I designed machined and installed an adapter to convert Brocock Bantam to FX STX barrel system, here is gun with 500mm slug liner installed. Works awesome, incredibly accurate.
Installed FX Slug Liner in Bantam Sniper
- Thread starter bzizzi373
- Start date
Very impressive work sir. You got pics of it in action at different distances? I am interested in seeing how accurate and what fps you're running.
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I actually did a 500 & 600mm liner, the 600mm pellet liner shot 25.4 JSB Redesigned @ 900 FPS and I imagine a 600 slug liner would be even faster, The 500mm slug liner shoots the 18.1's really accurate @ 900 FPS,, had them going 950 but did not group as good as 900-920. The farthest I shot the Bantam with STX was 50 yards, regular STX pellet liners did pretty good as well. With the 600mm liner I was able to get the 18.1's to 1000 FPS but they shot better under 950. I had the regulator around 140 BAR. To adapt the STX system to the Bantam I had to do a-lot of testing, first I made a prototype adapter that was able to accept a FX outer liner, the adapter needed internal probe O ring groove and O ring grooves on both sides of transfer port. The X liner starts right after the transfer port. I had extra parts from my Crown that I was no longer using and modified them to correct length. I also made an adapter so FX shroud would screw on over entire STX inner liner. Not everyone has the means to do this, I use Solid Works Modeling CAD to design the adapter, next I used a Harding's tool room lathe with metric threading capabilities to make adapters to fit the FX metric threads on shroud. I have been a journeyman Tool and Die Maker for the past 40 years and have access to a complete machine shop. Also used a Bridgeport Milling machine in the process to drill transfer port hole and mill counterbore flats for set screws.Overall accuracy using the STX barrels is considerably better in my Bantam than the factory LW barrel. I made blueprints for all the parts necessary to convert a Bantam to a STX Bantam and plan on making more adapters and will offer them for sale. My plan is to offer a drop in kit, loosen two set screws, slide out factory LW barrel, slide STX barrel that includes liner, outer liner and shroud, tighten screws, replace scope and start shooting.
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I did the same! Works awesome. I went with the 700mm and did carbon fiber shroud. Looks great!
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I think that’s really cool and I admire your idea and skills. But I have to ask since you haven’t shot it past 50 yards. Did you get a really bad LW barrel with your Bantam? I’ve had a Bantam with LW barrel and it was a laser beam easy dime sized 5 shot groups at 50 yards. I can see the benefit if someone wanted to shoot slugs from their Bantam, but unless they got a raw deal on a stock LW barrel the STX is no more accurate with pellets than an LW barrel that isn’t defective.
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While I would love to install a stx barrel on my 22 streamline for the wider range of projectiles it would shoot, I think I would be better selling it for a dreamline or crown. I think in the long run I would be happier with the crown. I do wonder which barrel tends to show the highest bc for the given pellet.
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I have several PCP’s and some have accurate LW barrels but overall have found that the STX barrels are consistently more accurate than the LW barrels I have had on guns over the years. My Bantam was relatively accurate but I was getting way too many flyers and if I wanted to take my Bantam to the next level I had to go in a different direction. Now I have the flexibility of the STX barrel system, my Bantam has the capabilities of achieving velocities I never could have gotten with the stock LW barrel. I can even shoot slugs now simply by swapping out barrel liners. My Bantam is a .22 and typically is not a long range gun like a .25 or a .30 cal but the STX barrels let me shoot farther, faster and more accurate with a flatter trajectory. I will eventually shoot at farther distances with the newer slugs being introduced to the market by FX and JSB. The only .22 pellet I have found to be really accurate past 75 yards are the JSB 25.4 redesign. The lighter .22 pellets just don’t carry energy down range and buck the wind like heavier pellets do.
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I just installed one of the .22 Brownells in a Mini Raptor Prototype fully regulated and shooting 39 gr. cast NOE slug at 900+ and it is a laser! It is the .22 short bbl. It set up with one wrap of an tight fitting 7075 t-6 hat treat and hard anodized Easton Alu. arrow shaft, then two thick walled twill wrapped cf tubes. It is incredibly stiff for a very rigid set up yet feather light.
I have two TJ's being set up for it now. One in .250 and one in .22 for slugs. Looking very forward to the testing, as a well known Slug maker that uses the swagging process is on board for the testing. Air Velocity Sports. Along with my own casting efforts.
So far, the 39 gr slugs, hand cast are printing 1/2 average at 80 yards from the Brownell's liner.
Knife
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The LWs can take a little work to polish up, but when you get them squared away they can be phenomenal. I had to remove a tiny bit of material out of my R5 .30 barrel's throat for 62-66gr slugs, it's a full-time slug gun but it will still shoot pellets like a laser if I need it to.
I re-chamfered that LW barrel and the one in my Lelya (22 cal), but the end results from the work that I put in was perfect groups, near complete elimination of flyers, and savings on patches for cleaning (one wet, one dry, and the third is usually clean). I'm not sure how Brockock does their barrel crowning or whether or not that it's easy to mar up, but I'd be looking there and at polishing the bore / choke real well.
My STX liners have been decent, but the harmonics are a challenge (high power). They're pretty thin compared to LWs and TJs.
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And exactly why I use them as true liners,and wrap them in thick walled CF tubing until they are bull barrels. Works wonders!
An Ultra-Light Bull Barrel. Woo-Hoo!! :<)
Knife
An Ultra-Light Bull Barrel. Woo-Hoo!! :<)
Knife
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Very nice work. 
i am going the other way, I am replacing the fx barrel on my impact for a LW, my impact is accurate but not as accurate as my other guns. There are just too many things about the liner system I don’t like for me to have confidence in it.
Bb
i am going the other way, I am replacing the fx barrel on my impact for a LW, my impact is accurate but not as accurate as my other guns. There are just too many things about the liner system I don’t like for me to have confidence in it.
Bb
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Thank you much for that. I have the FX liner and the thick walled CF tubing but the FX liner fits a bit loose in it. I was looking around for something to fill in the space and make it tight. The arrow shafts I have will not werq but armed with the idea I think I can finally finish my barrel.
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I acquired a 600 mm X Barrel assembly that I am considering installing on a custom Marauder build using a JSAR SS Large Port Balanced Valve! My Compatto has already been rebarreled with an unchoked LW Poly barrel (.25) and the original Compatto barrel found it's way to a custom "2540" Regulated Bottle fed gun..
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Select the cf tubing only 1 mm larger in dia than the liner. This will give you 1/2MM of space around the liner to fill with a good slow curing epoxy.
The dealer I purchase from has a huge selection of cf tubing, and very-very inexpensive. I will get a link.
The only reason I used the Easton shaft was I was out of the tubing, and was in i a hurry. LOL ;<) And I had the shaft in stock.
At the bottom of the ebay page, there is a huge selection of the tubing. However, he ships slow as sin!
www.ebay.com/itm/Glossy-20mm-OD-16mm-ID-500mm-Length-3K-Roll-Carbon-Fiber-Tube-20-16-500/283042430118?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
The dealer I purchase from has a huge selection of cf tubing, and very-very inexpensive. I will get a link.
The only reason I used the Easton shaft was I was out of the tubing, and was in i a hurry. LOL ;<) And I had the shaft in stock.
At the bottom of the ebay page, there is a huge selection of the tubing. However, he ships slow as sin!
www.ebay.com/itm/Glossy-20mm-OD-16mm-ID-500mm-Length-3K-Roll-Carbon-Fiber-Tube-20-16-500/283042430118?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
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That is amazing, I've been searching everywhere to find information on how to do what you have done and stumbled upon this thread. I really want to do this to my Brocock Sniper XR, which is the same as a Bantam MK2 but has the side lever cocking action. Did you make the conversion kits available? I would like to buy the kit if you have them. Any other information on this subject will be most appreciated.
Kindest regards
Solly
Kindest regards
Solly
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