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FX impact M3 unchoked barrel

I have an FX impact M3 600mm barrel and I am trying to shoot custom made lead free slugs and pellets. Since the lead free ammo is harder than the standard lead versions they choke seems to have a much greater and negative effect on the bullets especially with slugs since the lead free alloy is harder than lead. I was wondering what the best way to get a unchoked barrel or barrel liner for an impact. The two ways I could think of are buy 700mm heavy liner and have it cut down to 600 mm and recrowned by a local gunsmith. The second option is to get a barrel blank from TJ or Lothar Walther have have it milled to fit the transfer port which sounds like it would be much more costly and I worry if the gunsmity has never fit a barrel to an impact maybe it wouldnt turn out as well but if done right could be a better barrel in the end. Are there any other options I am not thinking of to get an unchoked barrel for my impact M3?
 
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It would be cheaper just to buy a 700 and have it cut down to 600 and recrowned
I am thinking that would be the easiest and cheaper route but wanted to see if there were any other ideas. I would like to try a TJ barrel but I would be more comfortable if I could find someone with experience fitting them to the impact but I haven't had much luck finding someone who does it.
 

It was Qball that had it. Try PMing him for details.
 

It was Qball that had it. Try PMing him for details.
I’ll try that thanks!
 
I would suggest first trying the 700 cut down liner. If you are handy at all, this is something you can do yourself. crowning being the most tedious part. You could try multiple twist rates etc. for less than you may spend on a single blank and machining.
I am moderately handy but I don’t think I have any tools to precisely cut and recrown. I know a guy with a lathe I think he wouldn’t charge me much for such a small job and it would be better than anything I could do.
 
The good news is shortening an FX liner is as simple as it gets, whether it’s shortening from the breech end to preserve the choke or shortening from the muzzle end to remove it. The steps of cutting off the excess length and facing off the end require practically no special attention other than remembering that the liners are thin-walled so don’t apply too much force.

Otherwise the only step that demands careful attention is the crown. If performing this step on the lathe, the workpiece needs to be indexed to the bore (not the OD)…meaning with the use of a spider or 4-jaw chuck or something similar. Use a supremely sharp cutter (e.g. freshly touched up HSS) swept from the inside out to avoid a burr. If a burr develops, the brass screw method or careful use of an abrasive can be used.

Or skip the lathe altogether for crowning and just use the brass screw approach to develop a shallow bevel. That’s how I prefer to do it.
 
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