case length tolerance for 45acp
What is the tolerance when trimming 45acp. Trying to get best possible accuracy from my new Kimber. My cases run from .890" to .896" after sizing. This has been posted on the reloading site too.
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I don't trim pistol brass, maybe hot magnum brass, but never any standard brass.
Rifle brass is different, I check the brass after every firing and trim as necessary.0 -
+1. As long as you taper crimp your bullets, the extractor controls the headspace. The 1911 platform was designed by John Browning as a controlled feed firearm.
Some overly anul bulleye shooters trim their brass. I always felt they were wasting their time. PS might have a different opinion though.0 -
In a magazine I bought in 1982 thats all about the .45 the author stated to NEVER trim .45 brass. I never have, and Ive never had a problem with it. 0 -
I was under the impression that 45acp seated on the case mouth. 0 -
quote:Originally posted by rufe-snow
+1. As long as you taper crimp your bullets, the extractor controls the headspace.. . .
I totally disagree. The 45 ACP seats on the case mouth. Headspace is controlled by the case length. You check your loaded rounds by dropping them into a chamber, making sure the rim is flush with the barrel extension.
The M1911 is not a controlled-feed mechanism. It can be loaded and fired without an extractor.
I've shot thousands of 45 ACP and never trimmed a case.
A 45 ACP revolver can be fired without using half-moon clips. The cartridge seats on the case mouth. There's no extractor involved at all.0 -
quote:Originally posted by Cheechako
quote:Originally posted by rufe-snow
+1. As long as you taper crimp your bullets, the extractor controls the headspace.. . .
I totally disagree. The 45 ACP seats on the case mouth. Headspace is controlled by the case length. You check your loaded rounds by dropping them into a chamber, making sure the rim is flush with the barrel extension.
The M1911 is not a controlled-feed mechanism. It can be loaded and fired without an extractor.
I've shot thousands of 45 ACP and never trimmed a case.
A 45 ACP revolver can be fired without using half-moon clips. The cartridge seats on the case mouth. There's no extractor involved at all.
Horse pucky. Using 45 ACP dummies load a magazine and put it in the 45. Cycle the slide, as the breech moves into battery the top round is stripped off, and forced forward into the chamber. As the round moves forward and up, the rim is behind the rear face of the extractor. This is the definition of controlled feed.
The only problems I ever had with crimping was with a S & W Model 25. I was shooting it without the half moon clips. The 45 ACP's I were using were roll crimped. This caused headspace problems, and many failures to fire. In retrospect this would be the only drawback of using a roll crimp, rather then a taper crimp when loading 45 ACP. As the 1911 platform is controlled feed, the roll crimp would have no affect vis a vis a taper crimp.0 -
rufe - Controlled feed has nothing to do with headspace. An extractor is designed to extract, not control headspace.
Edited to take out the bad stuff. Sorry rufe.0 -
quote:Originally posted by Cheechako
rufe - Controlled feed has nothing to do with headspace. An extractor is designed to extract, not control headspace.
There's no polite way to say this. I've probably hand loaded and shot more 45 ACP in both M1911s and revolvers than you've ever seen in your lifetime. I recognize horse-pucky when I smell it and see it. Your posts are just that. Stick with things that you know about.
+1000
Here is a post from 10 years ago that will explain it better. Head space and extractor should NOT be used in the same sentence with the 1911.
""In light of realizing that so many good folks are misinformed on the subject of correct headspacing in the 1911 pistol, I took the liberty of doin' this thread in the interest of our continuing education, so that all may be armed with the knowledge to make a call of: "SHEEPDIP!" whenever some gunshop
commando drops a round into a barrel chamber...shows that the rear of the rim is flush with the face of the hood...and pronounces it good to go. While that condition may well exist in a pistol with perfectly acceptable headspace,
that, in and of itself, is NOT an indication.
Headspace falls into two categories.
Static headspace is the measurement between the breechface and the cartridge stop shoulder with the pistol in battery. Static headspace only changes with wear and/or locking lug deformation or setback...or wear on the breechface.
Live...or working headspace is the difference between that measurement and the length of the cartridge case that is fired in the gun...and varies with every shot unless all brass is trimmed to exactly the same length.
Excessive headspace is defined as static headspace that falls outside of acceptable limits as set by the SAAMI for the caliber. Static headspace is correctly determined with a gauge...typically GO and NO-GO. Precisely measuring headpace requires a determination of the exact dimension, usually done by using a GO gauge and an appropriate feeler gauge in conjunction.
GO...plus feeler gauge thickness equals total static headspace.
Headspace limit for the 1911 pistol is .898 inch minimum and .920 maximum. GO and NO-GO sets are made to these specifications.
Headspace can be excessive and still be safe. It can be excessive and be dangerous. It depends on which direction that the excess goes.
If the stop shoulder is reamed too deep in the chamber, it can be outside ot the maximum limit, yet still be safe. If the locking lugs are incorrectly located,
incorrectly cut, or deformed...the excess can be dangerous , because it allows partial opening of the breech on firing. The case backs out of the chamber until the slide reaches the limit of its rearward travel as determined by the horizontal lug to lug fit...and the case head loses chamber support.
You can ream the chamber too far...file the hood to perfectly flush with a chambered round or GO gauge...and it will look like good headspace...but it's not.
You can ream the chamber perfectly at minimum dimension...with a cartridge
or GO gauge dead flush with the hood face...and if the lug fit allows the breech to partially open beyond NO-GO limits on firing, you have a dangerously excessive headspace condition.
To better understand this, we need to understand that when the pistol fires, the slide and barrel are tied together by the horizontal lug engagement. The barrel is slammed forward by the bullet while the thrust of the expanding gasses are driving the slide rearward in a 20,000 psi tug of war...and are doing their level best to separate the slide and barrel. If the lugs allow the slide to move rearward beyond safe limits...NO-GO...the case follows the breechface...loses chamber support at 6 O'Clock...and bulges or blows.""0 -
Thanks to all , my question has been answered. 0 -
quote:Originally posted by Cheechako
rufe - Controlled feed has nothing to do with headspace. An extractor is designed to extract, not control headspace.
There's no polite way to say this. I've probably hand loaded and shot more 45 ACP in both M1911s and revolvers than you've ever seen in your lifetime. I recognize horse-pucky when I smell it and see it. Your posts are just that. Stick with things that you know about.
You can shuck and jive till the cows come home. Control feed is dictated by the interface of the rear face of the extractor with the rim of the cartridge. This controls the headspace, not the length of the cartridge. This holds true for not only the 1911, but any other firearm that uses control feed.
This is what I advised you to do in my previous post. If you do it correctly, with a open mind, you will understand what controlled feed is.
"Using 45 ACP dummies load a magazine and put it in the 45. Cycle the slide, as the breech moves into battery the top round is stripped off, and forced forward into the chamber. As the round moves forward and up, the rim is behind the rear face of the extractor. This is the definition of controlled feed."0 -
quote:Originally posted by rufe-snow. . . Control feed is dictated by the interface of the rear face of the extractor with the rim of the cartridge. This controls the headspace, not the length of the cartridge. This holds true for not only the 1911, but any other firearm that uses control feed. . . .
rufe
Take the extractor out of any controlled feed weapon you want to use as an example - pistol, rifle, whatever. It will still feed and fire. So, what is controlling the headspace with the extractor gone?0 -
Staying on topic, SAAMI specs for case length for the .45 ACP is
0.898-0.010"
If your case length is 0.887" or less, discard them.
If they exceed 0.898" trim them or discard them.
http://www.saami.org/PubResources/CC_Drawings/Pistol/45 Automatic.pdf
Your cases are within spec.
http://www.saami.org/PubResources/CC_Drawings/Pistol/45 Automatic.pdf0 -
Hello CHEECHAKO I will take you up on that challenge of rounds fired of 45ACP[:0] The question is "Should I trim 45ACP cases" The asswer is DON'T BOTHER. The reason is "straight walled 45ACP dont get longer they get shorter evry time they are fired". Now to the pissing contest on how a 1911 works . Both sides of this debate have valid points. Most Colt Automatic cartridges are designed to headspace on the case mouth. However we are not talking 50,000 psi in semi auto pistols the cartridge needs to fully chamber under the
force of the recoil recoil spring pushing the slide forward. The best accuracy in 45acp is about .006 head space This can be checked by removeing the barrel dropping a loaded round in the chamber and having the combination of how far the head of the case is below flush to the end of barrel hood and add this to clearance between barrel hood and slide breach face when the empty barrel is reinstalled and slide is closed. Now to the question of what makes up headspace I shoot mainly semi-wadcutter mostly Lead with a VER sharp shoulder these head spaceon the front edge of the lead bullet shoulder. The jacketed also head space this way I taper crimp .to a case mouth diameter of.469 Ball ammo does not have a sharp shoulder but I head space on the bullet diameter itself. I have tested 45acp ammo on a ransoms rest thousands of rounds every year for very close to 40 years . . Case wall thickness varies a lot between manufacturers. That is why you need to read my sticky on the reloading forum crimping semi auto cases . Cheers PERRY SHOOTER 1972-2005
"praise the hardball gun"0 -
Perry Shooter - Challenge accepted.[;)] Started handloading in 1950. I shot my first pistol competition in 1955 at the Norfolk Naval Base. Held a Masters card in both indoor and outdoor NRA pistol. Qualified with both a pistol and a revolver. Of course, the minimum for Master was a lowly 275 back then, but try that with a revolver.
If you've been shooting for the past 40 years it's obvious you also have a lot of experience. Since I no longer shoot pistol due to eyesight you'll probably catch and surpass me.
I admit that I can no longer leap tall buildings with a single bound, so let's call it a tie?
Ray0
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