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Texan carbine/horrible accuracy
- Thread starter PolarisRngr
- Start date
Measure that slug you tapped through the barrel...That's your barrel bore diameter... That easy
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I use pin gauges or a hole gauge to measure the bore diameter. Slugging with an oversized slug and then measuring the reduced slug diameter will give the groove diameter.
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After pushing an oversized slug through, measure the outside diameter at the widest points. For an even number of grooves, that will give the actual groove diameter. For an uneven number of grooves, the measurement might come out a little under the actual groove diameter.
On unchoked barrels. I like to size to (GROOVE_diameter - 0.001") to start. Check velocity/consistency/accuracy. Go up or down about 0.001" from there for further testing.
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Hi I looked at slug , Yoe need to do what I said , fire lap I as you can see the barrel is too rough to be accurate look at the slug you pushed threw , if you got a lathe spin it and polish in lathe
YOU NEED TO DO THIS BY HAND OR LATHE , I made this years ago , either do it this way or atleast firelap with same things I am using in video
LOU
YOU NEED TO DO THIS BY HAND OR LATHE , I made this years ago , either do it this way or atleast firelap with same things I am using in video
LOU
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I don't think anyone has said it outright yet, RETURN it for a refund. You shouldn't have to fix a 1k+ pcp with a sh$t barrel.
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Ask them what ammo they say will work in it well and ask for 10 free ones to be mailed to you for testing on the condition if they suck, PA will take the return and refund you.
Don't hold your breath, they won't go for it. I'm sure they are well aware that many texans have hopeless barrels without one heck of a lot of work on them. They just want your money.
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NSA ammo is the only swaged airgun ammo available in .510. It should be adequate for accuracy. You would think...My 2 cents
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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
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
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My 50 cf full length shoots best tethered 3625 psi power wheel maxed out. Shoots the best with any 4 cast designs I shoot. I'd say poopty barrel... Return or lap the barrel...
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@durbs75 , if you start out with a bad barrel, your tuning will not work no matter what. Glad you got a serviceable barrel on yours, it is not uncommon to get an extremely bad one. Before I worked on my barrel, just pressing a slug into the breech, every land would shave the front of the bullet, big curls of lead, that was with any slugs(from .355 to .38. If the rest of the barrel was good, that alone would end up leading up the barrel instantly and have no chance of shooting. From the OP's pic of slug, at least his isn't doing that. Once I got all the lead out that airforce put in it before sending me the replacement rifle for my fist non-functioning rifle, my barrel was pitted, and rusted in the pits the full length. I honestly think airforce sent me someone else's problem that was returned to them and not a truly new one. The phone calls were not amusing... and I gave up on airforce for all future consideration. It took me a long time firelapping only with coarse grit, cleaning, inspecting, rinse wash and repeat a ridiculous number of times to get all the pits and tight spots out of my barrel. Then I got to move down to finer grit firelapping and polishing.
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Yes it does, I have worked with a push through sizing die slowly working it up to best velocity/accuracy and have essentially 0 leading, I go hundreds of rounds without cleaning and no loss in accuracy. I knew from testing that just a couple ten thousandths over .358 on the full wadcutter I used for initial testing after working on the barrel was slowish and not bad accuracy, and sizing it down to .355 ish was slow and less accurate. Slowly working the sizer up in size, accuracy and velocity increased. I stopped at .3575 and was more accurate than at the original size of .358 and had the highest velocity I saw with that particular bullet. Not much difference between .3575 and the .3581 ish of original size, but very nearly cut group size by 1/3 and was 30ish FPS faster than unsized. Balancing cheap/accurate/good for hunting I only shoot Hornady cowboy bullets in it now. I shoot 158gr semi-wadcutters into < 2moa with them at just over 900fps, but that is perfectly good for hunting. The Hornady bullets are swaged, knurled, lubed. They actually for the most part don't size down in my sizer, very few have any resistance pushing through, so I skip that on those bullets. Between the knurling and lube they use, they are extremely consistent. At the power level I shoot my texan is a two shot gun on the bench. I get ES of no more than 5fps and usually less for the two shots before topping off.
A third shot would drop up to 20fps, and add a little less than 20% to group size at my 110 yard target hanger. Damn texans flex so much, I think they are under built, that 20fps drop on a third shot makes that much difference.
If I wanted to get the most accuracy I could out of it, I do have a round that I can shoot 1.25moa all day with, but the prep work is way too much effort for it, and it is only good for coyotes and smaller imo.
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If you are going to firelap, you will need a spotlessly clean barrel, and one heck of a lot of patience. From my experience with my barrel, it was shoot two, clean spotless. repeat. When the barrel was clearly getting better and much less fouling from two shots, I upped it to 3 shots and clean. Never went past there. When I switched to the medium grit firelapping compound, I always fired 3 then clean and inspect. Did that several times before I switched to the fine compound.
For firelapping purposes, I used hard cast bullets around 15BNH.
For firelapping purposes, I used hard cast bullets around 15BNH.
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Ended up sending it in for an exchange. Hopefully the new one will be better. I think I will look at the barrel with a bore scope prior to shooting. Any other suggestions before I start shooting?
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Bore scope before shooting is required. If exchange is coming from airforce, cross your fingers and pray they don't send you someone else's problem child. Clean it thoroughly before you shoot it, check with bore scope after cleaning, shoot exactly one round(lubed) and no more, check with bore scope. If you bore has areas that have very clearly smeared lead after one shot, you either are shooting a bullet that is oversized for your bore, or you are screwed. I'm talking about jump right out and smack you amounts of lead in bore, not some tiny sheen. If large amount of lead then clean the bore again, get some ammo that is a thousandth smaller in diameter than what you currently have and try again. One shot. Borescope it. Pray you don't have large deposits of lead after and your original ammo was just too large for your bore. You can try going another thousandth smaller and try again if needed, but given you are using nsa stuff for the texan I kind of doubt it would be a couple thou too big for your bore, one thousandth sure.
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