Case length

[cdschoonie]

More learning questions. As it pertains to the case length, I am prepping 45 Colt for my Marlin lever. In the books on case length, they say minimum case length is 1.275, max is 1.285. I realize the difference between the two is not much more than a sheet of paper thickness. That said, it brings me to these questions, I just finished prepping 200 cases of range brass, and getting ready to prep 200 more new ones. The range brass lengths varied from 1.270-1.288, the new ones are from 1.267-1.277. I figured that the new ones would be the longest ones, but since it’s actually the range brass that is longer I need to ask some questions…

1) Now I have read many times that necked brass grows with every shot, averaging around .0005 (could’ve been.005, but I’m not looking at the threads I’ve read this in), extremely small amount I know. The growth happens not only in overall case length, but also when measured to the ogive. To this, I figured the necked cases stretched because they are bottle-necked, which would cause pressure against the neck when fired, which obviously could stretch them due to the explosion. Assuming straight-walls have no bottle, and a full opening for the explosion to be relieved, does this happen with straight-walled cases as well, do they also grow with every shot?

2) With the thickness between minimum and maximum trim length being so tiny, how imperative is it that they are in that length range? Meaning are cases, let’s say 1.267 (.008 below the minimum) no good, or is it acceptable to accommodate them with the bullet seating?

3) I’ve always thought it could be corrected by the COAL, so which is more important, the case length or the COAL when loading is done?

I’m sure this info, as with many of my questions, might seem ‘nit-picky’ to some of you, but I’ve always been a perfectionist. My Dad always taught me, anything worth doing, is worth doing right. I want to know everything I possibly can about reloading, but I’m not a ‘corner-cutter’, I want to know the correct and safest ways to do each step start to finish, mainly because I’ve grown attached to my limbs, as well as my firearms.

 

[Aries]

1) They will stretch a little, but not much and I've never heard or read of anyone who thought trimming straight wall cartridges were all the necessary. Semi-auto rounds that headspace on the mouth of the case, maybe but I doubt it. They'll probably never stretch THAT much. Rimmed cases, I can't imagine stretching enough to ever matter, they'll likely split before they get that far. I load 9mm and .45 acp and have never trimmed cases.

2) Most of my experience is reloading handgun calibers. I seriously doubt .008 is significant, and I'd rather they be short than long (within reason). Cases don't get shorter as you shoot them, so that one specifically has never been SHORTER than 1.267 so whoever made it felt that was within specs. I wouldn't be concerned at all, and I'll be surprised if you ever find one that's too short to use, unless someone over trimmed it.

3) Not sure on this one, I think COAL will more likely affect function (if it's too long to fit in a magazine) or accuracy (jump to rifling). As long as it headspaces on the shoulder and not the rim it shouldn't be critical, but if they are over max length I would trim them, as much for uniformity as anything.

All just my opinions, and smarter people than me will provide answers as well.

 

[cdschoonie]

1) They will stretch a little, but not much and I've never heard or read of anyone who thought trimming straight wall cartridges were all the necessary. Semi-auto rounds that headspace on the mouth of the case, maybe but I doubt it. They'll probably never stretch THAT much. Rimmed cases, I can't imagine stretching enough to ever matter, they'll likely split before they get that far. I load 9mm and .45 acp and have never trimmed cases.

2) Most of my experience is reloading handgun calibers. I seriously doubt .008 is significant, and I'd rather they be short than long (within reason). Cases don't get shorter as you shoot them, so that one specifically has never been SHORTER than 1.267 so whoever made it felt that was within specs. I wouldn't be concerned at all, and I'll be surprised if you ever find one that's too short to use, unless someone over trimmed it.

3) Not sure on this one, I think COAL will more likely affect function (if it's too long to fit in a magazine) or accuracy (jump to rifling). As long as it headspaces on the shoulder and not the rim it shouldn't be critical, but if they are over max length I would trim them, as much for uniformity as anything.

All just my opinions, and smarter people than me will provide answers as well.

These are the answers I’d hoped for, not only because I felt I was on the right track, but I’ve yet to find any less than the .008 I mentioned. I’ll continue to measure each case in the prep stage, if they are over the max, I’ll trim them, otherwise if they are close or slightly below I won’t worry too much about them.
To this point, I’ve actually trimmed everything that was over the middle point of the min-max range, example on these with a 1.275-1.285 range, if they were 1.280 and up, I trimmed them. My Lee trimmer is pretty accurate, usually +/- .002 out the desired length.
Anyway, this will save me a lot of knuckle busting in the trim stage. I’m cheap, so I use the Lee drill-chucked case holder, with the wood ball-handled cutter. Get a tight one in there and quicker than I can blink, the case will pop out and I shove my knuckle into the drill head, don’t know if I can take much more of that lol. That’s the type pain that goes straight to your gut, makes you want to puke!

 

[swampratt]

Here is what you need to do with the straight cased round.

Find a long one that is past the max length spec.
Size it. DO NOT trim it.
Insert the sized case into the chamber of the weapon it will be used in.

Does the case keep the action from closing?
If yes then you will need to trim it.
Now load that same case with a bullet.
Will it still chamber?
If yes then you can delete some trimming.
If you are adding a crimp to the loaded rounds it is nice to have all cases the same length for consistent crimp.

Now when i was playing with the 45 Colt i had issues getting brass.
You know me I usually do not buy new.
I found with 5 different brands I got 5 different case thicknesses.
That created poor accuracy.

Hornady critical defense nickle cases were very short and very thick.

I have 1 German 357 Magnum that will not accept a lot of factory ammo because the chambers are a bit short.
I must trim all of it and I have not noticed any growth of case length after many shots fired.

I have shot 38 cases in 357 and that is way short..short is a non issue if you clean now and then.

My older savage model 10 in .308 I could go to 2.035" before I had to trim.
Max trim length for the .308 is 2.015" I believe.
I have trimmed them short also. 1.95"

 

[swampratt]

Oh on that lee trimmer.
I take the cutter and remove the ball and chuck the cutter in the drill press.

I then take a case by hand and tighten it into the lock stud/shell holder and hold it with both hands and run it up the cutter stem and in seconds it is done.
Since I have a grip on the case and the lock stud it will not untwist easy.

No busted knuckles.

 

[Aries]

This is VERY quick and easy for case trimming, and you can use it with a power drill or a hand crank, whichever you prefer. i used the hand crank, and it was quick and easy enough. AND you don't have to chamfer the case mouth!

https://leeprecision.com/deluxe-power-quick-trim.html

 

[cdschoonie]

Oh on that lee trimmer.
I take the cutter and remove the ball and chuck the cutter in the drill press.

I then take a case by hand and tighten it into the lock stud/shell holder and hold it with both hands and run it up the cutter stem and in seconds it is done.
Since I have a grip on the case and the lock stud it will not untwist easy.

No busted knuckles.

I fixed the trimmer, ok I re-engineered it. I figured out, by going through all the cases, with the varying wall thicknesses, some cases slipped on flush with the cutter, others (about 1/3 of the range brass) went on up to halfway onto the top shoulder of the gauge. So I chucked the gauge backwards into my drill, got a piece of Emory Cloth, an spun it through that. It took the thickness of the gauge down just enough where the thicker case would go on. Before, I would have needed a hammer to get the case all the way to the cutter, now it’s still snug, but loose enough to get it to the cutter with very little effort. I checked the ones that went on easily before, of course they are easier still, but have no side to side movement either. So, no more knuckle-busting! I’m am going to try the way you described, and see which way I fancy more.

 

[cdschoonie]

This is VERY quick and easy for case trimming, and you can use it with a power drill or a hand crank, whichever you prefer. i used the hand crank, and it was quick and easy enough. AND you don't have to chamfer the case mouth!

https://leeprecision.com/deluxe-power-quick-trim.html

Unfortunately I bought one of these, along with 45 Colt and 45-70 dies, got it in a couple weeks ago. I say unfortunately, because, I tried it with 3 different cases (thinking maybe it was something with a cases and not the trimmer), that thing scratches the heck out of the cases! I realize scratches are just cosmetic, but if I’m going to spend the time to clean and reload, I want them to be nice and shiny like new.
Extremely disappointed in it, so if anyone wants one, I have one, plus the dies for 45 Colt and 45-70 I’ll sell you…

 

[Aries]

Hmmm... I never noticed mine doing that. I guess something up inside the die grips the case, I wonder if there's some dirt or something in it that could be scratching?

 

[cdschoonie]

I cleaned them well, since they were new dies. I have a couple junk cases, I’ll clean the die again and try it, see what happens.