The 35 XCB, the sledgehammer I've been waiting for

[Bjornb]

I received my first rifle chambered in 35 XCB around the middle of May, and not until now do I feel confident writing about it. Make no mistake: The cartridge is clearly a premium hunting chambering, holding slightly more powder than a .358 Winchester while sporting the long neck of a .35 Whelen.


My rifle is a sporter built on an FN Mauser action, with a 26" Douglas barrel and a McMillan Hunter stock. A Timney trigger and a Nikon scope round out the package:


I loaded and shot a few rounds rather randomly, trying to get a feel for the rifle. I even loaded up some 358009s, which had to be nose-sized (Buckshot nose sizer) so I could seat the bullet in the cartridge neck. These are samples from my first range day:

Nothing spectacular, but the gun clearly wanted to shoot. I re-grouped and tried again:

Not what I had dreamed about, and both Goodsteel and I were scratching our heads. I shipped the rifle back to Tim, and he is in the process of cutting an inch off the barrel to see if that will change the harmonics and improve accuracy. Funny thing is, before sending the rifle to me Goodsteel stabbed 7 shots in the same hole, and we were convinced we had a perfect rifle. I still think we have a perfect rifle; she just may need a little tweaking before I take her moose hunting.

Fast forward, Tim recently sent me his "Felix" target rifle so I could keep shooting (Bertha is being re-stocked and that's a time-consuming affair). He also sent along 3 barrels: A 30 inch Shilen in 35 XCB, a 26 inch Shilen in 30-06 XCB, and his own Brux in 30 XCB.

I shot the 35 XCB barrel today, had time for a short range trip and made 10 rounds each with the NOE 35 XCB bullet and the Barnes 225 X-bullet in .358. Both were loaded over 50 grains IMR4320. The load was arrived at by interpolating loads from the Sierra manual (358 Win, 35 Whelen, 35 Rem Mag). The results were encouraging, even though they need more work. Speeds were pretty good:

Notice the first shot with jacketed (100 fps slower than the rest). Excluding this shot everything else showed really good ES and SD.

I was especially happy with the NOE bullet at speeds exceeding 2500 fps.
This gave me something to build on.

[taco650]

I realize you're searching for the best groups possible but if the groups don't get better, your moose will still be DEAD!

[bearcove]

Yep dead moose. 2-3 MOA is plenty good for moose where I've hunted them.

[velocette]

A dead moose is NOT good enough. The dead moose must be perforated in precisely the correct location with a projectile of the correct diameter, weight and speed.
Only then will the (properly terminated) dead moose be good enough.
Bjornb; Enjoy your vacation!

[Yodogsandman]

Bjornb, Sure hope you can show us how that 35XCB does on a monster moose! Good luck!

[MBTcustom]

A dead moose is NOT good enough. The dead moose must be perforated in precisely the correct location with a projectile of the correct diameter, weight and speed.
Only then will the (properly terminated) dead moose be good enough.
Bjornb; Enjoy your vacation!

Finally! Somebody who UNDERSTANDS!!!!!

[bearcove]

Finally! Somebody who UNDERSTANDS!!!!!

Should of got a 35 whelen it does just that.

[NoAngel]

Nothing new under the sun.

[MBTcustom]

It's very true there's nothing new under the sun, but saying the 9X57 is the same as the 35XCB is about as accurate as saying the 35 Remington is the same as the 358 Winchester.
Somebody, somewhere, sometime, did this cartridge and had a name for it. I call it the 35XCB because it is part of the XCB project.
I wanted a 358Winchester with a little bit more case capacity, and a Whelen style neck, and I wanted a 35 caliber bullet with a better BC for doing a long toss.

(BTW Excess650, that is a truly gorgeous rifle!)

[bearcove]

AH! Almost a 35 Whelen.

[MBTcustom]

Well, going by internal case capacity, it's almost a 358 Winchester. Going by case length, its almost a 9X57. Going by neck length, it's almost a Whelen.
It's got the same neck wall thickness as the 30-30.
The 35XCB was designed to feed flawlessly and to be a dyed in the wool hunting cartridge for Mauser rifles. I'm hoping to get one built for myself by November so I can bust a deer with it. But if that doesn't happen, I'm sure Bjorn will be stringing up much more impressive critters from Alaska.

[bearcove]

Sounds fun, I have thought for a long while, a long necked 358 would be about right.

[MBTcustom]

Sounds fun, I have thought for a long while, a long necked 358 would be about right.

Get that man a cigar!!! That's what I've got going on here!
Now, I always thought that the 358 and the 308 were just a little bit conservative on case capacity, and the 30 and 35 XCB take care of that too. When loading these two cartridges, I use 308 and 358 load data respectively. I usually figure that max data for one is starting data for its XCB counterpart.

[taco650]

Tim,

Could a 358 Win be "bored out" to 35 XCB with out re-barreling?

[MBTcustom]

Tim,

Could a 358 Win be "bored out" to 35 XCB with out re-barreling?

Fraid not. The XCB has the 30-06 shoulder diameter which is too small to clean up a 308 chamber. I had considered redesigning the 30/35XCB with a more improved 308/358 style shoulder so that 308/358's could be reamed out, but that would negate several other attributes of the cartridges.
It takes a slow twist to really realize the full potential of the cartridges anyway. I mean the RPMTH of the typical 12 twist is 2300FPS, and I can get that with a dad gum 30-30. The XCB's were bread for SPEED and accuracy.

[taco650]

Fraid not. The XCB has the 30-06 shoulder diameter which is too small to clean up a 308 chamber. I had considered redesigning the 30/35XCB with a more improved 308/358 style shoulder so that 308/358's could be reamed out, but that would negate several other attributes of the cartridges.
It takes a slow twist to really realize the full potential of the cartridges anyway. I mean the RPMTH of the typical 12 twist is 2300FPS, and I can get that with a dad gum 30-30. The XCB's were bread for SPEED and accuracy.

Ok, thanks for the info. Which twist is preferred for this one (sorry, I missed the intro)?

[MBTcustom]

I would prefer 16 twist but given the limited selection of barrel makers that have that twist, I went with 14. The 14 twist will get you to 2600FPS and definitely maintain 2MOA or less.

[Larry Gibson]

It's very true there's nothing new underthe sun, but saying the 9X57 is the same as the 35XCB is about as accurate assaying the 35 Remington is the same as the 358 Winchester.
Somebody, somewhere, sometime, did this cartridge and had a name for it. I callit the 35XCB because it is part of the XCB project.

Why such a new cartridge (1922)?. The 9x57pre-dates 1900.

I designed the cartridge quite a few years back actually. I called it the 35x57 back then. The concept was in conjunction with the 30x57 (30 XCB) which was to have a standard 8mm/'06 head size cartridge with a tapered case to feed through Mauser actions of M91 - M98 types with out an action alteration being needed. Many of those only have 3" long magazines hence the 57mm length. The case was also designed to have the 30-30/30-40/30-06 length neck for better support and alignment with cast bullets.

An additional concept was that standard or match 30-06 and 35 Whelen reamers could be used to just short chamber the barrels w/o the expense of custom reamers. The same was for dies; standard 30-06 and 35 Whelen loading dies could simply be shortened so expensive custom dies would not be needed. Easily available 8x57 or any of the '06 family of cases could easily be used to form the cases. Cases could be easily formed with the standard FL dies and simply trimmed to length.

Tim has done an outstanding job taking the concept one step further with the tighter necks and thus the excellent 30 and 35 XCB cartridges. They are ideal for use with Mauser actions but can be used with other actions ast well.

Larry Gibson

[MBTcustom]

That's the truth Larry, and thank you for letting me run with your original idea!

But the point I was making is that no matter what you do, you can find something that was similarly done by someone else to accomplish a goal they had. What really makes the XCB cartridges, bullets, casting equipment, loading equipment, and measuring equipment different is the way we are using it, and what we are achieving using these things.
The XCB project is not about doing anything new. It's about humbly pointing out what's been there the whole time but hindered by one thing or another, or not used the way it really should be in order to achieve the goal.

2 years ago, there were no sub1.5MOA, 3100FPS+,10 shot groups posted on this forum. Now there are dozens. The XCB project didn't change reality in any way shape or form, it just exposed reality for what it is, and we accepted it and are better for it. Albert Einstein was correct when he said: "Once we accept our limits, we go beyond them" and that is what we have done here.

All of the things I have done in the XCB project have been thought of, theorized, postulated, dreamed about, written about, and hinted about by other people long before I was born. I take little credit for these ideas even if I just happened to use my own common sense to come to the same conclusions. All I did was decide I was going to make it happen. I grabbed a rope and started pulling. Lots of others came to help me and I hope others will too, but I'll keep pulling until I get where I want to go with the XCB project.
There is still a lot to learn.

[Larry Gibson]

"no matter what you do, you can find something that was similarly done by someone else to accomplish a goal they had."

I certainly concur with that as the 35x57 I came up with was meant to be ballistically the same or close to it as the 358W or the 9x57. What was different about the 35x57 is it was designed to;

have a case taper to fit Mauser actions and feed reliably w/o action alteration.

to have a case neck of 30-06 or 35 Whelen length.

to use standard readily and commonly available reamers to chamber a new barrel with.

To use standard and readily available common dies w/o resorting to expensive dies or custom dies.

to use readily available common cases to easily form cases w/0 extensive equipment.

The 30x57 and the 35x57 both meet all of these requirements. The cases for both cartridges are easily formed with the standard, shortened FL die that comes with standard 30-06 and 35 Whelen dies, especially if a standard RCBS dies set is used. If 8x57 cases are used case trimming is many times not even necessary. Neither of those cartridges would even require neck turning if a standard or match reamer is used.

The .308W, the 9x57 nor any other wildcat cartridges meet all of those requirements. The 30x57 and 35x57 do meet those requirements. That's why I designed those two cartridges that way. The other benefits of higher velocity with cast bullets was a result of postulation of using slower twists to keep the RPM in check as Tim suggests. I was correct in that postulation and many thanks to Tim for his impetus in moving us forward with the 30 XCB past what I was doing with my 14" twist .308W Palma rifle. Tim deserves a lot of credit for the progress we have made. Yes there is still a lot to learn about shooting cast bullets at HV and we are still learning.

Larry Gibson