Cartmann’s complete .308 Reloading Step by Step (pictures included)

[EricCartmann]

Nice armory. Always very impressed with your sense of order and detail. Makes me think of starting a thread on the well stocked bunker.

Thank you.  Some people say OCD is a handicap though. 

[gunner69]

Eric..... you fuckin' amaze me.......    Keep up the good work.

[MickeyC]

Dues deserved, it's a lot neater than my setup.

[DSM]

Dues deserved, it's a lot neater than my setup.

And why there shall never be a pic of my shit pit bench!

[MickeyC]

Here's mine








.308 results out of a Tikka T3

[EricCartmann]

Nice set up Mick.  I see you have a dedicated pistol and rifle set up not to mention all those tool heads and powder dispensers already set up for other calibers.

Nice grouping!  One of these days I am going to have to do more 3 shot groups (instead of 5), to get my groups tighter 

[MickeyC]

Thanks, it's nowhere near as clean as yours. I have two Dillons, one for large primer and one for small primer with the Co-Ax for the really accurate, expensive or low volume stuff like .338Lapua, .303 or competition ammo.

The group was loaded with the Dillon on the left (Large primer) using RA brass and CCI primers with 2520 powder pushing 168g .308 SMKs. When I ran a series of ten rounds through the chrono I got six right on 2754fps, and that is out of a dillon powder measure.

Regarding groups, behave. I use three shot groups on bolt guns and five shot groups on semi-autos. Three shot groups are fine on a bolt gun and give a better indication of zero for a cold bore shot and also the accuracy the load is capable of. For semi-autos I find a five shot group is much more indicative of the slightly wider spread they achieve.

Here is .338 Lapua group, this one is loaded on the CO-AX and using the Luman DPS to meter every powder charge. Later this summer I'll move grouing to 300 as it should go better. At 100 the round is still unstable so 100 yards doesn't really show the full potential. It has shot consistently under 1" at 200 yards but 300 seems a more reasonable benchmark.

[EricCartmann]

I was just joking, we all know bolt guns kick ass over semi auto when it comes to pure accuracy.  Nice groupings! I don't think I am there yet, even if I had the ultimate bolt gun.

[MickeyC]

 

I figured.

I shot crap, barely under an inch with the same rifle when I started again a few years back. I reduced my caffene intake drastically and cut it out completely 48 hours before a shoot and it made a huge difference. anyway out of a semi auto your groups are pretty damned good as it is. Get a decent bolt gun and you'll be shooting quarters all day long.

[EricCartmann]

That "no caffeine" rule is no joke, I heard another guy talking about that.  The world (and scope) just seems to stand still when you are totally relaxed with no caffeine in your system.

[EricCartmann]

Get a decent bolt gun and you'll be shooting quarters all day long.

You are evil, I really don't need anymore influence to spend any more money I should not be spending! 

I am just going to stick with the AR10 for my precision shooting till the end of the year.  In 2011 if the world does not end by then, I'll start work on my precision bolt gun with all the goodies!  Thinking of going 6.8 creedmore, but the .308 is more common and wins it's fair share of matches, so Limitation seems to be the trigger pulling device and not the round or the gun.

[aziator]

Thanks, it's nowhere near as clean as yours. I have two Dillons, one for large primer and one for small primer with the Co-Ax for the really accurate, expensive or low volume stuff like .338Lapua, .303 or competition ammo.

The group was loaded with the Dillon on the left (Large primer) using RA brass and CCI primers with 2520 powder pushing 168g .308 SMKs. When I ran a series of ten rounds through the chrono I got six right on 2754fps, and that is out of a dillon powder measure.

How much 2520?  I was thinking about loading with that and picked up a pound to try.

[MickeyC]

45 grains. It's spherical so it meters really accuratly in a volume based meter.

[aziator]

My book shows that right at the max so I will work up towards that.

[MickeyC]

It is, but I seat the bullet slightly forward in the case to get it closer to the rifling so pressure is a little lower than max.

[EricCartmann]

It is, but I seat the bullet slightly forward in the case to get it closer to the rifling so pressure is a little lower than max.

That's right, longer OAL is more pressure.  The ogive of the bullet actually occupies the chamber.

[aziator]

I bought some milspec 168 bullets from wideners recently and they are just slightly longer (1.23in) than the 168 SMK (1.19in).

[MickeyC]

Would those be the PriviPartizan tips?

I had some and they were longer but the ogive on my batch hasn't been an issue, as that is what is being seated. The ogive to the rear of the bullet affects case seating while the ogive to the rifling can affect accuracy and stability. Some 168g tips have a longer ogive than others so you'll need to test a few different seating combinations. I only move the tip out a little so any pressue increase is minimal and despite the load data showing this as the maximum I'm fairly sure there is a safety value built in as most handloading data rarely meets the velocity promises of factory ammo.

Work the load up. I fireform the brass and use a neck die to maximize brass life. Just keep an eye on your primers and watch for case issues. I find 45g works fine, at 46 I was having issues so I wound it back down. Within a few tenths grouping didn't suffer at all. I'm pretty sure I am not at max pressure as brass is lasting six to seven reloads at this point.

When it comes to accuracy I find that consistency between each round is more important than the actual velocity. Take your time loading and make sure even and consistent powder charges are dropped. AA2520 is the most consistent powder I have found both in terms of metering by volume and velocity.

There is an interesting article here , browse down, on OAL and pressure. http://www.barnesbullets.com/resources/newsletters/september-2007-barnes-bullet-n/

[EricCartmann]

Good link Micky, and a very interesting read.

If we are talking precision, check out this link: http://www.thefiringline.com/forums/showthread.php?t=372917

It seems for accuracy concentricity of the bullet and brass is much more important than anything else (powder charge, seating depth, etc).

[EricCartmann]

Signs of Overpressure

is something we have not covered yet.  I found this pic over on the FALfiles and it explains it all.

[MickeyC]

Good link Micky, and a very interesting read.

If we are talking precision, check out this link: http://www.thefiringline.com/forums/showthread.php?t=372917

It seems for accuracy concentricity of the bullet and brass is much more important than anything else (powder charge, seating depth, etc).

It is but that is more something that benchrest shooters try, plus roling brass etc.. is a pain in the ass. Other extremes include sifting powder to get uniform sized grains to ensure burn uniformity etc.. It all comes down to how far you are willing to go and how tight a set of groups you wish to shoot.

[DSM]

When you're looking for extreme accuracy it's all a matter of trivial details.  I'll ream flash holes and primer pockets, I'll neck turn sometimes, weigh brass and sort into batches, etc, etc.  Each additional step may only gain you a fraction of an MOA but all of them added together can really add up.  Get a hold of one of the Sinclair reloading books, they do a real nice run down of the steps and such.  I think there was a write up on the Sniper Country site from someone that did it too.

For so many rounds it kind of fun but if you try to do too many it is crazy.

[EricCartmann]

I did not do any of the stuff that bench rest shooters do such as measure runout, size to my chamber, and measure every case by water volume, but then again I am reloading for a gas gun so it's really over kill.

I used badly malformed machine gun brass that were FL sized with $10 Lee sizer dies set straight from the factory, measured how far the shoulders pushed back with only calipers, this is not precise at all because you can't really eyeball 3 thousandth of an inch (was too cheap to buy case gauges, but I just now bought 2 from Dillion, a .223 and .308).  I did weigh the bullets for he hell of it, but not weigh the cases... well long story short, I got .59 MOA out of a gas gun.

When I build my precision rifle though, I will be doing all the fine details... to a benchrest shooter there is a huge difference between .25 and .50 MOA, for me not so much because I like to shoot prone without rear support other than my non-trigger arm.  of course the biggest weakness of any groupins is the machine (or fool) that pulls the trigger.

[aziator]

Would those be the PriviPartizan tips?

Not sure, they came in a big plastic bag. 

http://www.wideners.com/itemdetail.cfm?item_id=8439&dir=278|281|727

The weights aren't all exactly 168 but they are close.  I am going to start out loading them to 2.785 OAL and go from there.  I will do 44gr of 2520 and increase by .2 until I show signs of over pressurization.  I am shooting out of a 18" barrel with a can so I will probably be at the higher end of the powder just to get the velocity up.  I bought 5 different powders to try and see which one I like the best.  I figure I should be able to work up a nice load from one of them.

[MickeyC]

I'm pretty sure they are Privi-Partizan. Pretty nice bullets actually. I shoot the 75 grain .224 for practice and save the SMK for competitions.

Let me know how you get on with these as I've been considering some for a while.