.308 Texan SS .. Sporadic accuracy Fliers...

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Shooting Targets

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Jan 7, 2017
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So, I have .308 stock texan ss. I been running some test with different bullets along with the rifle being tethered to a larger tank say 2600 PSI.

I can get like 2 or 3 within 1 inch at 50 yards. Out of a 5 shot group 3 maybe 4 are withing an inch the rest are extreme fliers. like 3 to 4 inches out. I do not understand this as my FPS spread on the rifle is about 6 to 8 fps over 30 shots. It seems to want to like the ammo yet just when it shows signs of being dialed in it throws out the next 2 shots or so. No clipping going on at the barrel. Thinking of Clean the barrel maybe polish the barrel as well ? I would not think a simple thing as that would clean up the group thou right ?

Curious I should just move on to different ammo ? Big bores are more of a mystery to me.. Normally I would have a ton of different ammo selections and just shoot shoot shoot until I find something it likes in wide various conditions. Your thoughts ?
 
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You really need to keep a big bore clean and unleaded. Assuming you have slugged the bbl and use the correct sizing die on your slugs. That with weighing and lubing should smooth things out. Pay attention to hold when shooting groups. Next culprits could be harmonics and even the scope. Make one change at a time. Good luck
 
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Sham, thanks for the reply. Is harmonics an issue with very regulated air of say 2 fps on some of these shots ? I have heard guys saying they keep their barrels leaded up and they shoot fine. I mean not problem running and really cleaning it up .... Will hold be a huge or a smaller issue, say shooting at 55 yards ?
I had groups that were near touching each other say 4 shots in 1 inch and bam flier of say 3 inches out which kind of says Yep something with the barrel right ??
Thanks again,
Jay
 
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jaydog said:
Sham, thanks for the reply. Is harmonics an issue with very regulated air of say 2 fps on some of these shots ? I have heard guys saying they keep their barrels leaded up and they shoot fine. I mean not problem running and really cleaning it up .... Will hold be a huge or a smaller issue, say shooting at 55 yards ?
I had groups that were near touching each other say 4 shots in 1 inch and bam flier of say 3 inches out which kind of says Yep something with the barrel right ??
Thanks again,
Jay
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Harmonics can be an issue with anything, pb or air. If you happen to be right on the fine line of a bad spot in harmonics, a small change can make an abnormally big change, but your 3 inches at only 50 yards probably couldn't be explained by that, that is massive. Texan has a long barrel and slow bullet, eons of time with the slug in the barrel before exiting, shooting form can and will change impact a great deal if you are not absolutely consistent. How good is your follow through? Is every single shot on the bench moving your scope crosshairs to the same spot, or is it wandering a bit? Do you watch the slug flight through the scope? If you can't see the slug in flight through the scope you have shooting form problems, I can pick up my 22lr pb in the scope easily before it hits 50 yards. . If scope is settling after shot in different spots, it is your shooting form, need to work on it.
 
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karl_h said:
Harmonics can be an issue with anything, pb or air. If you happen to be right on the fine line of a bad spot in harmonics, a small change can make an abnormally big change, but your 3 inches at only 50 yards probably couldn't be explained by that, that is massive. Texan has a long barrel and slow bullet, eons of time with the slug in the barrel before exiting, shooting form can and will change impact a great deal if you are not absolutely consistent. How good is your follow through? Is every single shot on the bench moving your scope crosshairs to the same spot, or is it wandering a bit? Do you watch the slug flight through the scope? If you can't see the slug in flight through the scope you have shooting form problems, I can pick up my 22lr pb in the scope easily before it hits 50 yards. . If scope is settling after shot in different spots, it is your shooting form, need to work on it.
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Karl, well so I do shoot a fair amount. I can usually spot a pull on a shot pretty easy. The .308 does have muzzle jump as it is shooting out 200 FPE of energy. So me watching the follow through of the slug is not possible as the rifle jumps up and hits the target before I am able to pick up the bullet as the rifle scope is falling back to the target. I usually spot some partial impact as the rifle is coming back down into the viewing area. I guess I can back out on the zoom and maybe see more hmmm but the gun does kick and more in an upward fashion much slower than say a .22 lr.

I basically have the gun in a gun rest so I really try to make sure every shot is the same amount of pressure on the stock and trigger and hold. hmmm I agree the shot cycle is way slower on these rifles. What I noticed in many of these Big Bore is that once I get above say 90 FPE i start seeing muzzle jump more and more. The rifles just do not seem as accurate overall vs a well balanced rifle with much less power.

I will look at my form but if this .308 is that hold and form sensitive it is worthless to me. I mean I do not think anybody my friends included would be able to do much difference. You will have to shoot like a god for it to make any groups. hmmm...

I noticed the same grouping patterns at 25 yards a little less but that was shooting of a sandbag at an indoor range. a few right on top of each others and bam 1.5 to 2 inches out ....

Thanks again for replying, just trying to narrow down variables.
 
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Do you know your bore size and are your slugs all the same diameter +/- no more than a few ten thousandths? If slugs vary by 1 thousandth or more, that could cause some issue, in my 357 texan, slugs that are 1 thou under what mine likes start going everwhere, less than half a thousandth over I lose some velocity but almost same accuracy, at 5 or 6 ten thousandths over what mine likes both velocity and accuracy start to suffer. I size my texan slugs to avoid that, slowly worked up a lee push through sizer to get just the perfect size for mine.
 
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Ahh, so I am working with ammo maker. These rounds are very high price about 70 cents a round. They seem about the best ammo I have seen very high quality. The ammo builder has worked with John McCaslin the owner of Airforce airguns. I guess John's favorite texan is the .308 with this ammo. So I am getting more details on the PSI and setting, FPS speed for the ammo as well. Long story but this ammo was suppose to get the end all be all from working with a few guys. Cant say much else but will start to really get into the bore size and talk with other guys as well. I am sure there are variances in the bore size as you mentioned a few then thousandths +-. Back to the drawing board. I have to fire lap, clean the barrels before anything else.

Thanks again...
 
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karl_h said:
Do you know your bore size and are your slugs all the same diameter +/- no more than a few ten thousandths? If slugs vary by 1 thousandth or more, that could cause some issue, in my 357 texan, slugs that are 1 thou under what mine likes start going everwhere, less than half a thousandth over I lose some velocity but almost same accuracy, at 5 or 6 ten thousandths over what mine likes both velocity and accuracy start to suffer. I size my texan slugs to avoid that, slowly worked up a lee push through sizer to get just the perfect siz
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jaydog said:
Ahh, so I am working with ammo maker. These rounds are very high price about 70 cents a round. They seem about the best ammo I have seen very high quality. The ammo builder has worked with John McCaslin the owner of Airforce airguns. I guess John's favorite texan is the .308 with this ammo. So I am getting more details on the PSI and setting, FPS speed for the ammo as well. Long story but this ammo was suppose to get the end all be all from working with a few guys. Cant say much else but will start to really get into the bore size and talk with other guys as well. I am sure there are variances in the bore size as you mentioned a few then thousandths +-. Back to the drawing board. I have to fire lap, clean the barrels before anything else.

Thanks again...
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Interesting info. Something to think about
 
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jaydog said:
Ahh, so I am working with ammo maker. These rounds are very high price about 70 cents a round. They seem about the best ammo I have seen very high quality. The ammo builder has worked with John McCaslin the owner of Airforce airguns. I guess John's favorite texan is the .308 with this ammo. So I am getting more details on the PSI and setting, FPS speed for the ammo as well. Long story but this ammo was suppose to get the end all be all from working with a few guys. Cant say much else but will start to really get into the bore size and talk with other guys as well. I am sure there are variances in the bore size as you mentioned a few then thousandths +-. Back to the drawing board. I have to fire lap, clean the barrels before anything else.

Thanks again...
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Make sure you really want to firelap, I had no choice on my texan, the bore looked like the surface of a concrete block and it had many extremely tight spots in the barrel. And that was the replacement air force sent me when my first one was completely non-functional. To get my bore smooth with no craters, rust, and tight spots, I ended up really opening up the bore and taking down the lands. With the coarse fire lapping compound, you can really take a lot out quickly, and more than you think with the medium compound. Go slow, clean, inspect. I have a non-fouling barrel now, I can shoot hundreds of slugs without cleaning. But there is no slug out there made by anyone specifically for a .357 texan that would even remotely work in mine now. Biggest I've seen is .357 and most smaller, that size in mine would be extremely slow from blow by and not able to hit the side of a barn. I take .358 pb bullets and size them down a few ten thousandths. I have an extremely dim view of airforce, not just because I got two sh^t guns in a row, but the phone calls I had with them. I will never get another under any circumstances, or touch anything that company has anything to do with.
 
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karl_h said:
Make sure you really want to firelap, I had no choice on my texan, the bore looked like the surface of a concrete block and it had many extremely tight spots in the barrel. And that was the replacement air force sent me when my first one was completely non-functional. To get my bore smooth with no craters, rust, and tight spots, I ended up really opening up the bore and taking down the lands. With the coarse fire lapping compound, you can really take a lot out quickly, and more than you think with the medium compound. Go slow, clean, inspect. I have a non-fouling barrel now, I can shoot hundreds of slugs without cleaning. But there is no slug out there made by anyone specifically for a .357 texan that would even remotely work in mine now. Biggest I've seen is .357 and most smaller, that size in mine would be extremely slow from blow by and not able to hit the side of a barn. I take .358 pb bullets and size them down a few ten thousandths. I have an extremely dim view of airforce, not just because I got two sh^t guns in a row, but the phone calls I had with them. I will never get another under any circumstances, or touch anything that company has anything to do with.
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Much thanks for the reply. Wow I am hearing more and more about experiences with these airguns on the negative side. Will keep an eye out on this one.

Jared
 
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Mike is right, I did have a .308 Texan, but I sold it. I like the Airforce platform, but for whatever reason, I just couldn't get the .308 to do what I wanted it to.

As Mike said, I switched to the .457 and I love it! Attached is two, 3 shot groups I did right out of the box... one at 75 yards, the other at 100 (I was shooting for groups, not accuracy).

I'm having some work done on it now but I'm really looking forward to shooting it at the Ashland, RMAC and EBR tournaments this year. -Dave

BTW... for the ref test above, I was shooting at 3,000 PSI with the wheel in the middle. NSA 350gr HPBT @ about 800 ish fps

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