OT-.257 Roberts question(s)-found rifle, more questions

[awp101]

I understand the .257 Roberts is based on the 7x57 case. Would a previously sporterized Mauser just need a rebarrel and headspacing?

What if the aforementioned Mauser was already redone in .308? Is there a difference in case head sizes between the 7x57/.257 Roberts/.308?

I can't access any of my usual sources of info here at work and I think bringing copies of Cartridges of the World and P.O. Ackley's works might get me asked a few questions...

Thanks!

[TedH]

I used a 95 Mauser in 7x57 for just a project. New 257 Roberts barrel/headspace, lightweight synthetic stock, and new safety/bolt shroud. Used a 20" light contour Adams & Bennet barrel from Midway. It shoots great and makes a dandy light deer rifle.

[Rusty]

Wouldn't you need a new extractor as well? I think the head would be a different size.

[model55]

No difference -rebarrel, headspace and go shooting.

[awp101]

OK, even if the bolt is modified for .308? Or would the bolt face have been modified from it's original 7x57 for .308?

[mescalero1]

There was no difference in the parent cases as far as diameter goes.

[Bruce]

My local shop has a Remington pump in 257 if anyone is interested. It is an odd ball by our local standards and will probably be there awhile.

[awp101]

OK, I'm a little slow sometimes (all right, usually ) and when I'm putting my face behind the bolt I want to be 100% sure things are kosher. Lots of things would improve my looks. A bolt sticking out of my eye isn't one of them...

I got my copy of CotW and pulled the following data:

-------------------base dia ---- rim dia ---- rim thickness ----- case length ----- COAL
.257 Roberts ------- .468 ----- .473 ---------- .045 ----------------- 2.23 ---------- 2.74

.308 --------------- .470 ------- .470 ----------- .049 ---------------- 2.01 ---------- 2.75

7x57 ---------------- .470 ------- .474 ---------- .055 ---------------- 2.23 ----------- 3.06

7.9x57/8mm ---------- .469 ------- .473 --------- --- --------------- 2.24 ------------ 3.17

All I know right now is that it is a sporterized Mauser 98 that has been converted to .308 as stamped on the barrel and it's not a factory job. I do not know if it is a large or small ring and the markings are covered up by a scope mount. That's why I included the 7.9/8mm data.

Having said/typed all of that, does it still seem to be a straight rebarrel and headspace or am I looking at a deeper project now?

There's a bunch of "if's" in this project though. IF it's still there when I go back, IF it's just a barrel swap and not a deeper project that includes fiddling with feed issues, IF a 'smith doesn't want an arm and a leg plus a 14 month wait, IF my ADD doesn't kick in and tell me I want some other whiz-bang project instead, etc, yadayadayada .

[mescalero1]

AWP101,
PROCEED,
you are splitting hairs, it will work
I have a Mauser 257 Roberts
The only bad thing that will happen is you will neglect your other guns if you do a decent job and it shoots.

[2ndovc]

You could get yourself a nice old Arisaka and be just like me


jb

[awp101]

You could get yourself a nice old Arisaka and be just like me


jb

Thought about it as the shop has a sporterized Arisaka as well. No idea how long ago it was done but it wears a J C Penney branded scope...

[awp101]

AWP101,
PROCEED,
you are splitting hairs, it will work

Good to know my paranoia has some usefulness...

[piller]

Just because you are paranoid, it doesn't mean that someone isn't out to get you. Since that rifle is going to be used, why not make sure it is perfect to start with.

[marlin shooter]

My local shop has a Remington pump in 257 if anyone is interested. It is an odd ball by our local standards and will probably be there awhile.

Bruce
I sent you a PM
Karl

[Bruce]

Karl,

Sent you a few back.

Bruce

[awp101]

Found a K88 today, seller said it was .257 Roberts. Very rushed pics, sorry. I did notice that the barrel isn't stamped .257 anywhere. Anyone recognize the front sight or what it may say?

[2ndovc]

Hey that's sharp!!!

Let me know when you get tired of it!!!



jb

[awp101]

Hey that's sharp!!!

Let me know when you get tired of it!!!

I'm not 100% on this one. Before buying it, I talked to a guy I know about it. His Dad was a gunsmith, he took over the business when his Dad retired but I don't think he 'smiths anymore. He said it should be OK as long as I don't hot rod it, which I don't do anyway. If I need more power, I go up in caliber.

If nothing else, I figure at least I got a barrel out of the deal or another project for a different caliber.

[2ndovc]

Hey that's sharp!!!

Let me know when you get tired of it!!!

I'm not 100% on this one. Before buying it, I talked to a guy I know about it. His Dad was a gunsmith, he took over the business when his Dad retired but I don't think he 'smiths anymore. He said it should be OK as long as I don't hot rod it, which I don't do anyway. If I need more power, I go up in caliber.

If nothing else, I figure at least I got a barrel out of the deal or another project for a different caliber.

Don't part that one out. It's a leftover from an era where men made what they wanted from what they
had.

I'm serious. If you decide you don't want it let me know what you want for it.
I have a soft spot for mil. sporters from that era.


jason

[mescalero1]

2ndovc,
Will that hold the pressure?
I think it will have to be loaded with stripper clips?
that front sight looks like any number of standard European front sights.

[Wind]

Hey there awp101 - I'm a Mauser 98 fan. They can be loaded individually. One of mine is a .257 Ackley Improved. Jaeger barrel. Shoots under one minute of angle at 300 yards. Your front sight may or may not be European. Here is a similar Lyman. They were made to slip over the end of a barrel often seen on military conversions. I gave a friend my grandads Springfield sporter recently and it had one on it. This one came off another Mauser in 30-06 when I put the scope on it. Hope this helps. Wind

[awp101]

Thanks Wind. I need to look closer, but someone on another board thinks the front sight says "Safari".

[awp101]

OK, here's what I've found and heard so far...

From the style of stock and checkering pattern, I'm going to guess that this is an American made sporter.
The soldered on front sight band is I think, also an older American design as made by several makers.

The Model 88 was very popular with German custom rifle builders up to WWII because of the lightness and smooth action, but some American makers of the 1930's and even after WWII used it, mostly as a "nostalgia" European look build.
The 88 is not a really strong action, so don't push it. The .257 Roberts was popular up through the 1960's and is a necked down 7mm Mauser. Stick with those pressures and you should be Okay, AS LONG as a gunsmith looks it over and checks for proper head space and any signs of hot-loading.

This is the part that's confusing me. Everything I've run across shows the 88s chambered in 7.92 which I've always seen rounded up to 8mm Mauser.

Per the SAAMI pressure table here: http://www.leverguns.com/articles/saami_pressures.htm 8mm Mauser is listed at 35,000 PSI and the 7mm Mauser is 51,000 PSI. .257 Roberts is listed at 54,000 PSI (58,000 for the +P loadings which I'm not interested in). So by all indications I should be loading them no more than 35,000 PSI, correct? What kind of performance are we looking at for those pressures? (I'm about to get into reloading so I have to figure out how to load down to those pressures...)

The 8mm is kept low (35,000 psi) to prevent a .318" bore gun from blowing up when you push a .323" bullet down it. .318" was the original K88 bore.

You can probably keep to 7mm specs and be safe. I.E. 45-50 kpsi.

The part regarding low SAAMI pressure specs makes sense as many .45-70 loads aren't much above Trapdoor Springfield pressures for the same reason.

Does anyone see any flaws in that logic train up there?

I plan on separating the metal from the wood tomorrow, I'll see if the bbl was stamped below the wood for some reason. I know it will chamber a .257 Bob because I tried it last night (VERY carefully) just to see. Doesn't mean much I suppose but there you go. If it's not stamped and it does prove to be a proper .257 barrel, I WILL stamp it.

I don't remember the trick to check headspace without gauges. I remember it involves masking tape or scotch tape but I also need to find the headspace specs. Anyone have a lead there?

My 'smith is closed Sun-Mon so it will be Tuesday before I can see if he has headspace guages for this and can do a chamber cast. If he doesn't have the guages, I need the info for the tape version. If he wants too much for the casting or can't get to it in a reasonable time, I think a buddy of mine still has some Cerrosafe. If so, we'll cast it when he comes by to help me set up my reloading bench.

And it turns out BOTH boxes of factory .257 I bought from another table are +P loads. The price tag was covering the +P on both boxes and I didn't think to look at the OTHER end of the boxes until I got home and started reading. So now I suppose the best thing to do would be to pull the bullets, dump the powder and work them up fresh.

This is a Commission 88 variant. I had never heard of the carbine version (more proof that I'm not a know-it-all ) until Saturday so I didn't know they were part of the same family. What I know about 98s wouldn't fill a thimble and I know even less about 88s of any flavor.