Texan carbine/horrible accuracy

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durbs75 said:
Do you know how to tune the Texans? Do my procedure and you’ll find the tune where accuracy is best for EACH bullet. This procedure works as a guide for the .457 and .510 CF TX2 in any configuration. Slug your barrel.

Start there and use the chronograph so you know where you’re at for velocity. Once you have velocity, you can use a ballistics app to help get you close for fine-tuning.

Now, your fill pressure and power wheel when tuning will give you the results you seek. In my .457 CF TX2 long barrel, I shoot a variety of ammo but right now I am using my 324 grain solid nose cast bullets. I fill to 3450 to 3500 psi and wheel at 7/8. See pic attached. I size my cast bullets at .45720 which is the groove diameter of my rifle.

You need to tune your rifle which is the long and short answer. To do this whenever I develop a new bullet I use the following procedure which will help you find your bell curve in your optimum fill pressure and power wheel setting. For each three shot string, shoot at a fresh target. You will see in real time how feel pressure and power wheel settings affect your accuracy.. You will see that faster doesn’t always mean better!!!

NOTE: if you only have the aluminum bottle with a 3000 psi maximum fill, DO NOT exceed 3000 psi. You did not state which model of rifle do you have but the principle is the same whether you use my procedure as shown below with the carbon fiber TX2 valve.. If you have the old bottle, start with 3000 psi and go down to 2500.

Record all of the data including the velocity and beginning pressure for every single shot. This will help you in creating a DOPE card.



3600 psi fill

PW max, take 3 shots

Refill to 3600 psi

PW 3/4, take 3 shots

Refill to 3600 psi

PW 1/2, take 3 shots



3500 psi fill

PW max, take 3 shots

Refill to 3500 psi

PW 3/4, take 3 shots

Refill to 3500 psi

PW 1/2, take 3 shots



3400 psi fill

PW max, take 3 shots

Refill to 3400 psi

PW 3/4, take 3 shots

Refill to 3400 psi

PW 1/2, take 3 shots



3300 psi fill

PW max, take 3 shots

Refill to 3300 psi

PW 3/4, take 3 shots

Refill to 3300 psi

PW 1/2, take 3 shots



3200 psi fill

PW max, take 3 shots

Refill to 3200 psi

PW 3/4, take 3 shots

Refill to 3200 psi

PW 1/2, take 3 shots



3100 psi fill

PW max, take 3 shots

Refill to 3100 psi

PW 3/4, take 3 shots

Refill to 3100 psi

PW 1/2, take 3 shots



3000 psi fill

PW max, take 3 shots

Refill to 3000 psi

PW 3/4, take 3 shots

Refill to 3000 psi

PW 1/2, take 3 shots

View attachment 321778
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Thanks for posting this picture! I'm a Texan newbie and I saved it to my phone for future reference.
 
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I was only able to get 2 shots in this weekend do to cold temps. I tried pushing a .510 slug into the barrel using a rod, and again I would have had to pound it through. The slug would only go in about 3/4” I removed the slug by tapping it with a rod from the muzzzle end. I shot 2 rounds at 30 yards and they both hit a 2x4 so hopefully that going to be a trend. When the temps get above zero in a few days illl be at it again.
 
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Here’s another pic of the muzzle. Seems to be consistent to me. 0B405200-87EB-4881-B530-F9555E3C50C2.jpeg
 
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TG Reaper said:
How tight of a fit was the 18 mm ID tube? Was it a press fit or did you epoxy it onto the barrel? Or...?
Click to expand...
Slightly loose slide on fit
I put a thin coat of red thread locker to glue it on.
No isues.Accuracy improved greatly
You will need a custom made barrel end cap if you play to run the tube through the cap.
 
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Reedmosser said:
Cold temperature sucks for air guns. You leave the house with 4500 psi fill and by the time you shoot the pressure drops to 4000 psi. Hopefully spring is in a hurry!!!! Through a 650 grain in when you do shoot!!!! It s difficult lol😁😄😂
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I think hot temperatures suck worse, have to leave house with very low pressure in my Texan so it doesn't heat up enough to get into valve lock. Just plugged 4500 psi fill in my spreadsheet I set up for hunting with my Texan to check expected temp swings in my planned hunt and what pressure to fill to before going out. Yellow background are the variables I type in, green is calculated. All formulas for pressure/temp calcs in closed system are in kelvin and pascals, so have to do the conversions. The formula is very simple, just look up the conversions from one unit to another.

P2=(P1 * T2) /T1 Temperature and pressure are in Kelvin and Pascals. Alternatively, it is linear, at least for realistic temps. Change is just a tick under 42.1 psi for ever 5 degree temperature change.

barChange.jpg
 
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When I hunt I leave my Texan in the car and then fill it. When target shooting like I do taking my scba tank tethered I loose some a good number of shots from pressure drop. I do take my 5500 psi Scott tank fill it put outside in cold and let temperature drop the pressure and fill again. Helps but pain in butt... Yes just running tank on gun in heat of summer black bottle and sun definitely raises pressure. We can't have it all with airgun s. Maybe one day we will. I hope to one day get a air driven booster pump and be able to fill up my Scott 5.5 5500 psi tank and will much more room to play... I wish I could run the African Air Ordinance valve on my 50 and get 900+fps with a 650 grain spire point boat tails.. But the way my Texan breaks in stock configuration don't now if its really possible for long term. My Texan has wore out the pin going through the sear now...Don't imagine more powder will do anything but break it faster.. Here's a picture of my worn sear pin.. I had to.find the problem... Don't think Airforce techs are able to diagnose problems... Just skilled enough to change out all the internal parts. Here's a picture of the wore out sear pin!!!! Yes definitely more powder with the 50 than this small soft pins can handle...

16752650184077883220723671902868.jpg
 
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Reedmosser said:
When I hunt I leave my Texan in the car and then fill it. When target shooting like I do taking my scba tank tethered I loose some a good number of shots from pressure drop. I do take my 5500 psi Scott tank fill it put outside in cold and let temperature drop the pressure and fill again. Helps but pain in butt... Yes just running tank on gun in heat of summer black bottle and sun definitely raises pressure. We can't have it all with airgun s. Maybe one day we will. I hope to one day get a air driven booster pump and be able to fill up my Scott 5.5 5500 psi tank and will much more room to play... I wish I could run the African Air Ordinance valve on my 50 and get 900+fps with a 650 grain spire point boat tails.. But the way my Texan breaks in stock configuration don't now if its really possible for long term. My Texan has wore out the pin going through the sear now...Don't imagine more powder will do anything but break it faster.. Here's a picture of my worn sear pin.. I had to.find the problem... Don't think Airforce techs are able to diagnose problems... Just skilled enough to change out all the internal parts. Here's a picture of the wore out sear pin!!!! Yes definitely more powder with the 50 than this small soft pins can handle...

View attachment 328546
Click to expand...
Did you ever consider having a machinist make you a sear pin out of a better material?
 
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I have two more.from.Airforce... Maybe harder pin would be better. But better yet it needs a larger diameter pin .. This completely locks up your handle and makes gun non functional... For the price and supposed reputation of.Airforce this is a scrappy deal. I'm sure I'm not the only to have this problem. I just diagnosed and found the flaw in there design. Maybe it ok for under 400 foot pounds. Definitely not ok for the 50 cal. Come on Airforce they can do better!!! I don't think the techs at Airforce even now. They just change out all the parts for warranty. So.at best this crappy small pin cost you $75.00 in shipping to Airforce to fix. That is if they don't make some excuse not to warranty your gun.. For $1200 I shouldn't have to correct there engineering problems.. Not impressed Airforce.. They should spend less.money on content providers making B.S videos and more on actual testing....😥
 
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I have a lathe so I could make a pin. This pin almost cost me $430.00. I had to fight with Airforce for 3 months to get my gun back. So much aggravation. My luck put a harder pin in and the hole will oblong in frame...lol. Then I'd have to bore larger hole through sear and frame. I'm not any good with milling machines.. Lathes I'm ok. Easy fix at factory... This will happen to anyone who actually buts some rounds through there 50 maybe 45 too tx2 valve especially shooting heavier slugs. Karl h i just vent online in hope.it helps another Airforce customer who has same problems. I love big bores I want our industry to get better!!! Hopefully customers like us will put some.pressure on manufacture to improve product and quality control.
 
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PolarisRngr said:
View attachment 328738Todays 60 yard group at 3600psi. I maybe over estimating the usefulness of the Texan.
Click to expand...
I'm definitely NOT an Airforce fanboy, but I'm breaking in and doping a new .50 cal Texan also. Check out my thread for my range session today. All of my groups were with 388 grain, .510" hollow points topping off with a max fill of 250 bar for each shot. I didn't get good accuracy until I hit the 388s and was ready to turn my Texan(s) into tomato stakes.
IMG_1050.jpeg
IMG_1047.jpeg
IMG_1051.jpeg
 
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The 50 cal texan will work well with the TX TWO valve and stock barrel, only thing changed on this rifle is a 1.1 liter tank instead of the tiny .5 factory tank. Yes, this is 17 consecutive shots no valve lock. The 50 cal Texan rifle was really made to shoot 400 grain bullets. This shot string is with 420 grain .510 powder coated bullet. The entire shot string grouping will be inside a 3 inch circle at 50 yards. I set this up for hunting and yes I have added a custom Mad Dog stock. Yes I did fire lap the barrel nothing was done on the crown nothing done to the chamber.
Start at 300 BAR stop at 2000 psi

Texan50BB420.jpg
 
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dwjr said:
The 50 cal texan will work well with the TX TWO valve and stock barrel, only thing changed on this rifle is a 1.1 liter tank instead of the tiny .5 factory tank. Yes, this is 17 consecutive shots no valve lock. The 50 cal Texan rifle was really made to shoot 400 grain bullets. This shot string is with 420 grain .510 powder coated bullet. The entire shot string grouping will be inside a 3 inch circle at 50 yards. I set this up for hunting and yes I have added a custom Mad Dog stock. Yes I did fire lap the barrel nothing was done on the crown nothing done to the chamber.
Start at 300 BAR stop at 2000 psi

View attachment 328811
Click to expand...
Carbon bottle?
 
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PolarisRngr said:
View attachment 329947

60 yard group with a gun 1/4 of the price of any Airforce. #gauntlet.25
Click to expand...
What is the comparison? A small caliber regulated pellet gun vs a non-regulated heavy slug shooter?
I’d expect better at 60 yards with a regulated pellet rifle. That looks like a 2 inch group at the least from it!
 
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