7.7 Japanese Arisaka Type 99 Bore

[Pirate69]

Think I need some help on this one. I understand, from searches, that the Type 99 has an elipitical bore. And, slugging my rifle I found the slug ranged fom 0.302" to 0.3165". I assume the 0.002" greater than the max groove does not hold true here. What cast boolit diameter should I be targeting? Do I average and add 0.002"?

[MtGun44]

Why not? Probably work fine, but I have only shot j-bullets through mine. Haven't got
around to boolits with that one yet.

Bill

[303Guy]

You know, I don't hear much about Arisaka's, let alone 7.7's. It would be great to hear of your results with yours. :Fire:

[3006guns]

Your measurements are correct and a .317-.318 boolit should work...HOWEVER...that is assuming that the neck portion of the chamber is large enough to allow the case neck to expand safely. An easy way to check this is to use a case, fired in that gun, and see which is the largest boolit you can push into the neck. It should be a firm fit and allow you to chamber the round. If it won't chamber due to expanding the brass a bit, it may be time to take drastic action...but try it by all means. The boolit can be unsized (but lubed) right out of the mold if that's what it takes to reach your size.

My Type 99 slugged at .3155, yet I can get a .3165 (closer to .317) into the case and still chamber the round easily. I've been using a plain base mold for the .32-40 Winchester, which drops at around .321 and size it down to .3165 in a honed out Lyman die. This makes for some funny looking lube grooves, but they still hold enough to do the job.

If there's one thing I've learned about the Arisaka, you need to cast 'em big and cast 'em hard. That Metford style rifling requires a harder boolit. About 9-10 grs. of Trail Boss makes for some fun shooting, but you'll have to crank the sight ladder up to about 600 meters to hit your aiming point.

[Sgt Petro]

I second 303Guy's post. Really like to hear about how you're going about it.

[303Guy]

I'd forgotten about the Metford style rifling (which I only recently found out about). I've only shot paper patched boolits through bores with rifling that mimmic Metford rifling and those seem to work so why not cast.

[Larry Gibson]

I helped several shooters with 7.7 Arisaka's with similar sized bores as yours. Very, very good accuracy was obtained with all using a Lyman Lovern design 323470 (Mine weigh 169 gr cast of WWs+2% Sn fully dressed). They are sized lubed and GC in a standard 450 Hdie at .324/.325. A Lee .314 sizer was easily honed out to size them at .318 and the sized, lubed and GC bullets are then pushed through the honed Lee sizer for a .318 size. Very accurate at 1850 - 1900 fps using H4895 and a 3/4 gr dacron filler.

Larry Gibson

[Pirate69]

Brass and dies are on order. I have some casts running 0.316"-0.317". Its only a matter of time before I get a chance to see what she will do.

[runfiverun]

what 30-06 and larry said, works best for me too.

i use a 4% tin and 6% antimonial alloy in my 7.7 but get away with 313 sized boolits.
i use a loverign design that is from nei [yeah an old walt one] but it's similar to the lyman.
i have tried paper in it too but couldn't get the fit quite right wiith the boolit i wanted to use [but get spectacular 1 shot groups dead center at 100 yds] and just kinda moved onto another rifle.
17 grs 2400 works fine for me.

[hydraulic]

10 grs of Unique under a the old '06 311413 Lyman shoots great in my 99. In fact, I can shoot better groups with it than I can with my M1 or 03A3.

[wallenba]

It's a Metford type rifling, cut more like a four leaf clover. Originally used to improve cleaning. I was confused about measuring my 99 accurately for sizing. A C312-185-1r Lee @ .314 over 12.5 grains of Trail Boss is working for me though. (Mold is lapped oversize)

[303Guy]

You mean the 'corners' of the grooves are radiused? That's brilliant!

[3006guns]

That's right.....smooth "corners", no place for fouling to get a foothold. On top of that, most of the type 99's had a chrome bore. I have several that look absolutely AWFUL on the outside (battle scars, etc.) but the bores are still like new. I don't know of any other military that went to that much trouble to keep the bores trouble free.

The only problem seems to be that lead boolits don't get a "bite" like cut rifling, which is why mine are cast fairly hard.

[wallenba]

That's right.....smooth "corners", no place for fouling to get a foothold. On top of that, most of the type 99's had a chrome bore. I have several that look absolutely AWFUL on the outside (battle scars, etc.) but the bores are still like new. I don't know of any other military that went to that much trouble to keep the bores trouble free.

The only problem seems to be that lead boolits don't get a "bite" like cut rifling, which is why mine are cast fairly hard.

Yep, mine is like that. On the outside it looks like it spent an hour in a cement truck. Inside, the chrome lining is bright and beautiful.

[dbldblu]

Few people are aware that the Arisaka is one of the few rifle designs where the bolt lugs engage the barrel directly as opposed to the receiver. This makes them particularly strong. P.O. Ackley did some blowup tests of various military rifles and the Arisaka was the strongest, stronger than a Mauser, stronger than a Springfield. Much is made of "last chance" Arisakas with their cast receivers but, in reality, it doesn't matter. The receiver does nothing other than hold the parts in alignment. With that said, mine sees a steady diet of cast bullets.

[Pioneer2]

The cast recievers were actually trainers not meant for live ammo.Eliptical rifling..........Harold

[gew98]

Few people are aware that the Arisaka is one of the few rifle designs where the bolt lugs engage the barrel directly as opposed to the receiver. This makes them particularly strong. P.O. Ackley did some blowup tests of various military rifles and the Arisaka was the strongest, stronger than a Mauser, stronger than a Springfield. Much is made of "last chance" Arisakas with their cast receivers but, in reality, it doesn't matter. The receiver does nothing other than hold the parts in alignment. With that said, mine sees a steady diet of cast bullets.

You might want to rethink that barrel engagement blanket statement. The type 38 trainers as made as trainers were made for wooden bulleted blanks for very good reasons that need not be expanded upon.
The ONLY japanese rifle that had the locking lugs as part of the barrel was the Naval Type 99 'Special'....which is quite a rare find to a jap rifle collector !.

[Multigunner]

You might want to rethink that barrel engagement blanket statement. The type 38 trainers as made as trainers were made for wooden bulleted blanks for very good reasons that need not be expanded upon.
The ONLY japanese rifle that had the locking lugs as part of the barrel was the Naval Type 99 'Special'....which is quite a rare find to a jap rifle collector !.

Wasn't there a quick takedown parachutists rifle that had the barrel extension lock up, and the idea for using the same system for the Naval Special rifle came from this.
The Japanese built several takedown rifles and carbines, some were manufactured in Germany for their use.
The one I'm thinking of has a barrel extension that slides straight back into the receiver ring and in locked in place by a bar that slides across engaging a cut out in the bottom of the barrel shank.

[Multigunner]

You mean the 'corners' of the grooves are radiused? That's brilliant!

They are using radiused corners for some of the most advanced rifling patterns these days.
besides making cleaning easier the raduiused corners allow a more effective bullet jacket to bore seal, reducing blowby.

[gew98]

Wasn't there a quick takedown parachutists rifle that had the barrel extension lock up, and the idea for using the same system for the Naval Special rifle came from this.
The Japanese built several takedown rifles and carbines, some were manufactured in Germany for their use.
The one I'm thinking of has a barrel extension that slides straight back into the receiver ring and in locked in place by a bar that slides across engaging a cut out in the bottom of the barrel shank.



No. Neither type of 7,7 takedown para rifles had barrel extensions that had integral locking lugs. One type had interrupted threads for QD , and the other a solid lug for QD on specially made barrels , but the receiver was still the load bearing receiver as the basic rifle action was not otherwise modified. Initial trials showed that these early patterns loosned up enough at 2,000 rounds to cause excesssive headspace and rupture the brass. Was redesigned in making it more beefed up in lockup and accepted.... but locking lugs for bolt were still the receivers domain.

[Char-Gar]

Harry Pope rifled his barrels with rounded corners.

[dbldblu]

I stand corrected on the barrel engagement tangs. P.O. Ackley still found the Arisakas to be the strongest actions, the type 38 was #1 and the type 99 was #2.

[Multigunner]

No. Neither type of 7,7 takedown para rifles had barrel extensions that had integral locking lugs. One type had interrupted threads for QD , and the other a solid lug for QD on specially made barrels , but the receiver was still the load bearing receiver as the basic rifle action was not otherwise modified. Initial trials showed that these early patterns loosned up enough at 2,000 rounds to cause excesssive headspace and rupture the brass. Was redesigned in making it more beefed up in lockup and accepted.... but locking lugs for bolt were still the receivers domain.

I'd looked up a video clip of the type 2 being broken down, and though the clip does not show the breech very well theres a large squared off cut out at the breech which has me confused.
If the bolt does not lock into the barrel extension, that cut out would extend into the chamber. The rear of the shank extends far aft of the cut out.

What purpose does this cut out serve?
Its not part of the take down itself so far as I can see.

[Pirate69]

OK, brass and dies have arrived. Now to load some and try them after this hurricane leaves. My rifle does not have the original bolt so I plan the load them long into the bore to eliminate any headspace, and fire-form the new cases. I understand that Bullseye is typically used for fire-forming. Anyone have a suggested load for my 172 grain cast? It will be gas-checked. Want to make sure I get good fire-formed casts.

[Arisaka99]

I have an arisaka type 99 as well, but it had a 30-06 reamer run thru it. I use sierra game king 180gr .311 j words. I use 06 load data and it works well. I refinished the stock and put a limbsaver on it, as well as put a lyman 57 reciever sight on it. It should make a good deer rifle.

[Japlmg]

All Japanese service rifles from the Type 30 on used Metford rifling.
Metford rifling has rounded lands.
Gregg

[bruce drake]

Run the first sets of new-formed brass with 10gr of Unique or 9gr of Red Dot with those 172gr cast loads. The loads will be very light but they should fireform the shoulders of the cases so you can load up a bit more on your next cast loads.

Bruce

[Pirate69]

Thanks Bruce

[Pirate69]

I have started to develop some cast boolet loads for my Type 99. I am using a 172 grain gas check boolet that is tumble lubed. The boolets are fired as cast; unsized, running 0.136" to 0.317".

This is a 10-shot group at 50 yards from the bench. It his hitting to the right of the POA and I am having trouble drifting the front sight. Also shows a 100-yard group.

http://i718.photobucket.com/albums/ww187/Pirate69-photo/Jap%20Groups/77japgroups004.jpg

I shot two 4-shot groups to see the difference between the ladder sight and the battle sight at the same setting. Both groups measured 2.75" edge to edge. The battle sight had a much lower POI that the ladder sight.

http://i718.photobucket.com/albums/ww187/Pirate69-photo/Jap%20Groups/77japgroups002.jpg

http://i718.photobucket.com/albums/ww187/Pirate69-photo/Jap%20Groups/77japgroups006.jpg

Still have a lot of work to do to make it a good shooter.

[bruce drake]

Its a good start. the front sight is on a very narrow base. Use a small pin punch and slowly tap the 70 odd years of corrosion loose.

Bruce

[madsenshooter]

You mean one can find the pin on 99s? I know my type 38 has one or two, but they're invisible! I did find one on another type 38, it took a very large hammer to get that corrosion loose. Now with this carbine that I can't find the pins on, I might just cut the sight off, the stock has been moderately sporterized anyway. You're getting there Pirate, keep at it.

[bruce drake]

The quality of hand work the Japanese put into their Arisakas, even the late war ones, makes the current CNC production rifles look like trash.

Its there on a 99. I pulled a sight blade off one and then modified a Lyman 17 Front Sight on a sporterized one a few years back. The sight blade looked like it took a 30 cal bullet or a good piece of shrapnel to it and really bent that wedge. probably why I was able to see the drift line on the sight base.

Bruce

[leadhead]

Pirate, What mold are you using that drops at .317?
Sure would like to get hold of one of them.
Denny

[Pirate69]

I am using the Lee MOLD DC TL312-160-2R. It normally drops about 0.314". I beagled it on both sides to get the extra 0.003". Also getting more weight than from an unbeagled mold. I am using 1.3cc (Lee dipper) of Red Dot powder to fire form my cases and get a mild load. I just snap the gas check on the botton and it holds enough to load. I flare the neck just enough to get the gas check started. The neck is tight enough that it secures the bullet and the check. The gas check becomes fully attached and seated upon the round being fired. Rounds recovered from my sand bullet trap show the gas checks still attached. Will replace the Lee expander in the resizing dies with a larger expander (larger one turned down to correct diameter) later so I can relieve some of the neck tension and shoot without the GC at low velocities without fear of swaging the bullet as it is seated. The GC prevents the swaging for the most part at this point. I like the low recoil rounds for people just starting to shoot.

Also heated the boolits to 460 degrees for an hour and water quenched to harden them.

[Multigunner]

The quality of hand work the Japanese put into their Arisakas, even the late war ones, makes the current CNC production rifles look like trash.

Its there on a 99. I pulled a sight blade off one and then modified a Lyman 17 Front Sight on a sporterized one a few years back. The sight blade looked like it took a 30 cal bullet or a good piece of shrapnel to it and really bent that wedge. probably why I was able to see the drift line on the sight base.

Bruce

I once repaired a 99 that had a broken wrist, the grip strap didn't prevent this break. I wondered about the force necessary to produce such a break.
Then after running a steel threaded rod through the grip from the inside and glass bedding it in place and filling the gaps, I found one side of the stock near the mid point of the action had deeply imbedded grit.
I'd taken this for volcanic sand, not after removing it I found it was magnetic.
Best I can figure this was part of a shattered cast iron grenade casing. I'd heard that most WW2 U S grenades had a tendency to shatter into tiny bits rather than break up along the grooves to produce sizeable sharpnel.
I figure thats what broke the stock, and did for the Japanese who'd carried the rifle.

That rifle had seen hard use. The original finish had been scrapped away, and the wood appeared to have been darkened with boot polish. I've heard more experianced jungle fighters often did this to make the rifle harder to see. I've seen a few Garand stocks that had been done the same way.

[NavyVet1959]

I have an arisaka type 99 as well, but it had a 30-06 reamer run thru it. I use sierra game king 180gr .311 j words. I use 06 load data and it works well. I refinished the stock and put a limbsaver on it, as well as put a lyman 57 reciever sight on it. It should make a good deer rifle.

I recently stumbled across a Type 99 Arisaka that has been sporterized for fairly cheap and was considering how feasible it would be to do something like that. Instead of just taking .30-06 cases and cutting them down to the 7.7x58, it seemed like it would make more sense to just take the .30-06 (7.62x63) brass and resize them to the same neck diameter as the 7.7x58 while still using the the 7.7 bullets. Basically making a 7.7x63 or a 7.7mm-06 wildcat? Unfortunately, my "fine machining" skills are more limited to just converting the .30-06 brass to 7.7x58 since it is similar to converting .223 to .300AAC (which I already do). :(

[Japlmg]

Use 8x57 (8mm Mauser) brass to make your 7.7x58 cases.
Lots less work!
Gregg

[NavyVet1959]

Use 8x57 (8mm Mauser) brass to make your 7.7x58 cases.
Lots less work!


But not as easy to find as .30-06... (at least around here)

[Scharfschuetze]

I have an RCBS case forming die for the 7.7 Jap. I've only used Lake City Ought-Six brass so far, but I understand the Mauser brass reduces the effort somewhat due to less or no trimming.

My Type 99 is in almost unused condition, but is missing its dust cover and Mum. Other than that it's close to NIB although that orange crate wood stock does look a bit shabby. My bore also measures on the wide side of .316 inches, but I recently received an NOE 316299 mould and I hope to try that out pretty soon. If that doesn't work, I'll try 32 Special or 8mm boolits.

A friend of mine claimed his Type 99 was mildly radio active. I never put a Geiger counter to it, so it's still just speculation and he's long since moved away.

That Metford rifling, even when pristine, looks worn out when compared to what we are used to.

[NavyVet1959]

With the .300AAC, I:



Rough cut to approximate length
Finish trim to final length
Debur
Run it through the .300 AAC resizing / depriming die
Finish trim to final length, in case the resizing caused it to grow
Debur


I figure converting the .30-06 to 7.7x58 could not be any worse than that. Well ... maybe add an annealing step at the end... It's a bolt action, so it's not like I will need to have a few hundred of the cases on hand.

The guy that has it for sale says that when he last fired it a few years ago, it was working, but when he took it out to send me photos of the markings yesterday and he dry fired it. He said that it make a "soft click sound" instead of a "normal dry fire sound", so he dropped the price to $125 from $175. I figure at that price, it's worth a chance. From what I can tell on the serial number and arsenal, it looks to be from around late 1942 or early 1943.

[Eddie2002]

I've a model 99 Arisaka that I've had for years, it has the chromed bore, airplane sights but is missing the monopod and dust cover. It must of seen service because the front of the stock has five or six deep small burns in the wood and the bore slugs at .314 at the throat and .312 in the barrel. I'm shooting a 100 grain .313 WW cast boolit over 5 to 6 grains of Bullseye or BE 86 with resized 30-06 brass. I trim the brass 20 thousands over, anneal the neck and then FL resize, and trim down to final length. It's accurate enough at 50 yds to make it a fun shooter.
Had to repair the stock at the wrist when I first got it, ended up fixing it with some JB weld which left a thin line in the stock but I've shot a few hundred jacketed rounds since then with no problems. $125.00 is a real good price for a model 99.