How long is too long

[briang7511]

How long is too long for case trimming? I am loading .308 primarily long range accuracy rounds and so far i have always trimmed the cases if they were out of range (longer than 2.010 i would trim to 2.005). My buddy who does not have a case trimmer says he doesnt have any issues and has not trimmed one case yet. So i have trial fit a case that has been resized inside both my rifles that measures 2.025 and i see no issues with it. It chambers just fine. So before i load a bunch of cases that i have to scrap :banghead: ive got to ask, how many people have been down this road? I dont really see where a longer case will affect anything but maybe someone has figured out the error in my ways already.

Using a RCBS single stage press with RCBS FL dies loading for a Rem 700 and a Savage 12

 

[tightgroup tiger]

Unless I'm crimping into a canular I don't trim my rifle brass unless they become hard to chamber.
As long as I know my die setup hasn't changed, I usually let them grow in length until I notice a little bit of resistance on chambering, then I check them all. If I find the the case to be over length then I check all of them and trim as necessary.
If you are shooting max loads and your friend isn't, he may not have to trim for a long time and you may have to trim often.

 

[jim243]

How long is too long will depend on YOUR rifle. The 308 indexes on the shoulder of the case and as long as you are full length resizing, you should get the shoulder of the case back into spec for the rifle.

As to the neck of the case, most bolt action rifles have the neck of the chamber cut a hair over spec and will accept cases necks a bit over spec, but that will depend on how each rifle was made. Most modern rifles will be within SAMMI specs (unless the throat of the rifle has been shot out due to hot loads.)

Can you get away without trimming the case, YES, SHOULD you do that, I would say NO. Trimming each case to the same spec will insure consistant size cases for crimping each round for better accuracy. The amount of tension on the bullet needs to be the same, shot after shot for small groups. Shooting for long distance you will definitly want to trim each case the same for accurate results weither you crimp or not.

For hunting, trimming is not as important and would be up to you.

Jim

 

[jjjitters]

One possible issue with letting the necks grow is when the neck pinches between the bullet and throat when chambering. When the round is lit off, the neck can't expand and release the bullet, bad things happen when the bullet isn't allowed to move. At best, accuracy will suffer.

 

[blarby]

How long is too long

When they don't fit anymore.

 

[briang7511]

most of my cases fall with in 2.012 and 2.018. this is winchester brass 2nd time firing. there are a couple of long ones around 2.022 and only 1 around 2.025. were talking .010 over max, a hair is about .003 dia. so were talking about 3 hairs long?? i agree take the long ones out but the majority is about a hair oversize.

 

[kelbro]

Sinclair sells a plug that will tell you exactly how long you need to trim in YOUR rifle. Saved me a lot of time and effort by not performing a case prep task that was not required. I do trim them all to the same length if I am going to crimp.

http://www.sinclairintl.com/reloadi...s/sinclair-chamber-length-gage-prod32925.aspx

http://www.youtube.com/watch?v=JKnXJxaAw2U

 

[gamestalker]

Since every throat is different, it greatly depends on that particular throat. But as a general rule according to SAAMI spec. the maximum before trimming is necessary is to prevent such bad things as mouth pinching when discharged. This is the primary reason why a SAAMI spec exists for brass maximum length before trimming is necessary. I do know that not trimming bottle neck cases can be a game of time and chance before something bad happens. As decribed above in Jitters post, when the mouth gets pinched during firing and delays, or other wise restricts the bullet from leaving the case, pressures can go through the roof, thus damaging the firearm, or even worse!

In most firearms the distance to a restricted point in the throat is some what generous, but still yet it is more than possible for the mouth to exceed that allowance. Every reloading book I own clearly explains the reason for trimming brass to within SAAMI spec..

GS

GS

 

[Sport45]

When a sized case is over max length I trim it to min length. Otherwise, I leave them alone.

 

[popper]

It's NOT the case length that is important, it's the neck length as measured from the shoulder datum point. Same with headspace. As a long range shooter, case mouth prep is important(as is EVERYTHING). As for crimping, the Lee FCD will solve the problem. You should have a case gauge and make measurements of HS and neck length referenced to the gauge. Write the numbers down and trim when needed. As Blarby says, 'when too long'.

 

[ArchAngelCD]

I resize once fired brass and then check every couple of firings to be sure the brass doesn't grow too much. It's really not all that hard to check a few cases once and a while. Now trimming them, that's another story.

 

[cfullgraf]

As jjjitters said, if the case get too long, the mouth will interfere with the end of the chamber and pressures could rise to unacceptable levels.

There are ways to measure that as have been already been suggested.

I measure all cases after resizing. Those that are over the suggested max length get trimmed. For me, I usually have to trim about 25%-35% of the cases sized.

I do not crimp my rifle cases so i do not need the cases to be exactly the same length. I might do things different for cases if I crimped.

 

[jim243]

Here is a fast way to tell if you need to trim.

Jim

 

[GLOOB]

If you have measured all your cases after sizing, and the LONGEST case easily chambers with a bullet seated, then go ahead and load 'em.

But you'll eventually need to trim them. When the longer cases finally start hitting the end of your chamber, I hope you're still paying attention.

(longer than 2.010 i would trim to 2.005)

BTW, is it just me, or isn't the SAAMI length of a 308 case 2.015? You can let it go a little longer between trimmings, my friend. As you have found out, you can go at least 2.025" in your rifles, with your current sizing setup. Like someone else mentioned, if you started sizing the shoulder back further, then 2.025" could now be too long and cause a problem if the round was chambered with sufficient force.

 

[Sport45]

How long is too long?

I believe that is defined as the amount of time that has passed since you ate your last bowl of Wolf Brand chili.

 

[Jdillon]

The Sierra manual recommends a trim length of 2.005".

 

[helotaxi]

It's NOT the case length that is important, it's the neck length as measured from the shoulder datum point. Same with headspace.

Misread, nevermind.

 

[wv109323]

The tolerance in one of my reloading manuals is .010". There will not be a problem until your brass outgrows your chamber. When you reach that point your chamber will crimp the bullet and pressure will exceed the maximum allowed. At that point or beyond you have catastrophic failure.
When that happens depends on case length, chamber length and how much resistance is put on the bullet by the crimping action.
I find that if you trim the once fired case you are good for two to four reloads.

 

[helotaxi]

The "trim to" length in a reloading manual is nothing more than 0.010" shorter than the max case length. It isn't a tolerance. The tolerance is listed on the cartridge print from SAAMI and is expressed as a hard maximum with a margin on the short side. For most cartridges the tolerance is 0.020". The published trim length gets you in the middle of the accepted range with allowance for some variation without running into problems.

If I'm bothering to full length size rifle cases, they're making a trip though the trimmer while I'm at it. Case length is one of those things that I don't mess around with.

 

[Big JJ]

I just started trimmimg my 308 win cases with a new Lee length gauge and cutter.
Timmed 3 cases and they came out to 1.956,1.949,and 1.954.
This is under the recommended Hornady size of 2.005.
Is this under sizing going to cause an issue?
What is the acceptable under sizing of a 308win case?
Why would the Lee gauge be so much shorter than the recommended size?
I used both the Lee hand trimmer and the Lee drill chuck trimmer with the same gauge and both cutters came out the same.
I thought maybe the cutters had a deeper cutting edge but this was not the case.
I am sure it is the gauge that is causing the issue.

 

[GLOOB]

Trimming each case to the same spec will insure consistant size cases for crimping each round for better accuracy. The amount of tension on the bullet needs to be the same, shot after shot for small groups.

For my bolt action, I started using a Lyman M die without a crimp to help seat cast boolits. A side benefit is that the section of the neck that gives tension is the same for all my brass, regardless of the length.

 

[blarby]

crimping each round for better accuracy

And thus, "mutually exclusive" was properly defined on THR.

Yes folks, you heard it here first !


Im sorry man- I know what you meant. But crimping is a "function of function" not an ingredient of accuracy.