Ready to start reloading-check my process

[Grendelshooter]

I think I'm finally ready to start loading/reloading.
Here's my process (starting from once fired brass).

-Run cases through rotary tumbler
-Lube cases
-Resize/deprime
-Deep clean with SS media
-Check case in Wilson case gauge
-Trim as necessary (length 1.515)
-Prime case
-Apply powder charge from chargemaster
-Seat bullet
-Factory crimp (shooting through AR)
-Lock, load, shoot, repeat.

Initial measurements:
Case length: 1.515
COL (measured to lands with Hornady checker).
123 AMAX-2.195
123 SMK-2.234
123 CC-2.185

So the only question I know to ask at this point is how much "jump" off the lands to apply? Should I start with the full length or start by backing off a bit?

[rabiddawg]

You will want to back off the lands a bit. In an ar15 mag length often prevents you from getting too close to the lands.

You will want to find your accuracy load first then tune the jump.

Don't forget to bump the shoulder back .003 to .005. I don't measure it. I reload for five Grendels so I adjust the sizing die until the case will chamber in all my rifles.

[Grendelshooter]

Given my COL measurements I don't think I'm going to have an issue with fitting in the mag-isn't 2.250 normally the max length in an AR mag?

Checked my brass to make sure it'll chamber, good to go!

So if I find my best accuracy load first,what is the point of tuning my jump? Does it make an accurate load even more accurate?

[StoneHendge]

Check your brass in the case gauge before sizing. You're base will most likely protrude "out of spec". Brass protrudes .010" from my Stoner/Saturn and 0.005" from my JP. You need to bump down about .003" from the unsized measurement. When measuring to determine if trimming is needed, be sure to incorporate that excess on the base when measuring case OAL to avoid unnecessarily trimming. (A lesson I learned the very hard way!)

[Grendelshooter]

I tuned my resizing die via my case gauge.
When it got to the point that it fit the case gauge without protrusion I locked the die down and started to measure for trim length.

That's the right way...right? Lol

[StoneHendge]

You don't need,to go that far. What is the unfired length? Your COAL measurements also seem really short. Someone could correct me since its been a while since I've shot factory, but I'm pretty sure factory Amax is 2.245.......

[LR1955]

Given my COL measurements I don't think I'm going to have an issue with fitting in the mag-isn't 2.250 normally the max length in an AR mag?

Checked my brass to make sure it'll chamber, good to go!

So if I find my best accuracy load first,what is the point of tuning my jump? Does it make an accurate load even more accurate?

GS:

Sometimes having a jump is better. Other times seating to the lands is better. The difference, if any exists, will be seen at 300 yards and beyond given a person spends a lot of ammo and time testing. And if they are holding High Master scores in competitive High Power.

I would say that for now, make sure the loads fit the magazine with some give and see how they shoot.

LR55

[rabiddawg]

Stonehenge I agree the measurements seemed short. I'm not familiar with his tool but I assume those measurement are from the ogive to the base of the cartridge?

I agree with LR55. I am loading to mag length at 2.25 (100 gr Nosler bt) haven't messed with tuning the jump. I can't go any longer and I'm not close to the lands so....

[LRRPF52]

Find out if your sizing process is moving the shoulders back enough before locking down the die.

I use the Hornady comparator set for this with the B350 bushing.



Virgin


Fired


Sized (this is a bit excessive at .0075" bump, when .006" is what works for me)


I use another stripped bolt with the same dimensions as my others, and make sure I can rotate the lugs into lock in the chamber with sized brass that way. The headspace measurement is where I size to, otherwise you end up with brass that won't go into battery even in a bolt gun.

For me, I have to push my shoulders back .006" from fired, otherwise no way they are going into battery.

I have never had to trim Grendel brass as of yet either. Chamber length to the mouth of the case neck is 1.530", and most fired loads don't go much beyond 1.520" for me.

I also changed my process to where I use a universal de-primer from Lee before polishing my brass for the initial tumble.

Make sure to seat primers .004". This sets the anvil so that they are optimally ready for impact and ignition, while recessing them enough to prevent likelihood of slam-fire or OOB detonation from debris.

[Grendelshooter]

I just re measured my chamber with the Hornady lock n load COL gauge...
Not sure what I screwed up the first time around but I was off, by quite a bit. I think I was trying to be too gentle with it.
New (correct) measurements are:
AMAX: 2.345
SMK: 2.391
CC: 2.306

So that being the case I set the seating die to 2.250, locked it in, and made up three dummy rounds.
All chambered and ejected flawlessly.

I may be able to get 2.260 out of my mags but I'll start with 2.250 as a baseline. Did the same with my 77gr 5.56.