Nambu Type 14 Failure to Feed

[brettkeating]

Took some ammo to the range for my Type 14 Nambu:

http://www.buffaloarms.com/8MM_Nambu_Ammunition_it-158148.aspx

Boy that gun is a blast to shoot.

The ammo was OK but had lots of failure to feed issues. The bullet kept getting caught at the tip, which was evident by looking at the dented bullet once removed from the pistol. Would happen once or twice per loaded magazine.

This is the only ammo I could find for my Nambu, and the only ammo I've ever tried to fire out of it.

I could try some different ammo, but I'm curious if anyone knows what could possibly be mechanically wrong with the gun and how I might diagnose and fix it?

[6mmintl]

1. Have you taken it apart and cleaned/lubed it?
2. Have you taken the magazine apart and cleaned/lubed it?

Nambu's are finicky and typically require higher pressure loads to cycle actions, similar to Lugers.

I am willing to bet if gun was properly cleaned/lubricated that the ammo is loaded on the light side causing you the problem.

You could handload a lot cheaper if you wanted to reduce cost, save your brass.

If in bay area drop me a line.

[brettkeating]

Yes I took it apart and cleaned/lubed it before taking it to the range. I also replaced the firing pin with a repro from Don Schlickman, and replaced the recoil and firing pin springs with Wolff.

I might try putting the old recoil springs back in to see if that helps... maybe the Wolff springs are a bit on the strong side.

[brettkeating]

I did not take the magazine apart, though, because the pins that hold together are original and cannot be reinserted... I'd have to use finishing nails and then Dremel the ends off to put it back together and it would obviously look messed with. I could also try a repro magazine... couldn't hurt to have an extra magazine anyway...

Also regarding saving the brass... I did save most of the brass I shot, but since the cases are reformed to begin with, I was considering starting from scratch with some correctly stamped brass:

http://www.buffaloarms.com/8MM_Nambu_Brass_it-157868.aspx

I've never reloaded before, but have been seriously considering it since I have these oddball Japanese firearms that I really enjoy shooting (I also have an Arisaka that I took to the range, and although the iron sights aren't easy to be precise with, my friend and I could group 3" at 100 yards... not great but good enough for hunting if needed).

[AmericanFreedom]

I did not take the magazine apart, though, because the pins that hold together are original and cannot be reinserted... I'd have to use finishing nails and then Dremel the ends off to put it back together and it would obviously look messed with. I could also try a repro magazine... couldn't hurt to have an extra magazine anyway...

+1 on looking at the magazine. Have not had experience on Nambu, but generally, on box-fed autoloaders the feed lips determine the angle that the cartridge approches the chamber. Sounds kinda like the feed lips are spread out a little too much in the front, raising the nose of the bullet, striking the top of the mouth. This could happen from over vigourous cleaning with a brush putting pressure and deforming the lips. If you have to use a plier to straigten, put a lot of duct tape on the jaws to avoid nicking the lip sides. Adjust very little increments, try, adjust, try, etc. Take out the firing pin first, or use snap caps if available! Hope that helps. Good luck! (Still trying to find snap caps for my .30 Luger!)

[gun toting monkeyboy]

Nambus are fun. They are meant to be loaded with a 108 grain bullet. Those 85 grain ones are a pain in the @$$. I like that they are inexpensive, but getting them to function reliably takes some doing. It takes a lot more powder to get them up to a high enough pressure to get the gun to cycle. Not something I like doing in either of the Nambu actions. If it is jambing the bullet nose into the feed ramp or chamber, it could very well be that the action is not moving rearward enough when you fire it, and closes faster than it should, not giving the cartridge enough time to travel forward. Look at trying it with the old springs. If that doesn't solve it, I would look at getting another magazine. That may solve the issue. If it doesn't you could replace the spring in one of them to see if that solves the problem. Oh, and with reloading, reformed cartridges work just fine. This is one caliber that reloading is a major plus for.

-Mb

[brettkeating]

Thanks. I will try another magazine, the old spring, and if I reload I'll go with the higher grain bullet.

[ZenMastaT]

I've had a similar issue with my own Type 14. I've only tried shooting it twice, once with the original firing pin which worked but had feed issues with 3 point jams, the cartridge nosing into the feed ramp area pretty hard and getting locked up there. I have two mags, one of which I noticed later has a cracked lip - so that may have been the issue there.

The second time I took it out I had an aftermarket firing pin in it which is just slightly oversized and doesn't travel cleanly causing it to light strike. I'm not sure if I should just try and take some material off the aftermarket pin or try new springs in the gun maybe.

[brettkeating]

Update on this. I took it to the range after thoroughly cleaning the magazine, but not disassembling it, with the same ammo... and had the same problems as before.

I took some calipers to the ammo and measured the OAL to be 1.228", but I've seen elsewhere that the OAL should be 1.248". The magazine dimensions look fine, but there does appear to be some wear/damage because the magazine sometimes "pops out" when the round jams on the feed ramp. I posted some images, sorry about how blurry they are... you can see along the side where the magazine catch scrapes against the magazine in these cases. The catch seems to work fine otherwise (i.e. I can't yank it out etc. without pushing the magazine release).

Finally, I hand-cycled about 100 rounds of this ammo through the pistol with the firing pin removed. Not once did I have a failure to feed or eject.

So I provided all that data in case anyone sees any of it as a red flag, but I think the most important piece of information is the success I had hand-cycling the ammo through the pistol. This leads me to conclude that it's not the dimensions of the ammo, or any flaw with the magazine or the pistol, but simply that the ammo is underpowered (as some have already suggested).

I have some 100gr bullets. I can try reloading some of the spent shells and see if that helps but I'm out of pistol powder so it might be awhile.

[knucklehead0202]

sounds like you're on the right track, let us know how you do.

[brettkeating]

Finally got a chance to try out my experiment. The results are a bit disheartening.

The pistol powder that I had available was 700X. I pulled 48 of the rounds that wouldn't cycle, and reloaded them with 3.0 - 3.5 grains (8 each at 0.1 grain increments), and the 100gr plated bullets from Huntingtons. I got those loads by combining a couple internet sources. The ammo I pulled is advertised as "one-fired reformed 40S&W cases."

3.0 and 3.1 wouldn't cycle the action after the first round. 3.2 got hung up after about 3-4 rounds (similar performance to the ammo I already had). 3.3 and 3.4 cycled the action fine for the entire 8-round magazine. 3.5 started blowing the magazine out, although the action did cycle.

I thought I was successful at 3.3-3.4, until...

Unfortunately, after collecting the brass, I noticed that a couple of the 3.3 rounds had split cases, and more of the 3.4 rounds did as well.

The OAL was 1.223", which is close to the OAL of the original ammo.

I'm not really sure how to proceed with this. It seems like if I get enough pressure to cycle the action, I end up splitting the case. I don't know if using a different powder would help here. I am thinking of retrying the experiment, but lengthening the OAL a bit (by about 0.025") to see if that makes any difference... I may also try getting my hands on some new correctly-stamped brass, in case the reforming from 40S&W is weakening the brass too much.

Any other ideas?

[gun toting monkeyboy]

Realize that the cases may be over-worked by whoever made them. The metal may be brittle because of that. I would try the old trick of annealing the EMPTY cases with a blowtorch in a shallow pan of water, and see if it solves the problem. As I stated before, these guns take significantly more powder than you would expect to get them to cycle. Especially with lighter bullets. The 100 grain bullets you are using shouldn't be too bad. I would stick with the 3.3 grains and see how it goes. You may just end up with reformed cases that are expendable. Get some of the actual brass from Huntington if they still have it, and see if you have the same problem.

-Mb

[brettkeating]

Realize that the cases may be over-worked by whoever made them. The metal may be brittle because of that. I would try the old trick of annealing the EMPTY cases with a blowtorch in a shallow pan of water, and see if it solves the problem. As I stated before, these guns take significantly more powder than you would expect to get them to cycle. Especially with lighter bullets. The 100 grain bullets you are using shouldn't be too bad. I would stick with the 3.3 grains and see how it goes. You may just end up with reformed cases that are expendable. Get some of the actual brass from Huntington if they still have it, and see if you have the same problem.

-Mb

Yep, I think I will go the route of getting purpose-made brass for the Nambu, once I find it available. Thanks for the tip on annealing as well... one extra step I'd have to do to the pulled cases that were loaded with 83gr bullets is deprime/reprime, but that's not such a big deal I guess.

[brettkeating]

I can't find any available purpose-made brass, so I think I may get some fresh or range-farmed 40 S&W and reform them myself. I already have the 30-30 dies needed for the job. I suppose having expendable brass isn't so bad... if I can be successful with reforming myself, 40 S&W is virtually free. It's very common to find it at the range I typically shoot.

One piece of good news in all this... I shot some really tight groups with the 3.3 and 3.4 magazines. I really REALLY love the feel and trigger pull of this gun. I'm seriously motivated to make this thing work!

[brettkeating]

It's been awhile but as an update, I have some proper brass on back order from Brownell's but I have no idea when or if I will ever get it.