Brass OAL questions

[blakheaven]

Ok, just so you guys know upfront I a prepping .308 Win brass LC match all the same year (2003) All I did to it was tumble 200 pieces out of the 1000 brass I have.

Afterwards I decided to measure them to see how close they were to each other and I was kinda disappointed.[ 308 win brass is max OAL in SAMMI specs is 2.015] and though I know often times chambers are longer and the longer you leave it without going too far increases accuracy.

Anyways my results was the shortest brass was 1.997 and the longest was 2.018 with the average OLA being 2.005'' The majority of the brass is in the 2.000-2.010'' range.

What do I do? Do I trim them back to 2.005 and discard brass shorter than this? Do I keep firing the different OAL brass till they grow to what I want them and not worry about them being different lengths??(which won't lie that option doesn't sound appealing but the most likely)Should I FL resize and remeasure? (I am a neck sizer so I bump back rarely) Also do you separate brass by weight before or after trimming? I have read the stickies and understand each of the processes involved but my question is what to do in this un-ideal situation

Thanks for any advice.

 

[LR-WSM]

Re: Brass OAL questions

Have these already been fired in your chamber? If so, trim to length, chamfer, debur, and segregate by weight. Done.

If they are virgin or once fired in another weapon, full length re-size to spec, trim, etc, then sort by weight.

Unfortunately there is no other way that I'm aware of if your batching by weight. Just consider yourself lucky you don't turn necks as well cause that would be another step before sorting.

BTW, are you shooting comps or are you just looking to squeeze the last drops. It's all fun till it becomes a hassle.

 

[gmiles]

Re: Brass OAL questions

Ironically, I came up with the same question yesterday as I was sorting brass. I have a bunch of LC and PMJ brass with some Hornady, WCC, and RP mixed in. I found the PMJ and LC brass were on average 2.010" in length, after FL sizing. The WCC and the RP were even longer. The Hornady and Nosler I think were 2.005 +/- a hun.thous.

Here's my plan: load 175 SMKs in the longer brass and trim anything longer back to 2.010 for the 175s. I have some loads with 135gr SMKs. I'll load the shorter brass with the 135s until they reach 2.010. The 135s are fine for a couple hundred yards. I'm working the load up for 300 yds max for the 135s.

incidentally, after FL sizing all my brass, the longest was 1.020" (WCC). I colored the bullet end with a sharpie and chambered the empy case. No resistance when closing the bolt and the marker was intact on the case mouth. I'm guessing that means the longest case will chamber in my rifle just fine without jamming in the end of the chamber. I don't know if my chamber is longer than normal.

FWIW, I'm new to reloading so use caution before following my plan.

 

[blakheaven]

Re: Brass OAL questions

I am shooting comps and I do neck turn. These have not been fired in my new chamber cause I having my action re barreled.

When you say trim to length, how do you decide what length that is when 99 percent of the brass is shorter than what its suppose to be(I don't know for sure but I expect my new chamber to be around the 2.015 area it being custom and new if not longer) And its no hassle its just I don't know which step to do first and what OAL to choose. BTW i am using the redding comp trimmer so i can get it to .001 accuracy

Ideally I wish all my brass was 2.015'' lol

 

[blakheaven]

Re: Brass OAL questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ilikeguns</div><div class="ubbcode-body">Ironically, I came up with the same question yesterday as I was sorting brass. I have a bunch of LC and PMJ brass with some Hornady, WCC, and RP mixed in. I found the PMJ and LC brass were on average 2.010" in length, after FL sizing. The WCC and the RP were even longer. The Hornady and Nosler I think were 2.005 +/- a hun.thous.

Here's my plan: load 175 SMKs in the longer brass and trim anything longer back to 2.010 for the 175s. I have some loads with 135gr SMKs. I'll load the shorter brass with the 135s until they reach 2.010. The 135s are fine for a couple hundred yards. I'm working the load up for 300 yds max for the 135s.

incidentally, after FL sizing all my brass, the longest was 1.020" (WCC). I colored the bullet end with a sharpie and chambered the empy case. No resistance when closing the bolt and the marker was intact on the case mouth. I'm guessing that means the longest case will chamber in my rifle just fine without jamming in the end of the chamber. I don't know if my chamber is longer than normal.

FWIW, I'm new to reloading so use caution before following my plan. </div></div>
Well closing the bolt handle is more of a Shoulder bump issue than OAL unless the brass is way to long but since most of the brass you (and me) have is under SAMMI spec of 2.015 thats not an issue. My main goal is to have the necks around the same length for uniform tension but to get them all the same length I ill be trimming all my brass back to 2.005 which to me is worse than cussing in church cause then you start running into concentric problems and the neck only "holding" a smaller portion of the projectile.

 

[JeffP40]

Re: Brass OAL questions

Trim to .010" under max length and go. No need to be worried about a little difference in a few. As long as they don't get too long and bind on the chamber, they are fine. After a while, they will grow and you can trim again. This should get them all to the same length.

 

[vman]

Re: Brass OAL questions

I agree just shoot them.

If your really concerned, sort them out

 

[LR-WSM]

Re: Brass OAL questions

blakheaven, the possibility that all 1000 pieces of brass you obtained were fired from the same weapon is slim. That will dramatically increase the variances in external measurements. I would F/L re-size them first, trim to 2.005 and then sort by weight. If you are going to turn necks for consistent neck tension I would do this before weight sorting.

 

[427Cobra]

Re: Brass OAL questions

IMHO anyboby who has spit out a trim number has given you OK advice, but every rifle has its own chamber, Sinclair sells a chamber length tool that will tell you exactly how long your chamber is, my trim length is minus .010, some use .005, had you always been trimming back to 2.005 I bet your trim length is very long.

 

[blakheaven]

Re: Brass OAL questions

As for the brass that is under 2.005 I sort them by weight and wait till they "grow"? Make them there own batch?
BTW tumbling 1000 pieces of brass is a pain in the rear lol and I am going through media cleaning up the brass lol..(using corn cob)

 

[MALLARD]

Re: Brass OAL questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">but every rifle has its own chamber, Sinclair sells a chamber length tool that will tell you exactly how long your chamber is </div></div>

+1

 

[blakheaven]

Re: Brass OAL questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MALLARD</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">but every rifle has its own chamber, Sinclair sells a chamber length tool that will tell you exactly how long your chamber is </div></div>

+1 </div></div>

I know and I actually have one but I dont have the barreled action atm to measure anyways.

If I did though I would have a number 2.0XX. Ok great now I have a number what do I do with that number? I trim brass to make them all the same and if that number is larger than the majority of my brass I have two options

Option A: I can trim all my brass to a certain length as make them uniform and hope they grow uniformly (or close to it) but doing so will make all my brass shorter and increasing the number of firings it will take for it to grow to that perfect number or

Option B: Using that number set my trimmer up to that number minus 5 thousandths and leave all the shorter brass than that as they are. But doing so will mean until the brass is long enough to be trimmed they will all be different lengths causing different bullet tensions and making it harder to seat bullets uniformly.

Which devil do I choose! lol

p.s. when I say reloading I do use redding comp set so I can FL resize or just neck size

 

[blakheaven]

Re: Brass OAL questions

Update: I FL resized which bumped the shoulder back from 3-4 thousandths but when I measured the OAL it grew around 4 thousandths average. I guess the brass had to flow somewhere when getting bumped back. Its weird cause I never knew that resizing could make the OAL length grow.

 

[XTR]

Re: Brass OAL questions

I've got a bunch of once fired BH match that I'm currently using. Once I re-sized everything I set my trimmer up to 2.010 and trimmed 'em all. Some of them the cutter never touched the rim, others it looked like it cut quite a lot.

I've heard of others that trim to 2.005.

It will get longer as you shoot it.

 

[Fuzzball]

Re: Brass OAL questions

Not that it really matters but OAL (and COAL) is the proper (loaded) over-all length term for a cartridge, case length is what it is.

 

[JeffP40]

Re: Brass OAL questions

So, do you really think that 5 or 6 thou. in length is going to make a difference in the grouping of the loads? From your limited experience, (not a bad thing), you will not even know which shot is long or short. There are so many other things to obsess over, you are basically wasting time worrying about this. If you really can't help yourself, sort them into the "proper length" and "too short", and load them. Your time will be better spent shooting. If you want something to get "microbial" about, check your loaded rounds for runout. That will effect your shots a lot more than brass length.

 

[blakheaven]

Re: Brass OAL questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JeffP40</div><div class="ubbcode-body"> So, do you really think that 5 or 6 thou. in length is going to make a difference in the grouping of the loads? From your limited experience, (not a bad thing), you will not even know which shot is long or short. There are so many other things to obsess over, you are basically wasting time worrying about this. If you really can't help yourself, sort them into the "proper length" and "too short", and load them. Your time will be better spent shooting. If you want something to get "microbial" about, check your loaded rounds for runout. That will effect your shots a lot more than brass length. </div></div>

I am not new to reloading by any means (not to say I am god's gift or anything and I am always learning) but I anneal, neck turn and trickle each of my charges to a tenth of a grain, so leaving an error of 5-6 thousandths of neck will result in undermining why I turn and anneal my necks and why I use redding neck dies cause I am in the pursuit of "perfect" neck tension. Say I did everything else perfect but had one round with a longer neck than the other its neck tension will be higher. I don't like this cause I want to have the same MV for every round.
The reason I posted is cause I never had this problem before of all my brass being so far from 2.015 (my old chamber max COAL (thanks for the tip on that) was 2.020) ) So I always trimmed my old brass to 2.015-2.018 depending on how hot of loads I was using.

 

[Fuzzball]

Re: Brass OAL questions

"Say I did everything else perfect but had one round with a longer neck than the other its neck tension will be higher."

The initial burn curve will obviously be impacted by the bullets inertia and, to some degree, by how firmly it's gripped in the neck but I can't see a few thou of case length making much difference. None of us can prove it one way or the other but I strongly suspect the case walls, including the neck, are slammed fully against the chamber before the bullet exits the mouth.

 

[blakheaven]

Re: Brass OAL questions

I am not an expert but isnt the shoulder slammed against the chamber as it expands then the brass flows rearward against the bolt face. the neck then streatches in the throat some but it isnt coming into contact with the lands after a single firing. I wish cause then after one firing all the brass necks would be the same length but I don't think this is how it works. I just think its the headspace (distance from head to shoulder datum) is what is fireformed to the chamber not the COAL.

Anywho back to the two options
"Option A: I can trim all my brass to a certain length as make them uniform and hope they grow uniformly (or close to it) but doing so will make all my brass shorter and increasing the number of firings it will take for it to grow to that perfect number or

Option B: Using that number set my trimmer up to that number minus 5 thousandths and leave all the shorter brass than that as they are. But doing so will mean until the brass is long enough to be trimmed they will all be different lengths causing different bullet tensions and making it harder to seat bullets uniformly.

Which devil do I choose! lol"

and why do you choose option A or B? I see advantages and disadvantages to both options so I am just in limbo

As always thank you for your help and input.

 

[Fuzzball]

Re: Brass OAL questions

"..isnt the shoulder slammed against the chamber as it expands.."

Yes.


".. then the brass flows rearward against the bolt face."

Not exactly. The brass doesn't exactly "flow"; it gets stretched just forward of the web.


".. the neck then streatches in the throat some .."

The only neck stretch that occurs is in diameter, not length.



"..but it isnt coming into contact with the lands after a single firing."

Necks getting progressively longer is mostly due to the effects of FL sizing, not during the firing. When sizing, the shoulder is set back and that moves wall brass into the shoulder, shoulder brass is then moved into the neck. That's part of why neck sizing helps extend case life a little bit, it reduces the case wall stretching that comes from setting shoulders back too far.

 

[blakheaven]

Re: Brass OAL questions

Fuzzball I have two words for you.
Thank-You

 

[Fuzzball]

Re: Brass OAL questions

'Welcome. Us blue-suiters got to stick together around all these ground-pounders and swabs...

It's been a long time since I last saw Tinker.