.38 Super Out of a .357 Magnum/.9 MM Blackhawk Convertible - Redux

[JBP]

In another life when I was a Jr. computer programmer a Sr. programmer when asked if some code would work always replied: A test is worth a 100 suppositions. I should have followed that advice when I made my previous post regarding .38 Super out of a .357 Magnum/9 MM Convertible specifically while using the 9MM cylinder. As Paul Harrel in his YouTube video on shooting .38 Super out of a .357 Magnum it depends on a combination of revolver and ammo.

This picture is my Blackhawk's 9mm cylinder on the left and the .357 Magnum cylinder on the right. The two leftmost rounds in the 9mm cylinder are .38 Super. Note that neither one fits in the chambers. The round at 6 o'clock is a 9mm. In the .357 Magnum cylinder on the right the left most round is an Amscor 125gr FMJ which does not fit in the chamber. The next is a PMC Bronze 130 gr. FMJ which chambers w/o any problem. The next two rounds are a .357 Magnum followed by a .38 Spl +P. The PMC round comes out of the cylinder w/o any problem.

I'll take the Blackhawk when I go to the range Friday to see how it handles the PMC ammo

.

 

[NikA]

Probably time to break out a book or read a few internet articles on headspace and how it is determined. This is 100% what one would expect in this case; the 9mm headspaces on the case mouth and therefore will never accept a longer case, and the .357 chamber overlaps the .38 Super in tolerances so will sometimes allow the semi-rimmed case to function.

That said, I'm still baffled as to the why given that you have other .38 Super firearms and that ammo doesn't appear to be more common that .38 Special or .357.

 

[led]

Will it work, probably. Can the blackhawk handle the pressure, yes. Should you do it, it's your gun. If you really want to shoot 38 super in a Blackhawk I'd find a doner 9mm cylinder and see about rechambering.

 

[JBP]

Probably time to break out a book or read a few internet articles on headspace and how it is determined. This is 100% what one would expect in this case; the 9mm headspaces on the case mouth and therefore will never accept a longer case, and the .357 chamber overlaps the .38 Super in tolerances so will sometimes allow the semi-rimmed case to function.

That said, I'm still baffled as to the why given that you have other .38 Super firearms and that ammo doesn't appear to be more common that .38 Special or .357.

Over the years I've tried reading articles regarding head spacing and come away being more confused than before I've read them.

As to why, just looking at different options. After this one range session probably will never do it again. When the ranges opened up during the pandemic I wasn't going to pay $1 per round for .357 Magnum ammo just for range work so I got a hold of some .38 Spl +P. I've always preferred wheel guns to semi-autos so this just gives me another option.

 

[JBP]

Will it work, probably. Can the blackhawk handle the pressure, yes. Should you do it, it's your gun. If you really want to shoot 38 super in a Blackhawk I'd find a doner 9mm cylinder and see about rechambering.

If I find that I really like shooting the .38 Super out of the Blackhawk that certainly would be an option I would consider. The T/C Contender barrel I have was rechambered from a 9mm by Bullberry Legacy.

 

[contender]

From what I've seen .38 Super factory ammo costs as much if not more than .357 Mag. By your logic of purchasing ammo, it seems odd. I was figuring you were handloading .38 Super. .9mm is usually much cheaper by far over these other (2) calibers. And heck, even .38 Spl is cheaper than .38 Super.
Options? Yes,, we all like them. But when looking at all this,, especially using factory ammo,, seems to defeat the purposes,, UNLESS you do not have other ammo options.

But I still go back to the fact that the Blackhawk has a barrel groove diameter that accepts a slightly larger caliber bullet,, and as such, the .355 bullets of .9mm & .38 Super are not as accurate.

And heck, I'll throw out a few other thoughts. You've mentioned .38 Super.
What about;
.38 Super Comp
.38 Super +P
.38 TJ

All these are very close to the .38 Super.

 

[Bigbore5]

All three of those are rimless vs the Super's semi-rim

 

[Wvfarrier]

Mine will fit some 38 super and not others. Just depends on the brand

 

[JBP]

From what I've seen .38 Super factory ammo costs as much if not more than .357 Mag. By your logic of purchasing ammo, it seems odd. I was figuring you were handloading .38 Super. .9mm is usually much cheaper by far over these other (2) calibers. And heck, even .38 Spl is cheaper than .38 Super.
Options? Yes,, we all like them. But when looking at all this,, especially using factory ammo,, seems to defeat the purposes,, UNLESS you do not have other ammo options.

But I still go back to the fact that the Blackhawk has a barrel groove diameter that accepts a slightly larger caliber bullet,, and as such, the .355 bullets of .9mm & .38 Super are not as accurate.

And heck, I'll throw out a few other thoughts. You've mentioned .38 Super.
What about;
.38 Super Comp
.38 Super +P
.38 TJ

All these are very close to the .38 Super.

It was an idea that after 50+ years of shooting I should have known better and dropped immediately. End result was a stuck case in a cylinder and $235 to Ruger for repair and shipping costs. From now on my .38 Super shooting is limited to my Contender and Colt.

 

[NikA]

@JBP, now I'm curious to know more. You fired some .38 Super in a Blackhawk and somehow damaged the cylinder and had to ship the whole gun to Ruger? Did you stretch/swell the cylinder? Seems like a .357 chamber rated at 44ksi should shoot any .38 Super at a max pressure of 36.5ksi that fits in it. Stuck case is somewhat expect given the tolerance stacking, but that should be able to be addressed with appropriate home shop tools.

 

[JBP]

@JBP, now I'm curious to know more. You fired some .38 Super in a Blackhawk and somehow damaged the cylinder and had to ship the whole gun to Ruger? Did you stretch/swell the cylinder? Seems like a .357 chamber rated at 44ksi should shoot any .38 Super at a max pressure of 36.5ksi that fits in it. Stuck case is somewhat expect given the tolerance stacking, but that should be able to be addressed with appropriate home shop tools.

1st 7 rounds of .38 Super fired fine. The 8th round's spent case backed out of the chamber after firing causing the cylinder to be inoperable ( wouldn't rotate) and couldn't be removed. Range officer was able get rim off of case and cylinder out of revolver leaving rest of case in chamber. I'm mechanically challenged and didn't want to take a chance damaging the cylinder any further. Both of the gun smiths I've used for years have retired so I sent it to Ruger.

 

[NikA]

1st 7 rounds of .38 Super fired fine. The 8th round's spent case backed out of the chamber after firing causing the cylinder to be inoperable ( wouldn't rotate) and couldn't be removed. Range officer was able get rim off of case and cylinder out of revolver leaving rest of case in chamber. I'm mechanically challenged and didn't want to take a chance damaging the cylinder any further. Both of the gun smiths I've used for years have retired so I sent it to Ruger.

What parts did Ruger replace when servicing the gun? Did the work order specify? Sounds like an expensive lesson...

 

[JBP]

What parts did Ruger replace when servicing the gun? Did the work order specify? Sounds like an expensive lesson...

Didn't replace anything. Removed case from chamber, cleaned and test fired.

 

[contender]

Yikes,, an expensive lesson for sure.

I enjoy convertible guns, and calibers. But when you study the actual case dimensions,, and think; "It's close enough to try" yet,, may not be,, issues can happen.

I've had a couple of guns brought to me over the years with similar stuck cases or locked up guns. Too bad you didn't know someone more local to fix it,, but at least you got the peace of mind that Ruger cleared it up properly.

 

[RJM52]

The problem is rim thickness as how the headspace is determined...

Place a .38/.357 round in the cylinder and then a .38 Super...Winchester will fit in most for some reason.

Close the cylinder and with feeler gauges check the difference in headspace between the .38/.357 cases and the .38 Super...it is a bunch...one can see it by just holding the gun up to the light and rotating the cylinder.

The firing pin has enough reach that it will set the primer of the Super off, but it is over extended and as the bullet exits the case, the casehead slams back against recoil shield with the over extended firing pin sticking out and locks everything up. Usually the primer gets pierced in the process.

S&W had to avoid the same problems with the 547 that didn't use moon clips for 9mm. They had dual pins...one was the firing pin for setting off the primer and the other held the casehead away from the recoil shield to keep the gun from locking up.

I've got several DA .38 and .357 revolvers that have been set up with second cylinders for .38 Super and 9mm using moon clips...the clip is what maintains the proper headspace. A second problem with the 9mm is that is a tapered case and once one gets into +P territory it will often back out of the chamber and lock the gun up. Have had this happen with both the S&W 942 and Ruger LCR...

Also recently purchased one of the Gary Reeder Trail Guns which is a Single-Six centerfire frame with 5 round cylinders in .38 Super and 9mm...runs fine with the correct ammo. Haven't run anything +P in the 9mm cylinder yet so I don't know if they will back out or not...

Bob

 

[Rock185]

RJM52 is correct about headspacing the .38 Super in a .38/.357 chamber. The thinner semi-rim of the Super as compared to .38/.357 may cause the issues he described. Even though the SAAMI spec may show the .38 Super rim to only be .010" thinner than the .357 rim, manufacturing tolerances of both gun and ammo may cause the actual variation in headspace to be even greater. And if primers are pierced due to the excess headspace, there will be firing pin and breech face damage. This may not be apparent on casual inspection, but under low magnification the firing pin, and breech face around the firing pin, start to resemble the surface of the moon....

 

[Springer2]

As others have mentioned there is little to gain with a 38 Super vs 38/357 in either cost or performance. We do have a 1911 with setups for 9mm and 38 Super that works very well. The barrels each have a fitted bushing, we do go 1 lb heavier on the spring with the 38 Super and use different magazines. 38 Supers are known for being very accurate and ours in no exception. Case length on 9mm and 38 Super is important because of headspacing on the case mouth.