View Full Version : My first experience loading 308 for an AR-10
So I have a GA Precision GAP-10 that I'm going to start reloading for. I've got plenty of Nosler brass, Mil brass, Black Hills brass, and some headstamped RP. I got some Sierra MK 175g HPBT bullets for punching paper and some Barnes 180g TSX bullets for hunting. I'll load the Barnes bullets later. For primers I got the CCI #34 military primers. I'm planning to use Varget for my loads but I also have some IMR 8208 XBR. I finally got all the gear I needed to load up some test rounds and here's how it went.
I decided to start with the batch of Black Hills brass (which bites be in the ass later). All of this brass has been fired in the GAP-10 so it's formed to its chamber.
- I used my bump gauge and set the sizing die on the Dillon to bump the shoulder back .003-.005. I did everything in accordance with the instructions and sized a batch of 50.
- Next I trimmed all of the brass to 2.005 and deburred/chamfered them. I also use a primer pocket cleaning tool and cleaned out all the pockets.
- While I tumbled the case-lube off, I figured out my seating depth.
- I used a comparator and sorted all the Sierras in groups within .005 of each other.
- I got the GAP-10 out and used a seating depth tool to get me on the lands. The measurement on the tool was 1.643 and the average bullet length on the batch I chose was 1.250. This meant that 2.893 OAL put the ojive of the bullets right on the lands.
- I assembled a dummy round. The neck tension is plenty tight so I did not crimp the bullet. I chambered that assembled dummy round with the force of the bolt and it chambered and extracted just fine. No change in OAL so it wasn't too long.
- Next I checked to ensure it would fit in the magazine, and low and behold, it did not. I was expecting this. I had to seat the bullet deeper to an OAL of 2.827 to get it to fit in the magazine. So the comparator sorting and seating tool were pretty much a waste of time. But they'll come in handy when I load something for a bolt rifle.
- Next I get the Dillon set up for large primers and get it loaded up with 50 of the CCI #34s. I got the Varget and the powder trickler ready and got the brass out of the tumbler.
Unfortunately, this is where I stopped. I found out the hard way that Black Hills crimps their 308 brass and I couldn't seat any primers. The Noslers and RP brass are not crimped but I ran out of time. I haven't gotten a tool to swage pockets yet so I couldn't go any further. But once I do I think I got it all figured out.
Is there anything you see here that I did wrong or have any advice for a beginner?
If your looking for a quick fix to get some rounds loaded. You can use your chamfer tool to cut the crimps away. I personally have done it just to get 25 rounds loaded. It worked great you just have to be careful to not go to deep.
I'm wondering if I ran into something similar with LC 308 brass last night. Some of the primers will seat although very tight and others just refuse to go into the primer pocket.
Is LC known to have tight primer pockets? I don't see anything that looks like a crimp.
Simply ream the primer pocket crimp. You can use a pocket knife or, as recommended above, your chamfer tool.
If you've reamed or swaged the pocket and primers are STILL tight going in try non-plated Winchester primers.
Don't push the shoulders back past .003 -- you'll get case stretching and wall thinning, shortening your case life. Are you using a small base die?
Best to hand-seat primers so you can feel whether or not you have loose primer pockets.
GI overall length for 7.62 match and long range is 2.800 +/- .030".
42.5 to 44 Varget to find your sweet spot.
Check your cases after firing and resizing to feel whether or not you're developing case thinning that will lead to separations.
Simply ream the primer pocket crimp. You can use a pocket knife or, as recommended above, your chamfer tool.
If you've reamed or swaged the pocket and primers are STILL tight going in try non-plated Winchester primers.
Don't push the shoulders back past .003 -- you'll get case stretching and wall thinning, shortening your case life. Are you using a small base die?
Best to hand-seat primers so you can feel whether or not you have loose primer pockets.
GI overall length for 7.62 match and long range is 2.800 +/- .030".
42.5 to 44 Varget to find your sweet spot.
Check your cases after firing and resizing to feel whether or not you're developing case thinning that will lead to separations.
I'm using Dillon dies.
I chuck my chamfer tool into my drill press and go from there. It only takes a second or two to trim out the crimp this way. To the best of my knowledge all Lake City brass has crimps. I'm assuming all brass loaded for military or federal government use has a primer crimp in it. kwg
Dillon dies are NOT small base dies. They should fit your GA, but George's shop usually chambers to match specs for best precision.
Lake City Match and LC Long Range do NOT have crimped primers. All other 7.62 NATO Cartridges (Ball, tracer, Special Ball, etc.) have crimped pockets. NATO-spec-ed GI brass will have the NATO circle-cross symbol at 12 o'clock on the head stamp.
Lake City Match and LC Long Range do NOT have crimped primers. All other 7.62 NATO Cartridges (Ball, tracer, Special Ball, etc.) have crimped pockets. NATO-spec-ed GI brass will have the NATO circle-cross symbol at 12 o'clock on the head stamp.
I saw the circle crimp after I put my glasses on! Thanks for the information Sinister and kwg, I was priming once fired LC M80 ball which, as you both say, definitely has a crimp.
I've loaded up batches of 42.6 & 43.0 grains of Varget under a 150gr Sierra MatchKing HPBT.
I also have a batch of lighter loads using 40.6gr of Varget under 150gr Hornady SST Softpoints, which according to the manual "should" be around 2500fps, we'll see.
Sorry for thread jacking OP.
No worries.
For either bolt or gas-operated rifles 42.5 thru 44 Varget is great for a 168, 175, 180, or 185. You can go up to around 46 for a 135 thru 150-155, but watch for pressure signs if you're not using a carrier weight or heavy buffer.
Dillon dies are NOT small base dies. They should fit your GA, but George's shop usually chambers to match specs for best precision.
Lake City Match and LC Long Range do NOT have crimped primers. All other 7.62 NATO Cartridges (Ball, tracer, Special Ball, etc.) have crimped pockets. NATO-spec-ed GI brass will have the NATO circle-cross symbol at 12 o'clock on the head stamp.
What's the benefit of using a small base die? What kind of issues might I run into by not using one?
If you don't know the pedigree of your 7.62 military brass (what type of weapon it was originally shot out of) you run the chance (if surplus) it may have been fired from a machinegun or a factory 308 Rem rifle with a large chamber.
Resize with a full-size die and it may not squeeze your brass down tight enough to chamber smoothly in a self-loader. Trying to squeeze a fat cartridge into a tight match chamber risks a slam-fire (triggering off the round with an inertia firing pin before the bolt is locked).
If you don't know the pedigree of your 7.62 military brass (what type of weapon it was originally shot out of) you run the chance (if surplus) it may have been fired from a machinegun or a factory 308 Rem rifle with a large chamber.
Resize with a full-size die and it may not squeeze your brass down tight enough to chamber smoothly in a self-loader. Trying to squeeze a fat cartridge into a tight match chamber risks a slam-fire (triggering off the round with an inertia firing pin before the bolt is locked).
All the brass I'm currently using has been fired through my rifle. I'm also using the mil primers. I'll see how everything goes when I test fire it. I'll also keep an eye on the brass to see if the bottom is getting bulged or develops a rut. I might just get a small based due for good measure.
I shitcan Black Hills brass as quick as I can I.D. it. Their primer pockes suck, the neck thickness it too thin unless you have a tighter custom chamber.... Just not worth the ass ache.
As far as unknown LC 308... you can get it to work, but if (as sinister pointed out) it has been fired in a large chamber, it'll separate in just a few firings.
Not a danger risk, but a bummer when you spend your efforts prepping cases that only yield a few firings.
I shitcan Black Hills brass as quick as I can I.D. it. Their primer pockes suck, the neck thickness it too thin unless you have a tighter custom chamber.... Just not worth the ass ache.
As far as unknown LC 308... you can get it to work, but if (as sinister pointed out) it has been fired in a large chamber, it'll separate in just a few firings.
Not a danger risk, but a bummer when you spend your efforts prepping cases that only yield a few firings.
I noticed that about the BHA cases. The pockets are off-centered as well as crimped. Funny that it says "Match" on the headstamp. I'll probably throw them out after this next firing and use all the Nosler, RP, and LC brass I have.
Some good info in here, thank you as I am keen on reloading .308 for the MWS. I didn't know about knowing the origin of the brass and weather it has ben fired in an MG or not. Is that due to the larger chamber that you were talking about?
I noticed that about the BHA cases. The pockets are off-centered as well as crimped. Funny that it says "Match" on the headstamp. I'll probably throw them out after this next firing and use all the Nosler, RP, and LC brass I have.
Black Hills and "Match" don't belong on the same PLANET!!! Their 300 WM brass is total trash. And their .223 brass is always sticking in my shell holders like PRVI does.
I didn't know about knowing the origin of the brass and weather it has ben fired in an MG or not. Is that due to the larger chamber that you were talking about?
Yeah. Some of the Military MGs like the 249 are really just designed to reliably sling bullets. Headspace can be pretty loose since the Mil doesn't care about reuseable brass.
I fired them off today. All 50 fed and fired perfectly. Accuracy was best between 42.5 and 44.5 grains. I'm gonna load up some more and see if I can narrow it down a little more.
I shot mine as well on Saturday. Thread below....It was too cold and I shot like crap. In addition, there were a coupe guys at the range yapping at me the entire time which left me quite distracted. I had pretty decent results with 43.1, going to try 44 grains next.
If you haven't tried them already OP, get yourself some 155 Amax bullets.
Shootin' Hot Loads (https://www.m4carbine.net/showthread.php?143794-Shootin-Hot-Hand-Loads-the-Range)
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