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head space dimension

Discussion in 'Gunsmithing and Repairs' started by x_wrench, Jan 2, 2013.

  1. x_wrench

    x_wrench Well-Known Member

    does anyone know what the head space should be on a marlin 1895 in 45-70 government? the lever keeps popping open, and i have tried the easy fixes. so i was thinking about what could cause it, and my theory is if there is to much head space, it might give the cartridge a "running start" if you will at the bolt, allowing the lever to pop. it never goes any further, but it bothers me. i know when the case swells from pressure it should be enough to keep it in place. my thinking is this happens while the case is still swelling. now that i said that, it makes me wonder if my reloading sizer die is on the small size. i can check that. along with a fired case to see if the chamber is over sized. i know the best way is cerrosafe and make a chamber casting. but money at this time of the year is always tight. and i just found out i am going to have a sizable unplanned expense paying my share of cancer surgery.
  2. NCsmitty

    NCsmitty Well-Known Member

    A query to www.marlinowners.com/ site might shed some light on your issue. They might be able to point you to a proper fix, as it may not be a headspace problem.

  3. rcmodel

    rcmodel Member in memoriam

    I seriously doubt headspace has anything to do with it.

    If the case grips the chamber tightly, it has to stretch to make up for available headspace and still hits the bolt face.
    If it slips, it is putting little more force on the bolt then it would if it stretched.

    It seems we were working on this problem almost a year ago.

    If you covered the points mentioned then concerning the lever plunger, spring, and recess?
    I would suspect now a few other things:

    1. You have a worn, bent or out of spec lever, not fully engaging the locking block when closed.
    2. You have a worn bolt or locking block.
    3. You have a stretched action.

    It might be time to send it back to Marlin and let them figure it out.

  4. Reloadron

    Reloadron Well-Known Member

    The 45-70 Government cartridge being a rimmed type cartridge is headspaced off the rim. I believe the nominal rim thickness is .070. The 45-70 brass can vary in rim thickness considerably. However, I doubt that is the problem. Not sure why the lever would "pop" open as you describe. Would this be a new rifle?

    The guy that would likely have a suggestion to the problem might be rcmodel who will hopefully come along.

  5. x_wrench

    x_wrench Well-Known Member

    i called remlin, and they seemed as interested in repairing this as they would be in taking the sesame seeds off from a hamburger bun. their answer was, they all do that. they said i could send it in, and they would take a look at it, but could not guarantee a fix. from what i have read about remlin, your better off taking a hammer to anything that needs repair, than send it in. i realize that not many will post positive experiences compared to bad ones. but there are so many bad ones, that i am not willing to send it to them. it also takes any steam from my sails about buying a remington rifle anytime soon.
  6. Reloadron

    Reloadron Well-Known Member

    The more I think about how you are describing this the more I wonder about what Marlin told you. I dug out my older Marlin 444 lever gun which is maybe 18 to 20 years old, long before Remington. Mine does that and yes, they all do that. It came new like that.

    With my rifle in a horizontal position the forward part of the lever lever rest about 1/2" down from the stock and the trigger safety pin which must be pressed by the lever for the hammer to drop and trigger be pulled. All of this having nothing to do with is a cartridge is chambered or not. Actually matters not if the rifle is cocked or not with the hammer in the half or full cock position. This is true of Models 336, 444 and 1895.

    Would the below image be what we are looking at?


    Edit: The more I look at this I wonder if it is normal? Not so sure now. Since when the rifle came out of the box long ago it was that way I just assumed (we all know about assume) that the gap was normal. Now I am not so sure about this and second guessing myself. The pictured rifle has always shot very well in every way and the safety features all worked fine. Anyone else have one of these and does it look like the one pictured? Suddenly I am not very sure at all about this quirk. The pictured rifle is about 17 maybe 18 years old and was a gift from my wife. Has maybe 100 rounds through it. However, as mentioned was as seen since day one. Beats the hell out of me?

    Last edited: Jan 3, 2013
  7. rcmodel

    rcmodel Member in memoriam

    No, that is not normal either.

    There is a spring loaded plunger in the lever right above and in front of the trigger in your picture. If you open the lever another 1/4" or so you can see it.
    (You can see the cross-pin that holds it in in your photo.)

    It snaps over a pin in the trigger plate when the lever is fully closed, and should hold it closed, with the trigger safety pin depressed.

    When you begin to open the lever, the trigger safety pin should pop out and prevent firing as soon as the lever is just beginning to open away from the receiver tang.

    But the lever is supposed to stay shut with the trigger pin depressed all the time, due to the lever plunger holding it there.

    From what I can see in the photo, it looks like your plunger is stuck in, as it normally protrudes about 1/10" when the lever is that far open, and I can't see it.

    Last edited: Jan 3, 2013
  8. Reloadron

    Reloadron Well-Known Member

    Many a thank you RC. I went to my friends local gun shop this morning and took a good hard look at another one and sure as God made little green apples and RC said, sure enough. That lousy plunger has been stuck in there sine that rifle left the store. Never shot it much and never gave it any serious thought. Plain as day that plunger is in there. So now it sits inverted with a few drops of PB blaster in there. That failing out come the punches and that is one tiny pin securing the plunger and spring.

    Again many thanks RC, very much appreciated.

  9. x_wrench

    x_wrench Well-Known Member

    well, the one thing that i do know is that for the first 4 years, and well over 2000 rounds of ammo, the lever never, ever popped open. no matter how light, or heavy of a load i put thru it. so it left the factory in a condition that the lever did not pop open. if i put my hand under the outside of the lever, i can hold it shut. but that does not feel normal at all, and is not friendly to fast cycling of the action for round #2. at this point, it is not dangerous, just annoying. i have been shooting a lot of lead reloads thru this the last couple of years. some of them down around the trapdoor level, and some (hunting and hunting practice loads) hotter, but no where near max. it has been a long time since i have fired a relatively hot jacketed load thru this. maybe it is time i do to see what happens. i have thought about weird things, like lead building up near the end of the chamber, or slivers of lead being down in the action. but i have had it apart many times cleaning it, and mostly what i find is oil, unburnt powder, and burnt powder residue. the lever is definitely harder to open since replacing the locking plunger and spring. but not enough to keep it latched.
  10. Reloadron

    Reloadron Well-Known Member

    If you look at the Illustrated Parts Breakdown in this manual and note parts 17 . . . . . Finger Lever Plunger, 18 . . . . . Finger Lever Plunger Pin and 19 . . . . . Finger Lever Plunger Spring is the plunger stuck in? That was my problem as RC noted and mine has been broke since the factory. Additionally you may want to check the cross pin the plunger engages in the receiver. If that plunger is not fully extending it could cause the lever to pop down as you mention.

    I got mine apart, completely cleaned and oiled and it now locks up fine.

  11. Kp321

    Kp321 Well-Known Member

    I have had a couple of 336's come in that had the lever bent so that the lever loop would hit the tang before the spring loaded plunger would snap home. Apparently the lever trigger guard area is not heat treated and can bend when the lever is operated too smartly.
  12. rcmodel

    rcmodel Member in memoriam


    I mentioned a bent lever in post #3.

  13. x_wrench

    x_wrench Well-Known Member

    sorry, it has been a little while since i have been here. EXACTLY what part of the lever gets bent? i can FEEL this spring loaded plunger latch into place on the little cross pin. i replaced the spring, plunger and retaining pin, cleaned and removed on tiny little burr in the lever where it moves back and fourth in. it definitely "catches" much more crisper now that it ever did than i can remember. but it is not keeping the lever from popping open. does anyone know if a new lever is a drop in install, or NEEDS to be fitted by a smith? the smith that my dad trusted for ever, that i used to go to, has let me down to the point i no longer trust his work. there is one local smith that i have used with mixed results, and the big problem there is he is a one man show, and it takes 6 months to get any work done. and it is not always fixed correctly. so i am kind of between a rock and a very hard place.
  14. rcmodel

    rcmodel Member in memoriam

    Levers get bent in the curve of the trigger guard section.

    Look at the rifle with the lever closed and see if the straight section of the loop is laying parallel with the receiver tang.

    If the back end of the loop is touching the tang and the front end isn't, its bent.

    A new lever should be a drop-in part.
    Or at least very nearly so.

    Here is a good read on checking lever fit, as well as fitting:



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