7.62 brass I'm prepping for use.

About 10 years ago when I lived in South Carolina, I stocked up on used NATO 7.62 brass. Over the years, I've reloaded about 1k rounds for plinking and deer/hog hunting. None of these rounds were intended for long range use. I would resize and reload in the same sitting.

On Monday (1/23/23) I resized about 100 cases of PMJ 06' using my RCBS Rock Chucker Supreme with a RCBS .308 F L Die Set (P/N 15501). On every 10th case, I cycled in the chamber of a R700 .308 and in Wilson Case Gage. Each round fit perfectly in the Wilson Case Gage and cycled in the R700.

Last night (1/26/23), when prepping the mouths of the 100 cases, I noticed that while they cycle in the R700, they now do not fit as well in the Wilson Case Gage as they did 3 nights before.

In reading from several sources later last night and earlier today, I read about a few potential causes: ( 1 ) "rebounding" if I don't hold the cases for 5-6 seconds per cycle, and ( 2 ) the possible need for small base die.

I noticed a crack in the toggle block (replacements parts are on the way) so my Rock Chucker is currently disassembled and can't try resizing currently.

Anyone with experience reloading NATO 7.62 brass willing to chime in?

Thanks,

Scrmblr1982cj8

During the time I did competitive shooting in the Army we shot a lot of 7.62 x 51 in various different forms. Not all NATO ammo is created the same. There was Lake City Match, where the empties were coveted due to their consistency and reload ability. The next step down was 7.62mm Ball ammunition. Both of these cartridges were loaded to be fired in the M-14 or sniper rifles. Then there was the 7.62 linked ammo which was designed to be fired from machine guns. This ammo was not loaded to the same standards as the ones fired in the M-14. There were inconsistencies in the cases, the powder charges as well as bullets used. There was not as much care taken during the loading process simply because the ammunition was designed to be fired out of a full automatic firearm so accuracy was not as much a requirement. This ammo if fired from a M60 did not get too damaged during the ejection process. The real problem came into play when fired out of Mini Guns, mostly mounted on Helicopter Gun Ships. The rate of fire of the mini guns was between 2000 and 4000 rounds per minute. Cases ejected from mini guns were usually pretty well distorted. Our uneducated and unproven theory as to why these cases did not load well was due to several factors. 1 - There were a lot of inconsistencies in the cases, they probably would have been rejects, or were rejected from match or ball ammunition production. Due to the fact that they were ripped from the chamber so fast our theory was that they were still somewhat expanded from being fired when they were literally ripped from the chamber, still hot and being dragged out causing the cases to stretch excessively especially at the shoulder.

7.62 mm brass shot from an aircraft was considered expendable. It did not have to be turned back in. Scattered around the helipads on gunnery ranges were thousands of empty cartridges that could be had for the taking and many were taken for reloading by both military and civilian shooters. I am sure that some of these cases found their way into the market as once fired cases, as did some of the better quality cases. Military cases are made heavier than their comparable civilian counterparts. This reduced case capacities somewhat but also made the cases more durable. I often got 6 to 8 reloads out of Lake City Match cases, somewhat less out of standard ball ammo and as few as two out of the cases fired in machine guns. There were some issues with the machine gun cases not chambering properly, could have been due to the shoulder issues you have mentioned.

 

[VinceMule]

I form the Lake City brass into:

6 XC-.400 long neck
6x47 Lapua
6.5x47 lapua
6.5x Creed
7/08
260 AI

The Chinese version will lose the primer pockets in one firing at the peak pressure accuracy node, all machine gun brass.

New Lake City is Golden, but you still have to check to see if the flash holes are off-center.

Also, I forgot to mention that when you get a hand full, take a small mini mag flashlight or similar, and inspect the inside of the cases for burrs around the flash hole. Some of the burrs are substantial from being punched. I deburr all of this brass, putting a small chamfer on the flash hole.

Paul Bike makes a really nice set of form dies to make the Lake City into about anything you can imagine, and in a quality barrel, groups are sub 1/4", and all necks are neck turned....labor of love.

 

[25WSM]

Personally I wouldn’t waste my time on any military brass unless it was just plinking ammo. All my match guns run Lapua brass except for the 7saum. Come on Lapua make some saum brass please. I I had to run military brass I believe there has been plenty shared here to make it work. Clean it good. Anneal it. Size it regular and small base. I would only do the small base one time. Once its fired in your gun you may never need the small base die again. Dwell time. I leave my press engaged until my next piece is lubed with imperial wax. About 5 seconds. The man who taught me 1000 yard reloading taught me that. Trim your brass to the standard .010 short. Remove crimp and address the flash holes. Should be serviceable at that point. Plus make sure your setting the shoulder back sufficiently. I would measure a piece of brass thats been fired in the rifle you intend to use it in. I dont believe in arbitrary numbers in reloading. Reload with a purpose even if it is just plinking ammo. So after all that I can say without feeling bad at all that man there is nothing like opening a new box of Lapua brass.
Shep

 

[308plinkerVT]

Having just wrung this out with a fellow shooter as well: Mil spec chambers are oft more generous to start with. Some of those implements may have to function after crunching on stuff, not just moving at high rates of speed. Chambers can be very generous in all directions but I can specifically speak about length from personal experience. We had one that you could put two pads of scotch tape on a 308 NO GO base and we saw over 80% closure (ballpark) of the final bolt travel on a m14 type rifle, this was compared with measurements from a gage supplier and found technically in spec. The cases did fit the Wilson but would need just a little nudge to fully bottom - I've also seen 300wsm ones that wouldn't drop past 1/2.
Other tidbits I've picked up picked up over time: Mil brass can harder, not always thicker, in its manufacturers design ideals for what pressure it's being designed to reach, ONCE. Keep that in mind. I haven't yet run across that posted anywhere but in my mind it makes sense with all the variables we normally think of plus whatever metallurgy aspects they don't tell us about. Some of the service rifles make them more like a banana too. Annealling and small base steps would be my way of treating them as you pull them "fresh" from your supply. Add a mandrel and the 3-10 count pause during case work steps depending how they feel when they go in the sizer will help with the springback. (I used to make 1000 300W each weekend from mixed milspec brass (mostly LC then) before the 300aac hit the market if that helps you understand my "feel" on press operations. Having spent some time with various new/used 7.62 cases too - all have different "going in the sizing die" feels that can help you determine the pause needed. Be diligent with your measurements and trimmings. A VLD chamfer will make transition over harder edges easier and less jacket damaging depending how ticky your being. The Sinclair tool that goes along with the Wilson gage you mentioned is good too, even if potentially causing more questions.
Considering what time you will spend on any non Lapua brass checking if it was "made on a Monday or Friday" it's good to have these tidbits known and notes taken to help determine how you will spend your time vs your saved pennies down the road.

 

[Laelkhunter]

FN's are the worst. ....

I have to disagree with you. My H&K 91 is without doubt THE WORST !! When fired, the case gets striations indented into the case from the mouth to the web (from front to back), the primer is smashed (crimped) into the case with a death grip, and upon ejection the case is bent in a 90* angle when it is kicked 30 feet from the gun. There is no way to reload them. At least I didn't have to worry about recovering any brass.

 

[Pointman]

Starline

I got mine from Star-Line.

 

[crkckr]

Budlight, I suspect maybe you're thinking about the HK line of rifles, with their gas eject system helping to eject the spent cases? Like Laelkhunter, I've had an HK91 and they nearly destroy the brass, assuming you can even find it! The cases get thrown easily 50' from the shooter and they leave sooty striations on the neck and shoulder that do not come out! I've had cases that were cracked along those striations that had been sitting loaded for a while (maybe 5 years or so) leaving the bullet loose in the case. The cases are also absolutely filthy when you find them and difficult to clean. The majority of the .308 cases I've lost have been through the 91. Fine weapon but extremely hard on brass. My buddies FN was no problem when it came to brass. Military rifles generally have somewhat higher tolerance when it comes to chamber dimensions, as well, and that doesn't help things at all. However, say what you will about either the HK or FN, I've never seen a failure to extract with either one!
Cheers,
crkckr

 

[Laelkhunter]

Budlight, I suspect maybe you're thinking about the HK line of rifles, with their gas eject system helping to eject the spent cases? Like Laelkhunter, I've had an HK91 and they nearly destroy the brass, assuming you can even find it! The cases get thrown easily 50' from the shooter and they leave sooty striations on the neck and shoulder that do not come out! I've had cases that were cracked along those striations that had been sitting loaded for a while (maybe 5 years or so) leaving the bullet loose in the case. The cases are also absolutely filthy when you find them and difficult to clean. The majority of the .308 cases I've lost have been through the 91. Fine weapon but extremely hard on brass. My buddies FN was no problem when it came to brass. Military rifles generally have somewhat higher tolerance when it comes to chamber dimensions, as well, and that doesn't help things at all. However, say what you will about either the HK or FN, I've never seen a failure to extract with either one!
Cheers,
crkckr

Horrible on the brass, and a little heavy, but I wouldn't mind taking one into battle if I had a choice of weapons.

 

[scrmblr1982cj8]

Thanks to all for their responses!

I use these rounds for pig killing. I've got the Lapua brass for target work.

The photo shows the issue I mentioned in my initial post.

I've got small base dies coming and will try those later this week. I'll also try a pause on each round to determine how that will affect the brass.

 

[25WSM]

Wow that looks like it grew .025

 

[Rflshootr]

Wow that looks like it grew .025

Well the rim thickness is supposed to be .054. I'd say at least .025. something else doesn't seem right.

 

[Mike Matteson]

I did read an article I believe on here a year or so ago where a guy actually tested holding time on sizing brass and proved at least for his situation that holding the brass up for the count of 3 made better brass. He said it was to let the brass relax against the confines of the die. When you just go up and down the brass is flexing and recovering back somewhat to what it was. By holding it in place it comes to rest where you want it. He was mainly looking at case mouth but I would suggest to helps the whole case. Anyway I hold each one the at least 3 count.
Try it for yourselves. It not always about speed. Good workmanship makes better cases.

You know I think I came across that too. I know it's been suggest to me, by a Smith.

 

[Mike Matteson]

I did read an article I believe on here a year or so ago where a guy actually tested holding time on sizing brass and proved at least for his situation that holding the brass up for the count of 3 made better brass. He said it was to let the brass relax against the confines of the die. When you just go up and down the brass is flexing and recovering back somewhat to what it was. By holding it in place it comes to rest where you want it. He was mainly looking at case mouth but I would suggest to helps the whole case. Anyway I hold each one the at least 3 count.
Try it for yourselves. It not always about speed. Good workmanship makes better cases.

You got that right! Good workmanship go a long ways.