New reloader, question on bumping the shoulder back

[RealGun]

I would like to understand how one measures with such accuracy using the 1.4665 -.007 case dimension as a datum. There is no hard end point. The case gauge makes that so much simpler.

 

[kingmt]

My long term goal is consistent, accurate loads for each of my guns. I know this press is entry-level, and it's going to flex a bit. But it's a good place to start and see if I enjoy this hobby before investing in something more expensive.

No doubt that the press can produce usable ammo. I tried one myself one time. I seen it had a huge amount of flex in it tho. I sold mine about as fast as I got it. I'm not saying it is a bad press to start with only that I wouldn't trust it without knowing it's bumping off the shell holder. Have you checked to see if maybe it actually is bumping the shell holder? Even my Lee Classic Cast will vary a bit in different brass if it isn't bumping the shell plate. I use collet neck sizing dies for my bolt actions & bump the shell holders when loading anything that might go in my autos or someone's gun I don't have.

 

[MrSpiffy]

I would like to understand how one measures with such accuracy using the 1.4665 -.007 case dimension as a datum. There is no hard end point. The case gauge makes that so much simpler.

I'm using the Hornady Headspace Gauge Kit to get my measurements. And notice that this measurement has nothing to do with the SAAMI spec for headspace. All I'm checking is before and after reference measurements to see how far I've bumped the shoulder back. This means it's sized for my rifle, and the measurements will vary from gun to gun based on your own gun's unique chamber dimensions.

Have you checked to see if maybe it actually is bumping the shell holder? Even my Lee Classic Cast will vary a bit in different brass if it isn't bumping the shell plate.

I noticed the Lee dies use a rubber o-ring, which compresses as you tighten down the die. I'm not sure why this is... seems like it would cause too much variation. I ended up switching out the lock nut with the o-ring over to the Lee quick-change bushings that eliminate the o-ring and use a screw to tighten down the dies. This should help eliminate some variation while using the dies.

I'm not saying the press doesn't flex. I just noticed that I got consistent case measurements after sizing, which is what I was shooting for.

 

[kingmt]

What I was asking is dies the shell holder contact the die. The o ring can't cause variation because the threads are pulled tight. The o ring only keeps the nut from turning.

 

[RealGun]

I'm using the Hornady Headspace Gauge Kit to get my measurements. And notice that this measurement has nothing to do with the SAAMI spec for headspace. All I'm checking is before and after reference measurements to see how far I've bumped the shoulder back.<snip>

The number you gave corresponds closely to the spec number for case head to shoulder, just beyond the radius from the case body. You would get the same result with a case gauge, looking for how the case head compares to the min/max notch in the face of the gauge. The number you gave suggests that a standard length case should work for you.

 

[MrSpiffy]

What I was asking is does the shell holder contact the die.

I can't say, as I was only watching for bumping the shoulder back around 0.004" from a fired cartridge dimension. I can watch for this on the next batch, but it may be a little while as I sized all of my brass already.

The number you gave corresponds closely to the spec number for case head to shoulder, just beyond the radius from the case body. You would get the same result with a case gauge, looking for how the case head compares to the min/max notch in the face of the gauge. The number you gave suggests that a standard length case should work for you.

Makes sense that it's around what spec should be, but that number can vary from gun to gun. And an out-of-spec chamber (due to a worn reamer, or just out-of-tolerance machining) would mean a case measurement either too long or short compared to SAAMI spec.

For example: If my gun's chamber was reamed too large/long, I could have a dimension just longer than spec even after resizing. By bumping the shoulder back, I can get the case to chamber reliably in my gun without pushing it all the way back until the die touches the shell holder. While sizing all the way back within spec should work just fine and create reliable ammo for use in any gun, it works the brass more and shortens case life. And it could cause excessive head clearance in my gun, if the chamber is really out-of-spec.

The key is that the measurements are specific to my gun, and no one else's.