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Thread: Can't get old Vz24 7x57mm Mauser to shoot...groups

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    Member Float Pilot's Avatar
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    Default Can't get old Vz24 7x57mm Mauser to shoot...groups

    I have a Vz-24 JC light weight model, in 7 x57mm with an interesting history. A batch of 15,000 Bruno Vz-24s were being made for the Southern Chinese Army in 1929.
    The Chinese could not pay so Bruno's broker went looking for anotehr customer. They found a nice rebellion going on in Brazil. There was a group calling themselves the Constitutionalist who were trying to oppose the Brazilian dictator.
    Anyway,,, the rebels in Sao Paulo Brazil bought the rifles, which were re-barreled to 7x57mm. Unfortunately for them, they lost their rebellion around the end of 1930. About when the rifles showed up. As a result these commercially marked Vz-24s ended up being taken by the Government forces. Thus the second serial number on the right side of the receiver.

    I cleaned it up and the barrel is not too badly pitted, but the rifling is fairly shallow. Originally it shot HUGE groups. Like 20 inch across.

    So I re-crowned the barrel since there was a huge ding that went down into the rifling. .

    This seems to have helped some, but long boat-tails and a couple other bullets are still unstable. In fact the 175 grain Sierra boat-tails start to key-hole at very close range.

    So I was wondering if anyone has tried cast lead bullets at moderate pressures with a shot-out bore?

    Anyone have a few cast lead and lubed 7mm bullets they would like to sell so I can see if it works????
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    Quote Originally Posted by Float Pilot View Post
    I have a Vz-24 JC light weight model, in 7 x57mm with an interesting history. A batch of 15,000 Bruno Vz-24s were being made for the Southern Chinese Army in 1929.
    The Chinese could not pay so Bruno's broker went looking for anotehr customer. They found a nice rebellion going on in Brazil. There was a group calling themselves the Constitutionalist who were trying to oppose the Brazilian dictator.
    Anyway,,, the rebels in Sao Paulo Brazil bought the rifles, which were re-barreled to 7x57mm. Unfortunately for them, they lost their rebellion around the end of 1930. About when the rifles showed up. As a result these commercially marked Vz-24s ended up being taken by the Government forces. Thus the second serial number on the right side of the receiver.

    I cleaned it up and the barrel is not too badly pitted, but the rifling is fairly shallow. Originally it shot HUGE groups. Like 20 inch across.

    So I re-crowned the barrel since there was a huge ding that went down into the rifling. .

    This seems to have helped some, but long boat-tails and a couple other bullets are still unstable. In fact the 175 grain Sierra boat-tails start to key-hole at very close range.

    So I was wondering if anyone has tried cast lead bullets at moderate pressures with a shot-out bore?

    Anyone have a few cast lead and lubed 7mm bullets they would like to sell so I can see if it works????
    I'm betting the pitting will be bad news using cast. However I got an 1886 in 38-56 with shallow rifling and a badly pitted bore to shoot paper patch bullets just fine. The problem with conventional lead bullets of almost any hardness was severe leading. You could get the first two or three shots to do fine, then it went downhill fast. Shoot a bunch of shots, and you'll spend a bunch of time removing lead fouling.

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    Or just save the time and energy and give me the VZ. I'm just kidding.

    If the bbl is that shot out just get another one. you can buy them all day long on gunbrokers. sometimes its not worth the hassle, especially if the numbers dont match due to the history of the gun.

    If you are worried or want to keep it original, hang it on the wall.

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    Member Float Pilot's Avatar
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    The current barrel is serial numbered to the action. I collect Mausers. Although usually in better shape than this. This one just had an odd history.

    The pitting is very minor, And the bore looks as if it should shoot much better than it does.

    Maybe some cast bullets with gas checks loaded to around 1,800 fps...

    I can never get a good photo of a bore to work out.

    Remember the days of brand new military Mauser 308 and 7x57mm barrels in the shotgun news. I have not seen those for awhile.
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    This seems to have helped some, but long boat-tails and a couple other bullets are still unstable. In fact the 175 grain Sierra boat-tails start to key-hole at very close range.
    Have you tried shooting shorter, lighter bullets?

    It kinda sounds like a stabilization problem especially with those 175 grainers.

    Perhaps the twist rate of the riflling is too slow for the heavier, longer bullets........not that any of the other issues aren't contributing to the problem.
    Now what ?

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    Member Float Pilot's Avatar
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    I tried some 120 grain flat base bullets. They did not work either.
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    Default Common 7 x 57 problem

    Many 7 x 57s - including some commercial rifles - had throats that were way too long. Apparently the long throats were for the orginal 7 x57 rounds with long round nose bullets and no one changed the dimensions when they went to the light spitzer bullets.

    Try seating your heavy round nose bullets way way out - they will probably be too long to feed through the magazine - and see how it shoots.
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    Well I have the same gun as yours and figured some 140 gr. bullets would work.They did and it shoots tight now.

    140 gr, or 139 bullet
    Varget
    Pick your gr. weight and work up to the right level.
    Should work.

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    It turned out that I had a bulge in the barrel about at the midway point. The bulged area was about 2.5 inches long as well. So no matter what i tried I was always getting huge groups. Unlike my other 7x57mm rifles.
    So the action on this rifle has now been turned into a 416 Taylor classic style...
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    I went through some hair pulling with a 7x57 Remington rolling block rifle. Were the problem really was is with the 1900 7x57 brass and (that is what the chamber was cut for) And the 7x57 brass of today. Yes to the old longer bullets of year. I did not really care as I was using the action like you did, as a donor action for a black powder action even though it was a smokeless action. Chamber casts due have their place in this world and that got me on the road to figure all this out about the 7x57. Now that you have beat the problem once and for all, you probably don't really care any more.
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