.30 XCB wildcat, from scratch.

[runfiverun]

you ummm got an Ackley versioned 7mm type barrel in your shop right now...
making that into:
a 338 1-12 twist version with a 190 gr boolit would be a mud-stomping deer/pig [cow elk] type round capable of some impressive velocity/accuracy numbers.
it would be too much in some instances [think your 358] unless the meplat/nose was designed properly.

[cbrick]

On 7/24 Brad wrote:

Just spoke to Tim. Rifle should ship next week baring any problems. Woo hoo.

Ok, this mean the rifle has been shipped. Right?

Rick

[MBTcustom]

On 7/24 Brad wrote:



Ok, this mean the rifle has been shipped. Right?

Rick

Not quite. I thought I was man enough to go to the shooting range the day after laser surgery. I was mistaken.
The rifle will be shot this weekend and photographed professionally, and it ships Monday or Tuesday.

[MBTcustom]

you ummm got an Ackley versioned 7mm type barrel in your shop right now...
making that into:
a 338 1-12 twist version with a 190 gr boolit would be a mud-stomping deer/pig [cow elk] type round capable of some impressive velocity/accuracy numbers.
it would be too much in some instances [think your 358] unless the meplat/nose was designed properly.

Yeah, at some point you just have to start taking head shots so that you can salvage the back end of the deer. LOL!

[runfiverun]

http://www.accuratemolds.com/bullet_...=31-160G-D.png
tim is this the one we talked about today??

http://www.accuratemolds.com/bullet_...=31-165A-D.png
this is what i'll be working with to start [it has the things I pointed out] versus yours.
plus I already got it and have pushed it to 2400 in the 308 without issue.

[MBTcustom]

Exactly. That is the boolit I designed with Larry Gibson (and the input I got from you just before your last stint) for the XCB rifles for testing at close range.
There is a superior version being made by NOE, that is much more streamlined with a huge BC. It's basically the same design except for the improved nose.
My contribution to this boolit was perfect static fit of the boolit in the rifle, so that when used properly, it will have as much support as is humanly possible.
First I turned dummy boolits out of steel and seated them in brass and tried them in the rifle.
This is one of my test boolits that got stuck in the throat like a morse taper and was pulled from the brass about 1/8" upon exctraction.
Attachment 112416
Once I was sure I had the angles correct, I ordered the mold from Accurate cast some up and tried them in the rifle. I was very very pleased!
Attachment 112417
After that, I shot one at low speed into my sandbox to see if it gave the same "S" shaped land cut that some previous full support boolits had, and it did not. It has too much support for that.
Attachment 112418

This is what I am calling a "pre-slumped" design. My motivation was to make it so that when the boolit is launched, any and all matter contained within that boolit would resist crushing, and if it cannot, it will do so evenly. Both because of the shape of the nose, and the support it has, and the perfect fit of the boolit behind.
Basically, I wanted a chamber slug with a nose on it.
The two parts I don't have a clue on how to design is the nose profile and the lube grooves. I turned to Larry Gibson and SwedeNelson for help on those two issues.

My only contribution to this design is perfect static fit which is my main contribution to the world. In fact, my entire career is based on my ability to produce perfect static fit.
Unfortunately, I'm not nearly as sharp on other points like chemistry, or aerodynamics, so I would like to thank those who helped me in those two areas.

This boolit will be tested shortly and we shall see if all this was worth the head scratching. To be honest though, I'm holding out for the NOE version. That baby is going to be amazing.
This design will do for close range load development and testing, but the NOE is going to be the golden boolit for shooting accurately at long range (At least that's what I am hoping.)

The Accurate design should be excellent for hunting though.

[runfiverun]

Brad....Brad??
there ya go,,, the rl-19 powder speed will work very well with this set-up. [22 wouldn't be a bad number to work with either]
this is the straight line thing I am talking about.
once the brass is fire formed every thing is held in position on both ends, and with the boolit aligned like this you have very,very little room for error.
[try and make an alignment error, the rifle and boolit won't allow it]

I'm all over this mold, it has some very practical uses besides just the XCB..

[runfiverun]

funny, now that I look at it.
this is almost the same back and forth discussion and picture session from the mold section.
except with two different systems.
static fit [the 160-G], mechanical fit [how the pieces mesh together under movement, the 165-A]
and alignment, that is rifle measurement dependent and the huuuge hurdle..

[MBTcustom]

Yes, this mold should be very useful for many different 30 caliber designs, but I designed it to fit the 30XCB like a glove, and it does. The angles are precise. The length is precise. The weight is precise.
I threw everything I have learned about boolit design over the last three years into this mold, and had a lot of help from some of our best members.

I'm really glad you approve Lamar.

Just wait till the NOE hits Swede's website. It's enough to make a grown man week in the knees. It is all this and a bag of chips.
He was able to maintain perfect fit, while giving it a BC of .286
Attachment 112470
That is sweeter than mama's love IMHO.

This boolit will engrave exactly like the one that I have shown pictures of up yonder. It doesn't look like it will but it will. That whole area that looks like a borerider is actually the leadin engraving area. The very tip of this boolit is the only thing not completely surrounded by brass and steel when the cartridge is loaded in the gun. I was very very specific about not messing with the dimensions I insisted on in the original design. I didn't care if it looked like a dying duck. FIT IS KING whether it looks pretty or not.
I'm just so happy that Swede was able to make it look so pretty without compromising perfect fit. He is a very talented boolit designer.

[MBTcustom]

I made it out to the range with both Run5Run's rifle and Brads rifle today. I decided to shoot in one of my honey holes rather than the range with the Nazi. Big open field.
Brad has given me permission to post pictures of his rifle, and Lamar has also (much obliged fellers).
Here they are:
First up the one for R5R
Attachment 112567
Attachment 112568
Attachment 112569
This one shot solid sub MOA (nearly half MOA). It just isn't thrilling me though. It's close, but not quite what I expect.
I suspect the forend needs to be floated a little bit more. Anyway, it's almost finished. Just needs a few more of those details taken care of.

Brad's rifle came out of the corner swinging and performed exactly like I expected it to. It will be shipped tomorrow if I can get it packaged satisfactorily tonight.
Attachment 112570
Attachment 112572
Attachment 112573
Attachment 112574
Now here is the moment we have all been waiting for.
This is a 7 shot group at 100 yards shot off the hood of my truck whilst I stood on my tip toes (they need to mow that field sometime!) I had a rest.
The first six went into the same hole. I decided to be a jerk and shoot lower to see if I was really doing what I thought I was doing (let's just call it a called flier).
This was a jacketed load. Hornady A-max, 42.2 grains of 4895, Federal 210, HXP 68 brass.
Attachment 112576
Put a fork in it boys it's done!

[runfiverun]

considering you got a box o' parts, are working with a 75 year old military trigger, a long l.o.p. roll over 50 y.o. fajen stock, and had to relieve the barrel.
1/2-3/4 m.o.a is outstanding.
you probably didn't push the load hard/fast enough.
remember this one is designed to throw boolits 2600 fps, and light jaxketd to over 3-k...

[MBTcustom]

Excellent shooting Sergeant, as usual. Glad you like the design.

I am hopeful that the XCB project, and everything that issues from it, will advance the sport further than it has ever been before. Mine is a narrow slice of the pie, but I'm glad to be helping.
It's you fellers that have a talent for triggerwork that are really making a difference.

[MBTcustom]

considering you got a box o' parts, are working with a 75 year old military trigger, a long l.o.p. roll over 50 y.o. fajen stock, and had to relieve the barrel.
1/2-3/4 m.o.a is outstanding.
you probably didn't push the load hard/fast enough.
remember this one is designed to throw boolits 2600 fps, and light jaxketd to over 3-k...

Well, like I always say: "if you have a good barrel, it's going to try to shoot no matter what" and this one does. However, I am almost certain that I was seeing a weird harmonic caused by barrel touch. I had a hard time with the barrel channel in this rifle. I was trying to remove as little as possible, but with that huge barrel out there, I think I was getting stock touch on recoil. I'll know when I take it apart.
Something felt a little "muddy" when I shot it.

[MBTcustom]

Looks like Btroj's rifle ships tomorrow.
I gave it $3 worth of insurance, provided by Scotch LOL!
Brad, I honestly hope you love this rifle. It is a real pleasure to shoot. Just a simple tack driver. If anything will get you into HS cast lead, this thing will. It want's to shoot. I was shooting aspirine sized groups today. After the 5th shot, I really wondered if anything was happening down there. I believe I could have thrown 10 for 10 through my wedding band at 100 yards.
Pick your spot buddy, and send it.

[runfiverun]

they are the same as tims measurements for the truncated cone boolit.
the nose has been changed for a higher B.C.
the boolit is based on a slightly tight saami specced 30-06 throat leaving you room to adjust with slight alloy changes.

[MBTcustom]

I spoke to SwedeNelson on the phone today and he asked if I would mind if he went ahead and put a picture of the boolit up on his site (what a gentleman!) Of course I told him to please do so.
So the pictures should be forthcoming, but this is the preliminary drawing that we hammered out a couple weeks ago:
Attachment 112685
If you compare, you will notice that everything from the .299 diameter back is identical to the truncated cone boolit that I showed in previous pictures. Perfect fit was not compromised in this design whatsoever, and that nose from .299 forward is the only thing that is not fully suported once the boolit has been sized down to .308 by your barrel.
It should be the cat's, but like Lamar says: it's all an educated guess till the trigger is pulled.
However, something tells me we will have no shortage of booliteers willing to give this one a try.

[JonB_in_Glencoe]

That NOE boolit sure looks a lot sexier than that TC.

thinking to myself...I wonder how tight the chamber is on my old Win mod 70 (pre-64) that's looks like it hasn't been shot very much?

[runfiverun]

Jon: the ones I have dealt with have been fairly tight chambered.
it's part of the reason why they shoot so well with off the shelf ammo.

a .309 sizer is on my list of stuff to get soon, the XCB was designed with a 310 boolit in mind, this was determined by nominal brass thickness.
depending on the brass you use a 309-310 or 311 boolit can be used, I'd recommend the 309,3095 or 310 diameters though as they will align in the throat and will help avoid trailing edge and any riveting problems.

custom neck turning and proper length trimming your brass will also be in your best interest.
the 309 diameter will avoid some of the neck turning and allow you to fine tune finding the center of the barrel when the brass is made from the 0-6 family of cases.

[MBTcustom]

You know Lamar, in retrospect I would have speced the neck on this reamer at .333 instead of .337. I have not found brass that will clean up totally past the donut yet.
I think when this reamer is ready for a resharp, I'll ask Dave to correct that issue. Even .335 would be a huge boon to ease of attaining accuracy.

[MBTcustom]

THAT boolit is what you should put in your 300Blackout. If you want to try some before NOE cuts the moulds, PM me.

I would love to know how you plan to do that?
You gonna turn them out on a CNC? If there were a cost effective way to get ten boolits made before the mold is cut, I would have done so before sending Swede the drawings.
All I have at my disposal is manual machines. I can scare the heck out of it, but cutting ten perfect renderings of a design that does not physically exist yet, and doing so with enough precision that I could be confident that the real thing will work similar is a daunting task.
How do you do it?


On another note, here is the link to Swede's website and the thread that has been started on this boolit design:
http://noebulletmolds.com/smf/index....pic,242.0.html