270-7.7 jap

[ubetcha]

At my last Silhouette match, our match director picked up some 270 win brass and said to me to use it to make my 7.7x58 Jap loads. I know that 30-06 and 8mm Mauser brass will work and that 8mm requires less work, I have not heard about using 270 brass. Even though the 30-06 was the parent case for the 270, I have not taken the time to compare the two.
Any thoughts

[EDG]

I have used .270 brass to make both 8X57 and 7.65 Mauser so it will make 7.7 Jap too.

The 8X57 is the same length and has a larger case mouth then the 7.7 round.

[ubetcha]

Thanks EDG. When I get back to my loading bench, I will try running a 270 through the 7.7 sizing dies and see what happens.

[nagantguy]

Wondering what to do with these range pick up 270's. Thanks for the tip

[dualsport]

I never leave 'scrap' brass behind! Pick it all up, regardless. I have several RCBS 'form and trim' dies and use them with otherwise useless .270 (wouldn't have one if it was free won't kill anything) brass to make several types of old military brass. The RCBS dies are fairly inexpensive and very easy to use. After a run through the die it's trimmed in place in the die with a hacksaw and file, then cleaned up and put through a normal full length die for insurance.

[jimb16]

Just a suggestion, anneal the case mouths before you run them through the resizer. That much stretching can cause the case mouth to crack if the brass is too hard. Then anneal them again after you expand the case mouth. Remember too that you will be fireforming the case with your first shot so check the case dimentions after the first firing and retrim as needed. Yes, I've made 7.7 from .270 cases too.

[azrednek]

Thanks EDG. When I get back to my loading bench, I will try running a 270 through the 7.7 sizing dies and see what happens.

I've done plenty into 7.7 and most other Mauser calibers. I strongly suggest you trim them just a tad to long before re-forming. Trim away as much of the neck as possible. I found STP to be the best lube for re-forming although I'm sure others will disagree.

I did 7.7 by starting out with a 7.65 Argie trim and form die backed out enough I didn't cut it to short.

[leadman]

I have made many others cartridges cases based on the 30-06. No problem with not annealing before sizing.
The 8X57 is just a tad shorter then the Jap 7.7X58 but it is the easiest to reform for the jap. The 7X57 has a longer neck and is shorter to the shoulder but does fireform pretty well as the extractor will (should) hold the case against the bolt face.
I have used 30-06 also and did the same as azrednek and started with my 7.65 Arg. trim die.

[azrednek]

About 30+ years ago I lucked into several hundred Canadian 30/06 blanks. After punching out the disc, dumping the powder then de-priming the corrosive primer. I re-formed them into many different calibers. 7.7 and 8X57 were the easiest to do. I was having trouble fire-forming the brass. Being long before there was an internet. I wrote Speer Bullets. Speer suggested I fire-form at 90% of max. Did it and there was no looking back, a perfectly formed case after the initial firing. I never fooled much with annealing. I had enough brass on hand that anything suspicious looking was tossed. I did once anneal about 100 765 Argies and in all honesty never saw an improvement.

[UBER7MM]

I've made 270 brass into 7x57 and 30'06 into 8x57. For 7.7x58 the closer the size to the target case, i.e., starting with 8x57, the less chance of splitting the mouth you might have. 270 cases should work however. Shoot a reduced cast loads to fire form the cases for the first loadings.

I use brass black to mark the rims for safety. Anything from my box that has a blackened rim, isn't what the case head stamp says. A 7x57 cartridge in a 270 Win or a 8x57 in a 30'06 would be a real problem.

[azrednek]

I use brass black to mark the rims for safety. Anything from my box that has a blackened rim, isn't what the case head stamp says. A 7x57 cartridge in a 270 Win or a 8x57 in a 30'06 would be a real problem.

I never thought about brass black. I started using colored marking pens after somehow but fortunately harmlessly shot a 7.7 in a 8MM Mauser.

[dualsport]

I take a Dremel tool and very carefully grind off the original caliber markings. Just barely. Don't want to weaken the case.

[Eddie2002]

The 270 brass is a lot longer than the 7.7 Jap and will need a good bit trimmed off, I've a mini lathe that does fast and accurate work. I've resized 270 for my two Arisakas from range brass with no problems. Any of the 30-06 family of brass will work for full loads just expect a little bulge in the case as it fire forms to the chamber. I anneal the neck of all the brass I'm resizing just to make it easier to work. I have also resized 280 brass to 7.7 and had a little problem with chambering because the brass was too thick at the neck. I only shoot 30-06 and 7.7 Jap so it is easy to keep the brass separate but I do mark the base with a sharpie just to keep track of what is what.

[Multigunner]

7.92 X57 is close enough to the 7.7 that it will fit in a 7.7 if the chamber and headspace is loose.A gunsmith who visits another board told of accidentally firing a 7.92 in a 7.7 and blowing it up.Since the Chinese rebored or rebarreled capture Arisakas to 7.92 iwould pay to be absolutely sure of the chambering. A 7.92 might fit the chamber of a 7.7 but the neck clearance if any would be too little to let the bullet release cleanly not to mention the tight bullet to throat and bore fit.

[EDG]

You will need a tapered expander.
Using a trim die is also a good thing. When you size and cut the case off using a trim die you have less neck to expand.
You do not have to find a rare and expensive 7.7 trim die either. You can use a .308 Win die set to leave the shoulder length a little long. You might have to cut off and them trim after FL sizing but you can make good brass.

Thanks EDG. When I get back to my loading bench, I will try running a 270 through the 7.7 sizing dies and see what happens.

[leadman]

The Arisaka type 99s were chambered to several cartridges. 8 X 57, 7 X 57, 30-06, and 7.7 X 58. The 30-06 guns were conversions done by Thialand? after WWII as we were supplying them with goods.

The shoulder on the 8X57 is just slightly shorter, along with the neck, than the 7.7 X 58. So close that when I fire the 8X57 in my 3 type 99s the is no case stretch marks. The neck is actually made smaller but is not a problem as all of my 99s have plenty of neck clearance in the chamber.

[TCLouis]

Some of my original 7.7X58 is from 30-06, but then I realized there was no use for 270 brass and the last 200 were formed from 270.

[Mauser48]

https://m.youtube.com/watch?v=9N2XquAX57o

[mace2364]

I use .270 brass to make 7.7, since I don't own a .270. I just trim it and size it with the 7.7 die. I haven't had any issues yet. I do use imperial sizing wax for this sort of thing.