headspace issue w/Marlin 30-30?

Discussion in 'The Ammo & Reloading Forum' started by accident, Aug 10, 2012.

  1. accident

    accident Well-Known Member Supporting Member

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    This post is long and I apologize for it.I need someones knowledge to run this by.I'm having an issue with my Marlin 336 30-30.Sometimes when I inspect the fired rounds I can feel and see the primer has "ballooned" or come out a bit from the case head.This occurs in about 8 of every 20 rounds fired.When I first noticed this I thought it might be my reloads creating excessive pressure even though they are ok in my Winchester 94.I bought 2 boxes of factory Win. ammo and found the problem is there with factory rds also.By the way I do Full-Legnth sise my reloads so they can be used in either gun.The Winchester has never shown any signs of a problem, factory ammo or reloads.I wouldn't think that my reloads are too hot.They are loaded on the lighter side of the spectrum and work fine in the Win 94.Also since I have the problem with the factory loads in the Marlin leads me to not think its the ammo.I'm wondering if I might have a headspace issue.I've heard a bent lever could cause problems but mine appears ok.I took the gun and the spent cases that showed the primer ballooned or protruding to a gunsmith I have used and he told me it was normal and to keep shooting it.But I'm concerned about its safety.I've read headspace issues are common in lever-guns especially the Marlin 336.If it is headspace problems, I have no idea whats required to repair it.Work/wise or cost/wise.If the gun is dangerous it may cost more than the gun is worth to fix it.I tried to take photos of the cartridges and primer but the pics aren't clear enough to see the primer. You can definetly feel it and see it though.I'v seen pictures of what a too hot charge can do with the primer.Mine aren't as bad as i've seen but still I'm concerned about it.What do you suggest I do? Or what would you do if it were yours? Thanks for you're time and again sorry for the legnth. Joe
  2. myfriendis410

    myfriendis410 Member

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    It's possible there is a worn link or a bent one that is keeping the bolt face away from the case. I would expect to see other signs than that. It sounds to me almost like a light load condition. It's odd that it's not on every case. That sounds mechanical. You might look to see if there's bolt play when it's closed. The 30-30 should headspace on the rim.
  3. 243winxb

    243winxb New Member

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    Go with this advise. Not a problem unless pressure/gas is escaping from between the primer & case head. You should keep brass separated for each firearm & control the sizing of the brass for each.
  4. JLA

    JLA Well-Known Member

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    Marlins are notorious for having excessive headspace dimensions. Take it to a good smith and have them set the barrel back and re-cut the chamber to minimum spec.

    The marlin, as do most al lever actions lock up at the rear of the bolt, which gives you a rather slack lockup anyway. and when the round fires, and the pressures press all the slack out of lockup, its easy to see how a chamber on the max end can exhibit headspace issues.

    This can also be rectified somewhat thru careful handloading. if you necksize your .30/30 brass it will help the take up the excessive heaspace and improve the overall function of THAT rifle.. but Ill bet cha money that ammo WONT fit in another .30-30
  5. accident

    accident Well-Known Member Supporting Member

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    thanks for the suggestions guys. Joe
  6. DBMJR1

    DBMJR1 New Member

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    I'd like to add a bit.

    The brass you]re firing through your Marlin will 'grow' in length if there is excessive headspace. You'll feel a ridge inside the case, near the base, when you bend over a paperclip and scratch the inside. A sure sign of excessive headspace in a thurty-thirdy.

    If you can feel that ridge inside of that case, don't reload that piece of brass. You could end up with a case head separation. A real pain in the rear end to clear up.
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