setting headspace

[adam38654]

Im setting the head space on my savage 277wlv bolt action with once fired and resized LC brass that has been resized again in my Lee FL sizing die. Can I set the headspace to zero because this is a wildcat and all ammo will be hand-loaded for this rifle or should I add a .002 piece of scotch tape to the case to add clearance for the future in-case I switch to a different brand brass that may have a thicker rim?

[rjtfroggy]

I set my head space with tape that measures 0.015 3M scotch brand on the end of a go gauge. Rather be safe than sorry.

[Robinhood]

You will be fine setting the headspace off a sized case. You do not set the headspace tight on a go gauge. Do not set it tight on the brass case. As for a no go, use the shim/tape for a no go on the same brass case.

[adam38654]

I resized 3 LC-03 head-stamped shells with my LEE die, took them to work, and set the headspace. It closed easily on all 3, and wouldn't close when I added a .004 coke can shim to the bolt face.

When I got home those 3 would close easily but more resized from the same bag of brass with the same headspace closed with resistance and a light crush fit.

My JB firearms 90gr GD chamber easily but my RedStag 90gr TNT have a slight crush fit.

Now I am paranoid if I have a nice tight headspace for good accuracy or If I will have trouble chambering certain ammo. As is I would have to shave some off of my shell holder to get enough shoulder setback to chamber easily with some shells.

[bigedp51]

I have a Lee .223 full length die that will push the shoulder back .009 shorter than my GO gauge.
This same die will reduce the case diameter more than my small base die.

If you look at a SAAMI chamber and case drawing headspace is listed as minimum and maximum with .010 in between. A GO and NO-GO has .003 between them and are used for setting up headspace on a new or re-barreled rifle.

I don't know how many times I have read in this forum about someone using scotch tape to set their headspace. And then shortly after doing this their next post is their full length die isn't bumping the shoulder back far enough.

Below is a Colt 5.56 Field gauge (1.4736) in my calibrated Hornady case gauge.



Below is a fired case from my AR15 at 1.4675 and over .006 under maximum headspace



When full length resized the case will have .003 shoulder bump and be .0015 longer than a factory loaded 5.56 cartridge.

Bottom line, a loaded factory round should chamber and you do not want to set the headspace so short that a resized case will not chamber. Also note the brass spring back rate will increase each time the case is sized. Meaning if you set the headspace too short you may have to lap the top of the shell holder to get enough shoulder bump when the case shoulder becomes work hardened and not annealed.

The distance between the GO and NO-GO gauge is .003 for setting up minimum headspace and scotch tape and a resized case are not calibrated.