Little help with .308 sizing.

[jgh4445]

I shoot .308 a bit and am about to run out of factory ammunition. My rifles are a Sako Synthetic and a Win Mod 70 Supergrade. Somehow have ended up with a set of RCBS Neck Size Bushing Dies and a regular set (not bushing) of FL RCBS dies. I'm not a bench rest guy, I'm a hunter, but I do like little bug hole groups when I can get them lol. Am a pretty experienced loader but haven't loaded any .308. Now for the questions. Tell me about using bushing dies. I know the basics and what the bushing does, but is neck sizing as good as or preferred to FL sizing? Will I need a separate sizing die for each rifle? Can I use the regular FL sizing die to FL size the cases and then run them thru the neck sizing bushing? Is that just an unnecessary step? What would be the best course of action you think?

 

[Blue68f100]

Multiple guns, FL size every time or you will have to keep the ammo separated for each gun . You will eventually have to FL size anyway to move the shoulder back after 3-5 firings. If you want to use the bushing die as a std set, get a Body die, too. Redding's Type S is a body die + bushing for the neck. I'm not familiar, with the RCBS Bushing die, thinking it's Neck only. Bushing dies work best when the necks have been turned. You adj the bushing size depending on wall thickness to get the neck tension your looking for. Also a bushing die can not be used to reduce more than 0.005", need to be done in steps. So if this is being used on a production gun (not a custom cut chamber) I would stick with a Std FL die. It too can produce bug holes if the gun is capable of it.

I have both for my 6.5 CM and 223R. I FL size for 98% of my ammo. The other 2% I use the bushing die for brass that has been prepped for it ( neck turned).

Get an expander die and it will give you more options. Then you eliminate the expander in the sizing die which can pull the necks out of alignment.

 

[rsrocket1]

Agreed with Blue. For bench rest or competition shooting, neck size. For autoloaders, multiple guns and hunting, full length size. Reliability in feeding and chambering is more important than squeezing that last 1/4 MOA out of the cartridge. You need to know your limitations and ensure your ammo/gun can stay within those limits. No need to go crazy beyond that.

 

[hps1]

Whether .308 or any other rifle cartridge, each rifle chamber can, and usually is a bit different, so a case fired in one rifle may or may not chamber in another rifle of the same caliber.

Somehow have ended up with a set of RCBS Neck Size Bushing Dies and a regular set (not bushing) of FL RCBS dies.

There are several ways to approach the multiple rifles of same caliber and you have the tools to handle it properly.

First off, neck sizing only is often used by reloaders seeking best accuracy, but can cause issues if a case fired in the larger chamber is reloaded using neck sizer only and then inserted in the tighter chamber, thus, the easy solution in your case would be to set your regular full length sizer to fit the smaller chamber and forget the neck sizer die. Thus all your reloads will chamber easily in either rifle. This is common practice, especially in hunting rifles for which you are not trying for one hole groups.

One thing to remember about using neck sizer only, even if cases being reloaded were fired in the rifle for which you are loading is that after a few firings (usually 2nd or 3rd), the case will not chamber freely (again, even in the rifle in which it has been fired) and it must be full length resized.

Since both your rifles are bolt guns you should detect a slight resistance in chambering the round before it becomes a serious problem. In gas guns, this tight chambering can be a danger which could cause a slam-fire or worse yet an out of battery slam-fire.

I load for several gas guns and make it a practice to full length size every time, even if cases are used in one rifle only. Just set my sizer to push shoulder back about .003" from the fired dimension of fired cases. Since my .308 loading is for two different rifles, one bolt gun and the other a gas gun, and I'm always seeking best accuracy for both, I have two different full length sizer dies, one set up specifically for each rifle.

ETA: What Blue & rsrocket said.......I'm slow @ typing.

 

[bfalcon00]

As mentioned above, I full length size all my 308 as I have different rifles and am not gonna keep separate loads for each rifle.

I agree with getting rid of the expander ball and sizing the neck in a second step. Get an expander mandrel you'll love it.

 

[ms6852]

This neck sizing vs full length sizing is a never ending argument like , "is 22lr a good self defense round". I will tell you my opinion on this based on 58 years of shooting and over 40 years of reloading and this is my observation. Neck sizing won't make your brass last longer. Eventually you will have to full length size after 2 or 3 times of firing that neck sized brass because the rest of the brass will expand. You will notice that you will have to use more force to open or close your bolt, which in turn can break or dull the lugs of the bolt.

What I like to do is full length size than bump the shoulder about .001 or .002. If you measure all your brass your shooting will be as consistent and accurate. But it is a decision you have to make because there are others that swear buy it, yet after shooting that brass a couple of times they have no choice but to full length size again so that it can chamber properly. That mean that now you have to keep track of the brass as to which is full length sized and which is neck sized only. I just eliminate the extra step by full length sizing.

 

[Charlie98]

I'll echo what the others have said... just FL size them. You don't have to crush them to minimums... I do because some of my brass goes in an autoloader, or a lever-action with low leverage... but you will very likely find a setting that works for both rifles that won't excessively size the brass.

If you want to make your brass last longer... anneal the necks.

 

[HowardC]

I started out FL sizing cases, but soon decided neck sizing made sense to me. I separate brass by headstamp into discrete lots ID'd by chronological numbering and times fired. I don't have multiple rifles of the same cartridge but do delegate brass lots to specific guns.

I've had to set back shoulders only on my 3006. The 300WM has not presented problems yet (only 2-3 firings so far) and the Ackley cartridges have never been set back. Two of them have 9-10 firings on their brass. The 6mm No.1 is tight on one box of cases, so that box may need some shoulder set back. I also FL size my 30-30 cases for the lever guns. Of course, new brass gets a pass through a neck die, and recovered range brass all get FL sized after cleaning. And, if I get this AR built and running, it'll likely require FL sizing.

Admittedly, I'm not familiar with the neck bushing dies, but I don't see why the theory would be different.

-West out

 

[AJC1]

Use your fls die and get an assortment of mandrels if you want to play with neck tension.

 

[jgh4445]

Thanks guys. I'll stick to FL sizing and look into the mandrel thing. Have to research mandrels. I know the square root of zero about them.

 

[AJC1]

Thanks guys. I'll stick to FL sizing and look into the mandrel thing. Have to research mandrels. I know the square root of zero about them.

It's just a pin guage ground with a tip for smooth entry...

 

[AJC1]

Caliber Specific Expander Mandrel Kits

Our caliber specific expander mandrels are available in .0005” increments in calibers 22 to 338 and will range from .001” above bullet diameter to at least .003” below bullet diameter depending on caliber. This will allow the reloader to find proper neck tension to fine-tune their loads. The...

21stcenturyinnovation.com

 

[Walkalong]

Mandrels

 

[Nature Boy]

Agreed with Blue. For bench rest or competition shooting, neck size.

No one who’s competitive in any precision shooting sport neck sizes.

There’s really no reason for neck sizing in almost any reloading application

 

[Walkalong]

No one who’s competitive in any precision shooting sport neck sizes.

Correct.

 

[Varminterror]

For bench rest or competition shooting, neck size.

Not even for these. Nobody should neck size only. The fad is over, and the bad advice to follow it should die with it.

 

[bfalcon00]

Not even for these. Nobody should neck size only. The fad is over, and the bad advice to follow it should die with it.

Yep I agree.

 

[zeke]

I shoot .308 a bit and am about to run out of factory ammunition. My rifles are a Sako Synthetic and a Win Mod 70 Supergrade. Somehow have ended up with a set of RCBS Neck Size Bushing Dies and a regular set (not bushing) of FL RCBS dies. I'm not a bench rest guy, I'm a hunter, but I do like little bug hole groups when I can get them lol. Am a pretty experienced loader but haven't loaded any .308. Now for the questions. Tell me about using bushing dies. I know the basics and what the bushing does, but is neck sizing as good as or preferred to FL sizing? Will I need a separate sizing die for each rifle? Can I use the regular FL sizing die to FL size the cases and then run them thru the neck sizing bushing? Is that just an unnecessary step? What would be the best course of action you think?

The process you use can depend on your purpose, your specific firearm(s), the rounds being used and the reloading procedure being used. FL sizing is good practical approach if you want the rounds to function in both rifles. This may depend on the chambers in each one. In 308 a lot can also depend on the brass being used. There is a wide variance in case weights and brass thickness. A Bushing neck sizing die might be handy if wanting to increase bullet pull, if not using an expander.

What works in benchrest competition with custom cut chambers doesn't automatically correlate to loading for hunting rifles. One thing to increase your chances of improving accuracy is to get a good seating die while not pulling through a neck expanding button.

 

[Varminterror]

What works in benchrest competition with custom cut chambers doesn't automatically correlate to loading for hunting rifles.

Yawn - I really wish guys would stop saying this. The laws of physics and thermodynamics don’t change just because a rifle is used for a different purpose.

Ammo has to be built to fit the rifle chamber and has to be loaded to promote consistent ignition. That isn’t selective by application.

 

[zeke]

Yawn - I really wish guys would stop saying this. The laws of physics and thermodynamics don’t change just because a rifle is used for a different purpose.

Ammo has to be built to fit the rifle chamber and has to be loaded to promote consistent ignition. That isn’t selective by application.

yawn, physics directly relates to how the chamber is cut, the sizing die is being used, and the purpose. It's not just that the rifle is used for another purpose. As you state, rounds are for the rifle chamber. There is a very large difference in how precisely and accurately chambers are/were cut, and the purpose of the rounds being made. Just because something works well in a benchrest rifle, doesn't automatically mean it will work well in a hunting rifle. Loading a round with a bullet into the lands is just one example.

 

[jmorris]

I would use your FL die and set it for the tightest of the two rifles (so the ammunition is still good for the other) or use a case gauge.

Something like this,

Setting size die for bolt action rifle.

www.youtube.com

I only have 1 firearm (out of a bunch) that just doesn't like FL resized brass and still use a FL die, just adjusted far enough "up" the internal taper of the die cannot contact the body and just the neck is sized.

 

[Show Me]

yawn, physics directly relates to how the chamber is cut, the sizing die is being used, and the purpose. It's not just that the rifle is used for another purpose. As you state, rounds are for the rifle chamber. There is a very large difference in how precisely and accurately chambers are/were cut, and the purpose of the rounds being made. Just because something works well in a benchrest rifle, doesn't automatically mean it will work well in a hunting rifle. Loading a round with a bullet into the lands is just one example.

Like an specs on a Palma cut compared to a standard cut I was reading about. Not the same. New to me.

 

[Varminterror]

Just because something works well in a benchrest rifle, doesn't automatically mean it will work well in a hunting rifle. Loading a round with a bullet into the lands is just one example.

A bad example, a poor strawman.

Jamming a secant ogive bullet into the lands in a hunting rifle does promote precision in the same way it does in any barrel, but hunters may CHOOSE to not pursue that level of precision in compromise to be able to eject loaded rounds without leaving bullets stuck in the bore.

This example is yet again an example of physics and thermodynamics being consistent across all barrels, regardless of application.

 

[Varminterror]

Like an specs on a Palma cut compared to a standard cut I was reading about. Not the same. New to me.

Ammo has to be built to fit the rifle chamber

The fact that chamber dimensions for a given cartridge can vary is new to you does not mean anything has changed about the reloading practices or needs.

 

[N555]

If you know all your brass is 1x fired you might want a FL neck bushing sizer die.
You want the FL neck sizer bushing die because you always want to push the shoulder back. Then neck bushing sizing is one of the less invasive ways to make the case neck hold on to a bullet again. A FL neck bushing die will make 1x fired brass that's almost as good as factory fresh brass. To be able to correctly use a neck bushing die you will need multiple neck bushing collets and a tube micrometer and will need to sort brass at least by head stamp.