First Time Ordering A New Barrel/.300 RUM

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I am rebarreling a rifle in .300 RUM. This is the first time I have gone down this road so a couple of questions for the collective.

The purpose for this build is to get to the 1 mile, and 2,000 yard mark, so heavy fast moving bullets will be in order. Will a standard 1-10 twist work with the very heavy 240 grain bullet, or will I need to find a 1-9?

If I go with the 1-9 will I lose the ability to shoot 168/175 grain bullets?

Also I am thinking that a 30 inch tube will be the best place to start with so my smith will have plenty of real estate to work with, will this just be an added expense, or can it help get those last few feet per second?

And of course which manufacturer would you use, and not use for this project?

Are there any questions that I am not asking?
 
You are going to get lots of opinions, here is mine.
Twist rate -- I would go with the 1-9 for the 240 gr bullets. You would not lose the capability to use 168's.
Length -- Rule of thumb is that you gain around 25 fps per inch of barrel. A 32" blank is $50 to $75 more than a 30", make up your own mind if the gain is worth the price after consulting the ballistic tables. Remember the blank needs to be at least 2" longer than the desired finished length.
Manufacturer-- Kreiger, Bartline, Hart, Shilen, Benchmark. All make quality barrels. A 32" blank will be special order more than likely. Kreiger lead time will be 8 months, Shilen will be 8 weeks. You decide how fast you need it. Prices are similar among the manufacturers. $300 to $400 range for a long blank.
 
1:10 should stabilize 240s, but 1:9 would be a good idea if you mostly mean to shoot heavier pills. No, it will not limit your ability with lighter bullets, unless we're talking 110 or 125 gr. varmint pills that may exceed maximum RPM from a 1:9 .300 RUM.

On barrel length, yes, 30" will see an improvement over 24" or 26" with an overbore round burning huge quantities of powder like the .300 RUM, but longer barrels also whip more at a given profile. Faster bullet = less drop & drift, but more rigid barrel = greater mechanical accuracy. Spend some time reading about the benefits and detractors of longer and shorter barrels and make the call.
 
Thanks all, Sorry it took so long to replie, I have been fighting with a video app that is very buggy, and that pesky thing called work keeps getting in the way of everything.

I did go with the 1-9 twist with the outside diameter being 1.50. My gun mechanic lathe only goes to 1 9/16, or I would have gone with a heaver profile. I did stay at 32 inch, which after reaming it should have over 27 inches of usable rifling. Now it is just a sit and wait for Pac-Nor to get there part done, and ship it to D&D for the installation.

Hopefully It will be completed by April. I did not want to spend this money on this part of the project, it could of been better spent on optics, and components for load development.
 
I did go with the 1-9 twist with the outside diameter being 1.50. My gun mechanic lathe only goes to 1 9/16, or I would have gone with a heaver profile.

Are you talking about spindle through bore? Do you not have a steady rest or tail stock? My large machine has a 1.8" spindle bore, but I can turn pieces 10 times that diameter up to 53" in length with a 60" center distance (3" on headstock and 4" on tail given up to chuck and live center). With tail stock removed, a steady will allow you to turn a piece longer that the lathe, as long as the steady can support the weight hanging out in space, and provided it doesn't whip.

Muzzle threading should be done with a cat's head which, unless you have built a giant one like I did, yes, you need to use spindle through bore. But nothing wrong with profiling a barrel between centers or with steady rest.
 
I am not sure of the specifics of his equipment, I just drop off the stuff, and say fix it, then he gives me the bill. Here is a video of his setup it might be a better way to explain his setup, then me gibbering on about something I real don't know about.

 
Everyone has their own way, but honestly, he fumbles a lot. He should slow down a little. I'm very coordinated, but I don't try to move that quickly with gunsmithing activities. Slow is smooth, smooth is fast. But then, maybe your filming made him nervous.

I strip receivers completely, put them in the vise with aluminum blocks. I made my barrel wrench, which clamps down on interchangeable alumimum blocks for different barrel profiles and diameters.

I try not to judge, but IMO, a 3 jaw chuck doesn't have much application in gunsmithing unless it's an adjus-tru, which that one isn't. For profiling, I turn between centers with a dog, or using a 4 jaw & live center. For threading, 4 jaw with spiders, or cat's head, because no barrel I've ever encountered has a bore perfectly concentric to outside profile. I suppose it's OK for receiver truing, although I'd still use a 4 jaw independent and indicate the thing.

I use two different lathes for smithing. Most of my barrel threading is done on my Hardinge HCT with an auto threader. The auto threader is electro-pneumatic, and if set up properly, gives perfect threads. I can thread right to a shoulder at 1,000+ RPM, giving superior finish. I usually re-crown with a beveled counterbore, unless someone specifies otherwise. This is the Hardinge:

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And this is how the auto threader works (not my video):



My other primary machine is a 1920s Rahn-Larmon 17 x 60 engine lathe that I reconditioned and upgraded:

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Believe it or not, it's a very precise machine now. Just yesterday I had to repair a totally boogered 1911 that someone had already tried to install oversize grip bushings in and screwed the pooch. On this machine, I made a .252-60 internal thread, 5/16-40 external thread bushing from 316 stainless and saved the frame. Could have been welded I suppose, but that would have wrecked the cerakote and presented other problems.

And my giant cat's head, a 3.5" ID x 5.5" OD 6061 aluminum tube with eight 3/4-16 set screw I made brass tips for to center the work piece within. I can put an entire barreled action in this thing, including semi autos and lever guns:

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That's a 9" diameter bearing it rides in. That steady rest I made from raw stock as well, is 2.5" thick 7075 aluminum. For one, I couldn't find one at any price for this machine. Two, they likely wouldn't have had such a large capacity and three, I wanted a really trick set up with my fingers that allowed large contact area with bearings to avoid gouging the part. These are the fingers, which each have six ball bearings that self-align to the work piece as the adjustment screw is tightened due to my multi-piece design:

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I also made a rotary threading attachment for the big machine so that I can get right up to shoulders on that one manually rotating the chuck with no worries of crashing, or missing a mark trying to thread away. It's pretty slick, I used an ER-20 collet holder through a boring bar holder I pocketed for bearings, then made a 6.6:1 gearbox to reduce the up to 30,000 RPM 40x92mm brushless motor down to a more usable range:

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Just messing around with a dovetail cutter on C360 brass:

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It also works much better than a static cutter for interrupted cuts, or threading really thin tubing.
 
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I definitely was cramping his style, we were trying to get a lot done in a very small time frame. Drove up from Jacksonville, FLA. to Columbus, Oh. The next day drove the 100 miles to his shop, then back to Columbus. Then the next morning we were heading back to Jekyll Island.

The video, and your photos are neat, the bearing is a thing of beauty.

As far as the finish of the barrel goes it will come polished from Pac-Nor so that is not an issue.
 
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