7.7jap to .308

Discussion in 'Technical Questions & Information' started by midnight_cougar, Mar 18, 2008.

  1. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    I have an old 7.7jap bolt actoin, is the gun able to shoot .308 with an adaptor. I know they make adaptors to shoot different ammo. I found one for .308 online before but i am unable to find it again. I am sure they use about the same size bullet because i found some stuff on reloading. The .308 ammo is shorter then the 7.7 that is why i am wondering if anyone knows where i can find a shell adaptor. I have emailed a few places that have special requests for using different size ammo but nobody has gotten back to me. Can anyone shed some light on this problem. Or would the 7.7 be able to handle the .308 round if there is a shell adaptor? Can someone also give me the bullet specs or just tell me anything on the subject. Any info is greatly apreciated. thank you

    Heres some stuff i found on the .308
    .308 Winchester chamber headspace gauges:
    GO: 1.630"
    NOGO: 1.634"
    FIELD REJECT: 1.638"

    US Army 7.62x51 chamber headspace gauges:
    GO: 1.635"
    FIELD REJECT: 1.6455"

    SAAMI .308 Winchester chamber pressures:
    MAP: 62,000 psi
    MPSM: 66,000 psi
    Minimum Proof Pressure: 83,000 psi
    Maximum Proof Pressure: 89,000 psi

    US Army 7.62x51 chamber pressures:
    Maximum: 50,000 psi
    Proof pressure: 67,500 psi
  2. inplanotx

    inplanotx Active Member

    Jan 28, 2002
    The 7.7 Arisaka is a very strong action and I would bet it could handle the pressures of the .308 Winchester. However, I know of no known adapters for using a .308 in a 7.7 chamber. The only adapter I know of is using the .308 in a 30-06 chamber. There are also several adapters out there using .22 LR in different chambers.

    I own two Arisaka's and I do reload for them. The 7.7mm is actually .312, not .308. If using .308 bullets you will more than likely have accuracy problems. Hornady makes .312 bullets for the 7.7mm Japanese and the .303 British. Graf's has the brass and RCBS makes the dies. Very easy to reload for.

    Hope this helps.


  3. Mosin_Nagant_Fan

    Mosin_Nagant_Fan Active Member

    Jan 18, 2007
    Montgomery, AL
    Like most weapons from that side of the world, the bullet diameter will be larger then the American ammo, which will affect accuracy. I'm not aware of an adapter that makes a standard .308 fit in the Arisaka rifle/carbine.

  4. Alpo

    Alpo Well-Known Member

    Feb 3, 2007
    NW Florida
    Something you might want to try is to get hold of this guy http://www.mcace.com/adapters.htm and see if he can make you one. What might be an even better plan would be to get an adapter to let you shoot 7.62 x 39.
  5. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    I bought 2 boxes of ammo from graf's for a total of $40 w/ free shipping which isn't bad. I did email MCA and a few other places about what adaptors can be made with about the same size bullet, but they never got back to me. I know they made the 7.62 adaptor but i figured there would be a .08 difference anyways. Ammo would be alot cheaper. But i have read that they werent that bad on accuracy up to 100yds. but the ammo is alot smaller and seems like there wouldn't be alot of stopping power or distance. And the mag has to be changed to chamber a round, or one at a time. I'm gonna look at wikipedia to just see what other ammo specs are. I am gonna try to find out if the gun can be rechambered using the same barrel. I just want an awesome coyote gun. But it is too expensive to put a scope on the gun and have to change the bolt. I was trying to sell it so i can get a .308 or an decent american round. Maybe i will put some pics and info up in the ASK THE PROS WHAT IT'S WORTH and put it in the paper.
    If they make an adaptor for 7.62x39 why can't they make one for a 7.62 NATO which is about the same as the .308 I get so confused on stuff like this sometimes.

    Thanks for all your help.
    Last edited: Mar 19, 2008
  6. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    I found out the 7.7 rechambered for 30-06 are having accuracy problems. The hornady ammo i got from graf's if you shake them you can hear that they are not completely full of powder. Is there a reason for that? If the bolt is really strong can you make "hot" 7.7 rounds that will have less drop and more accuracy? If so how "hot" can you go? My gun has a cut stock, i think the correct term is "sporterized" the inside of the barrel is really clean and shiney, it has really deep grooves, the deepest i have ever seen in a barrel. My friends neighbor can reload rifle ammo (something i know absolutely nothing about). I have reloaded 12ga. He wants about the same as what a box of ammo will cost.

    inplanotx, About how much does it cost you to reload the 7.7 and what make of bullets do you use. You don't need to break it down to 20 bullets, you can just give me a rough estimite on any amount if you can.

    Thanks everyone

    **added** from graf's
    Norma brass 20/ $23
    PRVI brass 100/ $40 primed or unprimed

    PCI 20/ $17
    Hornady 20/ $24
    NORMA 20/ $36

    I might as well just buy hornady ammo until i have alot to start reloading. Is norma that much better then hornady??? There all out of 7.7 brass

    I looked for over an hour last night. Is there anyplace that still sells 7.7 military surplus or military surplus machine gun ammo?????? I can't find it anywhere.

    heres reloading info for the 7.7x58 if anyone wants it, and for my future reference. 7000grains=1pound
    Last edited: Mar 21, 2008
  7. Alpo

    Alpo Well-Known Member

    Feb 3, 2007
    NW Florida
    Let's see if I can answer your loading questions.

    Is Norma that much better? No, I don't think so. Norma is good brass, but it is not 250% better, and that's the price difference.

    Nobody sells 7.7 Jap surplus because the Japnese were the only ones that ever used it, and that was for less than ten years. You are lucky there is even a choice with ammo, because when my father-in-law was hunting with it, it was Norma or nothing.

    What I suggest is buy some Hornaday, because they have some. That way you would at least be able to shoot the gun. Save the brass for when you start to load. Notice, the Hornaday and the Norma are loaded with soft point hunting ammo, while the PCI is FMJ ball. If you just want to shoot your gun, the ball is fine, and usually cheaper, but if you want to hunt with it, it is not legal (in most states, for large game).

    7.7 Jap can be made from 30/06 brass. Takes a little work, and some more equipment. You would need one of these http://www.grafs.com/product/195391 Ought six is a whole lot cheaper than 7.7 Jap.

    I would buy the Hornaday ammo, place an order for 100 rounds or so (however many I was wanting to have) of the PCI primed brass, buy the dies, some bullets and powder, and a reloading manual. Lyman, if you are only going to have one.

    Occasionally you will see a load, in a loading manual, that says it is a "compressed" load. This means that the powder is packed tightly in the shell, and there is no air space. All shotshell loads are "compressed" loads. Most factory rifle and pistol ammo, on the other hand, is not. You can take almost any factory loaded rifle or pistol ammo and shake it and hear the powder rattling back and forth. This has nothing to do with the strength of the gun the ammo is chambered for. Generally, the most accurate of any ammo is a load that uses about 80% of available powder space, so factory ammo is loaded that way.

    Yes, it is possible to make "hotter" ammo. Usually this is less accurate. There is also a very good chance of blowing up your gun (and assorted pieces of yourself with it) when doing this. Do not exceed the loads given in the loading manual. Do not take loads that someone else tells you are fine (whether your buddy from next door, or somebody you've never met talking to you over the internet) and load them. Check any load data someone tells you with a loading manual. If you cannot find it, or the data is higher or lower than the manual's loads, do not load it. People get themselves hurt frequently by trying to make guns do what they are not designed to do. By 'hot-rodding" a load. You have a gun that is capable of cleanly taking any animal on the North American continent. There is no need in trying to make it more powerful. If it is not powerful enough for you, sell it and buy a new guy.

    Getting your friend to show you how to reload rifle ammo is a great idea. Buying reloads from your friend is not. If you reload, and you screw it up, and you blow yourself up, it is your fault. If factory ammo blows you up, you have someone to go after. If your friend's reloads blow you up, he probably does not have the huge liability insurance policy that Hornaday does, so suing him won't help much. And if it kills you, it will probably upset him.
  8. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    Thanks alot Alpo, you answered all my questions, and were alot of help.

    I wouldn't want to just start getting into reloading and resize brass. I couldn't sleep last night so i went through all my magazines and found everything for reloading the 7.7 (it was cheaper in the 2008 cabela's book) and broke everything down into 1rnd, 100rnd, 1000rnd price for all the brass, powder and a few different bullets according to the hodgdon website. What i couldn't find are any ballistic tip, V-max or likewise. I'm not sure which bullet types would be the best, i guess it would come down to trial and error. Then I went through and priced .223, but my gun flings them to far to try to find em. When i am about to buy a reloader i will have to ask ya'all about which one will be good for me and your reloading preferences.

    The powder and primer are important, but can you switch the type of bullet with the same grain?
  9. stash247

    stash247 New Member

    Oct 18, 2003
    Central Texas
    In a word, NO! If you change anything in a load, you back off to starting loads, and work up to a new load, with the new component, and take extensive notes, while doing so.
    I make this comment on the simple assumption that your eyes and fingers are important to you.
    As to the gear, Cougar, I do 95% of my loading on an old Dillon 450 Progressive press, bought new, with a lot of tooling, for a lot of calibers, back when it was the 'state of the art' offering.
    Prolly pretty cheap, on e-bay, and they cannot be worn out, a place to start, anyhow, AFTER you have a Reloading Manual!
    That 7.7 Japanese brass could be had from Midway, or several others, or formed, on a press, at home, on the cheap, had you a form die, and a case trimmer, but, unless you are in love with the Arisaka action, and rifle, a cheaper way for coyotes might be a modern rifle.
  10. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    I'm sorry. I meant switch the bullet type within the same grain and start with the starting load and work my way up. Theres different bullet sizes from .310 .311 .312 i think that the .312 should be more accurate. I checked ebay they didn't have any Dillon 450 they had a few higher number Dillon reloaders but there way to expensive for me. Price of ammo is about the same for the 7.7 from grafs as the box .308 from a store. I like my 7.7 it is fun to shoot but i like scopes but i'm not going to spend $100 to buy a scopemount and change the bolt handle. Thats the main reason i would like to switch guns. Coyote closes today so i have a while before i need to worry about it. Thanks guys
  11. stash247

    stash247 New Member

    Oct 18, 2003
    Central Texas
    Cougar, let me tell you this way.
    I have a very accurate, and expensive, .22 Hornet, of European origin.
    Wonderful rifle.
    But, .005" difference, in the overall length of the round, was the difference between an extremely accurate load, at almost .222 velocities, and blown primers, all else being the same; same brass, same primer lot, same can of powder, same box of bullets: this **** is serious, dude!
    I was looking for 'maximums', in a strong rifle, and I know this stuff, after 40 years, pretty well; but .005" in length?
    Your printer paper is .006" thick, if this offers perspective.
    Change nothing, without reducing the load, and working back up!
  12. midnight_cougar

    midnight_cougar New Member

    Sep 2, 2007
    Upstate, NY
    WOW.. Thats why I'm asking so many questions before buying anything or attemping to reload rifle. I've reloaded shotgun shells before, I knew reloading rifle would be harder but I didn't think it would be this much harder.

    I know a few people on here reload the 7.7. Before I buy anything I'll check to see what works the best in everyone else's rifles and go from there. It'll just be a good start. Plus i'll talk to me friend and have him talk to his friend that reloads, and just go over there one day when he is reloading. So he can show me some pointers and get me started.