case prep and neck sizing

[casullman]

i am looking for insights as to what others do (protocal) when neck sizing such as : is there a margin of tolerance wall thickness or is reaming and turning done every time ,do you trim to length every time, what range of wieght is used to sort brass, sizing before trimming , inside neck cleaning (plastic brush does not seem to work well), does the caliber or type of cartridge (belted mag, rimmless etc..) determine how much ofthe neck is sized ? any feedback would be delicious brain food thank you

[ancestor]

I only neck size 375 H&H, and only load to H&H original velocities. I use micrometer and measure the neck of new brass and then check the neck of fired brass after sizing; this way I can tell If the brass is getting thicker. Also measure case length after every firing. and trim to ensure all the cases are exactly the same length. I have experienced little case length increase and trimming is seldom necessary, check for any sign of separation. I randomly select fired cases and split with a fine tooth saw to check this the brass thickness throughout. I realise 375 H&H is a relatively low pressure cartridge and I have loaded some shells over 5 times ; this may not be Ok for other cal's. If I am doing this wrong some one please tell me; regards g

[versifier]

Reaming or turning is usually only necessary when reforming brass to a smaller caliber or when prepping for a match rifle with extremely tight chamber tolerances. It is never necessary for brass that will be fired in a commercially production rifle's chamber, unless you get a bad batch of brass, which is best returned to the seller for replacement. (If the neck thicknesses vary greatly from case to case or they are uneven, there are very likely other problems with the lot which are not obvious to the eye that you do not need to find out about the hard way. You only get one face, best not to decorate it with shrapnel.)

Some will neck turn cases, but it is generally not a good thing to do beyond removing just the high spots as it can weaken the neck/shoulder junction of the case if not done correctly. It's about the easiest way I know for a newby to totally ruin a batch of good brass.

Trimming is almost never necessary when you neck size, but when the cases eventually get hard to chamber, you have to full length size, and that is when the cases are measured and, if necessary, trimmed.

I only sort brass (and bullets) by weight for VERY accurate rifles. In fact, I only bother about it with my varmint rifle. It makes a difference in any rifle, but for big game rifles that will be used within 250yds, I don't think the potential improvement is really worth the effort. I sort cases to within 5gr, bullets also.

The only time I think case necks need to be brushed clean is if you shoot black powder, then the whole case gets washed after firing. I use those brushes to apply dry mica to case necks before FL or conventional neck sizing to ease the passage of the neck expander ball.

Usually the entire neck (and just the neck) are sized. It makes no difference what kind of case you are working with, except straightwalls. There are four ways to neck size that regular (non-bench rest) shooters use:

1. Conventional NS dies have an oversize body and works only the neck. They have expander/decapper rods just like FL sizers. Their main drawback is that you have to be happy with whatever size the die leaves the neck - you cannot (easily) change it and if you are loading an oversized cast bullet it may work the brass much more than optimal and necessitate much more frequent annealing.

2. Bushing Neck Sizers also have oversized bodies but use replaceable bushings to exactly size the neck to match specific bullets and/or chambers. I have never seen one with a decapping rod. They are the most versatile, especially for match shooters, but they're also the most expensive.

3. Collet Neck Sizers use a decapping rod of a specific diameter as a mandrel to size the neck as a collet closes on it and returns it to the proper diameter. I am a big fan of them, but also use conventional NS dies. Like the conventional NS dies, they do not do well with slightly larger or slightly smaller bullets.

4. Partial FL Sizing uses a regular FL sizer die, but so adjusted that only enough of the neck is sized to just hold the bullet in alignment, usually about half. The case body is only minimally sized (sometimes not at all if the case was fired in a tight chamber).

Belted Mag cases don't always behave like regular cases. They have (generally) a very short life, sometimes with as few as two or three loadings. Higher pressure and larger caliber cases seem to have the shortest life. Many are dangerous game rifles that require FL or even SB sizing to insure flawless functioning - neck sizing ammo for such rifles can easily cause a failure to feed or chamber, creating a not-so-healthy situation, especially if the hunter has no backup shooter. Five loadings is not bad for the big H&H.