.45 ACP headspaces off of brass face, so ... (wildcat question)

labgrade

Member In Memoriam
.... how is it the .460 Roland cartridge (~.1" longer) can effectively shoot the .45 ACP interchangably - in the same barrel?

I've also heard that the .45 ACP-class "headspaces" off of the extractor ...

Which is it?

No matter either way, I'm just curious as I've heard both "reasonings."
 
Do an extractor test and you'll see the answer to #2.

Take the slide off, and for safety reasons, take the firing pin out. Now take a cartridge and stick it in the extractor. You'll see it doesn't touch the bolt face.
 
OK, yanky, = I'm an idiot & really have no idea .... zip experience with the .45 ACP-class pistols at all.

How is it that the Roland barrel can shoot both - interchangeably if they headspace off the cartridge face?

S4eems they must off-a the extractor ....
 
Well, the 460 Roland cartridge is actually only .010" longer, which is well within tolerances. Who knows how they came up with the "460" part of the name.

However, without a little smithing, I'd keep the Roland out of the 45ACP gun, and vice-versa. We're talking about some extreme pressure differences there, and bad things could follow.
 
Nah. They've done the tests, I've shot the round - all works pretty darned good enough so far & to me .... seems JMB's work re developing the 1911-style came up with a shooter that can withstand quite abit more than was earlier thought. Far as the "'smithing," that's in the barrel itself .... I'd guess.

".460" merely is a designation to diferentiate it from anything else same-wise in the .45-class .... same-same for a .357 Magnun in a .38 Special chambering (with that added extra .10" length). ... gotta call it something.

Can't believe that if the .45 ACP headspaces off the case mouth, the extra long Roland could work.

No disagreement, only questions.
 
That's what I though, until just did an internet search a minute ago.

Has somethin to with the extractor. I guess the Roland gun's extractors have a different pitch, or somethin like that. Apparently, some shooters just change out the extractor to fire 460's through their 45ACP guns, against manufacturer's recommendations.

I don't really know. Never messed with'm much. I'm too chicken-doodoo.:D
 
Why the .460?

I've done a fair amount of work with the .45 Super, and now the .450 SMC. These both use standard .45 ACP external dimension cases, and are fired in standard spec .45 ACP barrels. Either gives me 1,200 FPS out of a standard Government Model with 230 gr Pb bullets. The only modification to the gun is a heavy recoil spring and firing pin spring.

The question is, "What is the purpose of the .460 Roland, other than to sell a few barrels?"
 
"What is the purpose of the .460 Roland, other than to sell a few barrels?"

My understanding is that ballistically, the .460 Rowland smokes even the .45 Super.

Now, that said, I don't see a purpose for any of these non-.45ACP rounds. But don't hunt. Maybe that's it.
 
Uhmmm, isn't the MAIN reason for the .460 for safety & liability reasons - i.e. the longer case prevents the gun from going into battery if you try to shoot the round in a .45 acp gun. Unlike the .45 super, where dopes can shoot it (and thus kb it) in .45 acp guns? This also answers your question about headspacing, IINM. The bbl chamber must be reamed to that fractionally longer dimension, or the gun won't go into battery. If the longer case IS indeed "within specs", then it would go into battery, which would negate this main safety reason for the round, no? So, same mags, but different bbl, I believe. This results in less peeps blowing up their guns and suing the makers of the cartridge, as undoubtedly will happen with Triton, etc. The weird 460 name also I believe contributes to the a lower liklihood of peeps suing 460 rowland ammo makers, because it's SO different from ".45 acp", requiring greater negligence to chamber in a gun stamped ".45 acp", unlike ".45 super" - ".460" adds an extra digit (the zero), and adds a different second digit - six instead of 5, thus giving the ammo maker's attys much to make hay with WHEN they get sued. Liability, liability, liability!

Oh yeah, and slighty more ballistics, too.

PS. We could argue whether rowland or super gun's barrels actually have stronger bbls and more fully supported chambers, but it gives ammo makers somewhere else to cast the blame when they get sued for a kb, besides allegedly weak brass or overloaded charge relative to brass strength (or deep seated bullet or whatever). If peeps shoot rowland in acp guns, it's much easier to cast the blame on "wrong gun" than for example Triton - certainly they can and will (after all, their round is NOW the .450 xxx - forget the name - that's prolly why they called their .45 super this now, come to think of it!). If someone sells something called ".45 super", then it's a little easier for dopes with metal shavings embedded in their face to sue them when they shoot it in their old "forty-fahv".
 
FWIW I have a 625 that's been rechambered for the .460. In the revolver, the cartridge is held in place by the full moon clip so it's not headspacing on the case mouth. Theoretically, you could ream the cylinder straight through and still be able to shoot all the .45 variants although accuracy would probably suffer. I believe the Ruger Blackhawk headspaces on the case mouth so if you do a conversion on a Blackhawk you would only be able to shoot the Rowland. The 1911 conversion is a little more complicated and involves replacing the barrel with one rechambered for the .460, adding a compensator, and installing a much heavier recoil spring (26lb IIRC). Alledgedly you can still shoot 45acp in a .460 1911 because the cartridge will be held in position by the extractor; however, it would make more sense to switch back to your original barrel and recoil spring. The 460 Rowland will provide near 44mag performance (1500fps with a 180gr JHP); brass is available from Starline; Ga Arms makes loaded ammunition.
 
The problem with the .460 Rowland started with their marketing approach and saying that you can shoot .45 ACP or .45 Super from a .460 Rowland barrel. While that is true, it is not a good thing to do. The .45 ACP/.45 Super/450 SMC all headspace off of the case mouth. Problem is there are wide variations from one 1911 to another so some rounds will headspace properly while others will be held by the extractor. Being held by the extractor is not a good thing.

The problem we saw with the .460 Rowland was that it is too much cartridge for the 1911 platform. Even with a compensated/ported barrel and heavy duty recoil spring the life expectancy of the gun is shortened. I have also seen a Glock 21 converted to .460 Rowland. Now that scared me.

Triton dropped the .460 Rowland because it is too much cartridge for what the creator of it intends it for. People will get hurt with it.
 
Headspacing off of the extractor is great untill the time when the extractor fails to hold the cartridge, then the firing pin blow drives the case forward causing likely head seperation and subsequent nasties.

Sam
 
.460 Rowland

I shoot .45acp through my .460R CCU all the time.
Through the 16.25 Bbl, .45 ACPs sound like subsonic .22lrs!
No need for muffs.
.460 is a little loud though.You'll need muffs for them.
If you shoot .45s first, clean the fouled ring in the chamber before you shoot .460s and you'll be fine.
 
To MacMan10

You know, if you keep shooting 45ACPs and 460 Rowlands without hearing protection, pretty soon, you won't need any hearing protection. :p

I think that while you 'can' shoot 45ACP/45Super/450SMC through a 460Rowland chambered gun, those cases will cease to be 45ACP, etc. They will grow to the 460 Rowland length. Not a good thing to do.
 
Sam,

In your scenario, are you envisioning the firing pin striking the primer, having the case slip past the extractor, headspace on the casemouth, and then fire? I don't see how this could happen (not saying it couldn't, but I'm not sure how).
 
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