Looking for a gunsmith to convert 357 Blackhawk to 357/44 Bobcat

[Bloodhound689]

Good morning. I posted a while back that I incidentally found a Thompson Center Contender Barrel converted to 357/44 Bobcat. This barrel came with a set of dies and did not require the teflon/plastic rings originally needed on the Blackhawk chambered for this round.

I am looking for a gunsmith that can bore out a Blackhawk cylinder to chamber this round without using the teflon/plastic rings. Can this even be done? Not sure but I would purchase a new Blackhawk to make this happen.

[Bloodhound689]

I can send a chamber casting and a dummy round of what I am looking for.

[Tatume]

A nice conversion is the 356 GNR by Gary Reeder. He will rechamber your 357 Magnum cylinder and sell dies. The cartridge is based upon the 41 Magnum.

https://www.reedercustomguns.com/

[Bloodhound689]

Tatume - Appreciate the info but I am really looking for the 357/44 Bobcat chambering. Already have a bunch of loaded rounds and dies to continue loading for it.

[Tatume]

Yes, I know the feeling. I have some orphaned ammo and sometimes think about buying guns to fit.

If you do decide to buy a Blackhawk for this conversion you might want to consider the 357 / 9mm convertible. Then you could re-chamber the 9mm cylinder and keep the 357 cylinder for its intended purpose.

Good luck.

[Bloodhound689]

Yes, I know the feeling. I have some orphaned ammo and sometimes think about buying guns to fit.

If you do decide to buy a Blackhawk for this conversion you might want to consider the 357 / 9mm convertible. Then you could re-chamber the 9mm cylinder and keep the 357 cylinder for its intended purpose.

Good luck.

Didn’t think about that. Great suggestion!! I will more than likely go with that.

[Nobade]

That is a good idea!

[DougGuy]

Yep that's smith territory, Oblunder's 2016 EO says that isn't gunsmithing it's manufacturing. Alan Horton or Andy Horvath, Doug Turnbull are a few you may check out.

[Tatume]

The person doing the work doesn't need to receive the gun. If there is no gun involved, I don't understand how it could be construed as manufacturing a gun? But there is no limit to the lengths anti-gun politicians will go to.

[challenger_i]

Something to consider is case set-back upon firing. You wouldn't experience such with the closed-breech system of the Contender, but it may rare its ugly head with a revolver.

[stubshaft]

Something to consider is case set-back upon firing. You wouldn't experience such with the closed-breech system of the Contender, but it may rare its ugly head with a revolver.

That was the main reason for the teflon rings. In a closed breech system there was never any problem but the old 44 Bain & Davis used to lock up revolvers.

[MarkP]

A gunsmith in Lincoln NE used to convert Ruger Super Blackhawks to 357 Bain & Davis. He would make a breech block that would replace the cylinder and chamber the bbl. Like the Ruger Haweyes in 256 Win Mag. He would also add Mn Bronze grip frames. I bought one of the Super BH take offs and put it on my 30 M1 Blackhawk.

[Bloodhound689]

Something to consider is case set-back upon firing. You wouldn't experience such with the closed-breech system of the Contender, but it may rare its ugly head with a revolver.

You are right. I do remember reading that. I would probably not move forward if it required the rings. Thanks

[Bloodhound689]

A gunsmith in Lincoln NE used to convert Ruger Super Blackhawks to 357 Bain & Davis. He would make a breech block that would replace the cylinder and chamber the bbl. Like the Ruger Haweyes in 256 Win Mag. He would also add Mn Bronze grip frames. I bought one of the Super BH take offs and put it on my 30 M1 Blackhawk.


I already have the dies for the Bobcat so the b&d doesn't appeal to me now. I did look up the difference a while back but cannot remember the exact differences between the two

[MarkP]

Yes I understand that just telling how a gunsmith made a bottle neck work.

[Bloodhound689]

Yes I understand that just telling how a gunsmith made a bottle neck work.

No problem. I appreciate the response and info.

[6string]

Rechambering a revolver for the 357/44 Bobcat might pose a problem being that it is/was a wildcat. I’m not sure I understand the logic of building up a custom gun to match a set of dies you have. But, if that’s the plan, I would take into account that part of the deal might be having to pay for a custom made chambering reamer to match your die set?
Imagine the disappointment of having the cylinder cut using someone else’s reamer and then finding out your handloads won’t chamber, or the chamber shoulder is several thousandths of an inch too far forward, etc, etc.

But, who knows, maybe look for Bob Booth, the guy who dreamed up the Bobcat?
It would be nice if you knew who converted that Contender barrel!

Here’s a diagram of the tentative dimensions, albeit in metric:


….323661

I’ll add one more caveat: In my experience, the headspace of bottleneck cartridges loaded for either revolvers or the T/C Contender needs to be closely regulated for good case life, reliable function, and good accuracy. But, the reasons in either case are quite a bit different. I suspect it would be very unlikely that ammo loaded to perform well in the Contender would perform well in the revolver, and vice versa.
Plan on preparing ammo specifically for one gun, then readjusting the dies to load another batch for the other gun. (That is, provided the chambering reamer issue is satisfactorily solved.)

[Ed K]

Rechambering a revolver for the 357/44 Bobcat might pose a problem being that it is/was a wildcat. I’m not sure I understand the logic of building up a custom gun to match a set of dies you have. But, if that’s the plan, I would take into account that part of the deal might be having to pay for a custom made chambering reamer to match your die set?

Yes, and then how would the Blackhawk chamber compare to the Contender chamber made from yet another reamer?

The farther one goes down this rabbit hole crafting handloaded ammo with cast boolits, I question the practicality of having multiple firearms in the same cartridge. There are certainly benefits from having a common source of components however it is not common that one loaded round is ideal for all firearms.

[racepres]

Other than the "designer" angle, I don't get it. Power?? There are loadings already out there that I doubt the Bobcat can best, But, I been wrong before!! One Question I have. Larger Cartridge Head (diameter)... cause More or Less Breech face Thrust??
Trying to remember which case head size tended to "stretch" contenders worse... and I suspect Breech face pressure is Breech face Pressure...No??

[Ed K]

One Question I have. Larger Cartridge Head (diameter)... cause More or Less Breech face Thrust??
Trying to remember which case head size tended to "stretch" contenders worse... and I suspect Breech face pressure is Breech face Pressure...No??

Larger case head = more pressure on the breech. You can fire 223 Rem 55Kpsi all day long but one shot with a 475 Linebaugh (50Kpsi) and your Contender is toast. Given the same case head and pressure, the cartridge with more body taper will exhibit greater case head thrust against the breech.

[Bass Ackward]

Bullcreekarms.com

[jdgabbard]

I guess I must not understand why the cylinder has to be machined like that...

Wouldn't it just be easier to machine the cylinder with the bottlenecks so the bands weren't necessary? Isn't that basically what the 32-20 did? Doesn't seem very logical to chamber the gun in that manner...

[challenger_i]

It has to do with the case taper/shoulder angle. The 32 WCF, 38 WCF and 44 WCF have relatively heavy tapered bodies, and a shallow angle shoulder, plus they are relatively low-power cartridges, so the set-back is not as extreme. The cartridge in question has a rather abrupt taper, and is a fairly powerful cartridge, which will exhibit a pronounced setback. The nylon sleeves allow adequate expansion laterally, alleviating the endward thrust of the cartridge.
An example I can offer, from personal experience is the 22 Hornet, and 22 K Hornet, in a K-Frame Smith (with two correctly chambered cylinders): the 22 Hornet performed well, with no issues, where-as the K Hornet cartridge would lock-up the revolver by the 2nd round.

[jdgabbard]

It has to do with the case taper/shoulder angle. The 32 WCF, 38 WCF and 44 WCF have relatively heavy tapered bodies, and a shallow angle shoulder, plus they are relatively low-power cartridges, so the set-back is not as extreme. The cartridge in question has a rather abrupt taper, and is a fairly powerful cartridge, which will exhibit a pronounced setback.
An example I can offer, from personal experience is the 22 Hornet, and 22 K Hornet, in a K-Frame Smith (with two correctly chambered cylinders): the 22 Hornet performed well, with no issues, where-as the K Hornet cartridge would lock-up the revolver by the 2nd round.

Interesting. I would think that with a well tolerances chamber that wouldn’t be an issue. But you learn something new every day…


Sent from my iPhone using Tapatalk

[challenger_i]

Well, I will say that every 38 WCF revolver I have owned (1 pre-1896 Colt Single action, and two Colt New Service) had what could be described as "generous" chamber dimensions. My Smith in 32 WCF doesn't exhibit such.

[Bloodhound689]

After reading all of your posts. I think I will just stick with the blackhawks that I have (2X 41 mag, 30 Carbine) and keep them separate from my Bobcat Contender. I did forget about the set back but JDs point of the 32-20 is interesting and the responses make sense

[Good Cheer]

It's hard to go wrong with a 41 Blackhawk.
Just be sure the barrel doesn't have any constriction where it goes into the frame.
And don't mess up your trigger finger shooting too heavy boolits.
Otherwise it's a one handed Winchester.

[challenger_i]

And, if after 6 rounds it doesn't fall down, look behind it to see what is holding it up!

[Ks Muleskinner]

Somebody on ebay has been advertising a ruger cylinder in that caliber I believe. You might look

[atfsux]

Revolvers are not chambered in high pressure bottleneck calibers for very good reason. Just ask S&W about their headaches with the .22Jet Model 53. Cartridge cases would tend to be swaged back in the chamber firmly up against the frame behind the cylinder, binding and retarding rotation of said cylinder. This isn't a problem with calibers like .32-20 and .38-40 and .44-40 because the taper is so slight. But once the taper or shoulder of a round gets past a certain angle of degree, the cases are pushed rearward in such a manner as to affix themselves with gusto flush against the surface behind the cartridge base.

[RJM52]

...glad you saw the light before spending the money...

Had Gary Reeder make a 5.5" 5 shot .41 Magnum/.41 GNR about 20 years ago. The GNR is a .44 Magnum necked down to .41... Zero issues with case setback but with topend loads there is only 50 fps difference between the .41 Magnum and the GNR. 26 grains of H110 vs 30 in the GNR...a lot more blast with insignificant increase in velocity. A 6.5" BH runs the same 26 grain/170 Sierra load 50 fps faster than the GNR.

So while a great cartridge in a closed breech Contender I think you would be disappointed in the Bobcat in a revolver...

Bob

[Tatume]

Had Gary Reeder make a 5.5" 5 shot .41 Magnum/.41 GNR about 20 years ago. The GNR is a .44 Magnum necked down to .41... Zero issues with case setback but with topend loads there is only 50 fps difference between the .41 Magnum and the GNR. 26 grains of H110 vs 30 in the GNR...a lot more blast with insignificant increase in velocity. A 6.5" BH runs the same 26 grain/170 Sierra load 50 fps faster than the GNR.

So while a great cartridge in a closed breech Contender I think you would be disappointed in the Bobcat in a revolver.

Bob

I gave a lot of thought to this conversion myself, as well as the 356 GNR. I finally decided that the 44 and 41 magnums are too good as they are.