Reloading for AR platform rifles

[CaNINE]

ok folks - I'm an experienced reloader for bolt action rifles but am about to make my first foray into loading ammo for two of my AR's:  a Sig 716 Patrol and a Colt 6920.  My question is regarding neck tension requirements.  My reloading practice for bolt guns is to expand necks for even 0.002 tension.  I would expect that will work just fine in a semi-auto but want to confirm with those with real world experience.  Any other special considerations when reloading for AR's?  Thanks for your feedback. 

[Fl0und3rz]

It is said that full length sizing is desirable to prevent failures to feed.  I also think you would want to ensure that each round is fully into battery by sizing to spec, due to the floating firing pin and possibilities of slam fires.

I don't know if you could get away with merely 0.002 tension (implying neck sizing or other non-FL sizing), because I only FL size.

Also, being gas operated, don't load more than enough to verify proper cycling in various conditions before you switch to bulk reloading.  Don't ask me how I know.

[CaNINE]

It is said that full length sizing is desirable to prevent failures to feed.  I also think you would want to ensure that each round is fully into battery by sizing to spec, due to the floating firing pin and possibilities of slam fires.

I don't know if you could get away with merely 0.002 tension (implying neck sizing or other non-FL sizing), because I only FL size.

Also, being gas operated, don't load more than enough to verify proper cycling in various conditions before you switch to bulk reloading.  Don't ask me how I know.

Thanks for the advise.  I definitely want to avoid slam fire and FTF.  To clarify, my process is to full length resize the case.  However, I remove the neck sizing stem from my expander dies and use a mandrel to expand the neck in a separate operation.  Good tip on not loading the mag to full capacity during testing! 

[Fl0und3rz]

Good tip on not loading the mag to full capacity during testing! 

My point about bulk reloading referred to reloading several 100 or 1000 rounds for your AR with a load recipe that you are not absolutely certain will cycle your rifle in all conditions.  Mine cycled fine on an 85 degree day.  In 35 degree weather, however, I was getting short-stroking and resultant FTF.   

[JLS]

you'll probably want small base dies.

[Fl0und3rz]

you'll probably want small base dies.

My problem was related to light loads and resultant undergassing.

[CaNINE]

Good tip on not loading the mag to full capacity during testing! 

My point about bulk reloading referred to reloading several 100 or 1000 rounds for your AR with a load recipe that you are not absolutely certain will cycle your rifle in all conditions.  Mine cycled fine on an 85 degree day.  In 35 degree weather, however, I was getting short-stroking and resultant FTF.

Ok I understand what you mean.  I'm planning to load 3 round batches up at different charge weights and check for function, velocity and accuracy.  Will confirm several times before I load a large lot. 

[ELKBURGER]

Good tip on not loading the mag to full capacity during testing! 

My point about bulk reloading referred to reloading several 100 or 1000 rounds for your AR with a load recipe that you are not absolutely certain will cycle your rifle in all conditions.  Mine cycled fine on an 85 degree day.  In 35 degree weather, however, I was getting short-stroking and resultant FTF.

Ok I understand what you mean.  I'm planning to load 3 round batches up at different charge weights and check for function, velocity and accuracy.  Will confirm several times before I load a large lot.

I have been working on some load development with CFE 223, starting with lighter loads and am not impressed with accuracy. My next trip to the range will be with loads closer to and including max charges. I hope to see tighter groups with those.

[CaNINE]

I'm going to use varget as a starting point for both guns. I picked up Berger 175 OTM and 77 OTM, winchester brass and I already have a supply of federal primers so will start there. I'll load to mag length COAL. I'll use starting loads as recommended by berger and work up in half grain increments. I just put LaRue MBT triggers in both guns and can't wait to try them out.