When is the 6ppc brass being oversized in a F/L die? (Jack Neary tutorial video)

[HopeToBe]

In his tutorial video (LAPUA) Jack Neary speaks about how you can use the F/L die to conclude of the brass is being sized too much or not. However, in the video it is hard to fully grasp what is being said due to noise.

Could someone please explain? Also so a non-native english speaking person could understand?

 

[HovisKM]

The best discription with pictures is in Tony Boyers book. However, there are three measurements.

1. Shoulder to Base length - this shows how much you are pushing the shoulder back for headspace.

2. Shoulder Diameter - this shows how much you are sizing the brass at the shoulder.

3. Base Diameter - this will show how much the base is being sized down.


Take measurements of the case prior to running it throug the die. Then take measurements after. This is what I look for for a perfect match.

1. Push shoulder back .0005
2. Reduction in shoulder diameter of .0008 to .001
2. Recuction in base diameter of .0008 to .001

With a well matched die, this is all you need. Some recommend pushing the shoulder back .0015-.002, but that is working the brass to much in my opinion, I would want no more than .001 in any of the measurements. Once i get the measurements, I then check the feel of the brass in the chamber. With the firing pin assembly out, and a sized piece of brass, the bolt handle should drop to 90 degrees and you should be able to use one finger to close the bolt and not disrupt the gun in the bags.

Of course, this if for BR guns. Factory varmit and hunting rifles are different.


Hovis

 

[Boyd Allen]

If I remember correctly, what a Jack was talking about was locking a caliper to hold the measurement of a fired case's shoulder diameter, sizing the case, and then seeing how far down from the shoulder of the fired case the same measurement is, by sliding the jaws down till they stop. Shoulder diameter measurements can be tricky. The shape of the point of the shoulder can be changed by a sizing die so that the reduction that you see is not really representative of the overall situation, particularly since the amount of reduction by sizing is tapered as you go down the case (in most cases). For a typical chamber and FL die, the reduction just in front of the extractor groove is a lot less than that at the shoulder. I believe that there is a tendency for shooters to look favorably on die to chamber fits that move brass the least, and which give the least case growth and longest life. I have fallen into this myself, BUT what may be the best for those things is not necessarily the best for shooting the smallest aggs, particularly when conditions favor "running" ones record shots. I believe that that is also a point that he speaks to. One of the great thing about videos is that we can stop, go back, and play again, as many times as is needed to clear something up. I have done that quite a bit when trying to understand details in videos.

 

[CYanchycki]

Ideally, a sizing die made to MIMIC

the chamber you are using is IDEAL. If you do all your own chambering work, then making a die to mimic your reamer I THINK is quite simple if you get the the sizing reamer that matches your chamber reamer. Get a die blank, have it reamed and hardened.

If you are like me and HATE paying someone every time you want work done you go the poverty route and use a Harrels that mimics your chamber as close as possible. The only kicker using one is it may squeze the shoulders a tad more than you would like but not by much. I put up with a bit more closing force on my bolt by leaving the shoulder set back a tad longer. I feel steady resistance for the entire length of the bolt close. I think NOT hard enough to disrupt my rifle in the bag.

The perfect world is pay the money and get a die made to your chamber.

I would sooner spend it on bullets, barrels, powder and primers and trigger time.

Again JMO. After going thru Tony's book numerous times I am pretty sure he would SHUDDER at the way I do some things. Then again I am not Tony.......... LOL

Calvin