Gents:

Would a set back and rechamber be enough for rechambering a 7x57 to a 7x64-- or are there problems waiting?

Thanks!

I think it depends on your barrel. This isn't a run a reamer through your barrel. THe 7x64 won't quite clean up a 7x57 chamber, it will always leave a ring on your brass.

The right way is to set the barrel back one thread, and reachamber it.

If you are in the US it makes more sense to go to .280 Remington.

It is a standard mauser mag and I would like a bit more zip without altering the mag or ramp.

This is deceptive it looks like it will clean up, the problem area is isn't the shoulder, its the cartridge neck. The 7x57 has a straight neck, and the 7x64 has a tapered neck. Right at the end of the 7x57 chambering is just under 1/2 way down the 7x64 ( 7x64 is longer ). The OD of the mauser round at the throat is larger than the tappered neck of the 7x64., where the mauser round ends. If you are willing to have your gunsmith run a straight taper reamer through the neck of the 7x64 and oversize the neck this will work, bad news is the 7x64 ends up with a oversized throat ( bad ).

The critical dimensions are just .0001-.0002" off, not much but it will leave a nasty ring on the throat of the 7x64 brass.

Are you handloading your 7x57? If not that is the quickest easiest way to get "ZIP" into your 7x57.

I wouldn't bother rechambering. What i would do is rebarrel to 280 Remington if you want more punch than the 7X57 offers.

AD

While re-barreling is probably your best bet, a 7x57 can be re-chambered to .280 Rem. as my experience with the following rifle demonstrates.

Some years ago, I hapened to find a Brno 21H "roundbolt" long barrel in 7x57; the stock was a wreck, but, the metal was very nice with a pristine bore. This is pretty typical of hunting rifles used in western Canada back in the day. I completely re-did the stock with Acra-Glas Gel and Dem-Bart oil and shot the rifle which really rocked. However, I have two other choice 7x57s and had no .280 on hand despite having dies and about 400 brass.

So, against the advice of one gunsmith while acting on information from the late Finn Aagaard, I had this re-chambered to .280 Rem. The reamer barely touched the chamber walls at the rear of the case and there is a faint ring on the neck of the fired rounds, however, a Nosler PT. Gold Molyfree over 59 grs. IMR-7828 goes almost 2800 fps-mv, this with mag. primer in Norma brass and usually shoots about .6" at 100. I consider this very acceptable from a 51 year old barrel on a rifle that has been used hard and so it can be done and done well.

I might add that I would NEVER modify one of these fabulous rifles unless it was a beater as this one was and I did this as I had the dies, etc. for the .280 on hand but only one set of dies and little brass for 7mm Mauser. This was my cheapest option and it worked so well that I put a Mod. 70 safety, a Dayton-Traister trigger and a Zeiss 4x on this rifle and will add a High-Tech stock when I have more cash to make up a superb mountain rifle, one gains about 125 fps over the 7x57 from this conversion.

Allen,

I was wanting to suggest the 280, but this has a similar problem. The 7x57 has a neck diameter of .321" vrs .315 on the 280, and .305 on the 7x64. The ring would still be there just not a deep. The case length on the 7x57 is 2.24" and the 280 is 2.54" vrs the 7x64 at 2.51", that still puts a ring about .25" down the neck that isn't going to clean up.

The best route is to set the barrel back, if you don't want to do that replace the barrel.

If you really must keep the barrel and don't want to set it back, look at the 7x57 AI, close to the 280 or the 7x64 in performance.

Me I would work on better handloads on the 7x57.

Kutenay,

I think everyone here knows I am a 7mm nut. After many years of fiddling with 7's, I am under the impression that only 1 of the mags really cleans up the the 7x57 chamber, thats the 7x61 Sharpe and Hart, it has a neck diameter of .320" and depending on the 7x57 this will be either .320 or .321. All of the other 7mm's are .312-.315.

Kutenay,

How was your brass life on the 280 conversion did the ring start a seperation after a couple of firings?

quote:

Me I would work on better handloads on the 7x57.

You got it....the 7 X 57 is no slouch with proper handloads.

Your points are well taken and my situation is due to the fact that one cannot set back these barrels due to the tiny chamber re-inforcement on them. So, this was a simply a way to increase the power of my rifle and use up a bunch of stuff so that I did not have to spring for more dies, etc. Even after selling/giving away several rifles recently, I still have 30 and I am trying to customize what I have to meet all my needs rather than buy more...not easy for a gunwhacko!

As to brass life, I have so much brass and ammo that I never use a case more than three times for hunting loads and five times for practice loads. I will never use what I now have, so, I don't worry about it. This rifle is for hunting late season bucks in the deep snow at home in the Kootenays due to it's superb action and light overall weight compared to my Mod. 70s, FN, Dakota, ZG-47 and so on. I ain't young anymore and I only enjoy backpack hunting as I hate quads and horses are too much hassle; you know the area and conditions so I think that you would like this little rifle.

Besides, if a person can't kill meat animals with a .280 with good handloads, then said person should take up knitting or macrame, IMHO.
I knew about the 7x61 S&H and almost snagged a classic style Dumoulin in that round years ago, but, doing a belted round on a 21H is very tricky and I wouldn't do it. WTF, if you use sane loads, a tiny ring on the neck of your cases is not a big deal.

Schromf:
Are you saying the chamber will clean up with a set-back? I have no issue at all with setting the barrel back a thread or two. Was worried that even after a set-back there might be dimensional problems of some sort.

Gents:
I don't want to rebarrel it--good barrel--have 7x57s and 280s on hand and do handload all. I know what one can get out of a 7x57

I'm reasonably sure the OAL of the 280 will require additional action work and do not want to alter the action (G33/40).

I thought about the 7x57 AI as well. Do currently have and have had other AIs and like fireforming about as much as I like case trimming but 4 grains is 4 grains, I guess.

Kutenay,

Actually other than the odd grizzly running around on my side of the border there isn't anything running around the Kootenays I can't cleanly take with a 7x57. Maybe not the best elk round, but if I keep my shots to under 200 yards, and use heavier bullets it will and has got the job done. In our neck of the woods all the range limitation means is I don't shoot across large clearcuts, and these big clearcuts are getting scarcer, most of these cuts in the last 10 years are smaller, its taking around 8-9 years once they decide to cut an area, to fight with the enviromentalists in court on every cutting operation nowdays. So the real long shoots are scarce and becoming a thing of the past.

quote:

Originally posted by tomk:

Would a set back and rechamber be enough for rechambering a 7x57 to a 7x64-- or are there problems waiting?

As others here have said, in effect, why would you want to do this? The 7x57 is a terrific cartridge in itself. If your rifle is a good one and shoots well, why try to gild the lily?

My G33/40 is a 7x57 also, mine is a Douglas XX it think. I would never consider rechambering mine, only if this barrel gets shot out will I be fiddling with my barrel, and that would be to have aother 7x57 barrel same length, twist, and contour back on it. This my favorite rifle of a whole rack full of stuff to hunt with, light recoil, great round that is just great for the my hunting conditions. I have to think hard about taking any other rifle into the woods, its always at camp even if I am not packing it, as my #1 backup rifle.

OK, I repent and promise to never consider this again.

Would it be OK to present this question in theory?

I know you're not doing it for extended range but never the less I ran the figures

Given a 140gr partition and a kill zone of 6" diameter then you go from:-

7x57 MV 2,900fps seated calibre deep and within CIP pressures. Zero 243yds, 3" high at 136yds and 3" low at 284yards ie PBR of 284yards.

7x64 MV 3,050fps (seated to CIP 3.3" as mag length otherwise is an issue but running at the higher 7x64 CIP pressure)Zero 253yds, 3" height at 142 yds and 3" low at 297yds ie PBR of 297yds.

Wind drift at the extreme range is identical for each.

Myself the only reason I would go 7x64 would be ammunition availability in Europe. This would be double edged sword as 7x64 is very rare in the UK while 7x57 is relatively easy to get hold of.

Tomk,

If you send me an e-mail I did a dirty drawing illustrating the problem. It not to scale but you can see what the problem is.

If you want it just let me know.

PM sent, thanks Schromf

Thanks 1894, for the data. You're right it isn't for the range, just fun and working with a "new" cartridge...this baby is staying and I have a 36 Mex in 7x57 that I like, which fills the 7x57 slot pretty well.

Noted on the pressure.

Well

Why not keep the 7X57 and build a 7X64? Problems with 280 is slow factory ammo, caliber is not very popular. Remington goofed up the cartridge right from start. In US 270 win is eating 280 rem's lunch. In Europe 280 have really never made it because of stiff competition from 270, 7X64 and 7mm mag.

7X64 is proofed to higher pressure and has straighter case, slightly more case volume(academic difference) Factory loads are plenty. 7X64 is pretty much Europe's 3006.

Personally I think 150-175 grain bullets are best in 7X64 or 280.

Cheers
/JOHAN

I'll keep the 7x57 and re-think the action work later.

The 280 is pretty popular around here, Johan...

The info ala Schromf didn't brighten the picture and it really comes down to another fire forming job, which I didn't realize till I gandered the body dimensions.

I certainly appreciate the information.

quote:

Originally posted by JOHAN:

Why not keep the 7X57 and build a 7X64? Problems with 280 is slow factory ammo, caliber is not very popular.

What you say about the 280 vs. the 7x64 is true, but in North America the 7x64 is rare. So, while the 7x64 makes a lot of sense in Europe, the 280 makes much more sense in North America.

If you handload you can overcome the problem that the 280 is underloaded in factory ammo.

I have a CZ550 in 7x64 that was rechambered from 7x57. It's been a while, but I believe the 'smith set the bbl back, rechambered and that was all.

Yes, you need to set the barrel back a turn...but a better solution is to have an 06 length magazine and a throat that will fit a 175 gr. Nosler seated half way to the cannalure..ala the Brno m-21 and 22...then you can easily duplicate the 7x64 and the 260 Remingtons that have a std. throat...Another option is the 7x57 Imp. a super round and add a long throat and magazine to it...

Correction: 280 not 260 Rem.

I have had both, what one does the other will do as well...except for cases and factory ammo. Advantage Mauser. OTOH, they are both older than me, so that's the basis for a good rifle regardless.

quote:

Besides, if a person can't kill meat animals with a .280 with good handloads, then said person should take up knitting or macrame, IMHO.

Went back to your post and reread it, I kinda have that same impression.

A G33/40 would make a sweet 280. Wish I could find one for sale actually I would talk myself into another gun project.

A far better option is the Brnos that Ray and I both love so much and they are out there. I honestly cannot think of another action that I consider equal for standard rounds and when done up right, most of which you can do yourself quite easily, this is probably the finest no-bullshit hunting rifle ever made. I have three now and keep my eye open for beaters to build on, if I find something I can't use, I will let you know as importing one from B.C. to Idaho is time-consuming but not impossible.

quote:

A far better option is the Brnos that Ray and I both love so much and they are out there.

I like commercial actions better in almost every manufacturers case. It's why I like FN's so much over military mausers. I was and have been on the hunt for a decent FN for a couple of weeks, I know where to get a mag action, but I really didn't have another mag in mind, but a nice old 06 that I could rebarrel to a 280 would make me happy.

Schromf: There is a gentleman with a new action for sale in the AR Classifieds. It is not a mag action, but one with the magazine block for a .308 or there abouts and the block can be removed for a .30/06 or so. You might want to check it out. Tom Purdom

Thanks, I'll go looking.

7x57:

Thanks a lot I would have missed that!!!!