Need guidance on reloading for AR

[jelenko]

Jelenko, I assume you mean .005 longer headspace, not .005 oversized base at the .200 line.

Frank

Absolutely. .005 longer headspace.

I would bet that .005 over at the .200 line would just be a jam.

 

[Chiquita]

I sized the case with a regular full sizing die, bumped shoulders about .003, but the bolt would not close and with a little force it git stuck. So looks like I need to use a SBD and see if it will work.

 

[RegionRat]

I sized the case with a regular full sizing die, bumped shoulders about .003, but the bolt would not close and with a little force it git stuck. So looks like I need to use a SBD and see if it will work.

Not trying to talk you into or out of the small base die. But this is a good time to take the opportunity to learn to inspect your brass for more than just shoulder datum and case length and learn to determine why it doesn't work.

Check the diameters at the shoulder-body junction and also a a line 0.200" above the base.

See if you can determine if one or both of those are the reason your resized case doesn't want to load.

 

[Coyotefurharvester]

MrBarrel would the case you moved the shoulder 0.003 chamber before sizing? I set my die to 0.0035 -.004. Most of my AR need to run in the winter hunting, when very cold I want easy chambering. Running the rifle with dry lube. I have no sb dies and pickup range brass.

 

[jelenko]

I set my die to 0.0035 -.004

How do you know your resizing die is set to move the shoulder back .0035 to .004?

My experience with an AR is it's best to resize the cases to '0' on a case headspace gauge like the RCBS precision mic, Mo's headspace gauge or a Whidden Gun Works one.

I spent many hours trying to determine what the headspace was of my brass fired out of an AR. Most of the cases ranged +/- 3 thousands. What made me stop was finding cases that were SMALLER than what they had been resized to. => no hope to find a reliable/consistent measurement for cases fired from - at least my - AR.

The other approach is to start with the resizing die set so that a resized case doesn't easily chamber. Then, adjusting the resizing die in smidgens, keep adjusting until a case easily chambers.
I then measure that case with a headspace gauge. Then, adjust the resizing die so it sets the shoulder back to what I want it to be. E.g., in your case 3/1000.

 

[arlaunch]

Consider firing a round with new brass, and "re-taking" your measurements from that 1X fired piece.

 

[Coyotefurharvester]

I set my die for easy battery, I also use a go gauge/comparator to get an actual measurement, use actual numbers against brass to see change when setting die. I zero case in comparator look for negative numbers as I screw die in. I use a 0.0000 caliper.

 

[Chiquita]

Not trying to talk you into or out of the small base die. But this is a good time to take the opportunity to learn to inspect your brass for more than just shoulder datum and case length and learn to determine why it doesn't work.

Check the diameters at the shoulder-body junction and also a a line 0.200" above the base.

See if you can determine if one or both of those are the reason your resized case doesn't want to load.

I love to know "why" and or "how" something work or doesn't work.

So Using the SBD on a case that was sized with a regular die, the junction of shoulder & body got reduced by an additional .0015". Now the dummy cycle fine.

 

[Eagle1899]

I process all once fired brass (that I didn't shoot the first time) as such.

Small base die - back to minimum spec.
Trim - back to minimum spec
Primer pocket - swaged

After that semi autos get bummed back .003 in a regular die with .003 neck tension and Lee factory crimp die on loading.

I've not had any issues.