.308 reload help

[ctracingraptor]

New to reloading, and my cousin and I are testing some loads and shooting from a .308 out of a 20" barrel DPMS AR-10. It's sub moa with premium ammo. I'm having a little pattern spread issues with reloads, and was curious if someone had a place to start from or a preferred powder or a solid setup. My pattern is consistently around 3-4 inches. I've been slowing working the charges up and the FPS spread is pretty consistent. Any issues with BLC-2 or spherical powder that I am missing, or should I try something else. Any help would be greatly appreciated.

 

Currenty Setup

168grain SMK (very little or no crimp)

308 Nosler brass(factory trimmed)

BLC-2 43grain

Sellior & Bellot primers

COAL--2.800"

[wayno945]

You are probably 3 or 4 grains short of max. I would switch to a magnum primer (cci34) and do .5 grain increments to 47 grains. Shoot 5 rounds per charge and you should find an accuracy node.

[willhunt4coues]

Seating depth has everything to do with group size. Go to Berger web site and look up the seating depth test to find what your rifles seating depth should be. Also do not do a crimp.

[ctracingraptor]

wayno, are you sure the cci primers (cci34) are magnum primers? I'm not seeing that they are magnum, says military. Also I was thinking of switching to the Federal 210M primers, they have good reviews, does anyone have input on the 210M primers?

 

Apparently I've missed something, I didn't know I needed a special tool to measure seating depth, does anyone have a recommendation on which one I should purchase?

Thanks again.

[CraigK]

Hornady makes simple tool. I used federal 210m with 175 matchkings and reloader15 shoots right at 1/2 Moa out of a tikka.

[wayno945]

Yes they are hotter than normal large rifle primers and have a thicker cup to prevent slam fires.CCI Web page says to use magnum primer data. You should use magnum primers with ball powders.

[roninflag]

Yes they are hotter than normal large rifle primers and have a thicker cup to prevent slam fires.CCI Web page says to use magnum primer data. You should use magnum primers with ball powders.

in additionto what wayno said- most shooting the 308 use either I4064, varget or re-15. br-2 or 210m

[ctracingraptor]

ok guys thanks for the help, im going to purchase a seating depth gauge and start over.

[willhunt4coues]

Hornady Comparator will attach to your calipers for measuring Ogive to base (cbto) instead of overall length (coal). Make sure you also get the correct insert for your caliber.

Hornady also make the Overall length gauge to measure your throat length in your rifle.

Here are the links to what you need.

 

Lock N load overall length gauge:

http://www.midwayusa.com/product/570611/hornady-lock-n-load-overall-length-gage-bolt-action

You will also need the modified case for you cartridge:

http://www.midwayusa.com/product/459683/hornady-lock-n-load-overall-length-gage-modified-case-308-winchester?cm_vc=sugv459683

 

Here is the comparator set:

http://www.midwayusa.com/product/231904/hornady-lock-n-load-bullet-comparator-basic-set-with-6-inserts?cm_vc=ProductFinding

 

Both of these 2 tools used together will give you a precise read of what your gun seating depth will be. Follow Berger's info on seating depth test and once you get close move in small increments to maintain the smallest group possible.

http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

[ctracingraptor]

Update. I purchase the Hornady OAL Gauge, also with the bullet comparator set. I installed the bullet comparator with the correct die, zero my dial indicator as instructed. I ran this procedure several time to get a average of my CBTO. Now either my math is off or something is wrong, I need someone to double check this for me please. Measure OAL with the gauge and checked it using the comparator measuring on the ogive.
My Numbers
2.366"
2.367"
2.368"
2.368"
Average is 2.367
I used the bullet comparator and measured a factory bullet on the ogive(which I know will change because its a different bullet) but I ended up with 2.218"

Even if I back the bullet 0.040" off the lands, I am still coming up with a bullet that is very very long, Oh and it wont fix in the magazine anymore.
Backing off 0.040 I ended up with COAL of 2.891.
Why is this bullet so much longer than the book telling me 2.810 is max? What do I do about it no longer fitting in the magazine?
My numbers are telling me I have roughly 0.150" jump on factory ammo?
Oh and I'm also running into the same issues with my AR15, Its obvious somewhere I have missed something, just not sure what?
thank you in advance

[wayno945]

You can only can load to 2.800" or shorter using the Pmags. If the barrel has a longer throat there is really nothing you can do about it. I would try a different bullet/powder combo or do a ladder test with varying charges, then a second ladder test using the best charge weight from the first ladder and vary the seating depth deeper i.e 3-5 rounds @ 2.800, 3-5 @ 2.795, 3-5 @ 2.790, etc.

[pwrguy]

It looks to me like you have a huge amount of freebore in your chamber? You may have to settle for what will fit in your magazine.

[ctracingraptor]

Is there any way to eliminate the "freebore" ??? Is there no way to tack up all the slack or gap ? Would switching to a match grade barrel help at all?

 

Thanks against

[pwrguy]

A different barrel will have a different chamber so depending on how the chamber was cut yes you could eliminate the excess freebore. I would do some testing first to see if it is anything you need to be concerned with. Shoot some groups loading your long bullets one at a time. If there is not a significant difference in group size don't get excited about loading the bullets close to the lands. I have not played with semi auto's much but that is how I would proceed if it was a bolt gun.