Brass too short

[Scottish Highlander]

Hi everyone, I am about to do some more reloading but I have hit a wee question with regards to brass length. I've sized all my brass out in different piles. I've 40 which are perfect as they are and don't need trimmed to size. The 40 are 2.008 inches long and trim size is min 2.005 and max col 2.015 so that 40 are good to go. I have 12 brass that are for some reason 1.999 inches long which are under the minimum trim length. Are these bin material now ?? I'm not wanting to go and use them if its a bad move. This is a 308 165 hornady load I'm making for reference. I read recently to long can be bad so maybe to short is bad to

Thanks for looking
Jamie

[Dave P]

The short ones will be fine - load and shoot them.

[steve4102]

Load and shoot.

[Scottish Highlander]

Thanks guys

[higgite]

Are you sure why the cases are too short? Short necks? Or too short head to shoulder dimension (headspace)?

[Traveling Fur Hunter]

If you're not sure....................................THROW THEM AWAY!

[89blazin]

Load and shoot.

[F. Guffey]

there are times I did not think I had a choice, when forming wildcats, 35 Whelen and 338/06 cases from 30/06 the cases shortened from .035 to .045", to solve the problem I started using longer cases.



Why didn't everyone use longer cases? Simple, I wanted my case to cover all of the chamber from one end of the chamber to the other, to accomplish that longer cases are required.



X sizer dies by RCBS, instruction, first, trim the case .020" before starting, some users of the X type die have the illusion they no longer are required to trim, by the time the case increases in length to require trimming the case should be ready to retire.



F. Guffey

[Scottish Highlander]

It's quite late at night and I'll compare a short case to a normal one tomorrow and see where the difference is in it but I cant work out how the hell a case can get to short any way

It's not that I've trimmed it to short by mistake. Isn't brass a standard length through production and once its fired in the chamber it basically personalizes it's self with your rifle and then you just neck size every time there after thus way you gain accuracy

The brass will stretch and that's why you check OAL before reloading and trim if necessary

Jamie

[F. Guffey]

“The brass will stretch and that's why you check OAL before reloading and trim if necessary”

true, the OAL is determined after the case is loaded and the bullet is seated, before AOL is case length, the case has a maximum case length, the case has a trim to length, the case length is not part of the OAL (case overall length as in an included length, the length includes the case and bullet). “trim if necessary” is determined by the length of the case.

The OAL is determined by measuring the length of the case with the bullet seated from the tip of the bullet to the head of the case.

It is possible to measure the length of the chamber from the beginning of the throat back to the bolt face. Anyone with forming die can form cases and trim to length for testing the length of the chamber. When forming the cases pushing the shoulder of the case ‘too far’ is key,

F. Guffey

[F. Guffey]

Scottish Highlander
Member

Quote:

Join Date: February 1, 2013
Posts: 41 It's quite late at night and I'll compare a short case to a normal one tomorrow and see where the difference is in it but I cant work out how the hell a case can get to short any way

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I measure before and again after, some cases I fire go through changes, part of the case body becomes part of the shoulder, part of the shoulder becomes part of the neck, reloaders claim the case stretches, not my cases, reloaders claim their shoulders move forward, not my shoulders, my shoulders do not move, the shoulders on my cases are/is what is left of the old shoulder with the beginning of a new shoulder. I know, there are those that sound like they belong on the old “TV show Welcome back Kotter” ,

http://www.youtube.com/watch?v=ll9-jEtEiiI

but to understand the case, when formed to the chamber ‘CAN’ shorten. That does not mean it ‘DOES’ shorten every time..

Then there is the total disregard for differences in designs of receivers. If there was total truth about the story that starts with “The firing pin strikes the primer and drives the case forward until the shoulder of the case hits the shoulder of the chamber etc., etc.. If there was a way to provoke someone to think that would be a good place to start, ‘BECAUSE’ when that happens the case gets longer.

Back to the beginning, I measure before and again after. When a case gets longer when fired I suspect the case stretched between the case head and case body.

F. Guffey

[603Country]

Many years ago, when I was relatively new to reloading, I was trimming cases for my 220 Swift. I was wondering, while trimming, why it was taking so long per case. The answer is that I had set the trimmer incorrectly and was shortening the case FAR too much. Well...those were the only cases I had at that time, so I just went ahead and trimmed them all too short (Norma cases, if that's of interest) and loaded them up and shot them. I got some great groups (0.25 and less at 100), so I just kept them till they wore out.

As for how much trimming is FAR too much, I never did measure them, but I did take some serious length off those cases. Probably somewhere in the neighborhood of close to 1/8 inch or a bit more.

[Scottish Highlander]

Thanks for all your reply's. I've compared the cases and I cant really tell the difference its so small plus I don't have any tools to measure neck and shoulder lengths accurately. Were only talking 0.010 inch (0.02 mm) shorter than the minimum coal. At a guess it will be the neck and not the shoulder that is shorter which just gives less neck to grip the bullet and that's about it. There are 2 that are 0.04mm shorter and I will chuck them I think.....

Jamie

[Bart B.]

There's no significant difference in neck tension across many thousandths difference in case neck lengths. For example, a .308 Win. case has a neck length spread tolerance of .020" as far as SAAMI specs go. The neck's about .300" long. Which means there'll be a but less than a 7% spread in case neck tension across a .020" neck length spread. Neck tension will vary exactly that much across a batch of cases whose length has that much spread if all things about the case neck and bullet jacket friction issues are exactly the same. There's no way neck tension could be held to that low of tolerance even with all cases exactly the same length and neck walls exactly the same thickness.

So, that much spread in case or neck length is not worth loosing sleep over. The most accurate ammo ever made will easily have a 10 percent spread in bullet release force or neck tension. I've measured ammo with a 20% spread in neck tension that produced 1/2 MOA accuracy at long range.

[F. Guffey]

Then there is the length of the neck and bullet hold, I am the fan of bullet hold, I want all the bullet hold I can get.

Then there is the 300 Win mag. neck length? The 300 Win Mag neck is .264” long (in the perfect world). I built a 30 Gibbs, the neck length is (or was) .217”, if the 300 Win mag neck is short, the 30 Gibbs neck is too short, and I fixed that, I increase the length of the 30 Gibbs by .040”, that made the neck length .257, that is not as long as the 300 Win Mag neck but it is an improvement over the .217” length neck. I did not have an issue with the short neck, I had an issue with the part of the chamber the case did not cover.

Then there are case formers and wildcatters, when forming 300 Win Mag cases some trim the neck, others increase the length of the chamber by reaming for longer necks then increase the length of the throat, that is not something that should be attempted without practice.

Then there is that slight chance of getting two different neck diameters as when the second reamer is smaller in diameter than the first reamer used to cut the original chamber.

F. Guffey