Case length question.

[Texas Sheepdawg]

I'm getting ready to reload some once fired brass. So I start reading the Hornady Vol. 8 reloading manual to see what my cases should be trimmed to, if needed at all. Now I find myself in a delima. Hornady book states case length as:
Max Case Length 1.516"
Trim Case Length 1.506"

However, Alexander Arms data states:
Max case Length 1.526"
Min case Length. 1.520"

To me, that's a big difference that could affect pressures, accuracy and case life. So what's the deal? Since I have an AA barrel, I want my brass dead nuts. Do I go with the Alexander Data or Hornady?

[ss355]

I went with AA data and trim mine to 1.520". I hope others chime in with their trim lengths.

[Smoke]

I trim to 1.520".. So far mine is as accurate as I could ask for

[QuadCam]

do you size and then trim to get the most consistancy? or do you trim before any other reloading process?

I have noticed, I get about .005" - ,006" length increase after sizing.

[mlmiller1]

I size, then trim. Too many things can happen if you trim first.

[Drifter]

I trim to 1.520 after sizing.

[bwaites]

Lots of my Lapua cases are less than 1.520 to start, how do I make them longer? LOL

I've never trimmed a single Grendel case, and I have some with more that 20 reloads. I know that LR1955 has similar numbers of reloads and doesn't trim his Grendel brass either.

[Texas Sheepdawg]

I always decap/resize, clean then trim if needed. It's not good practice to trim before you resize. Unless you like chasing your own tail. But that's another thread.
Why the variance between AA and Hornady? Is Hornady a typo? AA? Seems like AA would know their own specs so that makes me wonder about Hornady data on the whole.

[rasp65]

Dawg I measured my chamber length with one of these http://www.sinclairintl.com/.aspx/pid=32...ength-Gage
My chamber length is 1.540".

[Texas Sheepdawg]

Dawg I measured my chamber length with one of these http://www.sinclairintl.com/.aspx/pid=32...ength-Gage
My chamber length is 1.540".

So, with that tool, you just have to shorten the neck to allow the tool to have a bit of travel?
However, I'm still wondering why there is such a difference between Hornady and the creator, AA.

[koden]

I've never trimmed a single Grendel case, and I have some with more that 20 reloads. I know that LR1955 has similar numbers of reloads and doesn't trim his Grendel brass either.

Can you measure your brass and see how long it is getting?

My Hornady brass is between 1.532 and 1.536 after 2 firings. The no-go gauge is at 1.527 if I recall correctly. I don't own one yet but I think that's what I read the spec is.

I'll drop a piece of unloaded and untrimmed brass in the gun and see if the bolt closes and is allowed to fire. I would assume it should not fire if the head space and chamber are correct.

[sgt_murf]

I'm getting ready to reload some once fired brass. So I start reading the Hornady Vol. 8 reloading manual to see what my cases should be trimmed to, if needed at all. Now I find myself in a delima. Hornady book states case length as:
Max Case Length 1.516"
Trim Case Length 1.506"

However, Alexander Arms data states:
Max case Length 1.526"
Min case Length. 1.520"

To me, that's a big difference that could affect pressures, accuracy and case life. So what's the deal? Since I have an AA barrel, I want my brass dead nuts. Do I go with the Alexander Data or Hornady?

ok that is a big differance simple though to explain..... if one thinks about it AA has defined their reamer to 1.526" (?) trimming at this length keeps the brass from crimping the bullet while allowing as much neck as possiable. OTHERS whom chamber in this caliber or about the same thing ( all with sutle differances) have a little bit differances which is WHY Hornady is backing most reloaders down to 1.516" and under simply because they do not have Everybody's differant reamer specs and to provide safe limits they error to the safe side less neck.
SOOOOOO if I bought my barrel from AA I would trim to AA's max specs (or a thou under) if my brass made finally streatched that far. If my barrel was by someone else I would trim to Hornady's or my manufactuer specs that they recommend.
personally I want as much neck as possiable, as long as it did not pose a issue.
PS I have yet to trim annnnnyyy Grr brass just has not streatched to 1.516" yet.

[Mutt]

Here's the way I look at it. Hornady didn't design the Grendel ...... AA did.

[sneaky one]

It's an old thread, but I trim all my brass to 1.515.( My goal was to trim once, then never again over the life of the brass, I thought 10-12 times would be all) Back then( 2008) the wolf brass would stretch to 1.560 on some. I used 1.515 as a standard. Now ( 3 yrs. later), I've measured some older AA brass= after 12-14 reloads, and it all chambers fine, I don't even measure them anymore, just toss them in the chamber to test function=(good to go, or not) ... although it's time to take up annealing those old brass, as they don't hold neck tension as before. That's not because of neck length. Rasp 65 explained long ago how to test your chamber, for brass OAL's. I tried it and mine is 1.536. IIRC. This is a low maintenance round , if it's not hot-rodded.

[mseric]

ok that is a big differance simple though to explain..... if one thinks about it AA has defined their reamer to 1.526" (?) trimming at this length keeps the brass from crimping the bullet while allowing as much neck as possiable. OTHERS whom chamber in this caliber or about the same thing ( all with sutle differances) have a little bit differances which is WHY Hornady is backing most reloaders down to 1.516" and under simply because they do not have Everybody's differant reamer specs and to provide safe limits they error to the safe side less neck.
SOOOOOO if I bought my barrel from AA I would trim to AA's max specs (or a thou under) if my brass made finally streatched that far. If my barrel was by someone else I would trim to Hornady's or my manufactuer specs that they recommend.
personally I want as much neck as possiable, as long as it did not pose a issue.
PS I have yet to trim annnnnyyy Grr brass just has not streatched to 1.516" yet.

Ramshot and Accurate list a "trim-to-length" of 1.50, VV/Lapua lists a "trim-to-length" of 1.516. I was curious about the differences in case length between the powder guys and Alexander Arms, so I called em. I talked to Johan at Western Powders and asked him why his data was so much different than AA data. Without going into a lot of detail he told me "those are the exact specs supplied to us by Alexander Arms". My guess is if you contact Hornady you will find the specs they use were also supplied to them by AA.

[stokesrj]

I think some of you are mixing issues here so let me see if I can help clarify; case length is independent of head space. A go or no-go gauge is measuring head space which is the distance between the bolt face and a datum line on the shoulder of the case. It doesn't care about the neck length. It is possible to set head space correctly yet encounter a dangerous situation if the case neck is long enough that it is forced into the throat. This will cause the case mouth to be crimped into the bullet. This in turn will cause much higher pressures before the case mouth releases the bullet.
If the load is near maximum, and the case mouth is driven into the throat, then pressure will escalate rapidly until something gives. Usually this would be a blown primer and maybe a flame cut firing pin but could be worse.
This isn't likely with most Grendel chambers because there is ample room for the case to grow before this would occur. But not all chambers are the same. I have one early Grendel Reamer that requires a neck turn and has zero lead to the throat. With this chamber you had better trim and turn cases for or you will have major issues.
Bob

[Bill Alexander]

We made a mistake in our (AA) published figure for the case length. The chamber will easily absorb cases until they split but as most reloaders want a trim length I went with a figure that should not be exceeded and then a tolerance. ie once the case gets beyond 1.526 it should be trimmed back to between 1.526 -0.006. This is a reasonable tolerance for any small hand tool and a pair of cheap calipers.

In the absence of a temperature controlled inspection facility and laboratory type CM to measure the lengths I still find some quandry in asking someone to trim a piece of brass to an exact length +/-.000x nor should it be necessary. I frequently wonder during discussions such as these how a small mass produced hand tool can acheive a repeatable tolerance that exceeds a multi thousand $ CNC machine but that is my cynical nature.

Factory new brass is well short of the chamber transition and brass will rarely grow such that it demands to be trimmed. Hornady and Western both work from the case print so if in doubt use thier figure.

As we print updates to our load data we will correct our trim figures.

[sgt_murf]

I think some of you are mixing issues here so let me see if I can help clarify; case length is independent of head space. A go or no-go gauge is measuring head space which is the distance between the bolt face and a datum line on the shoulder of the case. It doesn't care about the neck length. It is possible to set head space correctly yet encounter a dangerous situation if the case neck is long enough that it is forced into the throat. This will cause the case mouth to be crimped into the bullet. This in turn will cause much higher pressures before the case mouth releases the bullet.
If the load is near maximum, and the case mouth is driven into the throat, then pressure will escalate rapidly until something gives. Usually this would be a blown primer and maybe a flame cut firing pin but could be worse.
This isn't likely with most Grendel chambers because there is ample room for the case to grow before this would occur. But not all chambers are the same. I have one early Grendel Reamer that requires a neck turn and has zero lead to the throat. With this chamber you had better trim and turn cases for or you will have major issues.
Bob

Bob,
If my explanation is misleading I never meant it to be even though I did not explain in detail headspace vs neck length as well as you did. The point I was attempting is that another manufacturer/gunsmith could shorten or lengthen the neck length. Thus creating the bullet crimping that you and I have attempted to explain, like you put it this doesn't affect Headspacing rather defines the trim length to control the neck length. Headspace is a completely different issue as it deals with a datum Dia in the shoulder to a back of case. Because, I have the AA Chamber I would go by what AA defines. My observation sthus far is that none of my brass has made it to the recommended max length (headspace of my brass is defined by my dies, not a trim length)

[Greyfox]

I had a loaded round that would not chamber. I found out that the brass was over 1.526". I pulled the bullet and trimmed the brass back to 1.520,reloaded it, and it chambered just fine. None of the other cases I have were long like that one. My rifle is an Overwatch.

[sneaky one]

Just like any other manufacturers rifle chamber-no two are the same. As long as we know our own specs., we can trim-or not.