SB vs FL sizing 308

[survivalshop]

  I just got what I think is the correct neck bushing for my Redding type " S " bushing , full length sizing die & sized 70 LC brass cases to load. After the SS tumbling media did its thing & they dryed , I set out to check & trim the brass , well after I got done going over the brass , I only had twenty that needed trimming & the other fifty were under , trim to length , measurement. This brass was reloaded once before & was trimmed to 2.005" , why did they shrink ? Well then it dawned on me , I Full Length sized them & didn't work the brass as much as the Small Base sizing I did on the last reload . 

  To prove this is the case I took one of the short cases & measured it , 2.002" ( almost all the short ones (50) are at this measurement or real close ) lubed this one case up & put it through the SB sizer die , remeasured & it came to 2.007" ,  That's a 0.005" difference , so now I have to decide if I want to load the short ones & shoot them & see if the get long enough to trim to use or just start with new brass , since I will be using the Redding die from now on .

  I'm going to retire the SB , RCBS die, been loading with it for almost thirty years , time to replace it , the replaceable neck bushings are a plus ,not to mention a new sizer die . 

 

 Interesting .

[98Z5V]

I was just wondering this same thing - but backwards - when I was loading the 300BLK that I cut down.  The die set I picked up for the Blackout was RCBS AR-Series 300 BLK dies, which are small base dies.  In Dawn Marie's new build, the very first rounds I hand-cycled through it were my cut down 5.56 cases, fully loaded ammo.  I had a hell of a time fully closing the bolt on them.  After two or three attempts for the ones that failed to chamber, they'd go.  If they failed to chamber in hers, I'd run it through mine and it would chamber.  Her rifle would chamber 110gr Barnes TTSX factory loaded ammo.  My reloads were the issue, including some once-fired (but now reloaded) 300 Blackout factory cases.   Pissed me off.

 

Headspace was checked before the barrel went on, with the bolt for her rifle.  So, my final conclusion on it - tight chamber.

 

Let's go shoot it. 

 

Now, my question is:  those small base dies messing with me, for some reason?  Or is it a combination of the small base dies and her chamber?  Or would it simply be "just her chamber?"  That was an aggravating experience, before I just said fuk it, and shot the thing.

Edited March 1, 2014 by 98Z5V

[shibiwan]

Unless it's pouring tomorrow morning, I'll be at Usery with my buddy Ed (with his 50 BMGs) at Rio Salado/Usery Mountain Range.... probably around 8. Gonna do some sighting in and breaking in the 300 upper.

 

Lots of ammo to shoot,

Edited March 1, 2014 by shibiwan

[survivalshop]

I was just wondering this same thing - but backwards - when I was loading the 300BLK that I cut down.  The die set I picked up for the Blackout was RCBS AR-Series 300 BLK dies, which are small base dies.  In Dawn Marie's new build, the very first rounds I hand-cycled through it were my cut down 5.56 cases, fully loaded ammo.  I had a hell of a time fully closing the bolt on them.  After two or three attempts for the ones that failed to chamber, they'd go.  If they failed to chamber in hers, I'd run it through mine and it would chamber.  Her rifle would chamber 110gr Barnes TTSX factory loaded ammo.  My reloads were the issue, including some once-fired (but now reloaded) 300 Blackout factory cases.   Pissed me off.

 

Headspace was checked before the barrel went on, with the bolt for her rifle.  So, my final conclusion on it - tight chamber.

 

Let's go shoot it. 

 

Now, my question is:  those small base dies messing with me, for some reason?  Or is it a combination of the small base dies and her chamber?  Or would it simply be "just her chamber?"  That was an aggravating experience, before I just said fuk it, and shot the thing.

Test chamber a sized empty case, that will tell you if the case length is OK . If it wants to stick in the chamber & takes a lot of effort to extract , there may be some thing not right . Also watch COL with some bullets types & manufacture , the 300BLK may require them to be seated deeper in the case. I have a sheet some where from the guy that was in with the development of the 300BLK , I just have to find it , it had a bunch of COL for specific bullets manufacturers . I see if I can find it , i know I have one printed in my 300BLK binder .

 

The whole thing on this SB/FL kinda surprised me , I have not had the two type dies to compare to with the 308 . I have them in 223 ,but never though of comparing them , I don't need to now , I know there will be a difference .

 

Was always told the SB die worked the brass more , now I know for sure. the short brass will be put in my short brass container that I have now . Its good brass , but not for target loads I need right now & will probably get some 150 FMJ for blasting ammo , at some point. 

[shibiwan]

Doesn't the SB sizer make the cartridge smaller - i.e. looser in the chamber?

[planeflyer21]

Doesn't the SB sizer make the cartridge smaller - i.e. looser in the chamber?

 

In diameter.  Remember, when you cold work metal it flows, so it has to move molecules somewhere.

[survivalshop]

 I sized a bunch of once fired LC brass today with the Redding FL sizer & there is plenty to trim off them , so this is where I will start my new loadings.  

 

From the RCBS web sight.

 

Q. I see a Small Base Die Set listed for my caliber. Do I need these or should I buy a Full Length Die Set or Neck Die Set? How does each set differ?

A. The Small Base Die set is intended for use for ammunition to be used in auto, semi-auto, and lever action rifles so that the loaded round chambers and extracts easily. The Small Base Sizer Die sizes the case from the shoulder to the head of the case a couple of thousandths smaller than a Full Length Sizer Die. In certain calibers it also sets the shoulder of the case back a thousandth or two more than the Full Length Sizer Die. The Full Length Die Set or Neck Die Set is not normally recommended for ammo to be used in auto, semi-auto, or lever action rifles. The Full Length Die set is recommended for ammunition used in bolt action rifles, particularly for ammunition to be used for hunting. The Neck Die Set can also be used to produce ammunition for use in bolt action rifles. The Neck Sizer Die sizes only the neck of the case so it will hold the bullet firmly. It does not size the body of the case nor does it set the shoulder back. Neck sized cases will usually chamber for three or more firings, depending on the powder charge and chamber dimensions. However, over a period of time, a slight drag will be noticed when the bolt is locked. At this point, cases will need to be full length sized and the shoulder set back so they will chamber and extract easily.

 

Now having a read on that , it also opens a bunch of questions , I for one think that if I was reloading for a pure combat rifle or as I do , many different rifles ,both semi & bolt action in the same .308 . I do not like to make a special load just for each one , so it why I have over the years used SB dies .

 I'm going try to do things differently now & make up loads for the different actions & even barrel lengths & going to use a FL sizer die & if it doesn't work out right , I still have a SB die , that I know has worked for me for a long time . 

Edited March 2, 2014 by survivalshop

[shibiwan]

I've been using regular FL sizer dies and not having any issues on the 308. Should I even bother sizing them using the SB dies at all? I figure the FL is the "standard" so it'll fit anything from a bolt action to my 308AR...or am I missing something here.

[Tripledeuce]

   Semi. and full auto guns frequently are cut larger in the head deminsion.  Thats why the SB dies.   They take the case back to SAAMI minimum chamber size.

    FL dies , often, do not size the base of the ctg enough  for the case to fit easly  in the chamber.

   With 25 years owning a retail gunstore, I'v seen it a number of times.

    Respectfully

    Terry

[survivalshop]

I've been using regular FL sizer dies and not having any issues on the 308. Should I even bother sizing them using the SB dies at all? I figure the FL is the "standard" so it'll fit anything from a bolt action to my 308AR...or am I missing something here.

If they are working , no need to size them with a SB , the minimum would be full length sizing . I know some that tried just neck sizing & had problems. If you read the answer from RCBS , it tells you to use SB sizer with an semi or auto firing rifle. but I know a lot of people that have been using the FL for a long time & had no issues . I don't doubt there could be chambers out there that may not like the FL sizing of the case & require the SB sizer, but if the FL works , better for the reusable brass case, less working it .

 

I have both loaded up , so when I get to the range this week I will have Chrono results , if they make a difference. There sure is sizing them , which makes me wonder if even though the SB sizes them a tad smaller , what would that do with chamber pressure , Velocity ? less , more ? Not enough to matter ?,

[98Z5V]

I have both loaded up , so when I get to the range this week I will have Chrono results , if they make a difference. There sure is sizing them , which makes me wonder if even though the SB sizes them a tad smaller , what would that do with chamber pressure , Velocity ? less , more ? Not enough to matter ?,

 

I'd think that sizing them smaller would increase pressures - sizing the OD slightly smaller, with wall thickness remaining the same - that MUST reduce case capacity, even a little.  Might be able to FL size some, run other through the SB die, and measure case capacity.  If the numbers are different, that's the easy answer - I think?

[survivalshop]

If the comparison Chrono results are no different or are off in some way, case capacity would be interesting , but if they both shoot the same , I guess which way you size them wouldn't matter, just how much you work the brass & that's important now a days . I have found since getting a Chronograph , that if the ES & SD are low , its going to be a good shooter all the way around .

It will be interesting to see what or how they compare with my Chrono Data I already have. 

[survivalshop]

  Today I re-lubed & sized the LC brass that was short ( see my first post ), with my RCBS SB sizer die & all but seven needed trimming & the seven were still short , ranged from 2.003 to 1.999 " & just threw them in the scrap ben. The ones I measured before & after went from 2.004 to 2.012" after sizing , so If brass is sized & trimmed using a SB sizer die , a FL sizer will not bring it back to my spec's  for trim to length measurement, have to stay with a SB sizer .

  I didn't know a SB sizer made that much difference , learn something new ever day.

Edited May 15, 2014 by survivalshop

[planeflyer21]

From another forum:  "I believe the minimum USGI case length for 7.62 is 2.000". The Accurate Arms load guide trims 308 Winchester cases to 1.995".

 

I've seen plenty of people claim to trim down to 2.000" with no issues.  There is a crapload of info about "308 minimum case length" if you search for it.

[bubbasks]

I dont know why people will throw it away. Can be used to make other calibers or do what I do. Good brass for reloading precision loads. poop brass for shtf/ plinking. Obviously not too poop but within a few hundredths, its on.

[Gibbs]

I ran into an issue the other day using my LEE .308 FL dies resizing my once shot Hornady brass, and the empty resized brass had a very hard time chambering as well as extracting.  Had to use a rubber mallet to tap and remove the brass.  Got an RCBS SB dies set locally and tried it and still had some difficulty getting the resized brass out of my DPMS chamber.  Might be a tight chamber.  What I did was something I did for my 6.8 SPC when I had that issues going from one barrel to the other.  I took the shell holder and put it in my lathe and took off about 0.004" of the top face.  That allowed the shell holder to go about that much tighter against the die and also pushed the case up that much further into the die.  Voilà, worked like a charm.  The new resized brass now chambers as it should and more importantly removes as it should.

 

On order is a Lyman .308 Case Headspace Gage so when it arrives I'll have to check the resized brass with the gage for specs.  OAL in my Lyman book says 2.005 trim to length.  SAAMI new case dimensions as 2.015"

[survivalshop]

 I have read that all shell holders are not made to the exact same spec's , even the same brand & have read others have done what you have done to make them size properly . I only use RCBS shell holders & all of mine are thirty years young . Fortunately I have not had any problems with sized brass not chambering.

[Gibbs]

Shell holders are not that expensive and easy to "hone" down a bit, so if you screw it up, spend a few bucks and get another shell holder.  Die's are hardened and would be a nightmare to try to hone down properly and if you mess up one of them, they are not just a few bucks like the shell holders, so I only work on shell holders and then it's "try and see".

 

The part that I work on is only the top, IE that which contacts the die.  This allows the shell in the holder to be pushed up just a few thousands more than it otherwise would. 

 

Edited August 19, 2014 by Gibbs

[survivalshop]

   If you go that far , make sure you are slightly cam-ing over on your press to take out any chance of play. I know that most make the sizing adj. for shoulder set back , but that may not work to chamber the brass. I set my sizing dies to cam-over , The last sizing die I purchased was this Redding die & the sized brass would not fit properly until I cam-ed the press over slightly .

[Pegasus]

A small base die does not make a case shorter, unless you have adjusted it wrong.  What a small base die does is to shrink the OD at the base of the case, hence the name "small base".

 

You adjust the shoulder bump in a die by screwing it in or unscrewing it and using a comparator to measure.

 

If you only measure the overall case length in your sizing operation, you're doing it all wrong.  The .308 Winchester headspaces on the datum line which is a point midway in the shoulder where the outside diameter of the cartridge measures .400 inch, if memory serves.  At that point the distance to the base of the case should be right around 1.634 inch give or take, and again that's from memory.

 

So, what you want to do is take a fired case, and measure its length from the base to the datum line and then set your die (small base or regular F/L) to push back that shoulder a couple thousands, IF (and that's an important IF) you will be shooting it in the same rifle.  If you want to shoot it in a variety of rifles, then push back the datum line to SAAMI specs.

 

Now, if you cannot screw in the die any further and still have the press operate, you may want to look at other shellholders as the one you are using may be too thick or dirty.

 

You can then trim the case to 2.005 or shorter, but only after it has been sized properly.  Doing it any other way is pointless and will cause various unpleasantness.

 

So, either SAAMI or .002 under your chamber.

 

Also, when you resize, count to 5 when the case is fully in the die to give it time to resize, then lower the ram.  People who just speed through the sizing operation are not doing it right.

 

Small base dies do not work the brass more, if you use them all the time.  This will only occur if the base has expanded due to sloppy chamber and or heavy loads. These cases are difficult to resize properly and will not chamber easily if some chambers even if all the other dimensions are right.

[98Z5V]

 

Small base dies do not work the brass more, if you use them all the time.  This will only occur if the base has expanded due to sloppy chamber and or heavy loads. These cases are difficult to resize properly and will not chamber easily if some chambers even if all the other dimensions are right.

 

Or, brass quality - as I found out on my 300BLK loadings. 

[Pegasus]

Yes, that is correct.  Brass  quality will factor into this equation.  I start with virgin Lapua brass in my match rifles, but in my AT-10(T) I use Winchester brass.  The ejection is violent especially compared to my bolt guns, so it's not worth spending the cash on Lapua.  However, Winchester is good brass, it just needs more prep than Lapua at the first loading and after that it's pretty much the same.  It is important to adjust your sizing die properly to get good brass life and you don't want head separation in a .308AR.

[Pegasus]

98Z5V, I did a search for your experiences with 300Blk loadings and brass quality and did not find anything right away.

 

Would you be so kind as to either point me to the discussion(s) or recap for me your findings here, please?

[98Z5V]

98Z5V, I did a search for your experiences with 300Blk loadings and brass quality and did not find anything right away.

 

Would you be so kind as to either point me to the discussion(s) or recap for me your findings here, please?

 

Nope, Fuk You.  Dig for that $hit on your own, as you troll the board, you rightly-banned a$shole.

 

Kinda funny - you listed the ONLY TWO THINGS that would cause this:

 

 

 

This will only occur if the base has expanded due to sloppy chamber and or heavy loads.

 

...then I gave ANOTHER reason.  Guess you don't know everything that you think you do, now.  Fuckin know-it-all.

 

I tried to tell you to shut your mouth and listen to some people here, but you couldn't do that.  That's called "Karma."  Feels pretty good, doesn't it?

Edited September 7, 2014 by 98Z5V

[unforgiven]

That went well...... <lmao>  <laughs> LMFAO.