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Discussion in 'Reloading' started by Marine sniper, Dec 5, 2008.
I'm assuming it was a mistake or you figured out that you need to turn your necks due to a tight neck chamber...?
No, after thinking about it if I did not resize them they would loose a percentage of spring back after every firing, so I would end up with a slightly different neck tension with a different number of firings...
I do neck turn them before I shoot them.
I don't think they would ever loose enough spring back to give you the recommended .003" clearance around the neck on a loaded round.
Sounds like you need to neck turn more off.
I think it could be work hardening or springback, but you should re-measure what you are working with, it could be too tight. It may be only a few cases, when turning make sure your cutter does not get hot, if it does, it will cause cutting variations. How much clearance are you getting or trying to get and how many reloadings are on your brass? Also, make sure you are getting all of the carbon or soot out of the necks, it will take up space as well.
OK guys, since you are responding to the post I deleted I guess I should put the original posts' thoughts back up.
What I was going to try was not resizing my brass after I fired them. I have a tight neck (.332) 300 Wby and noticed the other day that a fired piece of brass's neck is so tight that I can not press a bullet back into the neck with my hands. I thought "hey" this may be a way to cut down on run out, why not just knock the primer out, anneal the case, and go for it ?? The brass would be as close to perfect as possible.
I run a total of .001 neck clearance, so may it would work after all ? The only thought I had that would cause issues is if the brass did not completely spring back with each subsequent firing I would loose a little neck tension, but since I anneal after every firing, and only have .001 clearance anyway....it might work ??????
I am vigilant about cleaning the necks, probably ridiculous, but it seems to have a direct effect on ES.
I get 5-6 firings per piece of brass.
John, your neck clearance is why you can not seat them with your hand, there is enough springback to limit you with just hand strength , for ME, just my opinion, that is not enough clearance, (.001) if it works good for you and no stuck cases that is great. Ron Tilley
Ron, I have never had a stuck case and the rifle is extremely accurate, in fact here is a 300 yard group (.942) I shot Thursday. Not bad for a 300 Wby off a bipod.
The only issue I have is I tend to shoot a few 2 and 1 groups at 300 yards, after a lot of thought I think it is my position. I shoot off a bipod and rear bag only. I may get my vise out and see if I can eliminate the issue. I will test this and if it does not solve the problem I will put a post up and ask for some help. I think I will test some rounds not re-sized, primer punched, annealed and we will see.
I have a post going up about my HAT testing shortly also.
John, great group! I hope the Aluminum tips work for you, remember to measure the diameter of the new bullets, they may have a fat spot or pressure ring that is slightly larger and that will use up some of the .001 clearance that you have. again, good luck!
Some of the benchrest guys shoot with no neck clearance and just seat another bullet, but they are shooting mild load in perfect chambers with match bullets. .001" is not considered enough clearance in a hunting gun. Any trash will prohibit chambering or jam at the neck and could cause serious pressure problems.
When you fire all the imperfections are going to be pushed to the inside of the neck when you fire the case and the neck will fire form to the chamber and the outside will be as concentric as your chamber is cut.
IMO, you are walking a fine line and in a high pressure case like the 300 Wtby could be asking for trouble.
I understand your concerns. I agree that for the average guy .001 is not enough, but for a guy who does not mind the preparation it takes to run such tight tolerances the accuracy benefits can be worth it.
I am going to shoot tomorrow. I have a new 308 to break in......I think I will try some of the "non sized" brass.
Sounds like you have the perfect fit.
Form "Secrets of the Houston Warehouse" :
Virgil would then outside turn the necks for a total clearance of about .0007" between loaded round and chamber. Since the neck turner left cutting rings, Virgil sanded the necks shiny smooth, which typically resulted in a somewhat widened neck-to-chamber clearance of .00075". He emphasized that until the hills and valleys were smoothed, the case neck was prevented from laying flat against the chamber. Flash holes were cut identically and chamfered inside, but he didn’t uniform primer pockets or turn the case bases. He also had not the foggiest idea what amount of case-wall variances existed in any of his brass, but in those excellent Sako cases, probably not much.
Then came the final, critical step — the step requiring a sensitive touch and #400 sandpaper — the “tuning” step. “The secret,” Virgil said, “is to get the neck tension — the grip of the brass on the bullet — exactly the same on every case. You do this by firing the case and then feeling the bullet slide in the case neck as you seat it. Here, a micrometer won’t do you any good. Feel is the whole thing. If any case grips the bullet harder than the others, you take three turns over the sandpaper and fire it again, until you get exactly the same amount of seating pressure. Until the necks were tuned, I didn’t feel I was ready to start tuning the gun.”
Virgil continued: “You can change the powder charge slightly, and it won’t really make any difference, but if you change the bullet seating depth or the grip on the bullet, you’re going to see bad things happen fast.”
After a case has been fired a couple of times, another condition is created in the neck that requires sensitive feel. A tiny groove pressed into the neck by the pressure ring on a flat-base bullet causes the bullet to “snap” into place when it’s seated. Virgil emphasized that feeling the bullet slide down the neck and then snap into place told him everything he needed to know about whether that round was going to go into the group or not.
To sense these critical events, Virgil seated bullets in a Wilson straight-line tool BY HAND — not arbor press. He estimated that the seating pressure on his hand was moderate — perhaps 15 pounds. If seating requires significantly more pressure, the operation damages the bullet’s fragile pressure ring, bulging your groups. If the seating pressure is too light, he said you’re assured a mediocre .250" rifle.
Virgil did not size his case necks. With about .00035" clearance on all sides between the loaded round and chamber neck, the natural spring-back of the brass, in combination with his neck preparation, correctly gripped the bullets. Some other warehouse shooters, including T.J. Jackson, followed the same practice.
I don't resize cases on one of my custom rifles, but the brass and the chamber must be kept spotless. I had the gunsmith build a seating checker with the same reamer that cut the chamber and check all rounds just to be safe.