I need to know who can choke 11mm barrels and who sells barrels up to 28"?

[JimmyD.]

Looking to improve my Discoveries. Please email with any info as to who can choke existing 11mm barrels or longer ones I may get that are not choked.

[nervoustrigger]

Hi James, I don't know who offers a service to choke barrels but I wanted to ask if you have already tried applying the usual accurizing techniques, namely:

• crown touchup with brass screw
• deburr barrel port
• polish leade
• polish the bore with J-B

By most accounts, the Crosman barrels are often quite accurate after they've been cleaned up.  For example, here's a page of groups shot with a .177 Disco barrel I prepped:



Considering these were shot shouldered (not from bags), outdoors, and with no seasoning shots in between...having 3 pellets produce sub-MoA results and one of those half-MoA is pretty satisfying.  In fact, it groups better than the choked LW barrel on my 2400KT.

Also in case you  haven't seen it, some of Crosman's barrels have trashed rifling at the muzzle that no amount of polishing will remedy.  The damaged section must be removed and the muzzle re-crowned.   Pictures and description here: http://www.gatewaytoairguns.org/GTA/index.php?topic=110179

Perhaps you still want to pursue getting a choke applied, I just wanted to offer some perspective regarding common weaknesses of inexpensive barrels that need to be addressed.

[kj]

as jason mentioned the barrels often clean up well. if that doesnt work you could always order a l.w. barrel from crosman. the challenger barrel will work


peace
kj

[JimmyD.]

Barrels were done by professional gun smith friend on lathe, perfectly crowned. They are super accurate, just not with looser pellets like Premieres. I need a choke. Are Challenger barrels choked? I wanted a 26" Maximus barrel for more efficiency but they aren't coked either although reportedly different better rifling than old Discoveries. If I get 2 LW a .177 & .22 I want longer than the standard 23 3/4", I want 26 to 28" choked if possible and my machinist only charges me $15.00 per hour.

[Killo Coonadillo]

There are a few threads here concerning choking a barrel but it seemed somewhat ambiguous whether said methods were effective or not.

[kj]

yes the challenger l.w. barrels are choked. i believe they're only 20", i could measure one if you want. if you're only looking for speed, some report a slight loss in fps due to the tight choke. me, i'm an accuracy nut, so accuracy before speed for me. if the barrels you have are accurate, why not just pick the best pellet and use that one. once i find the best pellet for any given gun/barrel i just use that one unless i change the gun, or the application changes.
  all that said, i'm a big fan of l.w. barrels as they're accurate and usually not pellet fussy.

tinkering and testing is half the fun. enjoy.
peace
kj

[anti-squirrel]

A barrel can be choked using a pipe cutter; being sure to verify you either don't let the cutting disc touch the barrel or you remove the blade entirely.

As far as 'how much'... dunno.  I did my B-1 this way for giggles, definitely not as pellet picky...  But!  I need to re crown it.

[DonH]

A barrel can be choked using a pipe cutter; being sure to verify you either don't let the cutting disc touch the barrel or you remove the blade entirely.

As far as 'how much'... dunno.  I did my B-1 this way for giggles, definitely not as pellet picky...  But!  I need to re crown it.

How did you do it? I'd like to try it but not sure what kind of pipe cutter are you talking about? The stand up electric power ones you slowly tighten up the cutting jaws? Do you heat up the end of the barrel or leave it at room temperature?

[Taso1000]

Hi All,

This is the one I made for about $75:

http://www.gatewaytoairguns.org/GTA/index.php?topic=108629.0

Taso

ADDENUM:  I haven't had a chance to use and test the results yet.  If I had access to a longer property I would have done so.   

[JimmyD.]

http://www.gatewaytoairguns.org/GTA/index.php?topic=108629.0

  I have a master machinist friend so I can get 11mm, 15mm, 16mm and start choking barrels. 0.002 at last 1/2" of barrel is all you need and it won't slow your pellet that much at all, just size them a little and help reduce flyers somewhat.

[JimmyD.]

would make it easier and tighter tolerances.

[nervoustrigger]

May want to get some more input on the amount of choke.  I think general consensus is no more than one thousandth, and one master tuner recommended a quarter thousandth (0.00025").

I suppose if the bore is oversized, it would be tempting to choke to whatever extent is necessary to bring the muzzle to under 0.177".  I have doubts the outcome of that would be satisfactory, but I don't get the impression that is what you are dealing with.  You said the barrels are accurate, you are just looking for some improvement.