arisaka jumps the sear on closing?

[MBTcustom]

I have a Jap arisaca that is a cock on closing type mouser cal 7.7 I think. Anyway, everything works fairly well except for the super stiff trigger, and the fact that if I work the bolt like my life depends on it, it jumps the sear and I have to back the bolt up and go steady. Any ideas how I can make this problem go away? Maybe rebuild the bolt or the sear or both?
Is this action as strong as the German mouser?
I have not shot this one yet, but would like to wildcat it into something else.

[gew98]

You sound like it's a type 99 . By late 1943 they stopped chrome plating the bores to economize as well as shorting the cleaning rod and simplifying stock hardware and sights. Anyhow a pre 1945 made type 99 is one good rifle. I love the caliber and with the proper brass you can reall make it talk and accurately. It sounds as though you may have a weak spring - are the contact surfaces for the firing pin and the sear damaged in any way ?. If not it is a simple spring issue and would require dsimantling of the rifle to address that. As well most jap rifles have gobs of cosmoline like grease under the woodline - it will still be there if it has never been disassembled.And we all know old grease dries up and hardens especially if any springs are in the mix. Give it a good clean and see what happens then barring any damage to the sear contact points.

[3006guns]

Let me jump in for a second. First of all, does the bolt number (located on the underside of the handle at the root) match the last three numbers of the serial number on the receiver? If not, stop right there and get to a gunsmith that is familiar with Jap rifles. The bolt is from another gun...very common....and you may have headspace issues on top of a "froggy" trigger.

1.) If the rifle still has the military stock and the screws are "staked" ( a small, round dimpled punch mark in line with the screw slot) DON'T even think of taking it apart. Once those stake marks are violated the gun's collector value drops drastically. All the screws on these rifles were staked. If the screws have already been removed once you won't hurt anything.

2.) There very well could be dried cosmoline (or dirt) in the trigger group, causing problems, so a disassembly would be called for. I lightened the trigger pull on one of my 99's by clipping the coils of the trigger return spring one at a time until I was satisfied. Before that, the pull must have been around 15lbs.!

3.) To disassemble the bolt, remove it from the rifle and hold the bolt body in your left hand with the safety knob toward you. Place your right palm on the knob, push and turn clockwise. The knob will release and allow the striker and spring to slide out. Clean everything well and oil LIGHTLY. Examine the end of the firing pin to make sure it's rounded and even.

4.) To reassemble...and PAY ATTENTION HERE....if you look at the rear of the bolt body you'll see two notches, one closer to the rear of the bolt than the other. We'll call it the "high" notch. Reinsert the striker (firing pin) and make sure the sear is in the high notch. Insert the spring. Place the safety knob back on and push while turning counter clockwise. IF YOU PUT THE SEAR IN THE LOWER NOTCH YOU WILL LOCK UP THE BOLT IMMEDIATELY UPON INSERTION INTO THE GUN AND IT CAN'T BE REMOVED WITHOUT GOING THROUGH THE MAGAZINE WELL WITH A SPECIALLY GROUND SCREWDRIVER TO PULL THE SEAR BACK. Don't ask me how I know this.

The type 38 and 99 Arisakas are an improved Mauser. They were engineered with fewer parts and one Hell of a strong action as proven in testing following WWII. They do not lend themselves to easy sporterizing however. The safety is in the wrong location for most hunters and the action itself isn't quite as "slick" as a typical German Mauser. But they are stout! By the way, the threads on a 99 are 16.99 tpi...17 tpi is close enough if you're rebarreling.

Edit: Is there a possiblity that you could post some pics? There are still a few Jap trainers kicking around out there and you want to make sure you have an actual rifle, not a trainer. Attempting to fire live ammo in a trainer will get you hurt very quickly.

Second Edit: If the barrel is removed and the shoulder turned back on a lathe so that it will screw back in exactly ONE thread more (rear face and extractor notch have to be trimmed also) you will end up with a rifle that shoots 7.65 Mauser and a chrome lined barrel to boot.

[MBTcustom]

Sorry fellers, I already cracked the screws and cleaned the inside of the rifle. "I promise in the future I will check carefully to make sure the rifle has no collectors value." Anyhow I bought this rifle off gunbroker for $125, cheap enough. it was listed as a "Japanese type 77" and that's about it. I figured that the pore uninformed seller probably meant 7.7MM arisaka but that's just a guess on my part. I really don't know jack about this piece exept that it appeared to be a mauser type action. I bid on it 'cause it was too cheap to pass up and I was actually surprised that I won. I bought it for the sole purpose of using the action for a re-barrel.
The trigger was really bad, almost unusable, even for me, "usually I can deal with a stiff trigger but this one was more than I could compensate for." I pulled the rifle apart and installed a weaker trigger return spring and polished the sear engagement surfaces lightly, got the trigger down around the 8lb. area.
I checked the bolt number and it matches, I think it is highly unlikely that the barrel is chrome lined as you can see in the photos there is light rust in the tip of the barrel. That said, the bore is brighter than any military rifle I have ever seen.

Oh, and not to worry about reassembly, I completly disasembled the bolt and cleaned out the cosmoline and reassembled it. I was very impressed by the robust design and I may just recrown the barrel and use 30-06 brass to make cartridges for it. In fact I plan to do something of this nature before I pull the barrel just to see how it likes a gas-check. Who knows it might be a regular tack driver. Besides I love the sights and how light the rifle is. Sweat!!!

[gew98]

Your rifle looks like it's had the mum ground so to me no harm done. I personally never minded about taking them apart - staked screws or not. I very often found gobs of rust & dirt under the wood and the careful cleaning was necessary. When I loaded for accuracy I found that the jap 99's and my 303's loved those surplus 7,65 argentine 185 grain boat tailed FMJ bullets - I bought a 30 caliber ammo can full of them at an allentown PA gunshow back in the 80's. Don't know if you can find them today anywhere but they were great while they lasted.

[gew98]

Oh and if you are going to punch 7,7 brass out of 30-06 brass you would be advised to stay on the lighter side of loads as the 30 cal brass is a good bit smaller in case outside diameter and can swell quite noticeably..... hot loads ruptured cases are very likely. I had a fair stock of Norma 7,7 & 6,5 brass when I dabbled in japanese rifles.

[3006guns]

Looks like a late war version.....not quite to the "last ditch" stage but getting there. Still a good shootable rifle though. There's brass available on Gunbroker from a seller "Mr.Nambu" and it's good Privi stuff. Any of the commercial j-words designed for the 7.65 Mauser (Argentine) or .303 British should perform well in your Arisaka. Most loading manuals have the data.

I just tested some loads this afternoon in my type 99. I've learned that what they say is true when it comes to cast boolits.....make 'em big and make 'em hard. So, I'm using a Lyman 200 grain mold that's BARELY big enough to hold the .3145 bore and used an alloy with a fair amount of linotype. Intitial shooting was done at the 25 yd. pistol range, resulting in a 7/8" 5 shot group. Shows potential, but I still want to get a .316 mold to really seal that bore.

I like them. They're a good, stout gun designed to be easily maintained and lighter than most of their contemporaries. Be warned though.....they can be addictive! Enjoy.

By the way, if you want a Mauser action for a custom build I may have one kicking around.

[MBTcustom]

gew98, thanks for the heads up on 30.06 brass, I read somewhere that it cold be used to make cases out of. They also mentioned 8mm something-or-other. Seems like I just cant find a good deal on brass! I am trying to sell 7mm rem mag brass in the swappin&sellin area and they said they wouldn't give 15 dollars for 150 cases! said they can buy cases all day long for that price! Id love to know where they shop!
Thanks for the info 3006, 7/8 group sounds like a deer stopper to me! I was kicking around the idea of making a .416/06 wildcat and re-barreling this puppy for it. That way I could still use the magazine. Either that or cut this barrel back a little and bore out the chamber to 30-06 dimensions and load .312 boolits in 'em. Id really like to see how this rascal shoots "as is" first though. This jumping the sear thing buggs me though, Its like I know it will only do it when I really wouldn't want it to.

[gew98]

You may want to go to gunboards.com and they have a japanese arms forum and therein have a japanese specific trader forum. Post there about brass, as that is where I dumped all my jap brass, collector ammo and bayonets not with rifles when I got out of japanese rifles some years ago.
Part of the great pleasure in shooting these old military rifles is doing it in their original chambering.

[gew98]

The type 38 and 99 Arisakas are an improved Mauser. They were engineered with fewer parts and one Hell of a strong action as proven in testing following WWII. They do not lend themselves to easy sporterizing however. The safety is in the wrong location for most hunters and the action itself isn't quite as "slick" as a typical German Mauser. But they are stout! By the way, the threads on a 99 are 16.99 tpi...17 tpi is close enough if you're rebarreling.

I might disagree with you a bit on being an "improved" version of the mauser 98. While there is no question when the japanese were not pressed the quality of fit and finish of their 38 & 99 rifles was superb.... the heat treating they did especially on type 38 rifles was top potch. The ejector box is a bit more complicated than the 98 , and though the bolt had fewer parts the safety was very awkward and could with an accidental blow/hit jam up solid. I have encountered this often. The type 99 suffered from alot of non parts interchangeability throughout it's short life , whereas you can take the vast majority of 98 mauser parts from a ww1 rifle and pop them right on a ww2 98 rifle.
Anyhow it's getting away from the rifle's actual merits.

[BeemerMark]

Oh and if you are going to punch 7,7 brass out of 30-06 brass you would be advised to stay on the lighter side of loads as the 30 cal brass is a good bit smaller in case outside diameter and can swell quite noticeably..... hot loads ruptured cases are very likely. I had a fair stock of Norma 7,7 & 6,5 brass when I dabbled in japanese rifles.

I used to make 7.7mm out of 30-06 and it works very well. Once shot and fire formed your OK to go. However, Hornady now sells 7.7mm Ariska ammo that is almost cheap. I bought a few boxes of that last year for less than $25 a box. I don't like having brass stamped 30-06 that isn't 30-06.

[3006guns]

gew98...I base my "improved" comment simply on the elaborate heat treating, along with the reduced number of bolt parts. The gas handling system on a type 38 has two escape holes, most others have only one. The safety on a typical 38 or 99 is a wonder in itself as it performs three separate functions, i.e...holds all parts in alignment, functions as the safety and finally is a gas shield to protect the shooter in case of a primer puncture or case rupture. It's almost ironic that the Japanese went to so much trouble, as I doubt they had American shooters in mind!

As for "anti aircraft sights" and "monopods"...well, probably seemed like a good idea at the time

Don't get me wrong. I have quite a few Mausers of various flavors that I love and the Arisaka is a bit clumsy to sporterize, but I have to take my hat off to the engineers that designed the Arisaka. It's about as "soldier proof" as you can make it.

[MBTcustom]

I think I asked this question on the wrong forum.