I’ve been working on this .50 cal AR platform. It will have to have a specially designed receiver and mag well. I’ve been acquiring and buying a lot of tools so hopefully they can pay themselves off. Started with a 7.5 inch piece of titanium round bar stock with an OD of 1.375. So far I’ve gotten a barrel with an ID tolerance of .513 or 13mm. The OD of the other details start smallest at .810 in (threaded section), .910, and a .970 step up order. The angle of taper was supposed to be 10deg but I went a little far. The extension threads are 1-16. I have to turn maybe .320 inches off the end of it and chamfer the ID for ease of feed. I couldn’t find a chapstick reamer for the chamber so I was gonna use an H4 and H5 adjustable reamer to fix that and have the round protrude a little outside the section maybe 3mm just enough for an extractor to grab easily.
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.500 NE titanium AR50 Prototype Project
- Thread starter sw1ne
- Start date
- Replies 45
- Views 2,219
john.k
Diamond
- Joined
- Dec 21, 2012
- Location
- Brisbane Qld Australia
The gun would be so heavy .,you'd have to mount it in the back of a Toyota HiLux like the ragheads do.
moonlight machine
Diamond
- Joined
- Nov 19, 2007
- Location
- marysville ohio
I could not make heads or tails out of the text. Hard to tell for sure with the blurry photos but the finish looks terrible, is that the best you can do? I would imagine that is 6AL4V, pretty easy to get a good finish on that stuff.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
My first impression is your headstock is loose as a goose.
My second impression is your lathe spindle bearings needs some work too...
My second impression is your lathe spindle bearings needs some work too...
Heavy? Titanium is lightweight.
I haven’t deburred any thing on it yet because I was gonna get to making a barrel extension and tank muzzle. I unchucked it and got too lazy to chuck it back
mhajicek
Titanium
- Joined
- May 11, 2017
- Location
- Minneapolis, MN, USA
I can't imagine a reason anyone would want a .50NE pistol, but hey, you do you.
I'm wondering about the wisdom of choosing Ti for the barrel material; anyone have any experience with that? It's pretty darned elastic.
I'm wondering about the wisdom of choosing Ti for the barrel material; anyone have any experience with that? It's pretty darned elastic.
moonlight machine
Diamond
- Joined
- Nov 19, 2007
- Location
- marysville ohio
Not sure how you improve the finish by deburring it. Whatever.
I’ve seen some custom ar platforms that have titanium barrels. The companies didn’t have many complaints about theirs.
Don’t lie bro you’d love to test it.
memphisjed
Stainless
- Joined
- Jan 21, 2019
- Location
- Memphis
I had to do a brief internet look to see. Lots of steel lined ti barrels. Longthorne makes Sporting clay guns with ti barrels. Everything else was a steel lined ti. There must be a reason not to.
BoxcarPete
Stainless
- Joined
- Nov 30, 2018
- Location
- Michigan, USA
Titanium galls, probably lead and/or the copper jackets of bullets will stick to it and ruin the rifling after a relatively small number of shots. It's supposed to be possible to prevent that with an oxide layer, but Ti is notoriously tricky to anodize to a consistent thickness even under ideal circumstances, I can't imagine that getting a uniform oxide thickness over an entire rifled bore is worth chasing.
mhajicek
Titanium
- Joined
- May 11, 2017
- Location
- Minneapolis, MN, USA
Ti is also less thermally conductive than steel (about 1/3), so it'll heat up and move more. If you want light, why not go carbon fiber?
I’m thinking about putting a lining in but I already ordered a custom made buttoning tool. It’s like 1:15 and 6 flute 13mm
It honestly hasn’t changed much when machining. I’d imagine the turning induces the work piece under more friction than brass and powder can. The yield strength of titanium is high. Not sure how that plays out in other terms.
mhajicek
Titanium
- Joined
- May 11, 2017
- Location
- Minneapolis, MN, USA
I was thinking of how it will heat up and move in use, after it's finished. But with a 7.5" barrel you probably aren't going for MOA accuracy anyway.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
I'm a little confused that you've ordered a 13mm button reamer for a 12.7mm cartridge. But then, I don't think a rifled Ti barrel is a good choice period.
plastikdreams
Diamond
- Joined
- May 31, 2011
- Location
- upstate nj
Titanium has low wear resistance as well as not being very hard...
Machining heat and 50 cal round heat are 2 completely different types of heat input. From the way you've been talking I'm gonna guess you don't know much about what you are doing but saw something on you tube or the like and decided let's half ass try to make that...then post on a professional machinists website and think we are gonna eat this shit with a glass of kool-aid.
Machining heat and 50 cal round heat are 2 completely different types of heat input. From the way you've been talking I'm gonna guess you don't know much about what you are doing but saw something on you tube or the like and decided let's half ass try to make that...then post on a professional machinists website and think we are gonna eat this shit with a glass of kool-aid.
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