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View Full Version : Source for 7.7 Jap?



plumber
10-24-2009, 10:38 PM
Does anyone know of a source for Prvi ( PPU) brass? The only vendor I know of is Graf's and they have none.
Thanks

MtGun44
10-25-2009, 12:22 AM
Got mine from Grafs, sorry to hear they are out. Try to find loaded Prvi ammo at a gun
show, a bit pricy to get brass, but may be the only way. Have you called Graf and
asked when they expect more?

Bill

StarMetal
10-25-2009, 12:29 AM
Either what Mt said or buy Norma...I know expensive, but good long lasting brass.

Joe

dualsport
10-25-2009, 02:05 AM
It might be possible to form 7.7 Jap from 30-06 brass, I don't know for sure. I do make 7x57 from '06 with an RCBS trim die. Check out RCBS or Huntington Die s.

NickSS
10-25-2009, 04:38 AM
I made lots of 7.7 Arisaka brass from 30-06 brass. I just bought a size and trim die from RCBS and run them in and trim them. I have also made 8mm Mauser, 7mm Mauser and 7.63 Mauser from 30-06 brass. I ever made some 25-06, 270 Win and 6,5X55 Mauser from it too. I think there are other cases you can make from it. I do not do too much of this reforming now but when I was poorer and brass was expensive I did a lot of it.

perotter
10-25-2009, 09:31 AM
As for using 30-06 brass, one should be somewhat careful about the load. 30-06 brass is a little smaller in diameter. In Ken Waters "Pet Loads" he said that he quit converting 30-06 to 7.7.

Knowing that, I've converted 100's to 7.7 & shot 1000's. I've never had any real 7.7. I've just always kept the loads at less than "Don't Exceed".

Some of what I've converted started as 25-06. FWIW, at my place & my families places, if a loaded round says 30-06 or 25-06 on the head stamp it isn't either of them.

It should go without saying but, when one is doing conversions extra caution should be used before shooting a round.

azrednek
10-25-2009, 11:08 AM
I'm with perotter, I've converted hundreds of 06 to 7.7 Jap. Also a good many 06 to 7 & 8 MM Mauser and 7.65 Argie. Your initial fire-forming load to 90% of max, no more and you will remove a perfectly formed case. It is very important that you do use safety glasses at the initial fire-forming. Never had a Jap but did have an Argie where a little gas sneaked over the shoulder before that shoulde was formed. The Argie's chamber had a step-up in it i was not aware of.

TCLouis
10-25-2009, 11:26 AM
I used to be concerned about the 30-06 bras being small until I realized that my dies were resizing it and so it made no difference wht the brass was, the dies were smaller than the brass or chamber.
Luckily I have the Lyman drill press trimer so cutting brass to length is less of an issue.

Sure beats the way I started with forming 30-06 to 6.5X257 and 30-30 to 219 Donaldson and trimming to length with my Redding trimmer. That was a lot of cranking.

StarMetal
10-25-2009, 11:40 AM
I'm with perotter, I've converted hundreds of 06 to 7.7 Jap. Also a good many 06 to 7 & 8 MM Mauser and 7.65 Argie. Your initial fire-forming load to 90% of max, no more and you will remove a perfectly formed case. It is very important that you do use safety glasses at the initial fire-forming. Never had a Jap but did have an Argie where a little gas sneaked over the shoulder before that shoulde was formed. The Argie's chamber had a step-up in it i was not aware of.

Let me add to what you said here and see if you agree or disagree. First I want to say that I too use 06 brass for lots of calibers including the 7.7 Jap. First lets start with a factory round. They have to be smaller then the chamber in order to fit all the rifles out there. When you are holding our rifle the horizontal firing position the cartridge is actually laying on the bottom of the chamber. When it's fires it expands. Since the it's laying on the bottom of the chamber it expands up and to the sides also. If you examine a once fired new case you will see where the body expanded up to the thick web and will notice that there will be one side where you don't see the definition of expansion near the web. That is the part of the case that was laying in the bottom of the chamber. After a few firings you case will eventually be expanded equally around. To do it faster and the first time there is a trick of cutting narrow strips of Scotch Tape and wrapping them around the solid web part of the case. Let me explain that. That will be a strip of tape that will start where the extractor groove meets the body and only goes about 1/8th inch further. You make enough wraps of the tape to just let the cartridge slide into the chamber. It is a PIA to begin with, but many of us do not like to fire a case a few times to get it evenly expanded. Why do this? Well for the standard milsurp rifle with iron sights it doesn't make much of a difference, but the reason is to center the case as perfect as possible in the chamber, which in turn centers the bullet in relation to the bore better....all in the name of accuracy. Unless your firing pin is off center you'll notice if your case is off center by the firing pin indentation in it.

Now with that said I imagine that somewhere out there, there is a very fat 7.7 chamber and 06 brass in it might be dangerous with the max loads. Generally most of them aren't and the 06 brass woulds very well, especially with cast loads.

One more thing about the Scotch Tape thing. You have to remove the bolt from your rifle, insert the loaded round in the face of the bolt, then holding the bolt stop wide open, insert the bolt and cartridge into the receiver and then gently chamber the round in order not to scuff or scrape off the Scotch Tape. You can't strip them from the magazine successfully without ruining the tape.

Joe

VintageRifle
10-25-2009, 04:32 PM
Graf shows 7.7 Prvi in stock.

http://www.grafs.com/product/266861

plumber
10-25-2009, 04:38 PM
It is!! In my online cart!!
I'm ordering before this stuff disappears.
Thanks

plumber
10-25-2009, 04:43 PM
They have been out of stock for a while, I think the vendor at the gun show I went to last weekend cleaned them out. He had loads of odd ball Prvi brass. But unfortunatly, I can not buy brass there thanks to the convoluded laws of the Peoples Republic of Massachusetts.


BTW, is Graf's the only dealer of PPU brass?

abunaitoo
10-26-2009, 05:51 PM
I use 270 to make my 7.7.
Save the 30.06 for Garand's and Springfield's.
Also make 7.65 arg, out of 7.7.

dualsport
10-27-2009, 01:01 AM
Why didn't I think of that? I've been picking up .270 brass for years and never owned(or wanted) one.

azrednek
11-16-2009, 05:14 PM
Starmetal a few years ago at the range I saw somebody doing it that way. He was forming 765 Argie from 8X57. His reasoning was exactly as you explained. He was challenged by the range's female safety person. She thought he was loading a malfunctioning gun, loading the bolt with a cartrdige attached to it. I'm looking at some 7.7 Jap formed from 30/06 Canadian mil-surp brass on my desk and I don't see it. Could be that my Jap rifle is early production and every thing including the chamber is within specs. Your method sounds like a very good idea, especially with war time production.

StarMetal
11-16-2009, 05:20 PM
Starmetal a few years ago at the range I saw somebody doing it that way. He was forming 765 Argie from 8X57. His reasoning was exactly as you explained. He was challenged by the range's female safety person. She thought he was loading a malfunctioning gun, loading the bolt with a cartrdige attached to it. I'm looking at some 7.7 Jap formed from 30/06 Canadian mil-surp brass on my desk and I don't see it. Could be that my Jap rifle is early production and every thing including the chamber is within specs. Your method sounds like a very good idea, especially with war time production.

Well it's not my method, that is I didn't invent it, but glad you like it. My one good friend has a 7.7 that was arsenal rebuilt and the chamber is so tight that his dies won't size the cases down enough for it. Mine did. I have a 7.7 short rifle that is pretty minty and all matching. Have taken deer with it.

Joe

TAWILDCATT
11-27-2009, 09:04 PM
theres a quick way to trim brass.a harbor freight mini cut of saw.I use one and you can save the necks for scrap brass.

BIG GUN
11-28-2009, 09:49 PM
I use 8mm mauser brass to make 7.7 Jap. One pass through the die, load & fire. It's done. Then I do a final light trim to uniform the cases.

jonk
11-30-2009, 11:18 AM
I've heard about the dangers of slightly undersized 06 brass in the 7.7 chamber but it never seemed an issue. The Arisaka is a very strong action, has a gas vent shield like a Mauser, and the cupped safety design makes it even better on gas diversion than a Mauser. Do I want to see what happens when a case head fails? Well no but I think the Arisaka would handle it fine. I don't see this happening though. I use mainly military brass which is heavier to start with and the amount of bulge we're talking about is really quite minimal. Nor do I ever use max loads.

If Grafs has it back in stock, it is the easiest solution.

Another option would be to buy a few boxes of loaded PRVI ammo. Lots of places have it in stock. Aim comes to mind.