Help with proper neck tension

[squirrelsplitter]

WTB expander dies for 17 and 20 cal.
Not looking for a neck turning set up. Looking for sizing mandrel to set the neck tension after resizing to a smaller caliber.
I would also welcome input on the proper amount of neck tension required for AR reloading.
Thanks in advance for your help!

 

[F Class John]

You can use gage pins

or you can use mandrels

both accomplish what you want and are made to do exactly what you want. Lots of options to get the exact tension (or more properly Interference) you're looking for.

As for AR tension, I don't load for mag fed guns but you'll want higher than lower to prevent bullets getting pushed back. I'm sure someone can recommend better but I'd guess at minimum a .003-.005 tension.

 

[Richard Coody]

I wouldn't waste my time on brass prep and consistent neck tension for.an AR.. been there and done that. If you want to learn about.precision reloading buy you a bolt action 6br. Something.you can see.the.results as you progress.

 

[dgeesaman]

I did the gage pin thing but that the chamfer on the end is very important.

I’m using Sinclair and 21ST century expander mandrels and they work quite well. Carbide is even an option.

 

[Richard Coody]

I use the K&M kit. It comes with mandrels in .0005 increments. Ar's are way too hard on brass to waste time on extensive brass prep. You can get all you are.going to get just using standard reloading dies. Been there done that.

https://kmshooting.com/product/custom-standard-expand-mandrels/

 

[243winxb]

proper amount of neck tension required for AR reloading.

5.56 bullet pull is 35 lbs minimum. About .002" neck tension minimum.
When loading from the magazine, look for bullet movement. A change in COL.