7x57 barrel question..........

[3006guns]

Quite a few years ago a dear friend passed away and left me about 16-17 Mauser 7mm carbine barrels as part of his estate. These are original Mauser products pulled from guns (wrench marks) and are about 19" long. I picked the best looking one (many were externally pitted) and headspaced it into a spare Yugo M48 receiver. Only after I was satisfied with the headspacing did I think to check the bore size.

Yesterday I slugged the bore and the groove diameter was .288-.289 as close as I could measure....considerably more than the .284 usually given for the 7x57. I then placed a cartridge, bullet first, in the muzzle.........went right to the case mouth easily. Uh oh. Others in the lot were somewhat better, measuring .288 consistently but the rifling is somewhat "light" in all of them. On top of all this, the bores on the ones I picked out actually have some shine to them. I have a quantity of military j-words that I can use.

Somebody PLEASE pat me on the back....tell me these dimensions are somewhat normal in the military barrels and that I won't have to pull the barrel off and do the whole thing over again. It looks so cute......gonna be loud too!

[StarMetal]

Quite a few years ago a dear friend passed away and left me about 16-17 Mauser7mm carbine barrels as part of his estate. These are original Mauser products pulled from guns (wrench marks) and are about 19" long. I picked the best looking one (many were externally pitted) and headspaced it into a spare Yugo M48 receiver. Only after I was satisfied with the headspacing did think to check the bore size.

Yesterday I slugged the bore and the groove diameter was .288-.289 as close as I could measure....considerably more than the .284 usually given for the 7x57. I then placed a cartridge, bullet first, in the muzzel.........went right to the case mouth easily. Uh oh. Others in the lot were somewhat better, measuring .288 consistently. I have a quantity of military j-words that I can use.

Somebody PLEASE pat me on the back....tell me these dimensions are somewhat normal in the military barrels and that I won't have to pull the barrel off and do the whole thing over again. It looks so cute......gonna be loud too!

Those are normal. A good while back I bought a brand new 19 inch carbine barrel from Gun Parts Co. I was heart broken when it was .288. Those old Mauser barrels weren't cut to today's .284 groove.

Joe

[runfiverun]

i got a beautiful long bbl'd spanish mage 7x57 problem was even with j-words i had to sneak up within 25 yds to shoot a target, tried longer bullets it was somewhat better.
but...
just like everything else size of the bore no big deal it's the size of the bullet/boolit going through it that does.

[StarMetal]

i got a beautiful long bbl'd spanish mage 7x57 problem was even with j-words i had to sneak up within 25 yds to shoot a target, tried longer bullets it was somewhat better.
but...
just like everything else size of the bore no big deal it's the size of the bullet/boolit going through it that does.


Which means you have to get a special mould made for it or hope a current cast fast enough.

Joe

[3006guns]

Thanks StarMetal............that's a relief! I had a feeling that might be the case, but sometimes a guy just needs a little reassurance.

[pietro]

You've discovered one of the reasons, besides rebarreling to a diferent caliber, that those barrels got pulled and put in a scrounge box.

Since the barrel's already installed, I'd give it a shooting test, though.

.

[Bret4207]

I have a ratty old '93 Mauser in 7x57 that shouldn't shoot at all, but it does. My barrel isn't as bad as yours I admit. Yours' sound like a perfect candidate for a paper patched boolit.

[NickSS]

Years ago I bought about 5000 military 7 mm bullets (FMJBT) and found that I was getting pressure signs with a starting load in a Rugger 77 rifle I was shooting them in. I got them measured (this was before I owned a micrometer) and found that they were all .287 dia. I used them all up shooting lighter loads in my Ruger and several 95 mousers I had.

[3006guns]

What to do, what to do???

Well, for starters I'll finish building the carbine and go shoot it. No need to assume the worst until it happens. I'll chuck it in the lathe and clean the crown up a bit too. In any case, I selected another barrel that's a bit "tighter" and I'll swap it out if necessary. This may end up being a winter project.

After perusing the internet out of curiosity, I discovered that all those nice old surplus barrels that used to be out there are just plain gone! Whadjoo guys do...buy 'em all out from under me?

Thanks for all the suggestions and have a great day.

[Buckshot]

...............Back about the early-mid '90's RSI was selling a bunch of Brazilian M98-08's for $89.

http://www.fototime.com/93DF7AC146DC001/standard.jpghttp://www.fototime.com/FAE697FAF99DE7A/standard.jpg http://www.fototime.com/D3A7BD464EE81B6/standard.jpg

I ordered 3 of'em. This was one. One, mechaniclly as nice was in a Beech or Birch stock and the other was also in a nice (not as nice as this one!) walnut stock, but the action was stained and the bore was a bit weak. At the same time they had brand new (NOS) FN made 19" barrels for the M1922 Brazilian short rifles for $19. These were in the white, threaded and chambered.

I used one of the barrels and the Beech stocked rifle to make a 7x57 sporter for my daughter. Another barrel was used to replace a shot out one on a M95 Chilean carbine. I sold the 3rd barrel just a couple years ago. That other walnut stocked rifle I cleaned up and sold it to a pal for $125, and it ended up shooting very well.

...............Buckshot

[mooman76]

I picked on up that measured .289 and could not get it to shoot even with jacketed at 25y could rarely hit paper. I had this caliber stuck in my head so as a glutton for punishment got another. It looked better but still measured big at .287. Fortunately with a little work I got it to shoot pretty good.

[3006guns]

Buckshot, that is one gorgeous rifle. I only have one in that condition as all of mine are shooters.

Interesting side note: Mauser routinely sent stocks like that out on their foreign contract guns as the German army would only accept straight grained wood. I learned this from an old aquaintence while we were cleaning up his latest batch purchased back around 1985 or so. After the cosmo and accumulated crud was cleaned off, I was astonished to see the most beautiful tiger striping I had ever laid eyes on. Almost every one of them was like that.

I wish now I had more money in those days.....................sigh.