.30 XCB wildcat, from scratch.

[MBTcustom]

Nice to see someone is testing the gain twist. I asked about it a year ago on another disappeared thread, but there was no definitive yes or no on whether it was worth persuing.

Launch in a 1 in 14 and finish at 1 in 12 or faster.

I agree, it's a test worth pursuing. Just gotta get somebody to pony up the $$$ for it.
The big question is if the damage done to the boolit by the changing twist is less than that caused at the engraving event of a standard 10-12 twist.
Only one way to find out!

[Love Life]

I really don't see why damage would be done with the changing twist.

Oh, and no break from the lathe for you! I have a box of parts that I'll be mailing your way some time next week...

[detox]

If you look at the Match result pages on the Cast Bullet Association web site some shooters are doing good with gain twist barrels. Hardly anyone shoots above 2200 fps.

[geargnasher]

If I had a &$#%@&% small-shank barrel nut I'd be shooting it this weekend. Stupid Savage smooth nutz and metal bead-blasting+bluing the whole assembly to rust-lock it together kinda necessitated a little destructive disassembly.....anyway Numrich to the rescue since Savage doesn't see fit to supply any parts to the aftermarket anymore. Hurry up and wait, I guess.

Gear

[geargnasher]

......the Cast Bullet Association......Hardly anyone shoots above 2200 fps.

Bingo. They don't know how, and further, don't need to for plugging tiny groups at 100 yards.

Gear

[runfiverun]

Tim I'm willing to send the funds for a gain twist barrel
i need a hunting rifle in this xcb cal anyway 13-14 to10
would stabilize a 150-180 gr bullet at 26-2700 without issue
using it to fling some lead too wouldnt wear it out any sooner

[MBTcustom]

I really don't see why damage would be done with the changing twist.

Oh, and no break from the lathe for you! I have a box of parts that I'll be mailing your way some time next week...

What makes you think I ever take a break on the lathe? When I get a spare minute I make kewl stuff like this:
Attachment 119343
Attachment 119344
Attachment 119345

[Love Life]

Oooohhhhh! Nothing like a Rolls Royce of concentricity gauges. I can measure the runout of my run out. well, maybe not that but the one I use is 2legit2quit.

[MBTcustom]

Tim I'm willing to send the funds for a gain twist barrel
i need a hunting rifle in this xcb cal anyway 13-14 to10
would stabilize a 150-180 gr bullet at 26-2700 without issue
using it to fling some lead too wouldnt wear it out any sooner

Im down Lamar. Just let me know. Also, you remember you have a barrel here in the shop still?

[MBTcustom]

BTW, the worst of my XCB cartridges are within .002 TIR. The majority of them are .0005 or less.

[geargnasher]

Nice to see someone is testing the gain twist. I asked about it a year ago on another disappeared thread, but there was no definitive yes or no on whether it was worth persuing.

Launch in a 1 in 14 and finish at 1 in 12 or faster.

Only way to find out is pay the piper and go try it. Mine is 11.25 gaining about 3/4" over 24, so not much of a gain-twist test, I got it more for the 5R thing and the nice Bisley throat, going to try tight this time (.309-ish) and the .001-over-groove thing and see if it isn't a little easier to get good launches without all the un-necessary bullet squishing in these oversized throats.

Gear

[MBTcustom]

Only way to find out is pay the piper and go try it. Mine is 11.25 gaining about 3/4" over 24, so not much of a gain-twist test, I got it more for the 5R thing and the nice Bisley throat, going to try tight the .001-over-groove thing and see if it isn't a little easier to get good launches without all the un-necessary bullet squishing in these oversized throats.

Gear

You could chamber in 30 carbine, shoot lapping Boolits till you get to the muzzle, then rechamber in the cartridge of your choice so you have a good fresh throat, gain twist, and a slightly choked barrel to boot........

[geargnasher]

It's already choked, you see....

Lotsa little-known things about Rock Creek, the gain twist is another one they don't advertise, but sneak in on what I understand to be all of their barrels.

It also has already been chambered in the Bisley configuration, a quick chamber cast confirmed that. It's ready to headspace onto my 111, torque, and shoot.

Gear

[Bjornb]

If I had a &$#%@&% small-shank barrel nut I'd be shooting it this weekend. Stupid Savage smooth nutz and metal bead-blasting+bluing the whole assembly to rust-lock it together kinda necessitated a little destructive disassembly.....anyway Numrich to the rescue since Savage doesn't see fit to supply any parts to the aftermarket anymore. Hurry up and wait, I guess.

Gear

I have a takeoff Savage 308 barrel with the barrel nut off an Axis. If it will help you I can overnight it to you.

[geargnasher]

Man, I shoulda waited. Thanks a million, Bjorn, but I JUST finished ordering an SS nut and recoil lug from McGowan, we'll see which part gets here first. I'll probably use it to match the SS barrel. The XCB and my fresh brass should keep me busy until then.

Gear

[Bjornb]

Cool. Another experiment. Keep'em coming!

[Love Life]

Only way to find out is pay the piper and go try it.
Gear

That's my usual approach to things.

[Pinsnscrews]

Gear, there are several aftermarket suppliers of Savage Barrel Nuts Not to mention you can toss that smoothie and use a regular nut. I would order a few (which I did, though my supply is gone since I have saved several others in need since then)

[45 2.1]

Bingo. They don't know how, and further, don't need to for plugging tiny groups at 100 yards. Gear

If you have read their magazine for a few decades, you would have seen that the cartridges are limited to those velocities because of the case capacity. The guys that developed the current technology had accuracy in mind and found the smaller capacity cartridges gave much better accuracy. They also ran the common larger cartridges thru all possible permutations. Check the current group size records for some illuminating facts.

[runfiverun]

I remember the 7mm barrel there.
I got a ruger 25-06 and a win push feed 270 as well as another Mauser action here
i also have a 7x57 ackley finish reamer here.
its getting everything together in the right order.
that's My problem

I'll be home in a couple of days and give you a call about putting something together