Nambu troubleshooting...

[DavidJayUden]

I'm flying blind here so bear with me.
If it is stovepiping the fired case, might that suggest that the recoil is insufficient to bump the rim hard enough to eject it? Does it feed correctly using live ammo. (or dummies) and cycling the bolt by hand? Also is the ammo. of sufficient velocity go work the system? I understand that there aren't many choices of ammo out there.
Is the ejector long enough to hit the rim early enough?
Have you reverted back to the original mainspring? I'm also wondering if the replacement spring isn't too stiff.
Maybe give us a few more details on what it is, and is not, doing.
dju

[nukem556]

There's no feed ramp on my Nambu, just a slight bevel at the 6o'clock position. Yours is much larger. Maybe someone Dremeled yours out, or they changed that profile over the years (mine's a 1937). I've shot mine with Mr.Nambu loads and some ammo remanufactured from .40 S&W brass and it functions fine with the original springs. I'd kinda doubt that making that bevel larger would cause your problems though.

[Zorba]

Ok, random factoids.

Mine's a '43. The only ammo I've used in it has been the "Mr. Nambu" loads, which is good ammo by all accounts. I fired about 20 rds, with 4 or 5 stovepipes. Manually cycling with snap caps is even worse - predictably enough. I'll take another squint at the extractor - however, I noticed today when playing with the gun and snap caps, that it wedged and stovepiped on the FIRST round - nothing in the chamber to start with. It did this at least twice.

How would I know if the *ejector* was right or wrong?

[nukem556]

A "stovepipe" jam is usually referring to a FIRED case that isn't fully ejected and is caught between the bolt face and the chamber mouth facing up....hence a stove "pipe". What you're describing is a failure to feed and chamber. I'd suspect the feed lips on your magazine are sprung too wide allowing the round to sit too high to enter the chamber straight on.

[Zorba]

Originally Posted by nukem556

A "stovepipe" jam is usually referring to a FIRED case that isn't fully ejected and is caught between the bolt face and the chamber mouth facing up....hence a stove "pipe". What you're describing is a failure to feed and chamber. I'd suspect the feed lips on your magazine are sprung too wide allowing the round to sit too high to enter the chamber straight on.

Yea, its doing both - but your feed lip suggestion sounds like gold - the round does indeed look very high at the top! I'll try some "monkeying"!

[tomaustin]

if you haven't already found this site, google Nambu World, Teri Shaw's site......she has extensive connections and a wealth of knowledge.....I also have nambu interests and enjoy talking to her.....tom

[Zorba]

Originally Posted by tomaustin

if you haven't already found this site, google Nambu World, Teri Shaw's site......she has extensive connections and a wealth of knowledge.....I also have nambu interests and enjoy talking to her.....tom

An familiar with her site - I just wish it had a forum! Never thought to contact her directly though...

You guys here are great - if push comes to shove I'll take it to a 'smith, but Nukem's feed lip idea resonates with what I'd observed just today, and will try that first. I was wondering why the top round (snap cap) was so far up...