I had Greg Davis put a LW barrel on my 1st gen 22 cal Marauder. I haven't shot another airgun since 2012 that is more accurate. I have 2 FX500'S and a 400 that shoot great but not better than the Marauder.
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Is a TJ barrel any better than a LW barrel?
- Thread starter boscoebrea
- Start date
What's the normal method of finishing the chamber in a barrel blank. Is a reamer used like in powder burners? I'm mainly interested in the lead in to the rifling or what would be the throat area in a powder burner. Those with experience please share every detail you're willing.
Thanks
James
Thanks
James
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OK, here's what I do, is it the perfect way? Probably not, but it works for me. No.1 you MUST have a lathe...and a mill is best for the transfer port. But a pair of v-blocks and a good vice along with the ability to center up and lock a tube may make using a drill press possible. No, 2 I am assuming the reader knows at least a little bit about machining practices, like truing up a piece in a lathe, centering a piece in a mill, de-burring, proper cutting fluids etc. Further, It is also assumed that the reader know to always start with a slug that is properly SIZED for his/her barrel, Which is to say 1 or 2 thousandths OVER the groove to groove diameter of a soft, round slug of lead pushed thru the barrel with lots of oil and grease. Saying "groove to groove" is a fancy way of saying to measure the maximum O.D. of the slug.
Here is a reamer I might use to make a .458 chamber:
https://www.amazon.com/Special-Decimal-4600-Chucking-Reamer/dp/B07TZRRW4S/ref=sr_1_5?crid=187B4QLKZ6NAA&keywords=chucking+reamer+.460%22&qid=1647111179&sprefix=chucking+reamer+.460+%2Caps%2C118&sr=8-5
-Determine the slug you "think" you'll shoot thru the gun. This is not so hard as it may seem, read around here and find out what others have had good luck with. Acquire a sample of that slug. Slug your barrel with a round ball using lots of oil and grease. Get a straight chucking reamer a thousandth or two larger than that barrel slug.
-OK, on to the barrel, start by facing off the breech end nice and square.
-Using a counter sink, create a nice inside taper at the breech end. This forms the feed ramp...so to speak. Usually, the seal on the probe will slip thru this chamfer and into the chamber a tad. For barrels that use an inside mounted o-ring to seal the probe, you will need to cut an inside seat for the o-ring. A small boring bar is good for this. Go slow here and check the fit of your probe frequently.
-Determine where your transfer port must go. This can be done by locking the barrel into position in the breech with the probe in place and marking the barrel thru the port.
-Using a pair of V blocks, lock the barrel into your mill vice and center it up so that a drill will punch thru exactly at the mark you made above. Using a center drill, create a starter hole for the port. Using a drill sized the same as the inner diameter of your actual transfer port (or about 75 to 80% of your slug diameter), drill thru the barrel wall. The transfer port in your breech SHOULD be larger than the hole in your barrel.
-Measure the length of the slug you are going to be shooting. That is; the part of the slug that contacts the rifling, the bearing surface length.
-When you ream your chamber, you want to be sure that you push thru deep enough so that the chamber is a tad longer than the slug AHEAD of the transfer port. How much longer? That depends on your probe. Most rifles in my experience will have the probe tip go just past the window of the transfer port. The distance from the probe tip forward the length of the bearing surface of your slug is how far you need to ream. This is done with a chucking reamer a thousandth or two larger than your "sized" slug diameter.
-The tricky part, creating the leade. I like to use those clay filled rubber bits...what are they called? Look here:
https://www.amazon.com/gp/product/B01D1B7RLO/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
-Pick a bullet shaped bit from that assortment that fits nicely into your chamber and get out your Dremel. What you are going to do is to taper the riflings ahead of your chamber... just a little to give the bullet a nice easy start. Rather than an abrupt rifling edge to crash into.
-Put your barrel back in your lathe. Spin it up with the lathe while simultaneously plunging into and past the chamber with that bit while it is spinning in a dremel the opposite direction. You'll have to hold the Dremel with your hands, so be careful. In the end this step is not so bad, the bit is soft and cannot move a lot of metal in one cut, so you have lots of chances to get it right. You may even have to use more than one bit.
-Another tip: You can de-bur the inside of the transfer port just before cutting your leade using a cylindrical bit from that collection in the same way...spin the barrel one way and the bit the opposite...
-Polish all the machined surfaces with a felt bit in your Dremel and metal polish, I like Flitz.
Hope this sheds a little light on it
Chris
Here is a reamer I might use to make a .458 chamber:
https://www.amazon.com/Special-Decimal-4600-Chucking-Reamer/dp/B07TZRRW4S/ref=sr_1_5?crid=187B4QLKZ6NAA&keywords=chucking+reamer+.460%22&qid=1647111179&sprefix=chucking+reamer+.460+%2Caps%2C118&sr=8-5
-Determine the slug you "think" you'll shoot thru the gun. This is not so hard as it may seem, read around here and find out what others have had good luck with. Acquire a sample of that slug. Slug your barrel with a round ball using lots of oil and grease. Get a straight chucking reamer a thousandth or two larger than that barrel slug.
-OK, on to the barrel, start by facing off the breech end nice and square.
-Using a counter sink, create a nice inside taper at the breech end. This forms the feed ramp...so to speak. Usually, the seal on the probe will slip thru this chamfer and into the chamber a tad. For barrels that use an inside mounted o-ring to seal the probe, you will need to cut an inside seat for the o-ring. A small boring bar is good for this. Go slow here and check the fit of your probe frequently.
-Determine where your transfer port must go. This can be done by locking the barrel into position in the breech with the probe in place and marking the barrel thru the port.
-Using a pair of V blocks, lock the barrel into your mill vice and center it up so that a drill will punch thru exactly at the mark you made above. Using a center drill, create a starter hole for the port. Using a drill sized the same as the inner diameter of your actual transfer port (or about 75 to 80% of your slug diameter), drill thru the barrel wall. The transfer port in your breech SHOULD be larger than the hole in your barrel.
-Measure the length of the slug you are going to be shooting. That is; the part of the slug that contacts the rifling, the bearing surface length.
-When you ream your chamber, you want to be sure that you push thru deep enough so that the chamber is a tad longer than the slug AHEAD of the transfer port. How much longer? That depends on your probe. Most rifles in my experience will have the probe tip go just past the window of the transfer port. The distance from the probe tip forward the length of the bearing surface of your slug is how far you need to ream. This is done with a chucking reamer a thousandth or two larger than your "sized" slug diameter.
-The tricky part, creating the leade. I like to use those clay filled rubber bits...what are they called? Look here:
https://www.amazon.com/gp/product/B01D1B7RLO/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
-Pick a bullet shaped bit from that assortment that fits nicely into your chamber and get out your Dremel. What you are going to do is to taper the riflings ahead of your chamber... just a little to give the bullet a nice easy start. Rather than an abrupt rifling edge to crash into.
-Put your barrel back in your lathe. Spin it up with the lathe while simultaneously plunging into and past the chamber with that bit while it is spinning in a dremel the opposite direction. You'll have to hold the Dremel with your hands, so be careful. In the end this step is not so bad, the bit is soft and cannot move a lot of metal in one cut, so you have lots of chances to get it right. You may even have to use more than one bit.
-Another tip: You can de-bur the inside of the transfer port just before cutting your leade using a cylindrical bit from that collection in the same way...spin the barrel one way and the bit the opposite...
-Polish all the machined surfaces with a felt bit in your Dremel and metal polish, I like Flitz.
Hope this sheds a little light on it
Chris
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Don't think I read it within this thread .... TJ's barrel liners DOES NOT MAKE DROP IN BARRELS. They will sell you a BLANK at specs of Caliber/ Length / Diameter off there price list. Final machining to fit is end users responsibility to get correctly done.
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Yep, TJ's doesn't do any chambering, crowning or threading / finishing work.
Chamber reaming really has to be square and concentric for the best end results IME. There's several considerations for the chamber / chamber throat specifications, but a competent barrel smith should be able to figure out your use case in determining this.
Chamber reaming really has to be square and concentric for the best end results IME. There's several considerations for the chamber / chamber throat specifications, but a competent barrel smith should be able to figure out your use case in determining this.
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I've not owned one of those barrels, if I had to guess, I'd say that is a typo. Write to TJ's and ask them.
Chris
Chris
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People interested in this thread may like this one as well https://www.airgunnation.com/topic/finishing-a-new-barrel-blank/
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I'm bit late to this party but I have some info to the process that one should look for and consider.
One of the most important thing is the tools as already stated above. Imo, if you don't use an independent 4 jaw chuck, you're relying on luck for an outcome. I have yet to fi d a barrel that in concentric from od to bore. I always indicate to the bore. Typically use a gauge pin or grizzly rod. I have made a tool specifically for ag barrels that allows me to get on bore axis concentricly and along the axis as well. I'll post a pic of it.
All cuts that I make are true to bore along the length as well as concentricly. This tool is held in the lathe with a 4 jaw chuck. Any barrel over .25 cal, I use a boring bar. Otherwise , I use a reamer that I make. The ports and set screw flats are cut using a 4axis CNC so everything is 180deg. For fx barrel I make them dual port for those who desire such. IMO, under .30cal doesn't benefit. Perhaps if someone wanted to decrease power with a smaller port. Lol, but who does that? I have personally found high end manufacturers with barrel chamber to bore out of concentric by .003"+. Thats a heck of a thing to do to a CZ barrel. Atleast I was told that it was a CZ. That is indicative of using a 3 jaw self centering chuck. Set up is exceptionally more time consuming that making the cuts. 
One of the most important thing is the tools as already stated above. Imo, if you don't use an independent 4 jaw chuck, you're relying on luck for an outcome. I have yet to fi d a barrel that in concentric from od to bore. I always indicate to the bore. Typically use a gauge pin or grizzly rod. I have made a tool specifically for ag barrels that allows me to get on bore axis concentricly and along the axis as well. I'll post a pic of it.
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So you think tj is a small and unknown barrel company? Apparently you don’t mess with powder burners because they are well known and respected in the powder biting communityand make barrels for everything, I have a custom barrel made by them in my colt 1911.. as for airguns I have 2 jsar raptors and a war flex rifle that have tj’s and they are very accurate and are robust barrels, not like the fx liners that look brake lines on a car
and yes I owned impacts and know all about their barrel liners and how they work, needless to say I’m not a fx fanboy anymore and will probably never own another fx rifle again.. sticking to American made riflesUpvote 0
The biggest difference I see between TJ's and Lother Walther USA is the land and groove size. All the offerings I've seen from LW are larger than standard pellet and slug sizes while TJ's is the correct size for industry standard ammo in my opinion. Either company offers choked and chokeless barrels.
A .30 LW barrel has a land and groove size of .298/.306 If you put a .300 slug in this barrel you still see light around the slug.
A .30 TJ's barrel has a land and groove size of .294/.300 and should fit industry standard size projectiles better.
I have a Troy Hammer designed TJ's .22 barrel on my Avenger with a .217 groove diameter. First 5 shot group at 51 yards measured .395 outside to outside. subtracting the .2165 slug diameter = .1785 Not bad for an Avenger.
NSA 17.5gn .2165 diameter 950fps
If you're interested in this Troy Hammer designed TJ's barrel whether it be custom fit to your gun or blank it can only be ordered through Troy Hammer.
A .30 LW barrel has a land and groove size of .298/.306 If you put a .300 slug in this barrel you still see light around the slug.
A .30 TJ's barrel has a land and groove size of .294/.300 and should fit industry standard size projectiles better.
I have a Troy Hammer designed TJ's .22 barrel on my Avenger with a .217 groove diameter. First 5 shot group at 51 yards measured .395 outside to outside. subtracting the .2165 slug diameter = .1785 Not bad for an Avenger.
NSA 17.5gn .2165 diameter 950fps
If you're interested in this Troy Hammer designed TJ's barrel whether it be custom fit to your gun or blank it can only be ordered through Troy Hammer.
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As I've mainly used Lothar Walther because of availability, my experience has been that they are more consistent plus I really like the polygonal bore that LW offers. While fitting less than 10 TJ barrels, it's enough for me to prefer not to use them unless there's no good other option. They WILL need lapping if you want a fine bore of consistent size. They CAN be as good as any other if properly fitted and finished. On the plus side they can custom make different sizes and lengths and are not outrageously expensive before finishing.
Bob
Bob
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I too have one of TROYs Custom 3 groove TJ's .22's. Set up at 26" and under stretch tension in the JSAR raptor mini it shoots FANTASTIC with NSA 20.2 or JSB RD's at high 900 fps speeds
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Just curious, Scott... what outer diameter is your 3 groove and did you trim it much?
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it was a .500" diameter liner. here is my thread on adapting it into the JSAR where it also was further stiffened due to its length.
See: https://www.airgunnation.com/thread...-o-carbon-tubing-tjs-3-groove-barrel.1272026/
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