How to unchoke my hatsan bullboss barrel to shoot slugs
Mod edit: moved to Other Parts
Mod edit: moved to Other Parts
Remove Barrel choke?
- Thread starter tellis
- Start date
Yup that's about it. Cut it off and recrown it. The choke is only the last couple inches of the barrel push a pellet in from the breech end and when it gets tight towards the end put something in the crown end and make a mark to give you a good idea of how much to cut off. The barrels are fairly soft so cut well with a fine toothed hacksaw. Then you can put the barrel in a drill, spin it and hold a file to the edge to straighten and flatten the crown end up. A round headed screw in your drill with some fine 400-600 grit sandpaper attached will give you a decent crown. Or you can buy a crown tool for near $50. You can do a search for the barrel recrown on the net there are lots of ways to do it.
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Some shrouds have a simple end cap that screws off, baffles come out, and you unscrew shroud from receiver or mating threaded coupler.
If you unscrew endcap and see a tensioning nut. I wouldn’t go for it because they’re set up to work for that barrel length/OD/caliber power level harmonics, torqued to spec to work right.
I had an EDgun with a love/hate relationship as it was my 1st bull pup. I’m a lefty, tensioned barrel choked LW so I couldn’t easily add a 28-32” no choke TJ liner. It still somehow shot slugs and JSB 33.95’s in one hole when tuned right. The Raptor had me super excited but again I learn, tensioned barrel & yes we use TJ no choke if you want a slug gun but won’t be able to offer a long .257 because tensioning system works with barrel band to bottle & most guys want a bull pup or SBR lightweight multi shot sidelever. In this case you have an option. You COULD do it or have someone experienced do it for you. Chokes are usually 0.002-0.004” and since airgun steel is softer than rifle steel, hand lap that last 1 1/2 - 2” choke out. TJ liners are actually .25-20 rifle liners so more than likely very hard steel. They do come in any length you need. If you had a machine shop you could add extended reservoir or attachment to extend the original tensioning system to new barrels length. I’m not sure design would work well as it’s tensioning system is engineered to work harmonious & harmonically along with length/OD/power level as stated.
There’s no written in stone rule that a choked barrel won’t shoot some slugs very well. Many of our EDguns, Condors, Marauders do, & they use LW choked barrels from factory. I’ve seen no choke barrels put pellets hole in hole from my John Thomas tuned El Gamo 300 .177 that I cut down to 11” barrel. It’s only 7-8 fpe so no need for long leverage barrel. I cut with hacksaw progressively while practicing my crowning with Swiss files and a Helios square. It works but it’s more pellet fussy so it will meet John’s choke blocks & hydraulic press for a slight 0.001-0.002” progressive choke, tapered hardened tool steel choke blocks. Soft air gun barrel steel. Again I don’t know about TJ liners or messing with tensioned barrel.
So consider trying slugs from choke first. You can shoot both Diabolos & 100% to 98% lead slugs with great results & also shoot Diabolo pellets.
If you feel you must cut choke off or lap some of it out I suggest research or an expert. If I were going to try I’d simply use a short stiff pistol rod with a tight patch coated in JB embedded bore paste, valve compound. I’d finish with a good polish. Smallest micron particle abrasive I could find.
Please measure a pellet head with micrometers or calipers and document OD in thousandths & mm’s. Then load and push pellet all the way through, preferably with a one piece rod. A pellet should push through almost or with only the weight of the cleaning rod. You’ll feel it stop near the end & a slight push will have pellet drop out, now sized to choke. Measure & compare. Minus from 1st measurement straight from tin & you have your choke size. If it’s only 0.002” try slugs. There’s many a LW with 0.004” choke that can & do shoot slugs.
Break barrels or taking barrel off are necessary as it’s not easily done on guns like Sumatra or worse, a tensioned barrel with traditional bolt or sidelever. Another reason I really love Thomas & MAC 1 Hunter rifles. Swing breech allows fast swab from inlead out muzzle no problem.
If you unscrew endcap and see a tensioning nut. I wouldn’t go for it because they’re set up to work for that barrel length/OD/caliber power level harmonics, torqued to spec to work right.
I had an EDgun with a love/hate relationship as it was my 1st bull pup. I’m a lefty, tensioned barrel choked LW so I couldn’t easily add a 28-32” no choke TJ liner. It still somehow shot slugs and JSB 33.95’s in one hole when tuned right. The Raptor had me super excited but again I learn, tensioned barrel & yes we use TJ no choke if you want a slug gun but won’t be able to offer a long .257 because tensioning system works with barrel band to bottle & most guys want a bull pup or SBR lightweight multi shot sidelever. In this case you have an option. You COULD do it or have someone experienced do it for you. Chokes are usually 0.002-0.004” and since airgun steel is softer than rifle steel, hand lap that last 1 1/2 - 2” choke out. TJ liners are actually .25-20 rifle liners so more than likely very hard steel. They do come in any length you need. If you had a machine shop you could add extended reservoir or attachment to extend the original tensioning system to new barrels length. I’m not sure design would work well as it’s tensioning system is engineered to work harmonious & harmonically along with length/OD/power level as stated.
There’s no written in stone rule that a choked barrel won’t shoot some slugs very well. Many of our EDguns, Condors, Marauders do, & they use LW choked barrels from factory. I’ve seen no choke barrels put pellets hole in hole from my John Thomas tuned El Gamo 300 .177 that I cut down to 11” barrel. It’s only 7-8 fpe so no need for long leverage barrel. I cut with hacksaw progressively while practicing my crowning with Swiss files and a Helios square. It works but it’s more pellet fussy so it will meet John’s choke blocks & hydraulic press for a slight 0.001-0.002” progressive choke, tapered hardened tool steel choke blocks. Soft air gun barrel steel. Again I don’t know about TJ liners or messing with tensioned barrel.
So consider trying slugs from choke first. You can shoot both Diabolos & 100% to 98% lead slugs with great results & also shoot Diabolo pellets.
If you feel you must cut choke off or lap some of it out I suggest research or an expert. If I were going to try I’d simply use a short stiff pistol rod with a tight patch coated in JB embedded bore paste, valve compound. I’d finish with a good polish. Smallest micron particle abrasive I could find.
Please measure a pellet head with micrometers or calipers and document OD in thousandths & mm’s. Then load and push pellet all the way through, preferably with a one piece rod. A pellet should push through almost or with only the weight of the cleaning rod. You’ll feel it stop near the end & a slight push will have pellet drop out, now sized to choke. Measure & compare. Minus from 1st measurement straight from tin & you have your choke size. If it’s only 0.002” try slugs. There’s many a LW with 0.004” choke that can & do shoot slugs.
Break barrels or taking barrel off are necessary as it’s not easily done on guns like Sumatra or worse, a tensioned barrel with traditional bolt or sidelever. Another reason I really love Thomas & MAC 1 Hunter rifles. Swing breech allows fast swab from inlead out muzzle no problem.
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