9mm Blackhawk

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reynolds357

New member
Anyone had any experience with them? I needed a second 357 mag Black Hawk and the conversion gun was actually cheaper than any regular 357 I have found so I ordered it. Wonder how accurate 9mm is considering bore being oversized.
(It shouldn't be cheaper, but we in crazy times)
 
7

74A95

New member
The bore will not be oversized. 9mm and 38/357 have the exact same SAAMI groove specifications.
 
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Rob228

New member
I've only put a few cylinders of 9mm through mine, honestly could not tell a difference in accuracy between .38, .357 and 9mm. It does take every bit of the length of the ejector to get the brass out.
 
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Sharkbite

New member
Dang Aguilia. You rock!!!!

Ive been playing with pistols going on 40 years and have ALWAYS thought 9=.355 and 38/357 = .357

Thanks
 
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44 AMP

Staff
Now, go slug your barrels and see if they match the SAAMI spec, or not.

Its quite possible some will not. Especially older guns....

SAAMI is a voluntary group, and no manufacturer is under any compulsion to follow their standards.
 
7

74A95

New member
To be precise, the SAAMi spec for the groove diameter is .355 + .004, so any barrel between .3550 and .3590 will be within spec.

I've slugged over a dozen 9mm barrels, they were all within spec. Of the nine 38/357 barrels I've slugged, seven were within spec. Two were undersized, the smallest being .3532".
 
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Jim Watson

New member
CIP 9mm is .347 - .355"
CIP. .38 is .346 - .355".
I don't find their tolerance, but it is probably +.10mm/.0039" because .359" barrels are seen in foreign guns.

If you want a really nice barrel, pay for a PV test barrel blank, the SAAMI diameter tolerance is -0 +.0005".

In olden days, Colt .38s had markedly smaller barrel bore-groove diameter than Smith.
 
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Aguila Blanca

Staff
Sharkbite said:
Ive been playing with pistols going on 40 years and have ALWAYS thought 9=.355 and 38/357 = .357
Click to expand...

Bullet diameter, not bore diameter.

SAAMI spec for bullets:

9mm --> .3555 - .0030
.38 Special --> .3580 Jacketed, .3590 lead (both -.0030)
.357 Magnum --> .3580 Jacketed, .3590 lead (both -.0030)

As 44 AMP pointed out, SAAMI specs are voluntary. But they are the industry specifications, and as far as I know pretty much all firearm and ammunition manufacturers try to stay within the specs. The point here being that, although the specification for bullet diameter is different for 9mm, the specification for bore and groove diameter is not.
 
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Jim Watson

New member
Diameters are the same but SAAMI says
9mm lands are .100" wide, six groove, 10" twist while
.38 lands are .105" wide, six groove, 18.75" twist.

This is not much observed in production guns, there are a lot of 16" twist 9mms, and Colt is regularly cited for the superiority of a 14" twist .38.

One thing that is hard to check is chamber throat dimensions in an automatic. There are specifications but from the number of reports of guns not accepting some ammo, the barrel (and bullet) makers aren't holding real close.
 
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Rob228

New member
So, again I saw no real accuracy difference between the two cylinders but I will admit that revolvers are not really my thing but I had just bought a Henry and figured I needed a single action to go with it. I don't shoot any of my handguns off the bench so I can't give you group sizes etc, but no difference with my skill set at 10 yards on a 1.5" target. Last year 9mm ammo was a lot easier to find than .38 or .357 as well.

I had never really given any thought to 9mm vs .38 as far as pressure goes, but the first few rounds of 9mm after shooting .38 were interesting, I was not expecting any significant difference in recoil (158 grain vs 115) but the 9's were definitely more snappy.

I really wanted a .45 Colt when I bought my Blackhawk but this was the only one I could find, still looking for a .45 but I'll likely be keeping this one.
 
7

74A95

New member
S&W generally makes a 5 land/groove barrels, and Ruger often does 8 land/groove barrels on the 38/357 Blackhawks.

My 38/357/9mm Blackhawk shows no accuracy difference with factory ammo between these calibers, tested in a Ransom Rest. 9mm handloads have been the most accurate, testing .355 and .357 bullets. The smallest group was 1.4" with 24 shots at 25 yards using .355 bullets in the Ransom Rest. It's barrel slugged at .3577". Don't believe it when people tell you that undersize bullets don't shoot well (in a handgun).
 
B

BubbaBlades

New member
https://www.youtube.com/watch?v=s7inp5kOhps

I have 11 different 9mm revolvers including a Ruger Blackhawk convertible. I find that using the brand(s) of ammo that shoots most accurately in a particular gun is a more important accuracy factor than minor bore dimension differences .
I have found certain gun/ammo combinations that produce groups that are 3 and even 4 times as large as the same gun will produce with an ammo brand and/or bullet weight that it likes.

The 9mm/357 Blackhawk in my video is shooting Blazer 115 9mm factory ammo.
 
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reynolds357

New member
BubbaBlades said:
https://www.youtube.com/watch?v=s7inp5kOhps

I have 11 different 9mm revolvers including a Ruger Blackhawk convertible. I find that using the brand(s) of ammo that shoots most accurately in a particular gun is a more important accuracy factor than minor bore dimension differences .
I have found certain gun/ammo combinations that produce groups that are 3 and even 4 times as large as the same gun will produce with an ammo brand and/or bullet weight that it likes.

The 9mm/357 Blackhawk in my video is shooting Blazer 115 9mm factory ammo.
Click to expand...
Thanks. Every 9 I have ever owned shoots Blazer Aluminum very well. I have never shot Blazer brass, that I can recall.
I don't usually shoot that good one handed, so the Blackhawk 9 mm will probably shoot better than me.
 
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reynolds357

New member
It came in yesterday and is headed back to Ruger today. On the 9mm cylinder, two chambers misfire. With Federal primers, they all fire, but one is light strike and one is super light strike. With harder primers, one fires about half the time and one rarely ever fires. I guess Ruger done screwed up the headspacing on 2 holes.
 
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