You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
.308 Texan titanium barrel tension
- Thread starter rcpro88
- Start date
Starting from top to bottom, these are picture descriptions.
1. Split retaining ring - I made a ring made out of 316 stainless steel on my lathe with an OD of 0.8" and an ID of 0.60 and a thickness of .170". I cut a groove to match in the barrel. After I turned the ring on the lathe, I used a dremel to cut it in half, didn't really cut straight but it'll get her done.
2. This is the retaining cup. It has an OD of 1.03" with a through hole of .671" and a .170" deep recess with a ID of .795" and a shoulder on the other of the retaining cup that has an OD of .895" that the titanium tube sits snugly on. It is crucial that when the split ring is on the barrel, the fit between the retaining cup and the split ring is press fit, this ensures no separation of the split ring halve when I go to torque this puppy down.
3. Threaded the last 1.5" or so of barrel with a 5/8-24 thread
4. This is the barrel assembly without the titanium tube. The retaining cup is pressed onto the split ring halves and the muzzle brake/tension nut is screwed on 7/10ths of the way.
5. This is the complete barrel assembly with the titanium tube in place.
6. This is the retaining cup when the titanium tube is in place. I had to sand the barrel down a tad. There were slight burs left from machining as well as those left from the set screws prevented my .671" ID retaining cup to slide on. I smoothed it out with some 320 grit on the lathe.
7. This is the muzzle brake/tension nut. I put a long hex key through the holes in the muzzle brake and crank it tight.
8. Another picture of the muzzle brake and barrel assembly.
9. The whole thing. Yes the .308 Texan fits in my hard case with tank and new barrel on with an inch or two to spare.
1. Split retaining ring - I made a ring made out of 316 stainless steel on my lathe with an OD of 0.8" and an ID of 0.60 and a thickness of .170". I cut a groove to match in the barrel. After I turned the ring on the lathe, I used a dremel to cut it in half, didn't really cut straight but it'll get her done.
2. This is the retaining cup. It has an OD of 1.03" with a through hole of .671" and a .170" deep recess with a ID of .795" and a shoulder on the other of the retaining cup that has an OD of .895" that the titanium tube sits snugly on. It is crucial that when the split ring is on the barrel, the fit between the retaining cup and the split ring is press fit, this ensures no separation of the split ring halve when I go to torque this puppy down.
3. Threaded the last 1.5" or so of barrel with a 5/8-24 thread
4. This is the barrel assembly without the titanium tube. The retaining cup is pressed onto the split ring halves and the muzzle brake/tension nut is screwed on 7/10ths of the way.
5. This is the complete barrel assembly with the titanium tube in place.
6. This is the retaining cup when the titanium tube is in place. I had to sand the barrel down a tad. There were slight burs left from machining as well as those left from the set screws prevented my .671" ID retaining cup to slide on. I smoothed it out with some 320 grit on the lathe.
7. This is the muzzle brake/tension nut. I put a long hex key through the holes in the muzzle brake and crank it tight.
8. Another picture of the muzzle brake and barrel assembly.
9. The whole thing. Yes the .308 Texan fits in my hard case with tank and new barrel on with an inch or two to spare.
Upvote 0
A few things I need to do are:
1. The retaining cup needs holes drilled to allow the set screws to prevent lateral impact movement. Simply pressing up against the titanium tube/aluminum retaining cup will not be sufficient.
2. Make the barrel tension nut separate from the muzzle brake or silencer. This way if switching between an airstripper/silencer/muzzle brake you don't put more wear on the barrel threads.
A few things I've noticed:
1. The new barrel assembly has some weight. Not much, but its noticeable. I will say it seemed to have actually helped steadying when aiming the rifle off hand. The weight is added towards to center and front of the Texan. It could just be me as well.
2. The muzzle brake I made actually worked. When dryfiring a 3000psi fill, the felt recoil with and without the muzzle brake is what you'd expect from any other brake/shroud. The noise is reduced slightly but no where near the dB level of the Texan with an R&L shroud.
Why did i pick a titanium tube?
My local metal supply (Shapiro) stocks some titanium. When looking at buying options of carbon fiber online, I wasn't really sure if I would be getting the quality I'm expecting. Honestly, titanium was just the easier route as I also already knew how I could/can't machine it.
Tension vs sleeves
When I see carbon fiber barrels, they are generally a carbon fiber tube, pressed and epoxied on and might be repeated a few times to layer up. In this application, you increasing the stiffness/rigidity of the barrel as you are adding more material to the outside as well as using a material that is much more stiff/rigid than the barrel, enhancing overall stiffness/rigidity of the barrel. The reason carbon fiber is often used here over titanium is because of its more stiff/rigid than titanium. However I do not mean to say that you cannot/will never see a carbon fiber tube used in a barrel tension setup.
When a barrel is placed under tension, it not only aids stiffness/rigidity to the barrel but reduces the amplitude of harmonic vibrations/increases their frequency. This is true for whenever you add/remove material/weight to and from your barrel. However this effect is amplified significantly when compared additional weight when internal forces are acting on the barrel/when it is under tension.
1. The retaining cup needs holes drilled to allow the set screws to prevent lateral impact movement. Simply pressing up against the titanium tube/aluminum retaining cup will not be sufficient.
2. Make the barrel tension nut separate from the muzzle brake or silencer. This way if switching between an airstripper/silencer/muzzle brake you don't put more wear on the barrel threads.
A few things I've noticed:
1. The new barrel assembly has some weight. Not much, but its noticeable. I will say it seemed to have actually helped steadying when aiming the rifle off hand. The weight is added towards to center and front of the Texan. It could just be me as well.
2. The muzzle brake I made actually worked. When dryfiring a 3000psi fill, the felt recoil with and without the muzzle brake is what you'd expect from any other brake/shroud. The noise is reduced slightly but no where near the dB level of the Texan with an R&L shroud.
Why did i pick a titanium tube?
My local metal supply (Shapiro) stocks some titanium. When looking at buying options of carbon fiber online, I wasn't really sure if I would be getting the quality I'm expecting. Honestly, titanium was just the easier route as I also already knew how I could/can't machine it.
Tension vs sleeves
When I see carbon fiber barrels, they are generally a carbon fiber tube, pressed and epoxied on and might be repeated a few times to layer up. In this application, you increasing the stiffness/rigidity of the barrel as you are adding more material to the outside as well as using a material that is much more stiff/rigid than the barrel, enhancing overall stiffness/rigidity of the barrel. The reason carbon fiber is often used here over titanium is because of its more stiff/rigid than titanium. However I do not mean to say that you cannot/will never see a carbon fiber tube used in a barrel tension setup.
When a barrel is placed under tension, it not only aids stiffness/rigidity to the barrel but reduces the amplitude of harmonic vibrations/increases their frequency. This is true for whenever you add/remove material/weight to and from your barrel. However this effect is amplified significantly when compared additional weight when internal forces are acting on the barrel/when it is under tension.
Upvote 0
Why I think the Texan has a few hiccups:
When you can't free float a barrel you use a heavy one. The .308 Texan barrel is supported in the center of the rifle with 2 bushings which allow the barrel to vibrate like a tuning fork when shot.
The R&L shroud provides support to the end of the barrel from the body of the Texan. as you screw on the shroud you apply pressure to the end of the barrel which explains why it might be helping the .308 Texans accuracy issue.
Just one last thing, Matt @ R&L is the man to go to for all Airforce questions/ammo/advice. Matt has been a great help and source of GOOD information and advice.
When you can't free float a barrel you use a heavy one. The .308 Texan barrel is supported in the center of the rifle with 2 bushings which allow the barrel to vibrate like a tuning fork when shot.
The R&L shroud provides support to the end of the barrel from the body of the Texan. as you screw on the shroud you apply pressure to the end of the barrel which explains why it might be helping the .308 Texans accuracy issue.
Just one last thing, Matt @ R&L is the man to go to for all Airforce questions/ammo/advice. Matt has been a great help and source of GOOD information and advice.
Upvote 0
Airforce claims the .308 Texan will shoot a 1" group at 100 yards out of the box. I would normally shoot 200 yards with the Texan, I would get anywhere from 4 inch - 6 inch groups at 200 yards with various types of pellets. I never really spent a lot of time shooting 100 yards with the Texan before so I can't really compare my results today with past results.
Today I took the Texan to a 100 yard range and it shot consistent 1.2" 10 shot groups BUT if you were to remove the 1-2 fliers the 8-9 other shots were all touching/overlapping with a group size right around 0.75". I believe the groups can get better and well I'm also not a perfect shot either, I would try to put the cross hairs on the bulls eye every time but there was a guy shooting next to me with a loud gun and honestly I would jump sometimes when he shot which would effect my shot of course.
This is gear I was using:
.308 Texan
Primary Arms 4-16 zoom scope (should probably be upgraded)
$30 scope rings (no i did not lap them either, shame on me)
115 grain High Arc pellets
I used a scuba tank to refill the Texan. I don't have a regulator yet so I would fill to 3000psi, take two shots, refill to 3000 psi and so on.
I have the Texan power wheel all the way turned up. Matt at R&L told me the High Arc pellets like to be shot around 930-950 fps. I didn't chrono the gun yet with the High Arcs yet but I'm pretty sure a few of them cracked, so chances are they are moving around 1000-1100 fps.
Today I took the Texan to a 100 yard range and it shot consistent 1.2" 10 shot groups BUT if you were to remove the 1-2 fliers the 8-9 other shots were all touching/overlapping with a group size right around 0.75". I believe the groups can get better and well I'm also not a perfect shot either, I would try to put the cross hairs on the bulls eye every time but there was a guy shooting next to me with a loud gun and honestly I would jump sometimes when he shot which would effect my shot of course.
This is gear I was using:
.308 Texan
Primary Arms 4-16 zoom scope (should probably be upgraded)
$30 scope rings (no i did not lap them either, shame on me)
115 grain High Arc pellets
I used a scuba tank to refill the Texan. I don't have a regulator yet so I would fill to 3000psi, take two shots, refill to 3000 psi and so on.
I have the Texan power wheel all the way turned up. Matt at R&L told me the High Arc pellets like to be shot around 930-950 fps. I didn't chrono the gun yet with the High Arcs yet but I'm pretty sure a few of them cracked, so chances are they are moving around 1000-1100 fps.
Upvote 0