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Resizing ,,,,,How much to bump the shoulder back?
dcloco
Member Posts: 2,967
I purchased the Stoney Point "head and shoulders" gauge set, so I can, somewhat accurately, measure how much I am setting the shoulders back.
I reload 17 Rem, 223, 6.5x55, 7.5x55, and 270 Win.
Setting up dies, per instructions with three different die manufacturers, produce brass that has the shoulders set back 0.006". I have obtained the best accuracy with new brass, that has only had the mouth sized to make sure it is round.
Thanks in advance.
I reload 17 Rem, 223, 6.5x55, 7.5x55, and 270 Win.
Setting up dies, per instructions with three different die manufacturers, produce brass that has the shoulders set back 0.006". I have obtained the best accuracy with new brass, that has only had the mouth sized to make sure it is round.
Thanks in advance.
Comments
This is all predicated on how you intend to use these cartridges. If this is for general shooting and hunting even 0.006" is a lot for a case to move. You will be constantly be overworking the brass.
I measure my chambers accurately for headspace and I want to know how long the throat is also. Now I can set the shoulder back if required and I know the maximum bullet seating length. If these cartridges are for general use, the main concern is feeding and function. Resize your cases so they fit the chamber and function from the magazine. Then after firing, measure the cases and determine if the shoulders need to be set back. If they do, if possible on your dies, attempt to hold the set back to 0.001" or 0.002". As Tailgunner points out, the less you work the brass, the better the case life. The better the fit to your chamber, the better the accuracy should be.
Best.
I did have the split cases on some 270 shells, hence, the need for that thread....which led me to purchase the Stoney Point gauges and start looking at all of the shells that I am reloading for.
look at some fired primers from your FL sized cases. You may well notice that some have the primer strike off center,..that is due to the case laying in the bottom of the chamber due to it's being wayyyy undersized by the FL method in the directions. Now, try the PFL method and notice how much closer to center the firing pin strikes are (you can do this with PFL sized cases and just primers, no actuall shooting, just stike the primers). That is showing you that the shoulders being pulled fwd a few .001"s makes for a better alignment of the round and the bore, which will lead to better groups with less flyers. The shoulder angles hit the chamber shoulder, and as they are compressed by the bolt rotating into battery, the case will actually lift up off the bottom of the chamber as the boltface pushes these fwd shoulders against the far end of the chamber. The case is now "held in compression". Many of the BR guys are trying this over the long used NK sizing method, and from what I hear, many are boasting BETTER accuracy. I have been using this for about 2yrs now, and factory rifles really seem to like it, especially with factory (sloppy) chambers and barrels.
now that you have the headspace guage, you can set any dies to size EXACTLY where you want them to. That and a comparator along with the sinclair OAL seating guage will soon become non-replaceable tools on your bench.[;)]
The ..006 setback is designed for one purpose...that round will chamber in any SAAMI spec rifle.
Setting up the dies as instructed above insures that that case is formed to YOUR rifle...but may not even chamber in the very next rifle.
Nothing to be alarmed about...just aware of. Long case life depends on minimum working of that shoulder and case body.