Check headspace on a 45acp 1911

[cw308]

If I trimmed a case to .898 couldn't that be used as a Go Gage? With the barrel in your hand, then drop the trimmed case into the chamber , measure the back of the case to the end of the barrel, with a feeler gage, wouldn't that give you your chamber size? Whats the best trim size for case headspace. I'm a bench rest shooter 308 caliber, in rifle I size to .001 case headspace, need some input on 1911 45 acp

[nettle]

Most, including myself, do not trim 45acp cases. Unlike rifle cases 45acp cases tend to shorten with repeated firings instead of lengthening. When the cases become to too short to headpsace off of the case mouth the extractor will maintain the headspace.

[cw308]

nettle
Thanks for getting back so fast. With rifle brass I trim every time, keeping the case to the same case length. With 45 auto I would think it would be a most to trim to the same length, keeping the role crimp crimping the same crimp. This is my first go round with these fired cases, half measured .886 & .890 I kept them separated, Remington .886 Federal .890 Wouldn't you experience blown primers & misfires with too much headspace. I'm not having any problems so far only trying to get into the do's & don't
Thanks again Chris

[nettle]

I just checked some of my 45acp brass. The lengths on some are .884"/886". Some are as short as .878". These have been reloaded many times. I reload rifle and understand the need to trim rifle. With straight walled pistol brass that shrink after repeated firings there is not the need. It's not going to grow and cause pressure problems. There is no danger of blown primers. I have reloaded about 31K.

The only difference you may see is when flaring the case mouth during reloading. Longer ones will have a little more flare. Shorter ones a little less.

Dave

[mikejonestkd]

I have 45 brass that has been loaded at least 15-20 times and never had to trim any of it ever. unless you are a match shooter there is no reason to pay critical attention to case length

You mention using a role crimp, and I am assuming that you mean a roll crimp. This is not recommended for autoloading cartridges as they will no longer headspace off the case mouth. Please use a mild taper crimp - I use just enough to take the flare out of the case, but not enough to swag the bullet down in diameter.

[cw308]

mikejonestkd
Thanks for catching my mistake, I ment taper. I role crimp for my 44mag revolver. Back to the 45, doesn't the headspace start at the end of the chamber off the case mount. Just trying to wrap my thinking around this. When the case gets as short as 878 as with Dave , wouldn't that put a lot of space from breach block to the base of the case. With a rifle you would have case separation an backed out primers. I'm sizing with the RCBS 3 die carbide set. It seats & taper crimp on the same stroke , after proper setup. Warm weather I bench rest 308 cold months indoor range. Just picked up a new Colt New Agent 3" fun to shoot, that's why I'm into 45 acp reloading. Powders are still hard to get. Now I'm using Bullseye, not to hot, enough to work the slide using a 230gr Win. fmj. Thanks for the info
Chris

[243winxb]

Maximum chamber length is .920" for the 45 acp. Head spacing is on the case mouth, but the extractor stops forward travel first, most times.

Cut a 30-06 , 308 or 243 case so its longer then .920" by about .010" Size it in the rifle die before cutting.

Run the cut case into the carbide 45 acp die. Deburr and chamfer mouth.

Trim till action fully closes. Thats chamber length.

The longest brass is the most accurate when all of the same lot and brand.

I like Starline Brass.

[nettle]

The cases are going to shorten with repeated firings and you will be throwing a lot of brass away (or you could give them to me ). When the case becomes too short the extractor will maintain the headspace.

[243winxb]

The firing pin goes forward till it makes contact with the primer. There is no firing pin stop. A type of firing-pin in which the forward movement is restrained until it receives the energy from a hammer blow. It is slightly recessed in the breech face before being struck by the hammer and is shorter in length than the housing in which it is contained. Upon hammer impact, it flies forward using only its own kinetic energy to fire the primer.

Photo of my Colt Gold Cup 45 acp.

[cw308]

nettle
Thanks for getting back. When your cases shorten do to less flare. With rifle, some only neck size leaving the case fire formed. Can you do the same with the 45acp case? Just flare the case mouth & taper crimp to proper OAL. I sized all my fired brass or I'd check if the bullet would fit in a fired case. Can you fire form pistol cases. Come to think of it, its not a good idea to fire form for a semi auto rifle. Sorry I'm a bolt action rifle shooter. This winter I plan on doing a lot of 45 acp indoor range shooting & reloading. With the help from all of you, I'm getting a handle on it. Thanks for your input

Chris

[nettle]

Chris,

I'm not sure I understand. The cases shorten just by firing them. Nothing to do with flare. The flare is to prevent shaving lead (or coating if coated bullets) when seating. You mentioned seating and taper crimping with the same die. This may or may not work well for you. The preferred method is to seat with the seating die and crimp with a taper crimp die in a separate station.

[cw308]

243winxb
Good idea with the trimmed rifle case, will do
Your posted picture of the fireing pin. Never thought I'd admit it, l think yours is bigger then mine. Will have to give mine a look. Didn't think the pin came out that far.
Thanks for the info

Chris

[243winxb]

Neck sizing 45 acp fired brass.

RCBS - size just below the bullets base. I tried it= had feeding problems.

I set carbide size die so a nickel coin fits between shell holder and die.

End play. A lead swc can be seated into the rifling to improve accuracy. Slow fire target shooting only. The head to shoulder distance must be controlled, maintained very closely. Mine is .947"

[James K]

Unless something is wrong at the beginning, handguns rarely develop headspace problems because the pressures are not as high as in rifles.

With that said, handgun headspace is taken exactly like rifle headspace for the cartridge type, and for the same reasons. An improvised case can be used IF wear is taken into consideration and it is within the specifications for a headspace gauge; if not, and if headspace checking is a continuing need, it would be best to buy a set of headspace gauges for the appropriate caliber.

Case support - erroneously called "headspacing" - on the extractor is not appropriate or recommended; at best it will cause inaccuracy due to poor case support; at worst it can cause blown cases and damage to the gun or injury to the user. The worst results will be in the 1911 since, for reasons that seemed appropriate at the time, the clearance space between the breech face and the extractor is very excessive.

Jim

[243winxb]

The Colt New Agent 3" , if not hand fitted like a match grade target gun , may never benefit from match grade ammo. Sorry. Hope i am wrong and you got a good one.

[cw308]

243winxb
Nothing wrong with trying neck sizing, always looking to improve. Full sizing is the way to go though with 45acp. Proper OAL cuts down feeding problems. The New Agent did have some issues with the recoil spring assembly, mine wasn't one of them. So far I'm very happy with it. Its not a one ragged hole group gun, just a good conceal carry & fun shooting piece.
Thanks again.

Chris

[243winxb]

Brass fired many time.

The maximum rim diameter is .480"

If larger, brass will not slide up my Gold Cups bolt face freely. Its to tight. Even with extractor removed.

Brass from a S&W that was loaded at maximum many time had expanded. Not all were from extractor dings.

The same brass, loaded with target load , would jam about 4 out of 50 in the GC.

Took a while to find the problem.

[cw308]

James K
Thanks for your input. The Go Gauge is .898 having a cut case I would think would do the same job. I also think case headspace you should know when your reloading. May only have to use it once for each firearm, still its a measurement to know . Also free bore is another area, how far to seat . With rifle, single feed bolt action , much greater range then magazine or cylinder fed firearms. With my Colt New Agent 3" 45acp , they can be finicky. I think I will stick with the 230 gr fmj for which it is designed. Want it to function 100%, 100% of the time with my reloads
Thanks for your helpful advice

Chris

[James K]

"The cases are going to shorten with repeated firings "

Now that is a new one on me. What, pray tell, could cause cases to SHORTEN with use? Normally, with high pressure rounds the case will stretch (flow) forward due to pressure and lengthen, which is why cases must be trimmed from time to time, but that is a user action, not something that happens from firing. Another cause of case lengthening is due to the case stretching because the forward part of the case is held to the chamber wall as the case backs up as far as it can. But that also causes the case to lengthen, not shorten.

Jim

[rock185]

cw, just a couple or three comments. I also think headspace is something one should know. As I mentioned,I measured it on a bunch of guns. Unless you have a grossly under length case, and/or a chamber grossly over length, the case will not headspace on the extractor. This stuff about the extractor holding the case has been repeated so often, for so long, many shooters are sure it must be true. I have found that the extractor will on average hold a .45 ACP within ~.035" of the breech face. So if someone has a pistol that is actually headspacing off the extractor, something is very wrong.

As to neck sizing only, I wouldn't recommend it with a straight sided semi-auto pistol case. Been there, done that. The case will expand on firing near the base, especially in the unsupported area of the barrel throat/feed ramp. Unless you're are sure you only shoot the reloaded cases in the same pistol and make sure the most expanded part of the case is lined up with the barrel throat/feed ramp, 100% reliability will be less likely.

I have experienced the case shortening on firing. As with measuring headspace, I've measured a bunch of cases, before and after firing. Measuring new cases, I've found they may shorten several thousandths upon firing. Then after resizing, the cases will lengthen again. I've seen changes up to .007". As there is the same amount of metal in the case before and after firing, I suspect that as the cases expand radially, the length is decreased. When I resize the cases, the case is squeezed radially and some, but not all, of the original length is restored. Not back to the same length because the base of the case is not sized down back to factory diameter in standard sizing die. I've found taper crimping to be very beneficial too in achieving that 100% reliability...

[243winxb]

James K. and Rock185. On firing of a 1911, just where is the extractor in relationship to the case rim?

[44 AMP]

Maximum chamber length is .920" for the 45 acp.

I'm curious where this number comes from. I've never heard anyone else mention it, so why do you think it's significant?

0.898" is the listed maximum case length. 1.275" is the maximum overall length with bullet.

It is rare to find a .45ACP case that exceeds .898". Unlike most other cases, .45ACP rarely stretches (grows) in length, and often cases get a bit shorter with firing.

Back to the 45, doesn't the headspace start at the end of the chamber off the case mount. Just trying to wrap my thinking around this.

NO, sorry, you are using the term incorrectly here.

Headspace is that distance from the surface of the barrel or chamber that prevents further forward movement of the cartridge, to the face of the bolt or breechlock when the action is fully closed.

The term comes from the earliest days of cartridge arms, and was, literally the space for the cartridge head (rim) to fit into.

The firing pin goes forward till it makes contact with the primer. There is no firing pin stop.

The 1911/A1 design has a firing pin stop. It's the plate at the rear of the slide that stops the firing pin from coming out of the back end of the slide.

A type of firing-pin in which the forward movement is restrained until it receives the energy from a hammer blow.

This type of system, where the firing pin is physically locked in place by another part(s) until the trigger is pulled, is genrally called a firing pin block.
The original 1911 design does not have this, the series 80 pistols (and up), do have this kind of system.

It is slightly recessed in the breech face before being struck by the hammer and is shorter in length than the housing in which it is contained. Upon hammer impact, it flies forward using only its own kinetic energy to fire the primer.

This is called an inertia firing pin, and is what the original 1911 used.

Your posted picture of the fireing pin. ..... Didn't think the pin came out that far.

The firing pin is tapered, and will stop when the fatter section wedges itself in the firing pin hole, but only if the firing pin spring is missing/broken. With the spring in place, functioning properly, it stops the firing pin's forward movement before then. However, this only applies when there is no round in the chamber. The firing pin in the picture is being pushed forward and held there so you can see it.

The maximum rim diameter is .480"

If larger, brass will not slide up my Gold Cups bolt face freely. Its to tight. Even with extractor removed.

If the case head is expanding (at all) your loads are TOO HOT.

And, remember that the Gold Cup is a match gun, deliberately made with tolerances on the tight end of the range. What chokes a Gold Cup may run flawlessly in a GI issue spec pistol.

Also I would point out that many of the tricks used loading bench rest rifle cases for best accuracy are usually ignored by the .45ACP and the semi auto pistols it is commonly shot from. The many factors present in the pistol cancel/override the accuracy improvement from specialized loading methods.

In other words, you won't get as much of a benefit, (if you get any noticeable benefit at all), which is why most of us don't bother. Things like seating the bullet just off the lands, neck sizing, etc., are accuracy advantages in a bolt action rifle and some other guns, but in a semi auto tilt barrel pistol, where the barrel moves in relation to the sights, not so much.

On firing of a 1911, just where is the extractor in relationship to the case rim?

Not sure just what you are asking here. The extractor hook will be in the case extractor groove. It may be in contact with the front of the case rim, or it may not be, there is some tolerance (slop) in the fit, there has to be some, but some guns have more than others.

When the primer is struck by the firing pin, the blow drives the case forward, until it is stopped, either by the ledge in the chamber, OR if not, by the extractor hook. When things are set up correctly, the extractor hook doesn't play that part, but things aren't always set up correctly. Generally, the case being held to the breechface by the extractor will allow grossly underlength cases to be fired, but its not a 100% given will always work kind of thing.

The usual way we test for correct case length (calling it headspace, incorrectly) is the "plunk test" Remove the barrel, hold it vertical, chamber up, and drop a loaded round (or sized case -not flared) into the chamber. "plunk".

The base of the case should be flush with the barrel hood (that part of the barrel that is uppermost as you hold it). Cases below flush are short (though they may fire ok) cases that stick up above the barrel hold are too long, and may interfere with proper lock up of the gun.

Generally speaking, most semi autos function (feed) better with rounds slightly shorter than listed max COAL (loaded length with bullet).

[243winxb]

For your reading pleasure. http://www.saami.org/specifications_...ex.cfm?page=CC

[cw308]

James K
You sound like a rifle shooter like myself. All my cases lengthened, trimmed with every firing to the same length. With 45acp it seems like its a different animal. Its only my second time on resizing. As odd as it seems, it looks that way so far. Learn something new every day. Be Well
Chris