Small Base 308 die?

[JJE]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

 

[Martin52]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

Was the first firing in your AR-10 ? What FLS die are you using and what are the measurements of the fired unsized brass ?

 

[Ralph Littlefield]

I assume you are concerned with excessive working of the brass. If it were me, I would try using the small base die once and see if it cured the cycling issue. Then use it as necessary.

 

[Big Mc]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

Ralph is spot on Tommy Mc

 

[JJE]

Was the first firing in your AR-10 ? What FLS die are you using and what are the measurements of the fired unsized brass ?

First firing was not in my rifle, my regular sizing die is Hornady.

 

[chkunz]

I use it every time for my M14

 

[Kurz]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

Rifle brass is not generically interchangeable in other rifle chambers. This can be even more true when shooting AR-type platforms.

The AR chambers can be slightly generous in order to have the rifle function correctly throughout the entire cycle. This can require a small base die in many situations. Annealing can be helpful as well. I resize new brass and use a small base die when required for once fired or older.

Enjoy the process!

 

[762plinker]

First firing was not in my rifle, my regular sizing die is Hornady.

yep not a good first choice, run then thru a sb die when not shot in your rifle, then try a std fl die for subsequent firings.

 

[358WCF]

Dont forget that Lapua uses CIP specs, while SAAMI spec at the .200 line is a bit smaller. Not sure it will matter in an AR, but can be problematic in a snug chamber.

 

[Ray123]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

I use a variety of regular 308 dies over the years, from redding, RCBS. LEE, Hornady, Wilson, ...none are small base...none ever had a problem easily fitting the Wilson case gauge or any of a variety of 308 rifles many different bolts and many different AR 10s with 4 different finish reamers. All use the same die settings, so my 308 ammo will fit any rifle I own. Try another regular base die...the difference is only about one-half of one thousanth of an inch ...for regular to small base. I only have 2 small base dies because that's all that was in stock when I wanted to load them ...RCBS 223 & 6MM ARC ...all the rest for all calibers are standard base dies from 17 Rem to 50BMG....bolt or auto standard base have always worked for me...just FL size them every time in 308 especially sutos in a regular die even if fired in your AR chamber...everyone has a 308 die or 5, just laying around... borrow a 308 die from your neighbor if your FL die isn't doing the job.

 

[Coyotefurharvester]

Not all shell holders/die are interchangeable, are you using a Hornady sh ?

 

[JJE]

Not all shell holders/die are interchangeable, are you using a Hornady sh ?

Think Rcbs but have both.

 

[Coyotefurharvester]

Match up die/sh(no decapping rod), use some dwell time at top of stroke. Check length before checking in case gage. Adjust die according to gage fit.

 

[arlaunch]

JJE,

Ultimately you graduate into more tools and measuring things. It could be that you need to turn your die down more to take all the slack out of the shell holder assembly to get the brass to chamber.

It could be that your necks are sticking in the die, or your expander ball is pulling the neck back out on the downstroke. This is dependent on your lube, if your expander ball is polished or...

Brass has spring back. If the brass was shot from a huge chamber, and you run it through a die, it will spring back to a larger dimension than you want sometimes.

Small base dies can be a good idea for auto loaders. Most of the time not needed but...... I have an AR-308 with a Krieger barrel. To do a test on the last batch of brass... I am at 8 firings on it so far. All with a SB FL die.

Bumping the shoulder back way too far, and really hot loads will wear brass and pockets down fast.

If you have a bunch of rounds loaded already, and they need to be fixed... A body die is what you are after.

I just learned about this a year or so ago

 

[Rsadams]

Setup up the S/B dies for a minimum bump just like a F/L die.... I bump mine .003 and let them eat.... I would rather know it will chamber... I also wouldn't be using Lapua in an autoloader unless I was in competition.... To hard on the brass to worry a bunch about using S/B dies are not....

 

[Martin52]

First firing was not in my rifle, my regular sizing die is Hornady.

Ok, try annealing then adjust your FLS to see whether you can get it to size down sufficiently, then if that does not work consider a SB die. Some good advice above, note Post#7.

 

[Turpentine]

I had some brass that wouldn’t cycle well in my AR-10, once fired lapua. Brass was not fitting into case gauges or my gun the way I wanted. Do you need to use a small base die every time or is the initial sizing enough?

If you have a comparator measure base to shoulder on brass fired in the rifle you intend to load for. Factory ammo works well for this. You can also do this with your case gauge. I have case gauges but prefer the comparator. Then measure base to shoulder in some of your resized Lapua brass. Make sure your resized brass is approximately .003-.004 under your avg. (for an auto) or .0015 to .002 (for a bolt gun) of your measurement for thenbrass fired in that particular chamber. I have run into a similar issue using Lake City brass because of spring back and generally have to tighten my die down slightly when I use LC. I generally like to anneal LC cases as well.
As mentioned it could be shellholder and die variance so try a different shell holder or you may just need to turn your die in slightly. You can remove a couple thousandths from a shell holder if you would like just make sure you are square. Redding actually makes shell holders of varying height for this purpose And they are cheaper than purchasing a die. If your cases don’t fit after trying this you may need to try small base dies.
I have also had an issue before with not lubing the inside of the neck sufficiently with heavy LC brass. LC brass is a different animal but Lapua cases are stout as well. When the expander ball would pull back through the neck it would stretch the case enough to cause a headspace issue. Properly lubed cases would come out of the same die and setting perfectly fine. Generally you can feel this in the form of extra effort as the expander ball pulls back through.
I’ve used Redding, Hornady, Forster, Lee, and RCBS dies. My personal preference is Forster though I’ve had very good luck with RCBS and Redding as well. Lee is used for 45 LC and ACP. Hornady is my least favorite. I don’t know. May be a blond vs brunette thing but that’s my preference. I Mainly use RCBS shell holders. I’ve also worked with machine gun fired LC brass And they can be more difficult to get back into spec. I like to tinker a bit. I have not had a case where small base dies were necessary though when I started with LC I initially thought they were going to be. But then again, I’d never say never.

 

[Timberyote]

While I don't have a .308 auto, I have bolt guns and small base (RCBS) resize everytime. Using, originally, once fired Norma brass and on one batch of 200, I'm at load number 14 without any signs of separation, enlarged primer pockets.

I also SB my .223 brass foor both autos and bolts.