Poll - M98 rebarrel - 7x57 Mauser or 7x64 Brenneke?

[NorthIdahoDude]

Up front, this is my project and I'll likely decide whatever I decide regardless of what anyone says. I just thought we might have some fun as a group if I made a poll and discussion out of this, so... with that out of the way, here comes the rambling...

I am finally getting around to rebarreling my old Interarms Mark X Mauser (Zastava manufactured commercial M98). I was dead set on 7x57 when I started this. Besides the fact that I just plain really like the 7x57, it has some advantages in the Mauser action also - it feeds like hot butter (markedly better than anything else I've tried), and because of the significant taper on the case body (part of why it feeds so well), it will fit 5 rounds in the flush floorplate, where all the 308/30-06 based cases only fit 4). This is also gonna be about 9 lbs or so all-in, so a 7x57 would be almost unnoticable for recoil in that package (down around that of a 243 loaded hot in a Tikka Lite, maybe approaching a 6.5 Creedmoor with heavier bullets).

But, as the project progressed, I lucked into a 1:8 twist cut-rifled Benchmark blank (mostly because Brownells was sold out of #2 Shilen's the day I went to order, and the Benchmark was the closest I could find to a contour I liked in-stock), which in theory should be able to get down into 1/2 MOA or better territory if the smith does good work (and Kampfeld Custom does really, really good work), which would give it some accuracy reach beyond what a 7x57 can produce the velocity for.

So from there I started entertaining the idea of something with a bit more jam than 7x57 - but after test feeding 280, 280AI, even 284 Win - none of them fit more than 4 rounds, and and the 284 and 280AI both feed a little rough (rounds from the left side will sometimes pop out ahead of the extractor and push-feed - not the biggest deal, I don't suppose, but why a mauser if we aren't actually CRF'ing?). Straight 280 feeds fairly well (though not as nice as 7x57), but only fits 4 in the mag. So I was like "meh, back to 7x57"...

But then I remembered the 7x64 Brenneke - looked up the case dimensions, and lo and behold, it's a .470 case head and .425 at the shoulder (vs .473 and .430 at the shoulder for 7x57)... so it should both a) fit 5 in the mag, and b) feed approximately as well as the 7x57, and would add at least 100 FPS to any given bullet, while producing about the same recoil as my 7 3/4 lb 7x57 Tikka does... 175 or 162 ELD-X's would get +100 or more yards and stay within the expansion window, and I could get my preferred Accubond's out past 500 yards north of 2k FPS, which I can't do with a 7x57... Well now, that's more tempting....

I'd be getting fresh brass for whatever I go with, I have seating and neck sizing dies that'll work fine, and I have many pounds of powder in the right burn rates on-hand, etc, so the only 'extra' cost for 7x64 would be for the FL sizing die (not super expensive), and... I can get Lapua brass for 7x64, but not for 7x57... (though Norma and PPU brass both work great in my 7x57)...

And before anyone says "factory ammo" and "resale value" - a) I'm never selling this gun (sentimental), and b) My only use for factory ammo ever is to fire-form the brass for neck sizing and reloading.

Also, if anyone else has some idea for cartridge, as long as it's a) 7mm, and b) skinny enough to fit 5 rounds in the mag (or otherwise known to feed great in a Mauser CRF), I'd be open to hear it.

Anyway - that's the rambling backstory and the poll, vote and discuss.

 

[robtattoo]

Awwww maaaaannnn!!!

I was all hyped up to suggest either 9 or 9.3x57 until I read you already had the barrel.

Brenneke would absolutely get my vote. All the fun of the 7x57, with most of the kablowey of a 7mag.

 

[robtattoo]

Although 7x66 SE looks kinda interesting too

 

[NorthIdahoDude]

Although 7x66 SE looks kinda interesting too

I was about to get excited till I saw 90+ grains of H20 capacity, LOL. Early 28 Nosler, basically, ouch!

 

[NorthIdahoDude]

Awwww maaaaannnn!!!

I was all hyped up to suggest either 9 or 9.3x57 until I read you already had the barrel.

Brenneke would absolutely get my vote. All the fun of the 7x57, with most of the kablowey of a 7mag.

I'm kind of starting to lean that way. And unlike my 7x57, 30-06 brass would be easy conversion, if someday I cant get brass for it. (But really, 200 Lapua I would get day one, will probably be enough to shoot the barrel out).

 

[NorthIdahoDude]

Awwww maaaaannnn!!!

I was all hyped up to suggest either 9 or 9.3x57 until I read you already had the barrel.

Damn.. 9x57 looks fun. And I could "plink" with near-free bullets.

 

[Q_Sertorius]

Well, I love a 7x57 and that would always be my first choice.

My only experience with the 7x64 is with its rimmed cousin the 7x65R. We shot out the throat on a combination rifle in 7x65R pretty quickly. That was a serious barrel burner (probably no worse than any other 7mm magnum, but very frustrating in a rifle that couldn’t be rebarreled). Obviously, if you shoot out this barrel, you could just replace it.

 

[NorthIdahoDude]

Well, I love a 7x57 and that would always be my first choice.

My only experience with the 7x64 is with its rimmed cousin the 7x65R. We shot out the throat on a combination rifle in 7x65R pretty quickly. That was a serious barrel burner (probably no worse than any other 7mm magnum, but very frustrating in a rifle that couldn’t be rebarreled). Obviously, if you shoot out this barrel, you could just replace it.

Interesting, I wonder if there was something metallurgical going on there, as a 7x64 should be 0 practical difference from a 280 Rem (even less so in the rimmed version on a combo rilfe, that should have been low pressure stuff down aroudn 55 KPSI max - most loads are done around 48-52 kpsi for that).

But in any case, very fair point, burning more powder almost always = burning the barrel out sooner.

 

[Q_Sertorius]

Interesting, I wonder if there was something metallurgical going on there, as a 7x64 should be 0 practical difference from a 280 Rem (even less so in the rimmed version on a combo rilfe, that should have been low pressure stuff down aroudn 55 KPSI max - most loads are done around 48-52 kpsi for that).

But in any case, very fair point, burning more powder almost always = burning the barrel out sooner.

The point has been made many times around here that most folks who worry about barrel life will never burn out a barrel. And I would never let that be the sole factor in making my cartridge choice. But, based on my experience with the 7x65R in the BRNO, I'd make a rough guess of barrel life at 1000-1200 rounds. And, in the BRNO, once it was gone there was nothing we could do about it.

For me, 7x57 gets the nod because, for hunting, anything over 400 yards is long range to me. And anything over 600 yards is ELR to me. I have no practical use for a magnum rifle. And the sheer genius that went into making the 7x57 (and the cartridges based upon it, 6.5x57 and .257 Roberts) never cease to impress me.

 

[TaperPin]

7x57 gets my vote…or that fancy 6mmx7x57. A 7x57 necked down to 25 caliber would be even better!

 

[Chris in TN]

What's wrong with you people? This man clearly needs a 7x57AI.

(seriously I'd probably just go 7x57 or even 7-08, maybe 7-08ai or 6.5cm necked up to 7mm)

My grandpa used to have a sporterized Mauser - and I think it was a Spanish Mauser, I cannot remember - someone had reprofiled the old factory barrel down really light, rechambered it to 7x57AI, and added a Timney trigger and a really nice, very straight-combed walnut stock. The thing was absolutely gorgeous. I hate that I didn't make an effort to get it when he died.

I love old Mausers. Shot my old 25-06 98 most of a box of ammo, today, to turn factory ammo into fresh reloading brass.

 

[Aux Arc]

I voted for the brenneke, not for the extra power but the extra cool factor. Didn’t know lapua made brass for it but if you can find it rws does as well and so does norma.

I’ve got a 1909 argentine in 6.5-06 and it fits 5 in mag. The only mark x I’ve ever handled was 30-06 and it would also hold 5. There is some variation in followers between guns so I did have to swap followers around until I found one that worked with my 6.5-06 and that may be something you’re not interested but just wanted you to be aware that it is possible.

However, the brenneke rounds are super cool and like you mentioned with the taper they should fit and feed great without modification. Definitely post some pics of the result.

 

[NorthIdahoDude]

The point has been made many times around here that most folks who worry about barrel life will never burn out a barrel. And I would never let that be the sole factor in making my cartridge choice. But, based on my experience with the 7x65R in the BRNO, I'd make a rough guess of barrel life at 1000-1200 rounds. And, in the BRNO, once it was gone there was nothing we could do about it.

For me, 7x57 gets the nod because, for hunting, anything over 400 yards is long range to me. And anything over 600 yards is ELR to me. I have no practical use for a magnum rifle. And the sheer genius that went into making the 7x57 (and the cartridges based upon it, 6.5x57 and .257 Roberts) never cease to impress me.

I've only ever burnt out one barrel in my time (which was a Tikka T3 308 barrel). Took me somewhere around 5-6k rounds to do it, and even after it was 'gone', it still would have made most people pretty happy at 1.5-1.6 MOA.

I would also self-confess, I am pretty ridiculous in terms of how much I over-prepare to shoot a long ways, LOL. I live/hunt these last 20+ years in the land of thick trees and steep mountains (north Idaho/south BC), and long shot opportunities are few and far between out here (though there are a few places they can happen). The longest shot I've ever actually taken was around 300 yards, and that's not because I pass up shots longer than that because I don't think I can make em, I have historically passed on all those because of reasons like "I'm 100% not down to pack an elk out from the other side of this steep ass nasty valley/canyon, in the dark, by myself" kind of reasons, LOL.

But if we were going to have a rational conversation, we wouldn't be talking about guns and ammo, would we? hahahah

 

[NorthIdahoDude]

7x57 gets my vote…or that fancy 6mmx7x57. A 7x57 necked down to 25 caliber would be even better!

If bullet makers made bullets that really made me happy in .257, a 257 Roberts would 100% be in my future, LOL. Even 6.5 - which does have a fairly nice selection of bulelts, to be fair, but 7mm just has the better and broader selection of bullets that @NorthIdahoDude would be happy take hunting.

 

[NorthIdahoDude]

What's wrong with you people? This man clearly needs a 7x57AI.

(seriously I'd probably just go 7x57 or even 7-08, maybe 7-08ai or 6.5cm necked up to 7mm)

My grandpa used to have a sporterized Mauser - and I think it was a Spanish Mauser, I cannot remember - someone had reprofiled the old factory barrel down really light, rechambered it to 7x57AI, and added a Timney trigger and a really nice, very straight-combed walnut stock. The thing was absolutely gorgeous. I hate that I didn't make an effort to get it when he died.

I love old Mausers. Shot my old 25-06 98 most of a box of ammo, today, to turn factory ammo into fresh reloading brass.

About the only thing stopping me from a 7x57 AI is the fact I can fit 5 x 7x57 in the mag, but only 4 x the AI version. Otherwise, that'd put me at around 65.5 grains of H20 capacity (I get 61 in plain jane PPU and Norma 7x57 brass), and that would do everything a 284 Win would do, and be so close to a 280 or 7x64, I'd not care in the slighest about the difference.

 

[Q_Sertorius]

If bullet makers made bullets that really made me happy in .257, a 257 Roberts would 100% be in my future, LOL. Even 6.5 - which does have a fairly nice selection of bulelts, to be fair, but 7mm just has the better and broader selection of bullets that @NorthIdahoDude would be happy take hunting.

I won’t try to draw you too far off topic, but my winter’s project is working up a .25-06 load for the 134-grain ELDM or 138-grain Berger. And I’ve killed more deer with 117- or 120-grain .257 bullets than all other calibers combined. As it happens, the only other rifle I have ever burned out the barrel on was my .25-06.