"Rebounding" NATO 7.62 brass???

[C-130 Dude]

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

Is this the first time you tried to reload this brass since you obtained it? Others have mentioned that most of this type brass is probably from machine guns. That MG brass will swell differently (sometimes radically) from what a bolt gun will do. I have found that it works well to use the full length small base resizer from RCBS (or others) to return this type brass back to normal. Then try shooting them from your bolt gun. Allow 4-5 seconds for each shell to swell after firing to allow it to assimilate to your gun. As always, anneal before sizing and trim length as required. I have been shooting LC (and other makes) brass for over 35 years, well over 9500 rounds fired and find this process works well with a minimum of issues. No matter what you do, you will find there are a few bad cases out there causing headaches-that's just the way of things. This will happen to any make case. Expect it. Stay safe and have fun.

 

[VinceMule]

Letting the brass sit in the die when sized for three seconds is a good idea. Annealing prior to sizing is protocol.

The big obstacle to overcome on machine gun brass is the expansion at the web. When the round sits in a hot barrel, pressure on that round is HOT, thus expanding the web more. You have to be aware of this issue and cull that brass out. The first time you seat primers in your "new to you" LC brass, if the webs have been expanded, the primers will seat a lot easier. So, cull the brass with easier seating primers.

With the LC brass that I am shooting, the barrels are Krieger and Brux with custom Palma short freebore chambers for use with 155-169g MK and 175g TMK. Accuracy is fantastic with case culling and prep.

No doubt, it is a labor of love sorting/culling brass with case prep....pass the Lapua, please.

When I form the LC brass into 6 XC, turn necks, square pockets, and de-burr inside flash holes, accuracy is superb, to say the least. This is a labor of love in a Winter project, but the payoff is great.

We used to be able to get 1000 new Lake City for $159 per thousand, then it became $159 for 500, and now it is not available at any price. I have had great service out of once-fired PMC brass, but the use of a small base sizer is required.

Brass spring back is real, simple physics. For guys that shoot range pick-up brass, the issue of Brass spring back becomes a real issue for a custom chamber. Factory chambers have liberal dimensions, hence spring back will be less noticeable if at all. The same would apply to brass that has been fired in a Rem semi-auto or Browning semi-auto.

It is prudent to use Lapua for serious target work, and I have plenty. 5 years ago, I bought a bunch of once-fired Lapua that had been shot in Match rifles of some kind. I ran into the same problems, brass fired in different chamber issues with web expansion variations, which meant that my purchase was "penny wise, and a pound foolish."

 

[Rflshootr]

After considering having to buy a small base die and doing all the extra work, I think I would have opted to make 2 phone calls. Hello, Starline? Send me 100 308 Win cases for $55. Thank you. Hello, recycle center? How much are you paying for scrap brass? Just me thinking again.

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[squirrelslayer]

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

All of the roller delayed design (HK Cetme etc.) destroy the brass due to the fluted chamber. It's only good for scrap.

 

[EugeneKM]

Yes I've had the same issue with surplus brass, pretty much any headstamp unless it had the Long Range or match markings. Sizing twice with lots of lube helped, but I won't buy it again unless it's prepped, and at that price point you might as well just buy new starline brass.

 

[Hummer70]

Several things come into play. First off I am not aware of any machinegun and lets loaded rounds sit in a barrel be it hot or cold. Think about it, you have a barrel that is really hot and you chamber you are begging for a "cook off" which occurs when the round gets to around 400 deg F.

In the cook off tests we did at Aberdeen Proving Ground 500 rounds were fired in 500 seconds in M16 and 501st round chambered immediately and stop watch was started. A cook off will occur about 8 to 10 seconds later. In belt fed guns if you get a failure to fire you have to open bolt within 5 seconds of stoppage with a chambered round. If the gun crew does not open bolt in 5 seconds of less the testing is stopped and bolt not retracted for 30 minutes IIRC.

Machineguns chambers are not match dimension chambers and has the gun is fired there is wear on the locking surfaces and the base to shoulder length can increase a tad.

Military cases are designed for enhanced performance for many rounds and the they can get dents etc you will never see with a bolt action rifle.

Commercial dies can be a blessing or a curse in loading. For instance I have multiple sets of dies for 308 and 30.06. If you have a good set of calipers you and measure the inside diameters at the base of the die. Don't be surprised with dies made by the same vendor resize fired cases from .466 to .469.

I had custom chamber reamers made up to that restricted the amount of expansion in my cases. For instance 308 cases in unfired ammo can range from .466 to .469 diameter. Fired cases and measure upwards of .4734" and still be in SAAMI specs. Factory ammo can have a base dimension of .4703 and delivered with .4603 diameter loaded ammo and still be IN SPEC.

Think about it, you have a commercial 308 case that is .465 at the base and you shoot it in a chamber that can be .008" larger and you size it back down and first thing you know you get a case coming out that is only 1/2" long because the case was over worked. On my match rifles my cases only expand the base .002 to .003 and I don't the the "bulge"at the base which shortens case life.

I have never bought a small base die as if your rifle has the correct dimensions the ammo will go in and fire. Where the ship hits the sand is the makers of the dies have their reamers made on the large end of the range so they can be resharpened several times in the life of the reamer.

Another thing I have run into on multiple occasions is the dies are chambered too deep so the die does not contact the shoulder enough to set the shoulder back enough. I have 57 sets of dies and I have had to trim the bottoms off about 1/4th of them to get them to size the fired cases correctly. One die I had to take of .030" material to get them to size correctly. This is not restricted to one vendor either.

As well milspec cases are generally thicker in the wall areas because of the chamber sizes.

Back when primers/powder were cheap I ran tests. I have one 30.06 Match case I have loaded and fired 157 times and it is still waiting on me to get back to feeding it. I have run two milspec 7.62 cases to 90 reloads and still going fine.

I used to shoot with a buy named Marty Tyska, he was a ammo engineer at Frandford and Picatinny Arsenals and a highpower shooter and he made a statement I have remembered for the last 40+ years which was "You should never lose a case from a split neck, if you do you have not cared for your cases." You should only lose a case from the primer pocket getting loose which occurs quickly in commercial cases because they are designed to be made for the least cost possible. MILSPEC cases are heavier than commercial cases because the case walls are thicker and there is a hardness requirement so they can be run in semi and full auto weapons without a problem.

I had friends in the ammo industry and some cases are only good for two reloads and the primer pockets get loose quick. Yes they can still be reloaded but if you do so you will start to see where there is gas leakage around the primer edge that will cut a groove in your bolt face.

Now small base dies, why does this term come up. Remember above I said that the chamber reamers are resharpened. Once they get down to a certain point they are "under spec" and the vendors use them one more time and call them "small base dies" which is a money maker.

 

[mntnflyr4fun]

I am a big believer in small base dies in autoloaders of all makes/models

 

[BHP9]

I have used batches, of certain years, of retired military brass. DA (Dominion Arsenals), IVI (Industries Valcartier Industries), both Canadian, and some Radway Green, British, LC Match with great success.

I have never annealed (don't own an annealer) and always use a small base die. I have had to size on a standard die first and then use the SB die.

I don't bother with Military brass anymore.

YMMV.

 

[budlight]

I'm leary of range brass 308 because of Berdan primers. I've bent up a few primer punchers and now I've learned to look inside with a flashlight before I waste any time on brass.

I can't remember the make. But I found about 20 of them out of 100 a few months ago.

 

[scrmblr1982cj8]

Is this the first time you tried to reload this brass since you obtained it? Others have mentioned that most of this type brass is probably from machine guns. That MG brass will swell differently (sometimes radically) from what a bolt gun will do. I have found that it works well to use the full length small base resizer from RCBS (or others) to return this type brass back to normal. Then try shooting them from your bolt gun. Allow 4-5 seconds for each shell to swell after firing to allow it to assimilate to your gun. As always, anneal before sizing and trim length as required. I have been shooting LC (and other makes) brass for over 35 years, well over 9500 rounds fired and find this process works well with a minimum of issues. No matter what you do, you will find there are a few bad cases out there causing headaches-that's just the way of things. This will happen to any make case. Expect it. Stay safe and have fun.

This was the first time I tried resizing this brass after purchase. I did not use small base dies, but those are on the way from RCBS. I'll try them and report back.

 

[WYMIKE]

Such great info in this thread. With unknown military "Range Brass" I start by sorting brass by stamp, inside neck ream with Wilson tool, UltraSonic cleaning, dry brass out, lube with STP, dip neck into dry moly, run thru RCBS FL 30-06 die and hold down for 3 second, put 100 rounds into tumbler with stainless steel media and cleaner, let air dry, anneal brass with an AMP machine, lightly lube and run thru a RCBS small base die, trim neck length, chamfer inside neck, use deburring tool on flash holes, use large primer pocket tool to get proper pocket depth(seat), weigh brass and sort if you want too, prime and load. I ve had excellent results with CCI primers, H4350 and Hornady ELD-M bullets. Yep its alot of work during the winter months here in Wyoming.

 

[Mike Matteson]

Letting the brass sit in the die when sized for three seconds is a good idea. Annealing prior to sizing is protocol.

The big obstacle to overcome on machine gun brass is the expansion at the web. When the round sits in a hot barrel, pressure on that round is HOT, thus expanding the web more. You have to be aware of this issue and cull that brass out. The first time you seat primers in your "new to you" LC brass, if the webs have been expanded, the primers will seat a lot easier. So, cull the brass with easier seating primers.

With the LC brass that I am shooting, the barrels are Krieger and Brux with custom Palma short freebore chambers for use with 155-169g MK and 175g TMK. Accuracy is fantastic with case culling and prep.

No doubt, it is a labor of love sorting/culling brass with case prep....pass the Lapua, please.

When I form the LC brass into 6 XC, turn necks, square pockets, and de-burr inside flash holes, accuracy is superb, to say the least. This is a labor of love in a Winter project, but the payoff is great.

We used to be able to get 1000 new Lake City for $159 per thousand, then it became $159 for 500, and now it is not available at any price. I have had great service out of once-fired PMC brass, but the use of a small base sizer is required.

Brass spring back is real, simple physics. For guys that shoot range pick-up brass, the issue of Brass spring back becomes a real issue for a custom chamber. Factory chambers have liberal dimensions, hence spring back will be less noticeable if at all. The same would apply to brass that has been fired in a Rem semi-auto or Browning semi-auto.

It is prudent to use Lapua for serious target work, and I have plenty. 5 years ago, I bought a bunch of once-fired Lapua that had been shot in Match rifles of some kind. I ran into the same problems, brass fired in different chamber issues with web expansion variations, which meant that my purchase was "penny wise, and a pound foolish."

Interesting input. South Vietnam should be covered in brass of all types. I have seen 3 troops on line dumping ammo out. In area of 650,000 rounds per troop. That is about 2,000,000 in day and generally less time than that. More than 1 barrel was changed out on the 50's during the day. Bring behind the APC or Tanks, I watched more than one barrel in the 50's sending out flipping trasher rounds down line. Barrels red hot, and bent down. Those 50 were on hell of a pieces of equipment. I never learn how take down a 50 and put it back together. I often wished I did. Being a Medic I didn't see the value in it at the time. MISTAKE!.
The other thing was more if not all tanks and apc had two 50 cal actions on board.
I think the best one was. We had to cover somebody else fire support base one night. I noted as we pulled in there was a 50 setting on tripod. I thought myself they would leave that out during the day. The next moring as we were pulling out, I noted that the 50 was gone and the tripod was still there. I wonder where the 50 went? I still laugh about it even today.

 

[Chas1]

Wow that looks like it grew .025

I agree, that's quite a bit.

 

[TXTrained]

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

Are you not Annealing?

By

Anyoneno evidence of you Annealing the with experience reloaading NATOsee no evidence of you 7.62 brass willing to chime in?























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