superdude
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Posts posted by superdude
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The twist rate is different (though optional), but the groove diameter specs are the same. The groove diameter being the same is what people go nuts over.
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6 hours ago, varminter22 said:
I've never felt the need to slug barrels or simply try .355" bullets in my M627. Maybe I should.
But since .355 has been the industy standard for over a century, it still makes no sense to me that many, if not most, of us utilize .358" bullets in a .38!
Oh, and that .004" tolerance of which you mentioned, that surely cannot apply to barrel groove diameter, right?! IF it does, that would mean a barrel with a .359" groove diameter would be acceptable. Ugh.
You're really overthinking this.
The .004 DOES apply to the groove diameter.
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2 minutes ago, varminter22 said:
Ooops. Thanks.
But then, back to the original question: Why put .38/.357 barrels on 9mm revolvers.
Geez, I'm confused.
There is no such thing as a 38/357 barrel and a separate 9mm barrel. They both have the exact same specs.
If you buy a 38/357 revolver and the barrel groove diameter measures .355", does that mean it has a 9mm barrel? No, it doesn't. That's because .355 is within the SAAMI specs for a 38/357 barrel. It's still a 38/357 barrel.
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11 minutes ago, varminter22 said:
Still doesn't make sense.
And no, according the SAAMI specs in the link you provided, for 9mm it clearly states:
QUOTE
LAND AND GROOVE DIMENSIONS TO BE WITHIN TOLERANCES THROUGHOUT LENGTH OF BARREL.
UNLESS OTHERWISE NOTED, ALL DIAMETERS +.0005
UNQUOTE
That is one half of 1/1000. So a 9mm barrel "should" be at least .3456" and no larger than .3554" - according to SAAMI specs.
And same .355" except for a .0005" tolerance for .38/.357 - according to SAAMI specs.
Ah. You're reading the SAAMI specs for the pressure test barrel (Page 141), which is used for measuring chamber pressure.
The specs for the 9mm cartridge and ammo are on page 27, and for the 38 Spl. are on page 47.
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1 minute ago, varminter22 said:
I understand that!
But if that is true (and I saw your SAAMI ref), why aren't ammo manufactures (and us handloaders) loading all .38 Spec/.357 Mag/etc ammo with .355"/.356" bullets?
I also understand that barrels can and do vary, but they should be with the .0004" or .0005" tolerance, correct? And barrels can vary a little in bullet preference. But a .358" bullet in a .3546" barrel?? Interesting.
Ammo manufacturers are making their 38/357 bullets according to SAAMI specs for that caliber.
You can load 9mm bullets in 38/357 cases, but the cases (and our reloading dies) are designed to fit the presumed .357ish bullets, and smaller bullets will have less, or no neck tension. You can get around it by using an undersize sizing die, if you want. I've done it, and other people have, too. Accuracy with jacketed bullets is fine. Lead might be a different issue and I have not tested that.
You can also use .357/.358 bullets in your 9mm. The issue here is whether they will fit in the chamber, since the brass and chambers are made around SAAMI specs and a 'tight' chamber might not like a .357/.358 bullet. But, lots of us use these bullets in our 9mm guns without issue.
SAAMI barrel tolerances are +.004, not .0004, so a barrel with a groove diameter from .355 to .359 is within specs.
Colt is known for making some of their revolver barrels undersize. I have a Colt Magnum Carry with a .3532" groove diameter. I've not had any issues with the ammo I've fired through it.
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6 minutes ago, varminter22 said:
Okay. I guess. But I sure don't understand.
These ammo standards were established long before most of us were born. The 9mm and 38 Special were created around 1900, give or take. At some point in the past someone decided that such-and-such was going to be dimension X, and that other thingy would be dimension Y. We're left to sort stuff out. But SAAMI is the bible in the USA, and CIP is the bible for the rest of the world. They define the standards, and companies build their products around them.
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29 minutes ago, varminter22 said:
Something doesn't seem right about that.
Bownell's (Nominal Barrel Groove Diameters | Top Rated Supplier of Firearm Reloading Equipment, Supplies, and Tools - Colt (brownells.com) says:
Nominal Barrel Groove Diameters:
9mm Luger .354" .38 Special/.357 .357" If 9mm and .38 barrels are the exact same diameter as you say, why are [the vast majority of] 9mm bullets .355"/.356" and .38 Spec bullets .357"/358"?
What am I missing?
I don't know where Brownells is getting their information, but it is not consistent with SAAMI. SAAMI is the industry standards institute, not Brownells.
The bullets are different because their dimensions are also defined by SAAMI (and tradition). See the information in the Link I posted.
9mm bullets = .3555 - .003.
38/357 = jacketed = .3580 -.003; lead = .3590-.003
I've slugged many 9mm and 38/357 barrels and don't find a difference between them. Of the over a dozen 9mm barrels I've slugged, only 2 of them were less than .356".
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19 hours ago, varminter22 said:
Funny that when the 929 was introduced, and to this day, I don't recall S&W saying, "Check out our wonderful new 929 9mm revolver with a 38 barrel."
9mm and 38/357 have the exact same SAAMI barrel specs: groove diameter of 0.355" + 0.004". So any barrel with a groove diameter between 0.355" to 0.359" is within spec for both calibers.
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The funny part is that the Remington ammo catalog shows the primer used in 40 S&W is the 1 1/2.
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12 hours ago, Sinister4 said:
This table originated from the link below, and it has specific information about 9 Major in a short barrel.
https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/
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According to your numbers, you lengthened the OAL. This made the bullets faster?
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Since you are not loading for competition where a consistent power factor is useful, you can ignore extreme spread and standard deviation.
Testing has shown that there is no correlation between ES/SD and accuracy for the typical handgun at typical handgun distance.
https://americanhandgunner.com/handguns/exclusive-consistent-velocity-accuracy/
Serious accuracy testing is done at longer range and with a stable method. You can't tell much from a 5-shot, or even a 10-shot group unless the difference in accuracy is 4-fold plus. Group size will vary considerably even when shooting the exact same ammo. Even then you have to consider the method - offhand, bench, Ransom Rest.
https://www.ssusa.org/articles/2019/9/25/accuracy-testing-shortcomings-of-the-five-shot-group/
https://www.ssusa.org/articles/2021/2/17/accuracy-testing-how-many-shots-in-the-group
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As noted, you'll have to test your ammo.
That said, my notes show with a 115 gr bullet in a 9mm using 5.0 Silhouette in a 5" barrel going from 1.160 to 1.120 (0.040" reduction OAL) power factor went up 6.
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Some information here:
https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/
Always work your loads up.
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10 hours ago, xjwalt666 said:
Does a barrel with only popples work the same as with a comp? Use same type of load data for it and make more gas? Just trying to understand how this should work. Thanks and ask questions if I need to clarify more.
Popple holes work half-way like a compensator.
With a compensator, gas hits the baffle plates and this pushes the compensator forward (and anything attached to the compensator). The gas is also directed upward through those big compensator ports, and this pushes the compensator down, reducing muzzle rise.
With popple holes (barrel ports) the gas is directed upward and this pushes the barrel down, reducing muzzle rise - like a compensator. The holes also bleed off some of the gas pressure behind the bullets so they don't go as fast as they normally would.
A slower powder, specifically a powder that requires more charge weight to produce the same speed as other powders, will increase gas pressure/volume, and this extra gas pressure/volume is what aids compensators and ports. More pressure blasting up means more pressure force pushing down.
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1 hour ago, Rnlinebacker said:
What powder are you looking at starting with? Just thinking out loud you may not need as much powder as the comp guns to make pf.
You'll need more powder to make pf when you have popple holes / ports. They bleed off pressure as the bullet passes by, and the bullet won't be as fast as it would in a non-ported barrel.
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Some of the Berry's RN bullets have long noses which allow them to be seated long even in barrels with short throats. But the plunk test is essential to determine what length will fit in your chamber, and you have to sort this out first.
https://www.shootingtimes.com/editorial/reloading-tips-the-plunk-test/99389
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Just an FYI on the 45 versus other calibers and compensators - compensators work on a 45. The only difference between the effectiveness on a 45 versus smaller calibers is the bullet weight. 45s use heavier bullets than smaller calibers. If the bullet weight is the same on the 45 and smaller calibers, and they use the same gunpowder to push the bullet to the same speed, the compensated 45 will have less muzzle rise than the smaller calibers - because the 45 uses more powder weight because of the larger case and bore.
Tested 45 Auto and 38 Super:
https://www.shootingtimes.com/editorial/compensated-45-vs-compensated-38/99515
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Just now, je85 said:
Czechmate is actually the tac sport frame not 75 series so mags are a bit longer front to back.
Cool! I wasn't aware.
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You'll be limited by what will fit in the magazine. Isn't the Czechmate based on 9mm-length magazines?
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What is the perceived advantage of the 9X21?
The 9mm and 9X21 have the same loaded maximum OAL, so the only difference between them is the length of the brass. They reach the same ballistics with the same pressure (when at the same OAL).
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4 hours ago, zzt said:
I don't buy the primer flow rational. I load 9mm major with 115s and I get no flow even with Federal SPPs.
Page 1, paragraph 7
http://www.k8nd.com/documents/hl9x21.pdf
Page 2, paragraph 1
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My understanding is that rifle primers, which have thicker cup material, have been used to reduce primer flow from loads that were often exceeding normal pistol pressure limits. The pistol primers would sometimes have primer flow that could cause the primer to pierce or flow back into the firing pin hole and plug it up.
This depends on the powder and the primer and the pressure. Many people find that pistol primers work fine with their load in their gun.
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On 11/11/2021 at 12:37 PM, 10ring said:
Have any of you had 9mm Zero bullets that were listed as .0355" diameter but came in at 0.356"?
Yes. Not uncommon.
929 Grouping
in Revolver Forum
Posted
Was this from a rest (bench)?