Who to ream my 9mm chamber to .357 magnum.

unstableryan

unstableryan

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Hello all,
A couple smith's near me are either to busy or not currently doing new jobs and I would like to convert a Wiseman barrel just like one of these to a .357 chamber for velocity reasons. In the new standard, HG2 is a 124gr at 448 m/s and it is common practice in the industry to use .357 cases. Any recommendations and general time/cost of the job?
Thanks,
Ryan
Barrel.jpg
 
Base diameter of .357 is .379; base diameter of 9mm is .391. I don't think any responsible 'smith is going to run a .357 reamer into a 9mm chamber.
 
Thanks Tiriak, that's actually proper advice. I never checked that dimension. Ganderite has also shared some wisdom over the years. The barrel has a receiver section at 2 or 2.5" diameter with a 14" long 1" or so straight no taper. It's fired remotly from a single shot mini "cannon" with a real big breach block. If brass was now single use after the bore, that would be a pain because I do reload everything that stays under ~120% saami spec, but most commercial labs buy primed sized prepped brass and recycle it after 1 go.
I've reloaded since about 1994 so that hurts my feelings. I secured some pounds of bullseye today finding some in 2 out of ~40-45 shops I went though. I had unreliable numbers at 448 m/s with tight group and tight wad, tightwad is actually pretty awesome for the 398 m/s HG1 spec, but it velocity curves just about there and can't reliably do 448. if you cone the powder after tapping and shaking and put as much as possible, and seat a bullet that sometimes fails because of grains getting in the way of seating, tightwad will max out at 450 or so metres per second, but bullseye will do a full 550. That's 1800 fps with a 124.

Do not try my reload data. Promise, it's in a different environment. I keep personal reloading so far compartmentalized from work, it's not even as much fun anymore.
 
Are the barrels separate pieces fitted to the large breech collars? If so, a .357 barrel could be a straightforward replacement.
 
I’m buying a .357 mag barrel. It’s being made right now in College station Texas. It will have the proper 18.75” twist for the specified .357 mag projectile. My 9mm barrel is 1-10” twist. I want to push 448 m/s more into the middle of the reloading range than near the top. V0 is 448, if I’m going for V50 velocity, more room is nice.
 
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