Acceptable Tolerances for Resized 308 Brass

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GeeJ

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So I took the jump into the world of reloading (.40 & .308) a few days ago. The pistol ammo went very smoothly and was no problem & shot perfectly. I'm currently working my way through the. 308 side of it & am at the question of acceptable tolerances for cases after resizing; all for the sole intention of precision range/competitive shooting how to 1,000 yards. I am not much into hunting, personally.

So far I have not found any forums or other sources of information that talks specifically about casing tolerances. The manuals that I have referenced all seem to note the same measurements. I already understand the extreme importance of OAL and I know what the measurements are supposed to be but what about acceptable tolerances for headroom, shoulder, diameter below the shoulder, diameter at the base, & mouth? How close is close enough for for precision shooting?

I apologize if this specific topic has already been covered in a previous thread. I did search the forum beforehand but didn't couldn't find what I was looking for. If any of you are experienced precision reloaders, I would very much value your input on the subject or even any other input you feel is noteworthy. I'm all about learning something new, learning it right and doing it all with safety and understanding first.

I appreciate all of your time. Take care everybody and always have fun shooting as well as in life. Thanks.
 
There are a lot of variables in what you are asking. What rifles? For long range precision shooting it will take bench rest techniques. And some special equipment.
 
IF you are shooting a bolt action (big IF), the adjust the sizer until the case fits back in the chamber and the bolt closes with the barest of feel.

If for a gas gun, then simply/absolutely full-length resize and toss the cases after a half-dozen firings max.
 
Understand that every case is unique. They all size slightly different. I have seen a variance of plus/minus .0005" out of the sizer die. This is prolly due to inconsistent annealing. This kind of variance is inconsequential as far as accuracy is concerned.

Now, if you are seeing more than that in the shoulder and headspace dimensions, the expander ball is prolly pulling the shoulder forward on the upstroke. You should lube the inside of the neck to make that operation smoother, even if you have a carbide ball.

I stopped using expander balls along time ago. I feel the best way to size is by using a Lee Collet Neck Die. No expander ball. Better concentricity. Smooth. No lube needed.
 
Reloading for 1000 yard competition is a big jump for a beginner. Not that it cannot be done, but it is a little more involved than casual reloading for rifle.You really need to get advise from people who do it.

Taliv, 1858, USSR and others here shoot 1000 yard stuff. Sniper Central may be a good place to look as well. They could help with rifle selection, scopes, windage, and all the little things you must know to shoot well at that distance.

Don't get discouraged, you can do it.

I assume you have a rifle capable of shooting competitively at 1000 yards. Get some good factory ammo to hone your skills with, and then start the reloading side of it. No sense being frustrated with both to get started. Make it easier on your self.
 
I would suggest read read read. Google bench rest shooting and spend a few weeks first.:eek: Then start by separating sized trimmed brass by weight. Next do the same for your match grade bullets. And finally weigh each and every propellant charge to +/-.01 grain minimum. Next comes the fun part, finding best OAL--crimp or not -- all while putting LOTS of holes in paper. Mind you this is a good starting point for precision shooting. After you work up a good load there will be no need to ask us more questions I am willing to bet.:)
Me I am nowhere that good a shot and minute of critter dead at 100-150 yards is what I seek these days.:D
 
been reloading 3 years with no problems until i started 308s in a fal. i know now why they make head space gauges. the instructions that come with the dies will always size the brass down to the smallest amount possible so it will fit in any chamber. to get it to fit your chamber and stop case stretching and possible case head separation like what happened to me use head space gauges. i got the hornady gauge and that showed me how far off i was on full length sizing 308,223 and 7.62x39. i would say this is a must have tool to reload safely. the types of dies you use and the instructions that come with them can vary greatly .
 
Except that the case gauge is not your chamber. It is your chamber that dictates the amount of sizing needed, not some case gauge.
 
Totally agree, but the gauge does make a handy (and cheap) tool when loading for an autoloader. I use a cartridge headspace gauge and calipers to set up my dies for autoloaders. Unlike when loading for a boltgun, I can’t get a feel for the required setback in an autoloader and I don’t have any fancy mics for these cartridges. YMMV.
 
who has the time and money to make a cast of every chamber they reload for? the gauge will get you close enough to do the job better than the instructions that come with the dies like the lee instructions. that should tell you how cheap i am if thats all i can afford:scrutiny:
 
I think 918v is saying to use the chamber as the gauge. He is correct that is the best gauge available, but I just have trouble doing that w/ an autoloader.

You can use a standard cartridge headspace gauge as a tool for measuring. After firing, your brass roughly measures the same as your chamber. With clean, fired brass in the gauge, measure w/ calipers. Adgust die to reduce this measurement by a couple tho and see if it functions well in your chamber. If not, adjust die till it measures another tho less and try it again. IMHO, that's better than just keeping it between the low and high steps.
 
I think 918v is saying to use the chamber as the gauge. He is correct that is the best gauge available, but I just have trouble doing that w/ an autoloader.

Maybe this will help:

For ARs, screw the sizing die down incrementally until you are able to close the bolt using the forward assist.

For FALs, remove the top cover and feel the bolt close. It's that easy.
 
I'm know this is kind of a long winded reply but there where a lot of very good points worth thinking about and following up on. I definitely left out some useful information for you guys to help answer my questions. Sorry about that. As it turns out, my questions weren't even the right questions since I was misunderstanding the connection between the information that I did have.


While there's no substitute for getting out there & doing it, might start by reading the stickies at the top of this forum.


If I could, I would like to mail you a cold beer. I don't know if it was the sticky you were referring to but the post I read cause a spark in this dusty noggin of mine and that lead to another spark which lead to a series of connections between the knowledge I currently had. Previously, I simply knew the steps for precision reloading and had the necessary measurements; but now I'm finally starting to see more clearly the WHY that's so critical in precision reloading. The link you posted helped lift the fog.
Now, about that beer.....
There are a lot of variables in what you are asking. What rifles?

DPMS LR-308 with a 24" stainless bull barrel. A Harris bipod and Leopold Mark AR III that I'm using from my M 4 until I have the money to buy high quality glass. Optics are the one things that I will not limit myself on price, even if I have to save up for it.

Rifle3-1.jpg Rifle2a.jpg
the tolerances are pretty much up to you

It was more of a concern for safety with having never reloaded and not finding info on tolerances. I felt compelled to ensure I had a knowledgeable answer first. For now, I'm going with +/- 0.003 until I have a more definitive answer.
If for a gas gun, then simply/absolutely full-length resize.
Yessir, I'm using the Lee full length resizing die with proper lubricants
I feel the best way to size is by using a Lee Collet Neck Die.

I was actually looking into that yesterday. I have to be frugal with my money at the moment but I am considering this item, though.
Reloading for 1000 yard competition is a big jump for a beginner.

I'm not intending to jump right into such ranges or competition just yet. It is something I've been interested in or sometime. I found that a private 1K range is only 15min away so I've decided to join it & commit to the craft. First and foremost, I'm figuring how I want to proceed beforehand so that as I progress; I do so properly, affordably, efficiently, without training scars & allowing for a mindfully constructed base of knowledge as I gain experience working up to 1000 yards.
it is a little more involved than casual reloading for rifle.

This is *exactly* what I am interested in. I don't know anything about reloading and thusly have no bad habits or misinformed beliefs. I want to learn to reload for 1K consistency/accuracy from the very beginning. With limited money comes limited resources. I doubt I have the means to do so right now, but my equipment will improve over time. As an infant reloader, I plan to take time and mindfully build an understanding of how to do it safely, precisely & to do it right... here in the very beginning.
Sniper Central may be a good place to look as well

I've been reading them a lot in the last day or so but I'm hesitant to join with the intention of posting questions. I've seen a number of* harshly judgmental responses to a beginner's question who likely didn't know it was a stupid question. I will *definitely* use it for reading information but I'll wait a bit before joining. Isn't there one also called "sniper shot(s)" or sniper something?
Don't get discouraged, you can do it.

I'm not entirely sure that's possible right now. It's been a while since I've had something that I'm so interested in. My last job consumed so much of my life that I had almost none of my own. I just didn't have time. It's the first time in a long time, plus it's one I've always wanted to do. Now I can and I'm really enjoying it
I assume you have a rifle capable of shooting competitively at 1000 yards.
I got this rifle for a steal at a gun show & I've heard great things about it. It may not be the best 1000 yard shooter, but it will serve me well in the beginning/intermediate stages of my progression.Once I can reach 1000 yards, reload with fine precision, and have built up a solid base of experience; I will take I second mortgage out on my home and sell my wife to buy the most amazing equipment ever designed by alien hands. At the very least, that's when I will begin to consider dropping big time professional competitive super duper long range shooting kind of money.
Get some good factory ammo to hone your skills with, and then start the reloading side of it. No sense being frustrated with both to get started. Make it easier on your self.

Yup, I have a box of 168g Sierra Match King waiting for me on my bench.
I would suggest read read read. Google bench rest shooting and spend a few weeks first

I've been soaking up everything I could find for the last month or so but I genuinely struggle with learning new things unless I'm actually in the process of doing them.....if that makes sense
then start by separating sized trimmed brass by weight. Next do the same for your match grade bullets

That makes total sense. I have only been concerned with measurements and it never thought about weighing the casings. That morsel information is definitely going into my reloading log.
finally weigh each and every propellant charge to +/-.01 grain minimum

I already have a simple RCBS trickler on its way.
Next comes the fun part, finding best OAL--crimp or not -- all while putting LOTS of holes in paper. Mind you this is a good starting point for precision shooting
Also in transit is a Sinclair Bullet Comparator #2. I reckon once I establish a seating depth that gets the ogive *extremely* close to the land I might be able to finagle an OAL without excessive trial and error. Of course I could be wrong, after all this is a learning experience. Putting holes in paper is not a problem whatsoever.....well.....as long as they are circular holes that is.
Except that the case gauge is not your chamber. It is your chamber that dictates the amount of sizing.

I'm inclined to subscribe to the same idea. Why not have your brass as snug to the chamber as you can get it while simply treating just the neck? Again, I do understand I could be completely wrong. I have noticed, too, that many people seem to swear by resizing. As I have not had a chance to ask one of them myself, what reasoning do they commonly have for removing the shape of the chamber from there casing? Surely there's good reason behind it.
Totally agree, but the gauge does make a handy (and cheap) tool when loading for an autoloader

Touché
I think 918v is saying to use the chamber as the gauge. He is correct that is the best gauge available, but I just have trouble doing that w/ an autoloader

Is it safe to say then that using the chamber IS the best option; however, the difficulty of it leaves resizing as the next best option?
For ARs, screw the sizing die down incrementally until you are able to close the bolt using the forward assist

Unfortunately, my rifle does not have a forward assist.
 
The rifle would have been a big help. Better information gets better answers. :)
 
OAL matters for accuracy. Book OAL doesn't matter at all. In nearly 50 years of reloading I've never even looked at a book OAL, I find what works best and go from there.
 
I shot long range for quit a while I have a 886yrd p-dog hit with my .243VLS, I can tell you to get serious with long range you need OCD.

The main thing is CONSISTANCY, I sorted all my brass by weight, trimmed all to same length,all brass was fireformed in the rifle(I would get new brass and load up cheap bullets and fire them into a berm just to fireform them)My VLS wouldn't shoot very good until I had the brass fired at least once.I weighed all bullets(Sierra matchkings and varminteers are my favorite), I tested probably thirty or forty loads (in each gun)just to get my best ones, then tweeked oals,crimp/no crimp,up/down charges.

I kept notes with weather(temp,winds, barometer,mirage) at the time of the groups.

Cleaned gun religiously, then fired two to foul the barrel,timed shots so all shots were at the same barrel temp.

The list is endless, but it mostly comes down to consistancy!
Consistant : barrel harmonics,
powder charge,
bullet,
cases,
jump to land or non at all,
neck tension,
barrel temp,

I'm sure I forgot several

I had all my trigger tuned down to less than 1 lb(not something to do with an auto), watch your heartbeat and shoot between them, relax, read mirage,and on and on and on. Did I say you need OCD.
 
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I just adjust in tiny increments until the case will just chamber. No more, no less. And since I use a neck die most of the time, the only time I ever use the FL die is to reset the shoudlers just enough to allow for a tight chamber fit. No need for a gage here, and I think a dozen plus reloads off my high powered rifle brass says something for getting it right?

GS
 
Cleaned gun religiously, then fired two to foul the barrel,timed shots so all shots were at the same barrel temp.
Using an IR temp gun or a stopwatch? Unless you're waiting until the barrel is completely cooled between each shot, consistently timed shots will see the temp constantly increase for each subsequent shot. With a quality barrel, this is largely immaterial.

The list is endless, but it mostly comes down to consistancy!
Consistant : barrel harmonics
neck tension
bullet

Those are really the big ones. If you nail the barrel harmonics, the powder charge becomes quite forgiving within a range. If the neck tension is consistent, the case capacities only need be reasonably close. The jump/jam decision is determined by the bullet and what it works best with. Barrel temp really doesn't matter that much with a quality barrel.

You didn't touch on concentricity and bullet runout on the loaded round. That can matter a lot more at long range than at short as excessive runout can create a flying bullet with a diverging wobble that can increase group size eponentially with range and also possible send the bullet tumbling if it diverges too far.

Knowing how to read the wind is just as, if not more important than getting those loads that will shoot MOA and have <10fps extreme velocity spread. Depending on the cartridge and load, being off on your wind read by 10% will generate a larger deviation in POI than a 50fps variance in velocity.
 
I just adjust in tiny increments until the case will just chamber. No more, no less. And since I use a neck die most of the time, the only time I ever use the FL die is to reset the shoudlers just enough to allow for a tight chamber fit. No need for a gage here, and I think a dozen plus reloads off my high powered rifle brass says something for getting it right?

GS
Unfortunately since he's using an autoloader, this isn't really an option if he wants the rounds to feed and extract reliably. FL resize is essentially a must.
 
Well, if I were in your shoes this is what I'd do.
Glass- save up for a Nightforce of your choosing.
Trigger- install a match trigger.
Dies- I prefer Redding bushing dies, but they may not be the best choice for an autoloader. You may need a small base die..?
Brass- normally Lapua is the clear choice, but with the autoloader you might prefer using Winchester & carefully inspecing and sorting them.
Bullet- The SMK 175gr because it works at 1000 (unlike the 168), and it is not jump sensative. You will probably be OAL limited by your magazine & this is no big deal with these. You'll want to sort by bearing surface.
Powder- Varget. It's the staple for this combination.
Primer- CCI or Federal benchrest. Probably CCI because it's an autoloader- they're harder.
Brass sizing- I would see if pushing back the shoulder (with the FL sizer) 0.002" is reliable in the gun (for match loads). For defense or hunting loads you must full length resize, & you won't be using the SMK anyway.

Places where you should do a lot more reading than posting-
http://benchrest.com/forum.php
http://www.snipershide.com/forum/ubbthreads.php?ubb=cfrm
http://www.6mmbr.com/308Win.html

I don't really drink beer, but I always accept loading components haha!
 
Also in transit is a Sinclair Bullet Comparator #2. I reckon once I establish a seating depth that gets the ogive *extremely* close to the land I might be able to finagle an OAL without excessive trial and error.

That will be a great tool; I use a similar one. Regarding seating depth for your autoloader, bullet length is limited by your magazine. What’s worked well for me is taking the length that functions reliably through my mags and focus on charge weights to tune it in. You may go through a couple bullet types before you find the one that likes your rifle.

If you don’t already, find a way to set cartridge headspace the same every time. Cartridge headspace gauge and calipers will work ok; rcbs mic would be better if you can part with $50.

Keep notes. Write everything down along with the results. Over time you can go back through those notes and learn from them.

BTW, nice rifle!
 
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