45acp case length

I started doing some measuring  in hopes to improve my reloads and my cases all mixed brands very in length from .868 to .891 I had heard that they shrink  from reloading and I have been reloading them till they split down the side then through away. I guess the question is how short can they get before you might start getting light strike  and what length  is best for for wad gun or just shooting 185gr buttons?

I am sure you have read that the 45acp head spaces on the case mouth. That is pretty much dogma. I would like to say IMHO that that statement is pretty much wrong. I have fired a lot of 45 ammo. I have seen a couple of cases too long. I have never seen one too short. It would be hard to get one too short since I think they actually headspace on the extractor. Just my .02 worth.

Len

The longest brass seems to be more accurate for me. The inertia firing pin goes till it hits something.  Do use brass of the same lot. 

I have some very old military match ball ammo. The case lenght is low to mid 890s. There's a reason for this.. Headspace is a factor that contributes to accuracy at 50yds. The old armories were aware of this way back then.. If your extractor is influencing the cartridge case in anyway while in battery, it is not adjusted correctly.  The three big ammo manufacturers mostly keep the case length in the low to mid 880s.. Too short..even for an .898 chamber, you can have .018 +   headspace...Now, if there is belief that is condusive to 50 yd accuracy, we are not on the same page...  Starline brass is the best longline brass available.  It is closer to the old military ball match length.. The gun should be chambered for the ammo..
A chamber depth of .898 or less is possible, providing the shooter heeds reloading. Shortline is not that critical, and standard factory ammo can be mass loaded without much concern of an over length case.. I have never seen any over max length from Rem. Win. or Fed.. Headspace attention can help tighten up that 50 yard line...

Seating into the rifling with a lead bullet will help at 50 yds. When end play is removed, accuracy is better. I measure OAL to the shoulder for my GC. 

thanks to all for your wisdom and knowledge, I thought maybe the case would be hitting the extractor and brake it. I need to get some longer brass most of what I have has been shot many times. looks like I need to know how long my chamber is to find out what the shortest case should be. might have to start another thread bout head space.

SAAMI      I seem to remember cutting a 30-06 case to more than maximum CHAMBER length*,  .920"    Sizing with a 45 acp carbide die, lubed. Then check when the action would fully close by removing a small amount with my trimmer.

I was thinking I could measure with a depth mike to the bottom of a case then add the case length to that for a max length and try to get cases as close to that as I can, wonder if I can shorten my head space or does that have to be done when you put a new barrel in and cut the chamber depth after barrel is fit?

Need to be careful about seating lead bullets out to far. In my experience it will leave lead ring at case mouth area in chamber and cause seating problems when it starts getting dirty. I've inspected many guns that were having seating problems that were dirty with built up lead like this.
Jon

Correction.   Chamber length is .920" Maximum.  .898" is minimun.  I think a new barrel would be needed to adjust headspace??

If your ammo is headspacing off the extractor, you need to change that, possibly by visiting a gunsmith.  If you are using cast bullets, I would not load such that the bullet makes it to the leade.  I have, however, loaded swaged bullets (the old Stars) so they engaged the leade, with good results.  Cast, as mentioned earlier can start to cause trouble as the chamber gets dirty.  I would use the barrel, removed from the gun, to check your ammo.  The ammo should fall in and out freely and while in the chamber, should be slightly below flush with the hood.  If you are using a swaged bullet, you can get closer to flush with the hood.

First step to setting headspace.. WHAT IS  THE CHAMBER DEPTH...????? Then, all chamber designs are not the same, unless, a standard SAAMI reamer is used.. which is designed for the masses of the world...Not BE target shooting..What is the leade..SAAMI standard 5 degree.?? Let's use a 1-1/2 or 1 -1/4 degree leade angle which is proven in every venue of the target world to be beneficial regardless of the caliber..Would a BE chamber benefit from some freebore ?? Absolutely... and how about those sloppy chamber dimensions..??? Minimum wall taper..  The smokin hot guns that are approaching 1 inch groups at 50...have well designed chambers...
The first extractor is adjusted correctly. The hook touches neither the rebate angle nor the groove, and is pulled back to permit the case to seat flat against the breechface when in battery. Very little tension can be run, when so adjusted.
 The bottom picture is typical of the industry standard, and has a negative effect on both reliability and accuracy..

Hi Jerry,

   I think you just showed a picture supporting my 1st statement about the bullet seating on the extractor for industry standard 45s. The second picture shows the extractor hitting the bullet and holding it above the bolt face. If the bullet was actually in a barrel it wouldn't be cocked over but would be held in that position. In a perfect world the bullet would go into battery and just stop when it made contact with the case rim or stop against the bolt face as it pushes the bullet forward. In this world Newton says that is not going to happen. When the case hits it bounces back, when it hits the bolt it bounces forward. It rattles back and forth (whatever clearance you have) and settles somewhere between the extractor and the bolt face. Even if the extractor is not making contact with the case it is extremely unlikely (unless your shooting straight up or down) that the bullet would come to rest in contact with the bolt or the case rim. Newton evens things back out when the bullet is fired. The first thing that happens when the bullet is hit by the hammer is it is driven forward by the force of contact. The second thing that happens is the case (it is lighter than the bullet) is driven back against the bolt face until contact and then the bullet is propelled forward. The whole process happens fast but basically all cases are in contact with the bolt before the bullet goes forward. I know you knew all of that I am just letting you know why I think they headspace where I said.

Len

OldMaster64 wrote:Hi Jerry,

   I think you just showed a picture supporting my 1st statement about the bullet seating on the extractor for industry standard 45s. The second picture shows the extractor hitting the bullet and holding it above the bolt face. If the bullet was actually in a barrel it wouldn't be cocked over but would be held in that position. In a perfect world the bullet would go into battery and just stop when it made contact with the case rim or stop against the bolt face as it pushes the bullet forward. In this world Newton says that is not going to happen. When the case hits it bounces back, when it hits the bolt it bounces forward. It rattles back and forth (whatever clearance you have) and settles somewhere between the extractor and the bolt face. Even if the extractor is not making contact with the case it is extremely unlikely (unless your shooting straight up or down) that the bullet would come to rest in contact with the bolt or the case rim. Newton evens things back out when the bullet is fired. The first thing that happens when the bullet is hit by the hammer is it is driven forward by the force of contact. The second thing that happens is the case (it is lighter than the bullet) is driven back against the bolt face until contact and then the bullet is propelled forward. The whole process happens fast but basically all cases are in contact with the bolt before the bullet goes forward. I know you knew all of that I am just letting you know why I think they headspace where I said.

Len

Len
If the chamber is cut to allow only .003/.005 clearance with the case against the breechspace, and case mouth against the chamber edge or somewhere in between, that is the static headspace. It is measurable and repeatable to within the .003/.005 range irrespective of the bullet.  Frankly I like a little less. You're referring to dynamic headspace, and yes, most 45s have a considerable amount.. But that is not conducive to accuracy. On a minimum spec chamber, the case will seize to the chamber wall very quickly as the ignition process takes place.. Newton is there, but one thing I will argue, is nothing takes place instantly.  All things are measurable.. It takes very little pressure for the case to grab the chamber wall. So exactly when the case head contacts the breechface in a dynamic headspace situation, is subjective.. Even for Newton.. 
The extractor pictures show how the extractor should interface with the case rim. The rim only is making contact with the extractor body.. Not the hook, and with only a few ounces of tension, it is not shoving the back of the case against the opposite side of the chamber. If, the chamber is minimum SAAMI in diameter and taper, it's not possible for the extractor to push it very far anyway. BUT we all know that not every chamber mouth is not minimum..
In the second photo, when the case is forced against the breechface, where does the extractor go..?? It's jammed against the rebate angle, and can even, depending on how  precise the barrel is fit, force the rear of the barrel over..
In the first photo, the case is already in that position as it is fed into the chamber... and stays there during ignition. The .003/.005 clearence is negligible.

Jerry,

 Hi again. I agree with everything you just said. My wad gun was built by Toyota and I assure you I don't have an extractor that is not working perfectly. I was referring to the 190,000,000 (WAG) 1911's that were not made perfect or brought up to perfect specs. Now I have to go see what the extractor on my RO looks like. Hmm

Len

jerry, my extractor looks like the top picture and I measured my chamber to be .898 from the end of barrel hood and there is .005 between end of hood and bolt face that would make .903 the longest case possible I also measured from bolt face to extractor hook and that measure .081 so with all the rim thickness measuring .040 to .043 if .903 less .043 = .860 the shortest case could be and not hit the hook of extractor, none of my cases are that short but measured about two hundred today and they very .865 to .892.
I did order some starline brass today. to make long line loads. I also think the longer case should be more consistent group.
 Richard.

This is great reading you guys are really analyzing this subject. I have a question on measuring case length. I asked a whole bunch of shooter/reloaders how they measured case length. They all said they measured it after they cleaned it. Not one of them measured it after it was sized and deprimed. or a loaded round. I notice that my case length is different before and after sizing or when loaded. So when do you measure case length? Before sizing, after sizing, or when the round is finished with a crimped bullet in place?

pistol champ wrote:This is great reading you guys are really analyzing this subject. I have a question on measuring case length. I asked a whole bunch of shooter/reloaders how they measured case length. They all said they measured it after they cleaned it. Not one of them measured it after it was sized and deprimed. or a loaded round. I notice that my case length is different before and after sizing or when loaded. So when do you measure case length? Before sizing, after sizing, or when the round is finished with a crimped bullet in place?

At bullseye chamber pressure, there is not a great deal of stress placed on the brass. I find very little change from use. In fact,  the late Al Bacon and I machined a batch of 460 Roland brass to .900 and tested in a .903 chamber.. I still use this brass today, for testing, and it's still .900 after all these years.

Just did a box of PMC brass the other day and the case walls are thicker and the cases are longer than a bunch of USGI stuff (all the same make) with headstamps from WWII to 1998. 

Interestingly enough, the last 10 I loaded in PMC were with a light load that showed promise but they went into groups too big for me to use on the long line. Makes me wanna do some more testing...THANKS A LOT!!!

I check a few brass after sizing. Never had one too long. I find brass of the same lot (Starline) to be more accurate than range brass.  The longest brass i run into was IMI.

I always check after sizing I picked that up form loading rifle and I am not sure that 45 acp get shorter just something I read on the net some where but I am going to test that with some new cases.

Deerspy wrote:I always check after sizing I picked that up form loading rifle and I am not sure that 45 acp get shorter just something I read on the net some where but I am going to test that with some new cases.

Deerspy
There is more to it..
The chamber dimensions have an effect on the brass. A larger diameter allows the case to expand more than a chamber that is smaller... When metal moves, it has to go somewhere... If it expands a lot and then is resized, it has to grow slightly, when the metal is pushed back into the smaller shape.. High pressure is harder on brass than low pressure.. Many bullseye loads are 10,000psi or less..It's hard to pin point a bench mark with so many variables.

Jerry Keefer wrote:

Deerspy wrote:I always check after sizing I picked that up form loading rifle and I am not sure that 45 acp get shorter just something I read on the net some where but I am going to test that with some new cases.

Deerspy
There is more to it..
The chamber dimensions have an effect on the brass. A larger diameter allows the case to expand more than a chamber that is smaller... When metal moves, it has to go somewhere... If it expands a lot and then is resized, it has to grow slightly, when the metal is pushed back into the smaller shape.. High pressure is harder on brass than low pressure.. Many bullseye loads are 10,000psi or less..It's hard to pin point a bench mark with so many variables.

Jerry 
thanks, if you were going to put a new barrel in a colt series 70 government what brand has the tightest chamber.
I think what I really need is a hole new wad gun but may have to live with this one I have been shooting for 30 years.

KKM has/had the tightest, which must be reamed and head spaced.
I liked to single the chamber to just clean it up, and then the reamer has a true axis to follow. I have had some fantastic shooting KKM barrels..
I haven't used a KKM in several years, so things may or may not have changed..
Unfortunately,  things have a tendency to not remain the same.....
Jerry

thanks Jerry for the info. I don't have a lathe and don't know how to fit a barrel may be I could hit the lotto and have one built.