9mm Blackhawk

reynolds357 · July 16, 2022, 06:37 PM

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)

74A95 · July 16, 2022, 08:02 PM

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

Rob228 · July 16, 2022, 08:13 PM

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.

reynolds357 · July 16, 2022, 09:07 PM

Quote:

Originally Posted by 74A95

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

The bullet manufacturers don't make the jacketed bullets the same. 9mm bullets are .355 and 38/357 mag are .357 dia.

74A95 · July 16, 2022, 09:16 PM

Quote:

Originally Posted by reynolds357

The bullet manufacturers don't make the jacketed bullets the same. 9mm bullets are .355 and 38/357 mag are .357 dia.

Correct. What's your point?

reynolds357 · July 16, 2022, 10:04 PM

Quote:

Originally Posted by 74A95

Correct. What's your point?

Bore is different.

74A95 · July 16, 2022, 10:06 PM

Quote:

Originally Posted by reynolds357

Bore is different.

Nope.

**Aguila Blanca** · July 16, 2022, 10:41 PM

SAAMI specs: https://saami.org/wp-content/uploads...sting-Copy.pdf

9mm: Page 36
Bore diameter: .346"
Groove Diameter: .355"

.38 Special: Page 56
Bore diameter: .346"
Groove Diameter: .355"

.357 Magnum: Page 53
Bore diameter: .346"
Groove Diameter: .355"

reynolds357 · July 16, 2022, 10:46 PM

Quote:

Originally Posted by Aguila Blanca

SAAMI specs: https://saami.org/wp-content/uploads...sting-Copy.pdf

9mm: Page 36
Bore diameter: .346"
Groove Diameter: .355"

.38 Special: Page 56
Bore diameter: .346"
Groove Diameter: .355"

.357 Magnum: Page 53
Bore diameter: .346"
Groove Diameter: .355"

I just learned something.
Why are bullets different size?

Sharkbite · July 16, 2022, 11:08 PM

Dang Aguilia. You rock!!!!

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

Thanks

**44 AMP** · July 17, 2022, 12:33 AM

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.

74A95 · July 17, 2022, 04:47 AM

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".

Jim Watson · July 17, 2022, 08:50 AM

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.

**Aguila Blanca** · July 17, 2022, 08:51 AM

Quote:

Originally Posted by Sharkbite

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

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.

Jim Watson · July 17, 2022, 08:59 AM

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.

Rob228 · July 17, 2022, 11:50 AM

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.

74A95 · July 17, 2022, 12:36 PM

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).

BubbaBlades · July 19, 2022, 11:16 AM

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.

reynolds357 · July 19, 2022, 04:09 PM

Quote:

Originally Posted by BubbaBlades

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.

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.

reynolds357 · July 22, 2022, 03:25 PM

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.

TruthTellers · July 23, 2022, 03:58 AM

Quote:

Originally Posted by 74A95

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).

I've shot .307" bullets in a Ruger .327 with a .314" chamber throat and .312" groove diameter and the accuracy was it hit the target I was shooting at some 15 yards away, yet when I shoot factory .45 ACP in the Ruger Redhawk the accuracy is exceptionally poor compared to my handloads with either .45 Colt or .45 ACP.

Nothing is ever a given when it comes to shooting.

logeorge · July 24, 2022, 04:32 PM

SAAMI specs for .44 Mag. & .44 Special bullets are .432". How did .429 become standard? You can't even find bullet sizers in .432". To get one, I had to hone out a .430" and make an ejector punch to fit. This was for a Ruger with .432 cylinder throats and .431 grooves.

'

rodfac · July 24, 2022, 05:11 PM

Quote:

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

Yep, and mine don't plus 9mm dies are designed for .355" dia. bullets. And accuracy with my 9's is better if I use lead alloy or jacketed that measure . 357" YMMv, rod

zeke · July 25, 2022, 08:59 AM

Perhaps SAMMI specs may be better called SAMMI voluntary suggestions. Am not of belief they are actually mandatory product design specifications, although some manufacturers may use them as such.

Anyways, there is what is supposed to be, and what actually is.

logeorge · July 25, 2022, 03:07 PM

Zeke: I've said the same thing in a different way: "Things ain't always the way they're supposed to be."

July 16, 2022, 06:37 PM	#1
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	9mm Blackhawk 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)

July 16, 2022, 10:41 PM	#8
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,459	SAAMI specs: https://saami.org/wp-content/uploads...sting-Copy.pdf 9mm: Page 36 Bore diameter: .346" Groove Diameter: .355" .38 Special: Page 56 Bore diameter: .346" Groove Diameter: .355" .357 Magnum: Page 53 Bore diameter: .346" Groove Diameter: .355" __________________ NRA Life Member / Certified Instructor NRA Chief RSO / CMP RSO 1911 Certified Armorer Jeepaholic

July 17, 2022, 12:33 AM	#11
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,817	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. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

July 24, 2022, 04:32 PM	#22
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	9mm Blackhawk SAAMI specs for .44 Mag. & .44 Special bullets are .432". How did .429 become standard? You can't even find bullet sizers in .432". To get one, I had to hone out a .430" and make an ejector punch to fit. This was for a Ruger with .432 cylinder throats and .431 grooves. '

July 25, 2022, 03:07 PM	#25
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	9mm Blackhawk Zeke: I've said the same thing in a different way: "Things ain't always the way they're supposed to be."

July 16, 2022, 08:02 PM	#2
74A95 Senior Member Join Date: November 26, 2016 Posts: 1,564	The bore will not be oversized. 9mm and 38/357 have the exact same SAAMI groove specifications.

July 16, 2022, 08:13 PM	#3
Rob228 Senior Member Join Date: May 29, 2010 Location: Hampstead NC Posts: 1,450	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.

July 16, 2022, 11:08 PM	#10
Sharkbite Senior Member Join Date: November 4, 2013 Location: Western slope of Colorado Posts: 3,679	Dang Aguilia. You rock!!!! Ive been playing with pistols going on 40 years and have ALWAYS thought 9=.355 and 38/357 = .357 Thanks

July 17, 2022, 04:47 AM	#12
74A95 Senior Member Join Date: November 26, 2016 Posts: 1,564	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".

July 17, 2022, 08:50 AM	#13
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	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.

July 17, 2022, 08:59 AM	#15
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	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.

July 17, 2022, 11:50 AM	#16
Rob228 Senior Member Join Date: May 29, 2010 Location: Hampstead NC Posts: 1,450	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.

July 17, 2022, 12:36 PM	#17
74A95 Senior Member Join Date: November 26, 2016 Posts: 1,564	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).

July 19, 2022, 11:16 AM	#18
BubbaBlades Senior Member Join Date: April 22, 2013 Location: South Florida Posts: 121	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.

July 22, 2022, 03:25 PM	#20
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	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.

July 25, 2022, 08:59 AM	#24
zeke Senior Member Join Date: November 17, 1999 Location: NW Wi Posts: 1,671	Perhaps SAMMI specs may be better called SAMMI voluntary suggestions. Am not of belief they are actually mandatory product design specifications, although some manufacturers may use them as such. Anyways, there is what is supposed to be, and what actually is.