What twist for an Arisaka?

[Arisaka99]

I have an Arisaka Type 99. Does anyone know what twist they have and what weight boolit would be best? Right now I shoot sierra's in it.

[Larry Gibson]

The Type 99 should have a 9 1/2" twist. You might want to slug the bore as they apparently vary a lot. Cast bullets of 180 - 210 gr will do very nicely. A 314299 would be my 1st choice sized .314, Hornady GC and Javelina lube loaded over 4895 with a dacron filler. I'd start at 28 gr and work up from there. However, .303 Brit or 7.65 Argentine data is a good place to start if you can't find any other cast bullet data for the 7.7 Jap.

Larry Gibson

[Arisaka99]

Well, i loaded some today starting at 50.3grs of 4350 and going up to 50.7grs. Those are with 180gr sierras.

[curator]

Larry Gibson's advise is spot on. I have three type 99s and the throats on them vary from .314 to .317. Their "Medford" type rifling seems to require hard (BHN22+) cast boolits or "soft" jacketed slugs. I love Sierra bullets for accuracy in most of my rifles but found that the Hornady .312 -174 grain round nose flat base shoot the absolute best in the Arisakas. Apparently it is softer and takes the rifling better.

[Arisaka99]

ok, ill have to look into them, do they sell them at cableas and Midway?

[Wayne Smith]

Chris's Arisaka is a type 99 that has had an '06 reamer up into it without taking off the barrel and setting it back. Thus we are neck sizing his cases. Right now we are using a box of Serria 311" 180 gr that I bought years ago by accident and just held onto. Got a use for them now.

We can find the Hornaday bullets, Chris.

[Arisaka99]

ok, btw, the on with the wrinkled neck pulled the bullet out when I ejected it, the bolt wouldnt close on it either.

[DCM]

Finding the twist of your barrel is fairly easy, use a tight fitting patch on a jag with a cleaning rod that rotates freely. Once the patch has engaged the rifling put a piece of tape on the rod and mark the top of it with a pencil ect., pull the rod until the mark returns to the top and measure the distance it has moved from where it was originally this will tell you that you have one turn in x inches twist.

On the last post I am thinking that you are loading a .311 bullet in a 06 case for the bore size, but the neck area is not large enough to accommodate the oversize bullet in the neck of the case as a standard 06 reamer is intended to accommodate a .308" bullet not a .311". The quick fix would be to neck turn the cases if that is the cause. A good chamber casting would help tremendously there.

[DCM]

Rotometals 158-190 alloy is recommended for chamber casting. IMO I would strongly suggest doing a casting. Just remember that the casting shrinks slightly from the chamber. Might be best to google the instructions or check and see if Cerrosafe has them posted somewhere.