Re-size question

[feelinducky]

I'm trying to figure out how to get the correct shoulder bump for my 270wsm. It is a Rem 700 built by LRI. I have removed the firing pin from the bolt to alleviate the spring tension while checking the shoulder. The problem that I'm getting (I think) is the weight of the ejector spring compressing the case. It throws me off when I'm trying to feel the closing of the bolt. Is this a common problem? If so is there any remedy other than removing the ejector spring? Or is there something else I need to do?
Thanks

 

[sedancowboy]

Buy a Hornady headspace gauge and measure a fired case then resize your case .002 less and you will be GTG. Directions are included.

If you want to use the bolt resistance method then yes you will have to remove the ejector to get a feel for when the case gets tight.

 

[Deviant]

Yep, What he said ^

 

[Remmy700]

Just remember to ensure your brass is actually chamber formed. I have seen many times where one firing on new brass did not truly achieve chamber fire formed brass. I started just using neck die on first firing (if the brass still chambered after firing with no resistance). The hornady set is great for tracking your numbers once you truly have fire formed brass. This is a caliber specific dilemma sometimes depending on the load, pressure etc. Some calibers simply due to powder, bullet, brass, combo can achieve this in one firing and others simply can't.

 

[FURMAN]

Buy a Hornady headspace gauge and measure a fired case then resize your case .002 less and you will be GTG. Directions are included.

If you want to use the bolt resistance method then yes you will have to remove the ejector to get a feel for when the case gets tight.

This is the easiest way. Otherwise you really need to remove the firing pin and the ejector.

 

[Remmy700]

I have not used my hornady headspace gauge set in some time. I try to fire brass till I get a really hard/stiff bolt open from brass growth and adjust my die in small increments until I get the resistance I want. Using this method when I do measure them I am normally very close to that .0015-.002 area. But again I prefer a little more firm resistance on bolt close whereas some people don't.

 

[FURMAN]

Too much sizing and it's hard on brass. Too little is hard on lugs. The key to accuracy is keeping it the same.

 

[bigedp51]

Take a new unfired case and a spent fired primer and start the primer into the primer pocket with just your fingers.

Now chamber the case and let the bolt face seat the primer the rest of the way.

Now measure the case using the Hornady gauge from the base of the primer to the case shoulder.
You now know the actual headspace length of your chamber and can set your die up for the desired amount of shoulder bump.

Your head clearance is the amount of shoulder bump when the cartridge is chambered.

Below the bolt seated the primer of your test case and shows the amount of head clearance. And measuring from the base of the primer to the case shoulder with the Hornady gauge gives you the chambers actual headspace.

You do not need to take the bolt apart and go by feel, or fire the case several times until you feel bolt closing resistance. All you need to do is find a fired spent primer you tossed in the trash over a week ago.

 

[Remmy700]

That is an interesting way of doing it. It is a shortcut but if you are running a new rifle with new brass this does nothing to help you set up your dies and bump. I mean it gives you your headspace number but you still have to fire the brass and fire form it in order to accomplish this desired bump or you will be simply neck sizing and body sizing with a FL die, your comparator number you got from your method will be useless until you actually get brass that grows to that length. I could see this being very useful if you had shot brass already and say you got a new rifle this would be a speedy way to set up your dies. Very interesting, thanks for sharing brother.

 

[Rich Coyle]

Remmy700,
It seems there would be no difference how you check the headspace; using the primer part way in or fired case. You get the same number. Set you die for that length minus a couple thou and you're there.

 

[Remmy700]

Yeah I get the logic, an interesting way of doing it for sure. I might try this method coupled with fired case method and see how they compare. Thanks again for sharing definitely a different method. I ain't to old to learn some new tricks lol.

 

[Mikecr]

Remmy700,
It seems there would be no difference how you check the headspace; using the primer part way in or fired case. You get the same number. Set you die for that length minus a couple thou and you're there.

I like the critical thinking of Bigedp51 and Remmy700.
My 2cents; Case sizing is not static but dynamic. There is spring back, shoulder angle differences, and possibly lube in action (there is for me), so desired and getting there is trial & error.
I measure every single bump, every time, and it would vary case to case and over reload cycles if I did not verify & make it right every time..
I know that I cannot just screw a die down to a gauge, and 'expect' this to be right.
Not a chance in hell.

I see that primer method as a good way to determine chamber headspace -with fully formed cases having matched shoulder angles. But ultimately, brass has it's own character.

 

[bigedp51]

When you full length resize a fired case you reduce the case diameter and this squeezes the case shoulder upward in the die. Meaning if the die is adjusted .010 to .020 upward it is possible to make the resized case longer than the chamber headspace.

Using the primer method you can find your chambers actual headspace. Then resize a fired case adjusting the die upward with a .020 feeler gauge between the die and shell holder. Now keep using thinner feeler gauges until the case headspace is .001 to .002 is shorter than your primer method measurement.

The same thing can be done with Redding competition shell holders that gives you .010 bump to play with instead of using feeler gauges.

 

[Remmy700]

Good points, what u are talking about with your FL sizing die operation and how it stretches a case upward is basic reloading principles. Your method seems sound but i over analyze everything when in fact it's very simple. Saying u have a perfectly sound case, meaning exact shoulder angle (which in some brass is not the case when new) also assuming u have a primer that is absolutly flat (not even small amount of cratering) then I would say this idea would be pretty sound. But honestly there is not better example of chamber dimensions than brass that has been truly fire formed. If a new piece of brass is used with primer method and even a slight variance in shoulder angle when compared to the actual chamber that datum line that is used with the headspace gauge kit is null and void when that brass becomes actually fire formed. Maybe only slightly but we are playing a game of small numbers. I am going to try your method just because I like to test stuff lol!!!