Hi guys

I was just trying to partial full length size some brass & I don't quite understand. I searched through some old threads & now even more confused.

I started with a nickle's width in the press, sized one & it chambered fine, backed it off more & more & it still chambers. Then I tried a fired brass & it chambers too. I can see a slight ring around part of the neck where it has been sized enough to hold the bullet.

When I full length size the brass it grows by .008 to .009, so after 2 loadings they will need to be trimmed again. Also I've had sooty necks with factory & reloaded rounds, is this related. The rifle is a Sako 75 338 win, & stanard RCBS dies.

I'm getting groups, right at 1". So am I good to just neck size & am I doing it correctly, or do I have a problem.

Thanks, Euge

IMO ; Use Neck sizing dies to neck size only , use FL Dies to fully resize the case . Brass grows when fired seeing as the case body and shoulders are captured it lengthens in the neck .

You might want to Measure Neck diameter on a stock loaded cartridge , then on one of your reloads and after firing . Sooting can be from a few different things . Fire form a case to your chamber and measure that neck again . Tell us the differences in measurements .

Chambers Big ? Expander ball undersized ?. Are you shaving off any bullet jacket or brass upon seating the bullets ?.

Shoot Straight Know Your Target . ...

Okay, Euge, I think I understand your question.

This is not a technique I use, but it has a certain logic to it, and some of our most credible contributors are PFL advocates.

My guess is that you've read that in PFL, one sizes the case only enough to allow it to chamber--with some slight camming from the bolt--and you're not getting this resistance.

My guess is that you're effectively neck sizing part of the neck... and your cases currently don't need to have the shoulders set back.

Remember, cases can be neck sized four, and sometimes many more--depending on the angle of the shoulder--times before the shoulder needs to be bumped.

Most certainly, someone with more expertise than I will soon respond, but this is my intuition as to what is happening.

flaco

Prior to partial neck sizing with a FL die, take a magic marker and make a line from the case mouth just past the shoulder.

when you run the case thru the sizer, note how much of the line is erased. You should be sizing the neck and barely bumping the shoulder thus the line will be erased just at the junction of the shoulder.

When neck sizeing use a neck sizer, you will get better results then with a FL die.

Partial FULL SIZEING with a FL die is what it sounds like you are trying to do. I would set my die a turn or two off the raised ram and color the shoulder of a case with magic marker. size the case and see if the ink is still untouched. lower the die until you are just contacting the shoulder on about 1/4 - 1/2 of its surface and lock the die. You don`t want to push the shoulder back, just bump it emought to keep a crush fit between the chamber and case.

The cases will grow some from this but it will be minimal compared to regular full sizeing. The cases grow when the body is sized back down and the displaced brass has no where to go but up. This is related to the amount of working done to the brass and a sloppy chamber will show more growth after sizeing then a tight one.

Sooty necks are usually a sign of low pressures allowing gas to blow back along the case neck before it expands and seals off the chamber. If you are seeing soot with factory ammo I doubt this is the cause though.

Neck sizing is OK, but you will have to full length or partial full length resize every third or fourth time to prevent difficulty in chambering the rounds.

For bolt guns, I prefer to partially full length resize using an RCBS (or other brand) case mike. The case mike measures the headspace of a once fired round from your rifle. Using this measurement, it is a simple matter to adjust your full length die to resize the cases to .0015" to .002" under this measurement. This will insure easy chambering of the reloaded round.

The only thing you have to watch for is work hardening of your brass. The more times you reload the case, the harder it gets and it will spring back after resizing. You can reduce problems caused by this work hardening by keeping your cases in lots as to number of times reloaded and spot checking the resized cases to be sure they are, indeed, still coming out of the die .0015-.002" under your once-fired measurement.

Regards,
hm

flaco, exactly. I was under the impression that a fired piece of brass shouldn't fit into the chamber without bumping the shoulder back.

I'll try the magic marker to see what is happening. The main reason I tried pfl sizing was to reduce trimming. If I continue I 'll get a neck sizer. In the meantime, does the full length of the neck need to be sized to hold the bullet properly? The way I'm doing it, less than 1/2 of the neck is sized.

Dr.K, The neck on a factory round is .366, after being fired it's .371, & after sizing .361

Thanks for the help guys, I feel like a dumbass with all these questions.

Euge

quote:

Originally posted by euge:
...I with a nickle's width in the press, sized one & it chambered fine, backed it off more & more & it still chambers.

Hey Euge, You went the wrong way to P-FLR. Screw it "into" the Press.

quote:

I'm getting groups, right at 1". So am I good to just neck size & am I doing it correctly, or do I have a problem. ...

The Case will eventually Lengthen to the point that it is difficult to chamber. Then you will need to either FLR or P-FLR to get it to Chamber properly.
-----

If you are using your 338WinMag in Dangerous Game country, then I'd encourage you to FLR. The last thing you need in a Dangerous Game situation is fighting the Cartridge into the Chamber.

The Cases will need to be checked for Insipient Case Head Separation after each shot, but you don't need a Case breaking apart on you when in a Dangerous Game situation either. If you detect the Groove with the "L-shape" Feeler Gauge, it is time to either use them for Practice Cases "ONLY", or just trash them.

Best of luck to you.

If we must use the term Partial Full Length Resize (which is a oxymoron) okay. Set your die so you are resizing the neck down to the shoulder but not touching the shoulder. Better yet, set up your die this way, set the die so that you are indeed full length resizing your cases. Then get a piece of flat stock (or a fender washer) about the thickness of a dime and fashion a washer from it with a hole that will fit around the outside of the body of your die. After you have fire formed you brass, put the washer between the lock ring of your die and the top of the press. You are PFL resizing. If the brass gets to be hard to chamber, remove the washer, full length resize the brass one time and then put the washer back.
Anytime you are using reloaded ammo for hunting, you should cycle the ammo thru the action to make sure it loads smoothly and easily before leaving the house.
FYI, with many cartridges, if you do it in this manner, you are not touching the sides of the cartridge at all so you are indeed neck sizing with a full length resizing die. But, what the heck, with a little cyberspace misinformation, you can sell three dies instead of two.