Possible FR8 ammo issues with comm. .308.

Discussion in 'Curio & Relics Forum' started by Laufer, Jun 15, 2011.

  1. Laufer

    Laufer New Member

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    Just bought a nice example days ago, matching bolt/action with a very bright bore.

    Read two hours last night about the ammo confusion and concerns among so many people (much of it hearsay, or misunderstandings?), and part of the problem might be because guys lump together the weaker Spanish steel in the (7mm action) FR7 with the stronger 8mm action of the FR8.
    CETME 7.62 this, NATO 7.62 that....

    Only a few Internet Mauser guys feel that the stronger 8mm action allows the commercial .308 to be safe.
    The strong 8mm action has been used for conversions to much stronger rounds/calibers than just .308.
    Saami doesn't easily convert to C.U.P. pressure, and the actual pressure is very similar to NATO 7.62.

    The second issue is headspace.
    The rifle failed the Go/No go gauge today at the gunsmith, but he does Not have a Field gauge, which could be more accurate (?).

    In order to do the more economical reloading, would you use comm. .308, Or would you wait to use a Field gauge before using this ammo again, and Only if it passes the Field (a very exp. friend has one)?

    The used cases, all fresh from the Win. boxes look perfect: no tiny carbon specks, no wrinkles, cracks nor bright rings etc.
    He is a very experienced smith, and felt that -in general, with good case condition- the strong 8mm action should be safe to use with the modern .308 ammo.
    Last edited: Jun 15, 2011
  2. GOVTMOD

    GOVTMOD New Member

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    .308 and 7.62 NATO is fine in a FR-8. If your gunsmith has Forester headspace gauges they tend to be loose in NATO chambers and show excessive headspace (closing on the NO-GO). Clymer or NATO gauges will not show excessive headspace.

    FR-7s are a different matter, they make me nervous but there are plenty out there and seem to do fine with SAAMI spec ammo.
  3. Jim K

    Jim K New Member

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    This whole thing is such a minefield, with a lot of nonsense and people running around screaming that those guns will blow up in a mushroom cloud and wipe out at least the county if not the whole state.

    The FR-8 was built in a Mauser 98 action, and should be fine with .308 Winchester in any reasonable loads. GO and NO-GO gauges are properly used by factories and by gunsmiths setting headspace for new barrels. But many used rifles will fail the NO-GO test; the Field gauge is the only gauge needed for used rifles.

    Jim
  4. Laufer

    Laufer New Member

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    Thanks very much.

    While waiting for a friend to return to town in a week with his Field gauge, would you guys shoot just a few rds., knowing that the once-used commercial brass looks perfect after firing?
  5. Jim K

    Jim K New Member

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    I generally don't bother to gauge milsurps unless I see something suspicious (like an odd looking chamber or a replaced barrel). If the rifle fires OK and there is no sign of brass stretching, I wouldn't worry about it.

    Jim
  6. Laufer

    Laufer New Member

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    Thanks Jim.
    Even did the paper clip check in the bottom of all the cases. This was a first, and even ordered a Field gauge from Numerich for future trends.

    It's ironic, because I was never a bit paranoid about my five Enfields (matching bolts), Yugo Mauser or former MNs, and never had headspace checked, but they still shoot the same type of ammo they were designed for.

    Now the objective will be waiting for the front sight tool to arrive, to help elevate the front post sight-if oil can somehow loosen the very tiny sight set screw. Shoots way too high (10") and right.
  7. Snakedriver

    Snakedriver New Member

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    Definitely this, Jim K. thanks for a little sanity in a crazy world. The 98K design with the triple lug bolt is good to go with modern .308 Winchester loads. As with any older rifles, hot reloads in .308 Winchester are not advised. ;)
  8. Snakedriver

    Snakedriver New Member

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    What range are you shooting at when getting the 10" high? Funny thing is that many of these old guns were set-up for a 300 meter zero. When I look at some of the old Mausers with sight elevations that go out to 2000 meters I have to wonder who can see that far with iron sights? :confused:

    Attached Files:

    Last edited: Jun 16, 2011
  9. Jim K

    Jim K New Member

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    Hi, Snakedriver,

    Just a FWIW on those long range sight settings. No, troops were not going to be able to pick off individual enemy soldiers at 2000, 2500, 2800 yards or meters or some other "way out there" range. In the days before machineguns became common, infantry often engaged in what was called "volley firing". Officers would learn, in one way or another, that there was a concentration of enemy forces at some place like a railroad junction, a staging area, a forest, or whatever. They would calculate the range from a map, find some aiming point, perhaps a tree or a church steeple in the right line, and then order a whole company or even a regiment to set their sights at that range, aim at the selected point, and blaze away as fast as they could work the bolts.

    Did they hit anything? Probably not, but a rain of bullets from an unseen enemy can be destructive to morale even if no one is hit. And if some troops are unlucky enough to be hit, morale suffers even more. It is possible that the recipient of the attention will choose to disperse or leave that area, and the goal of the volley shooters will have been achieved.

    Later, machineguns took over the long range firing; same idea, just fewer guns to put out the same amount of fire.

    Jim
  10. jack404

    jack404 Former Guest

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    for some interest , Australian troops in new guinea caught a jap column in the open in a vally 2 miles away and opened up with volly fire, dunno how many japanese where taken out ( not many according to what i read) but the rest where forced back into the far end of the vally while troops moved up to block there advance , 50 folks on a volly fire would be terrifying if in the open ..

    it may not be the most accurate , but you'd have to be crazy to try to run through it all
  11. Bigbill

    Bigbill Member

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    I ran into this 308win and the 7,62 nato thing a while back and i purchased the 308win headspace gauges and the 7,62 nato headspace guage too. There two different headspacings with the 7,62nato being larger, i believe the 7,62 nato headspace is deeper in the chamber by a tad. I don't think the 308win headspace guages i usable in the 7,62nato chambers. I won't get into the 308 cetme, but isn't it the weaker round of the three. Since the fr8 was produced for there army to practice with before they received the Cetme's isn't the FR8 in 308 cetme??

    I just checked the headspace on my norinco M14 in 7,62nato with the 7,62nato headspace guage and it passed. The bolt didn't rotate on it(didn't close) so its safe to shoot with the chamber still being good. Bill

    BTW; The 7,62 nato headspace gauges cost more too. I purchased all the headspace gauges for all my military calibers. I did find 1 rifle with a bad chamber and if i didn't check it with the proper headspace gauge i may not be here today, it was that far off. It was suppose to be a rework to 308win and the chamber was so deep it wouldn't headspace on the 7,62nato field gauge. I wouldn't shoot it once it failed the 308win field headspace gauge but i wanted to see if they made a mistake and headspaced it at the 7,62nato caliber instead of the 308win. Its well worth the cost of the headspace gauges if were going to play with the military surplus rifles. I at least have the field and the no go for each caliber. On the rifles that i have rebarreled i have the go headspace gauges from them too. I just purchased them a little at a time. The cost vs an accident there worth having. trust no one but ourselves.
    Last edited: Jun 16, 2011
  12. Jim K

    Jim K New Member

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    The FR-8 was intended for the 7.62 CETME, but the action is the Modello 1936, which is a 98 Mauser and the barrel is standard 7.62 NATO. It is like saying that if I fire a Ruger Single Six with .22 Shorts that means it will blow up with .22 LR.

    That tiny discrepancy between 7.62 NATO specs and .308 Winchester specs has been the cause of a lot of heartburn over the years. I deal with it the easy way - I ignore it. I have never found that it made any difference at all, for all the handwringing and screaming about guns blowing up and killing thousands. Doesn't happen.

    On general principles, I don't care for reworking the old pre-98 actions, Spanish or otherwise, for .308 Winchester; they just were not made for cartridges in that pressure range. And some Chilean 7mm barrels were bored and then chamber sleeves installed to convert them to 7.62 NATO. Again on general principles, I don't like that.

    Jim
  13. Bigbill

    Bigbill Member

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    At samco global arms had the results of an outsourced test were they shot a 1916 spanish that was converted from 7mm mauser to 308win. well probably 308 cetme but there being sold to shoot 308win. The test lab pumped up the 308win round till the rifle blew up at 90k psi thats 30k psi past the highest pressure in the 308win round. Now do i feel safe reading that, i'm not sure but i would shoot only the lower pressure and bullet weights of 308win out of it. I'd like to shoot it within a reasonably safe condition. I think the 145gr or 147gr fmj or the 150gr soft points would be ok. The lighter weight bullets leave the case faster when fired with a lesser peak time in pressure. As to where the heavier bullets have a longer peak pressure timing because the heavier bullets take longer to get moving thus a higher pressure to move them. I like being safe too. Bill
  14. Bigbill

    Bigbill Member

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    The field headspace gauge is the last chamber test before the rifle gets pulled from action and reworked if it fails the field headspace gauge. I started off buying all the field headspace gauges first to get my surplus guns ok for shooting once i knew they were safe to shoot. But then i started thinking what if they pass on the field headspace gauge what are the chambers really headspaced at? I started buying the no-go gauges too. I also purchased some go gauges too mainly for my barrel chages so i can check the headspace after the barrels are swapped out. I believe i have more surplus military rifles that are ok with the go and the no-go gauges and only a few that were ok with the field headspace gauges. Most of them have good chambers.(99.999%) But its that "1" out of 100 rifles that will headspace bad. So we need to check everyone for safety anyway. Bill
  15. Laufer

    Laufer New Member

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    Update: the Field gauge arrived today. I have never before seen anybody use any sort of gauge, in any gun.
    The bolt only rotated a small angle then stopped.

    Can't wait for the front sight gauge to arrive. Based on some old comments on THR via Google, really hope to elevate the front sight enough to use the 200-yard peep at 100, maybe even 50 yards-without needing to aim very low.

    Snakedriver: Those very high shots were from 100 yards with the open sight, and even aiming about 4-5" low (the target a 12" Shoot N See), many shots still went high and right.
    But on the first day I used it, the bayonet was attached and most only went maybe 2" high, and right.
  16. Jim K

    Jim K New Member

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    FWIW, normal proof loads run about 125-150% of the standard working pressure. The "blue pill" for the .30-'06, which has a working pressure of about 50,000 psi, generates 75,000 psi. Since the working pressure of the original 7mm is 40-45k psi, 90k would be double that, and over 150% of the working pressure of the .308.

    Of course the 90k really applied only to one rifle, and some individual rifles, for some reason, may be weaker, or stronger. 90K is not in the Remington 700 class (one of those took 150k before it even leaked and then didn't blow) but it is a perfectly adequate proof test.

    Jim
  17. Laufer

    Laufer New Member

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    To change the subject a little, I read a very brief article from a newspaper (link) in PA a few months ago. Can't remember which gun website had the link, but probably 'Surplusrifle' or 'Gunboards', maybe 'Parallaxandcurio'.

    As for an original Spanish 7mm Mauser (Not an FR7) converted to NATO 7.62, the article only said that a guy died at a gun range when some part of his rifle blew out, and was using .308 ammo.
    There was no info as to whether it was commercial .308 ammo, reloaded, or anything which would help.
    Last edited: Jun 19, 2011
  18. Jim K

    Jim K New Member

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    Newspapers are never a good source of information on guns in any situation.

    Jim
  19. TRAP55

    TRAP55 New Member

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    I've seen lug setback, but had only heard of catastrophic failure shooting .308Win in a small ring chambered for 7.62 NATO. It was always someones cousins, uncles, brother in law that it happened to.
    Here's a FR-7 that came to me first hand. Ammo type wasn't identified, but I saw a FN Fal grenaded with Pakistani ammo, that had the same yellow residue around the chamber area. It was guessed that the round had been spiked with some kind of plastic explosive. Shooter survived, but had to have a piece of the bolt removed from his forehead.
    No telling what caused this failure for sure, but the rifle was shot with factory .308 Win. and NATO surplus.
    JimK, any guess WTH caused this one? I've never seen anything like it. Besides the obvious, I thought the position of the bolt handle and locking lugs looked out of whack, almost like firing out of battery.:confused:

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  20. Jim K

    Jim K New Member

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    The following is my best guess based on the photos; I have not seen or handled the rifle:

    I think the case head let go. You can see the rest of the case still in the chamber.

    That released high pressure gas into the receiver ring and that blew the receiver ring apart. That does not indicate a defect in the rifle; almost any Mauser type rifle (including the M 1903 Springfield) will do the same thing under those conditions. The yellow residue is not from some high explosive, it is from molten brass sprayed over the inside of the receiver ring.

    As to the bolt, I think the bolt held just fine and there is no sign of damage to the bolt lugs. The receiver ring blew before the bolt even got much pressure on it. The bolt position now is due simply to its having been opened after the damage took place. If the rifle had fired (not likely) with the lugs in that position, the bolt would have come straight back further than it is.

    The bolt release/ejector housing blew because of high pressure gas coming back through the left bolt lug raceway, also indicating that the bolt was closed (lugs up and down) at the time of the gas release.

    So my conclusion is that either there was a defective cartridge case or (IMHO more likely), it was a handload and a big overcharge. It could possibly have been way excess headspace, but normally a case separation won't cause that much damage. I think the case head didn't separate; it just dissolved under immense heat and pressure. Again, a WAG and FWIW, but I think that round produced at least 150k pressure.

    It is instructional to note how Mauser recognized some of the problems that could (and probably did) arise with those actions and corrected them with the 1898. They made the receiver ring stronger, opened the left lug raceway with a deep thumb notch, and enlarged the flange on the bolt sleeve to keep gas from taking the shooter's eye out. They also re-designed the bolt and firing pin so the rifle could not fire unless the bolt was fully locked.

    Jim
    Last edited: Jun 19, 2011
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