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All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: strever on February 08, 2020, 03:05:56 PM

Title: problem with .177 TJ barrel
Post by: strever on February 08, 2020, 03:05:56 PM
i purchased a .177 barrel from TJ and sleeved it with a CF like Bob Sterne described
i machine my own barrels for benchrest shooting and wanted to try something different
the TJ list only shows 2 airgun barrels available in .177 which i was doubtful of but tried anyway
here is the list below, notice the bore is only .172 dia way way too small for the precision pellets we shoot in Benchrest
it distorted them so bad the best group was close to 2" at 25 yds in a Thomas gun with the smallest heads i could find
has anybody had any experience with these .177 TJ barrels ?
Title: Re: problem with .177 TJ barrel
Post by: hpmr2400 on February 08, 2020, 03:13:23 PM
I believe these .177 barrels are strictly slug/bullet barrels.. I may be wrong. I do remember Tofazfou making a mrod based slug shooter with this barrel.
Title: Re: problem with .177 TJ barrel
Post by: moorepower on February 08, 2020, 03:30:44 PM
.172 is the size for .17 HM2, .17HMR, .17WSM. and all the centerfire .17's, not pellets. You can cast bullets to fit.
Title: Re: problem with .177 TJ barrel
Post by: rsterne on February 08, 2020, 03:33:43 PM
The .177 barrels listed on the TJ's Airgun price sheet are for pellets.... The .172 cal barrel for slugs is a 9" twist rate, 0.168" lands and 0.172 grooves.... That is what Ced used for his slug shooter, and is a completely different barrel than what Dick has....

Bob
Title: Re: problem with .177 TJ barrel
Post by: K.O. on February 08, 2020, 03:45:16 PM
well I for one am curious how this barrel would do with sniper mags, rabbit mags, monsters, beast and such... which twist rate did you get... Pile drivers might work but never had much faith in a round base...

I was curious a while ago and have a Savage 17HMR barrel blank .168/.172... So pushed a Sniper Mag thru just to see what it would look like after...

Pic below, does look like it has a chance to fly well... So yep maybe some of the cylindricals and the Heavy stuff..?
Title: Re: problem with .177 TJ barrel
Post by: Blutroop on February 08, 2020, 04:12:54 PM
I wonder how much lapping would have to be done to take a few thou off the lands? Also talk to varmit knockers. I bought some .172 slugs for my .172 barrel with 1-9 twist. He sized them to .172 for me and are too tight. He does swaged and cast and might be able to do you some slugs at .173-.174. I’d be interested in playing with it. Pm me a address and I’ll send you some 26 gr swaged slugs sized at .172 and see what happens.
Title: Re: problem with .177 TJ barrel
Post by: rsterne on February 08, 2020, 05:20:40 PM
You can size slugs smaller, but to make 0.173" or 0.174" slugs Dale would require a new die from Corbin.... $$$$

Even at 0.174" they would be too small for a .177" groove barrel, IMO.... About 0.001" under the groove diameter is about right for slugs, and for the nose of pellets.... full engagement of the rifling lands without rubbing on the grooves.... Pellet skirts will end up smaller upon chambering, of course, as they are designed to do....

Bob
Title: Re: problem with .177 TJ barrel
Post by: K.O. on February 08, 2020, 06:22:34 PM
Here is the thing to me... L.W. .177 specs are .176 land and .182 groove... I measured my 1985 daisy .177 L.W. barrel and the 2014 Air force .177 and they both are choked to about .177-.178 groove...

so that means at the muzzle lands would be about .172 or so...So bout the same specs for the TJ barrel... so yep heat the barrel a bit see if you can pour a  lap and taper lapp the snot out of it if you can... or just fire lap the snot out of it..?
Title: Re: problem with .177 TJ barrel
Post by: Blutroop on February 08, 2020, 07:30:53 PM
Might be a perfect candidate to try electrochemical machining. I’ve been thinking about trying to rifle my own barrels with this process and you can do it on the cheap with some redkneck injinuity. With this barrel you wouldent have to rifle just take the lands down some.
Title: Re: problem with .177 TJ barrel
Post by: makarov76 on February 08, 2020, 11:36:10 PM
I wonder how much lapping would have to be done to take a few thou off the lands?


A hole lot’ you would probably destroy the
Barrel unless you are some kind of lapping
God’

I have been casting boolits for about 20yrs’
I always size so they are .001” over groove dia sometimes .002” over groove dia’

I have always used ww and scrap with extra tin to make them cast better and pretty because I didn’t care about the cost’

I have a bunch I cast & sized yrs ago they
Have age harden a little & they also swollen
Up a good .001” they actually shot better than the fresh cast ones’
But pb is a little different the load means
Everything’
Title: Re: problem with .177 TJ barrel
Post by: strever on February 09, 2020, 12:57:29 PM
The barrel is useless for me
if some one can use a 24" long sleeved with carbon fiber to 16mm
PM me
Title: Re: problem with .177 TJ barrel
Post by: rsterne on February 09, 2020, 01:33:16 PM
The only suggestions I have are the obvious ones.... Crown?.... Clipping a baffle in the LDC?.... Have you tried it without any muzzle attachments?.... Did you lap the barrel at all before installation?....

I'm going to need a .177 barrel for testing .177 pellet drag with my LabRadar in 2021, and accuracy is unimportant.... but getting a barrel out of the USA is such a hassle....

Bob
Title: Re: problem with .177 TJ barrel
Post by: strever on February 21, 2020, 07:55:18 PM
i have been in contact with TJ

and they are telling me i am using the wrong size (too big) pellets

because nobody else has ever complained about these barrels before

with a .172 bore what head size should i be shooting ?

the smallest heads i have in stock of more then 500 tins, yes i have a large inventory

is 4.47 = .176 head size, and they do not work in this barrel

but are much too small for a standard LW barrel with a .176 bore

if i need smaller pellets? what size and where would you find them ?
Dick
Title: Re: problem with .177 TJ barrel
Post by: Long_Gun_Dallas on February 21, 2020, 08:24:48 PM
Get you a pellet sizer.  Mine is adjustable.  Courtesy of TR Robb
Title: Re: problem with .177 TJ barrel
Post by: Sbak on February 21, 2020, 08:34:34 PM
I think there is a little bit  of confusion going on here. Tj's makes two different .17 barrels, you are going to need to slug your bore. Bore size is the smallest measurement, .172 bore is pretty typical of all the .177 specs ive seen. If your groove size is .172 you have the wrong barrel
Title: Re: problem with .177 TJ barrel
Post by: strever on February 21, 2020, 11:37:07 PM
Long gun
i want a better barrel than the LW i have now and the LW will out shoot the TJ 10 to 1

plus i have thousands and thousands of pellets that do not need resizing for the LW

Sbak
you haven't looked at barrel specs
here is a typical non- chocked LW, as you can see the bore is .176 which is .004 larger then the TJ
Caliber:.177 air
Choke:no
Twist:17.7"
Material:precision rifle steel tube
Outer diameter [OD]:.63"
Length [L]:23.82"
Bore diameter:.176"
Groove diameter:.182"
Grooves:12
Weight:1.936 lbs
Title: Re: problem with .177 TJ barrel
Post by: Sbak on February 22, 2020, 12:29:27 PM
LW specs big, you still need to slug it
Title: Re: problem with .177 TJ barrel
Post by: strever on February 22, 2020, 02:37:05 PM
why would i slug a barrel to shoot pellets ?
Title: Re: problem with .177 TJ barrel
Post by: Sbak on February 23, 2020, 12:55:47 AM
Because, if you have the correct barrel, or a barrel within spec your inaccuracies are not barrel spec related. You can then go from there to troubleshoot whatever your issue is. One step at a time, slugging the barrel is just what I would do first. If you're not willing to even do that, you probably shouldn't be trying to do your own.
Title: Re: problem with .177 TJ barrel
Post by: strever on February 23, 2020, 12:46:32 PM
your first sentence is the point i am making
Title: Re: problem with .177 TJ barrel
Post by: Back_Roads on February 23, 2020, 03:38:26 PM
 From the OP, it sounds like you purchased a .172 .17 HMR barrel, a powderburner barrel specific to powder burner ammo, or very custom air rifles, that require home cast and swaged projectiles or custom sizing dies to make fit and accurate.. .

i purchased a .177 barrel from TJ and sleeved it with a CF like Bob Sterne described
i machine my own barrels for benchrest shooting and wanted to try something different
the TJ list only shows 2 airgun barrels available in .177 which i was doubtful of but tried anyway
here is the list below, notice the bore is only .172 dia way way too small for the precision pellets we shoot in Benchrest
it distorted them so bad the best group was close to 2" at 25 yds in a Thomas gun with the smallest heads i could find
has anybody had any experience with these .177 TJ barrels ?
Title: Re: problem with .177 TJ barrel
Post by: KnifeMaker on February 24, 2020, 12:37:03 PM
Without slugging the barrel, you don't really know what you have. Mix ups happen. ;) 
Title: Re: problem with .177 TJ barrel
Post by: strever on February 24, 2020, 01:52:48 PM
Michael
are you suggesting TJ's may have sent me the wrong barrel ?

for pellets the most important dimension is the bore as long as it is consistent
the groves are filled by the floppy skirts of a pellet and also need to be consistent
all i know now is this barrel does not shoot pellets even tho TJ's says it is a pellet barrel



Quote from: KnifeMaker on February 24, 2020, 12:37:03 PM
Without slugging the barrel, you don't really know what you have. Mix ups happen. ;)