japanese type 100 SMG model III 8mm NAMBU 1944
a customer (a liscensed CLASS III collector) brought one into the shop. he has been buying 8MM NAMBU bottleneck pistol ammo from us for years (we have the dies, correctly headstamped brass, and FMJ copper heads).
he recently experianced some failure to cycle / failure to feed problems. he brought the gun and the ammo we produced into the shop for inspection. we randomly pulled 15 the heads from rds out of a 50 count box, and checked the powder wieghts. they all were correct. we measured the OAL and they all speced out OK. we cylcled 10 rds through a PAPA NAMBU pistol and it all fired, fed, and extracted with no damage to the cases.
upon dissasembly of the gun (it took some digging to find a good parts diagram) it became apparent that while the outside of the gun, the bore, and chamber were clean and well maintained, the inside of the gun was in pretty poor shape (he never had the gun apart, or the mag).
there was a lot of fouling, unburnt powder, and rust. so we went back to basics and cleaned it piece by piece. my conclusion, confirmed by our gunsmith (the owner of the shop) is that the springs are shot. they are not compressing and expanding correctly. they are pitted, and the metal has a fatuiged appearance.
our customer arranged to have a COMPLETE REPRODUCTION SPRING KIT / JAP TYPE 100 SMG and a spare magazine shipped from a secret scource (the damn magazine cost $100.00, and its a repro... the originals cost more than the gun).
my problem is the the shorter spring that fits onto the recoil spring guide. it appears to have been spot welded to the guide itself. i cannot remove it without a heat source.
the longer spring is easily removed, and does not appear to have been welded onto anything.
the recoil spring guide was difficult to remove, and shot across the shop striking a co-worker in the behind with some force.
what is the best way to remove the existing shorter spring??? i do not weld...
what is the best way to atatch the new shorter spring??? does it have to be welded??? could a product similar to JB WELD work??? what about soldering???
any suggestions??? i am beyond the scope of my ability and knowledge at this point. i am not sure if the spring was welded originaly, or welded later. i could use some advice and opinions.
neat little late war SMG. light wieght, of poor repute. best regards, mike.(PS. email me at the shop at waltsgun@aol.com if you can provide helpful info, or respond here)
What other dungeon is so dark as ones own heart, what jailer so inexorable as ones own mind.
he recently experianced some failure to cycle / failure to feed problems. he brought the gun and the ammo we produced into the shop for inspection. we randomly pulled 15 the heads from rds out of a 50 count box, and checked the powder wieghts. they all were correct. we measured the OAL and they all speced out OK. we cylcled 10 rds through a PAPA NAMBU pistol and it all fired, fed, and extracted with no damage to the cases.
upon dissasembly of the gun (it took some digging to find a good parts diagram) it became apparent that while the outside of the gun, the bore, and chamber were clean and well maintained, the inside of the gun was in pretty poor shape (he never had the gun apart, or the mag).
there was a lot of fouling, unburnt powder, and rust. so we went back to basics and cleaned it piece by piece. my conclusion, confirmed by our gunsmith (the owner of the shop) is that the springs are shot. they are not compressing and expanding correctly. they are pitted, and the metal has a fatuiged appearance.
our customer arranged to have a COMPLETE REPRODUCTION SPRING KIT / JAP TYPE 100 SMG and a spare magazine shipped from a secret scource (the damn magazine cost $100.00, and its a repro... the originals cost more than the gun).
my problem is the the shorter spring that fits onto the recoil spring guide. it appears to have been spot welded to the guide itself. i cannot remove it without a heat source.
the longer spring is easily removed, and does not appear to have been welded onto anything.
the recoil spring guide was difficult to remove, and shot across the shop striking a co-worker in the behind with some force.
what is the best way to remove the existing shorter spring??? i do not weld...
what is the best way to atatch the new shorter spring??? does it have to be welded??? could a product similar to JB WELD work??? what about soldering???
any suggestions??? i am beyond the scope of my ability and knowledge at this point. i am not sure if the spring was welded originaly, or welded later. i could use some advice and opinions.
neat little late war SMG. light wieght, of poor repute. best regards, mike.(PS. email me at the shop at waltsgun@aol.com if you can provide helpful info, or respond here)
What other dungeon is so dark as ones own heart, what jailer so inexorable as ones own mind.
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Hello Mike. I've seen a sum total of three Type 100 submachineguns in my 25+ years in this business and never once had a chance to fire an example myself, although I have watched them being fired by their owners. Magazines are a BIG problem for these Japanese subguns and in most cases an original spare magazine is tougher to find than another Type 100!. You already learned that you need to control the spring guide during disassembly to prevent the spring from shooting out and causing a possible injury. So that you will know, the smaller 3/4" short buffer spring which is on the spring guide, was permanently attached during production and was never intended to be removed. When attaching the new spring I'd ask for advice from an experienced gun smith since welding can easily take the temper out of the new spring and render the gun usless.
Mark T. Christian0 -
Many,many years ago I helped a friend repair one of these.We decided to use silver solder as opposed to a true steel weld to hold the shorter spring in place.He was a machinist and had no problems.The heat is much less, and it worked perfect . I remember nothing of the details now.I would not recommend JB Weld since it is just an epoxy with metal particles. Very sensitive to heat, and softens at about 300 degrees.Talk to a real gunsmith, a machine shop, or even a jeweler that has brazing experience.Don't laugh, but I've had my local , long time muffler shop do some interesting welding and brazing jobs.{They even repaired a cracked fuel bowl on a 32 Buick-Straight 8[8D]]They've always enjoyed the projects. I wish you luck.
Love them Pre-64's!!!!-Bob0 -
MARK CHRISTIAN:
this guy owns 3 differant versions of the type 100. the takedown-paratrooper model, an early model with an elaborate bayonet attatcment, and a late war / final version with some very crude welding and machining. while he did locate a spare mag for the gun, it was a repro. there is nothing wrong with the body, but the spring is bad, and we could not locate a replacement.
its hard to understand how a collector of his stature could let the inside of some of these rare guns deteriate to this condition.
we had to custom tailor the load to work in the SMG. our standard 8MM NAMBU pistol load is a light load. we take the standard mil-spec data and subtract 5% due to the tendancy of these NAMBU pistols experiancing frame damage. this load was not doing well in the type 100.
the takedown was relativly simple, right up until i nailed a co-worker with flying parts. it realy only takes apart into 8 basic pieces. i had never handled one before, and some of my referance materials were rather lacking in detail. the gun seems to have a bad reputation, but it looks god to me. i am told that the long, forward curving magazine made the gun hard to handle in jungle conditions. it was a nice learning experiance.
HANGFIRE:
we are going to outscource the welding work to a local machinist who makes his own guns, and whose wife makes jewelry. we will do some gunsmithing for them in return.
i did some digging, and SMALL ARMS REVIEW recently published an article on the TYPE 100. i have emailed them requesting a copy, if available. of the 5 books on JAPANESE arms that we own, none had a breakdown procedure.
thanks for the assistance guys...
i can usualy dig up enough info on oddball, old, and obsolete guns to sound like i know what i am talking about, but the members here on GB are as good a scource of info. best regards, mike.
What other dungeon is so dark as ones own heart, what jailer so inexorable as ones own mind.0 -
Mike- Be sure and post back with results...
Love them Pre-64's!!!!-Bob0 -
the gun has been put back together, the spring reattached, everything cleaned (BLUE WONDER), oiled, and done right. i will relate how the range test goes when i get the information. best regards, mike.
What other dungeon is so dark as ones own heart, what jailer so inexorable as ones own mind.0
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