Small base vs regular rifle dies

I know that, but if there was a drawback to even keeping you from using it from the get go that’s what I was basing my statement on. Also why I said it might be a remote possibility, not a likely probability. Most likely not a good reason not to use a SB die from the start, but just something to consider.
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If a small base die is going to contribute to case head separation, it was a bad case to begin with.
We're not talking about swaging .308 cases down to .223. We're talking a couple more thousandths of an inch, in an operation already being performed on the cases. The point is not to form a new case, but to overcome the little bit of excess spring-back so the cases are in-spec again.

And you only have to use the SB die once, unless you have a rifle (or six) with a bad chamber, a rifle (or six) with a good chamber, and don't keep track of the cases.

If you have to use a small base die for every reload, something is wrong.
 
Some military teams tried full length sizing fired cases from M1 and M14 rifles with standard full length sizing dies. But they soon quit, but not because of any reliability or safety concerns.

Accuracy with such cases was poor because their case heads were out of square from being pressed hard at peak pressures against out of square bolt faces. Test groups shot 1 to 2 thirds MOA bigger.
 
This is from RCBS

The Small Base Sizer Die is for bottleneck type cases used in tight-chambering semi-automatic, pump or lever-action firearms. The sizer resizes cases below SAAMI minimums, reducing the shoulder and body by a few thousandths. It also de-primes the case. Note: Not recommended for ammunition used in bolt-action rifles.
 
Bart B. said:
Why? I've used standard full length sizing dies with once fired arsenal cases shot with semiautomatic service rifles. Functioned fine in commercial and service rifle barrel chambers.

Accuracy was not as good as when new but such is life with service rifle's out of square bolt faces.
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I have used plenty of Lake city that will not chamber in any of my .308 rifles without small base sizing. If you tried to give me machine gun brass, I wouldnt take it.
 
I have Redding/RCBS sb dies in 223 and 308, and on occasion they are needed. Am in possession of rifles with varying "chamber cuts". Military surplus fired in one FAL with military barrel will not function reliably if normally resized and fired in one tight chambered RR Lar-8 style.

Am of opinion the need for sb dies increased with manufactures cutting minimal sized chambers in search of better accuracy, and finding more range pick up brass from short barreled rifles/pistols of 223/308 caliber.

Prefer the RCBS brand sb, because they will set shoulder back further if needed. As opposed to Redding version.

Used to use a lot of range pick ups for reloading, and learned to sb size all of them for first sizing to help reliable function. Once bought once fired 308 mg brass, and it was not worth the effort for that specific lot of brass that lasted one firing.
 
Might wanna ask the manufacturers doing it. My most accurate 308 bolt rifles (sig ssg 3000/cz 550 varmit) have minimal headspace and chamber dimensions. I do not know if that is the only factor that makes them so accurate, or how much it contributes to it. Certainly easier to re-size the brass. Both these rifles will shorten most standard unfired cases base to shoulder datum by .001 just chambering a round. They work well enough for me, and not interested in changing em.

Have discussed this before.

If memory serves, have seen numerous comments/concerns over the last 15 years or so over tightly chambered 308 ar-10 target rifles.
 
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I don't think chamber diameters need to be minimum spec for best accuracy.

I've shot twenty 7.62 NATO primed cases reloaded with IMR4320 and Sierra 190 HPMK's shoot under 4 inches at 600 yards. The military spec chamber had 1.6305" headspace but diameters were near or at maximum. A new or almost new reamer was probably used.

While case shoulders always center perfectly in the chamber when fired, their back end is usually off center a thousandth or two. Extractors usually push them there. In a 7.62 or 308 chamber, for every thousandths the back end of a perfectly straight cartridge is off center,the bullet tip will be about half that much off center in the barrel in the opposite direction. No big deal nor cause for concern because it is very repeatable across all such rounds
 
Am simply not knowledgeable enough to agree or disagree. However, for target shooting would rather have the cartridge centered as well as functionally possible.
 
All records shot and matches won in competition events do so with cartridges slightly crooked in their chamber like I mentioned.

It's easy to put a case head in a bolt face then see how the extractor pushes it sideways.
 
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zeke said:
Am simply not knowledgeable enough to agree or disagree. However, for target shooting would rather have the cartridge centered as well as functionally possible.
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Then shooting and neck only resizing each case 3 ot 4 times will finally have the case body dimensions virtually equal to the chamber body. They'll be centered as good as possible. The bolt will start being hard to close on such cases so they'll need full length sizing for the next load then neck size a few more times.
 
Bart-Have done this with the 308 target rifles, and their chambers are similar enough to interchange the reloaded rounds. However the chambers on both are tight enough that regular full length sizing does not leave a lot of play. Have not done a detailed comparison directly compared the results of the 2 techniques and just using new brass. It does save a lot of effort to just re-size without expanding the necks, and use Redding comp die to seat the bullets straight.

Am thinking (guessing) the very slight forceing of the case neck into the chamber may provide a similar benefit, but it be a guess.
 
Tough to get consistent answers, as many different reasons/standards/goals people have for reloading. Asking about one specific step in the process is complicated as there are many differing process's where a function/purpose may have been dealt with in another step. Then add in every rifle can be a different, even if same manufacturer/model/year/batch, and various dies/manufactures of dies are different.

One of my favorite questions is "what is the best >>>>". Hard to find anyone that tried em all, and can actually answer that.
 
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