casting .308 bullets

tuckerjoy

New Member
looking for some help casting and shooting cast bullets thru a savage LRT 308 with adjustable gad block, I have read if you keep your speeds down you have know problem with leading. this has been a nightmare. to get the action to work I have to go almost to max charges on IMR 4198 4227 and accurate 5744. the accuracy is also horrible I,m lucky to hit a 8 inch gong at 100 yards. Any help on this would be appreciated
 

Rick

Moderator
Staff member
Possibly Winelover will chime in here, he has done a lot of work with his 308 AR.
 

tuckerjoy

New Member
any help would be appreciated this has been terrible. I have bought over 9800 pounds of lead in the last 5 years and going to retire in August. I make all my revolver and pistol bullets with little or no problems but this different
 

Rick

Moderator
Staff member
Yep, quite different as soon as ya toss in the AR and cycling the action. Ian has also done a lot with his AR. My M1A does fairly well with 4759 and does cycle the action. Could most likely get improved results with it but it's yet another project I never got back to.
 

popper

Well-Known Member
What alloy and twist? That mould is 309 which is probably too small. PC should help with the size, my ar10 takes 310 and full charge of 4895. Alloy needs to be in 24 BHN range.
 

fiver

Well-Known Member
you'll want at least .310.

I think that's the 332 not the 322.
I also second stepping powder speeds back to like the 4064, cfe-223, 335 area.
the 30gr area to begin with.
I'd also work on lighter [like .0015] neck tension.
 
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Ian

Notorious member
Hi Tuckerjoy.

You're taking on a graduate-level project with jr. High information. I'm gonna throw some things out there and you tell us if and where you get lost.

First, you need to fit the bullet to the rifle. Not the bore/groove, that means nothing. The meaningful fitment happens in the throat of the barrel. That means you need to know the chamber neck and throat dimensions of the rifle, which means make a cast of it somehow and get those measurements. Forget bore and groove fitment, if you want any kind of accuracy at the higher velocities necessary for reliable function, you have to think in tjree dimensions and not just two...and fit the throat. Also, forget jamming the bullet in the lands or trying to make a bore-rider fit, it just won't wirk fhat way with an AR and the weak camming action. The bullet needs to be free from contact when chambered, but still be "right there" to touch something the instant it moves out of the case neck.

Next you need to prepare your brass to hold the bullet correctly for the size it needs to be. Bushing neck sizing dies excel at this, standard dies do not because they overwork the necks off center. You will need an expanding/bellmouthing die of exactly the correct diameter also.

You will also need a good, straight-line seating die. If you cannot make concentric ammunition that fits your rifle the way it needs to with cast bullets, your results will not be good.

Forget the "reduced rifle" type powders. Use real rifle powders like you would with jacketed bullets. 3031 and 4895 are good, so is 4064 and Varget or even H414 and 4350. Try for at least 2000 fps with 3031 and it should cycle just fine and still be in the "easy" zone for accuracy.

Alloy.....19 bhn is plenty and then some, but how it gets 19 bhn is more important than just the size of the dimple the tester makes. Couple ways to go here, I like a low-antimony, lower tin alloy bumped with heat treatment, but something like Lyman #2 or Taracorp Magnum, water-quenched, is also good. Main thing is you don't want the bullets to be too brittle. Tough is good, brittle is not.

If you really want to cheat and skip to the end with 1.5 MOA groups out to 300 yards at jacketed velocity and no fuss, I can give you the exact recipe. It involves about $500 in new tools plus a custom nose bump die you'll have to make, plus learning a new process, but it works really well.
 

tuckerjoy

New Member
Boy you said it in a nut shell about jr. high information. First of all I’m far from a gunsmith so it seems I might have tackled more then I can handle. I had a huge amounts of wheel weights that I melted down and added tin to increase hardness in 1pound ingots. I water quench my bullets, to get to the 19BHN. Second is making a cast of the throat of the barrel. I have no clue how to do that or where to get it done. So if takes spending an extra 500 dollars I’m all ears if you can help me out
 

Bret4207

At the casting bench in the sky. RIP Bret.
Look up "Cerrosafe" at the Brownells website. It's a product with a very low melting point and known shrinkage/expansion qualities that will allow you to figure out your throat shape and dimensions. Or you can do a "pound" cast of the throat with soft lead.

Almost 5 tons of lead...I admire you already!!!!! ;)

Welcome to the site!
 

Winelover

North Central Arkansas
What Ian said, but I didn't go to those great lengths. I have yet to slug a barrel............any barrel. I just size as fat as will chamber. My Armalite AR10 accepts bullets sized at .3125 with no leading. Make sure you use an appropriately sized cast bullet neck expander............I use a RCBS .311 cast bullet expander.

I conventionally lube (Carnuba Red) on a Star. No powder coating for me.

I had no luck with powders faster than 4198. I have a whole loose leaf binder full of test targets, with ten shot strings. I tested a range of powders between 4198 and AA 4350, that I found would cycle the action. I gave up on Varget. Best groups, I shot were with R-15. Faster powders shot better but failed to cycle the action, so not going to pan out in a semiautomatic. Increasing the charge, only opened up groups to shotgun patterns, when they finally did start to cycling the action. Stay away from low charges of ball powders............unless you want to experience SEE.

BTW, good luck with finding data for any of these powers with cast bullets...............it ain't out there. All my testing was trial and error.

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P1040943.JPG

NOE's 311414 SP weighs in at 160 grains out of my alloy (close to WW alloy) but oven heat treated.

Good luck in your pursuit..............you opened up a can of worms. :eek:
 

fiver

Well-Known Member
is that a Hollywood I see there?

another thing your gonna be fighting is the bullet.
I think you'll be able to hit maybe 21-2200 fps before,,, well, before what your seeing happen now happens.
think about that bullet jumping forward and that front drive band taking a hit in the leade before transitioning into the barrel.
now think about it more realistically where the case is sitting on the bottom of the chamber and it is trying to slide uphill into the barrel, while the gas is shoving it straight ahead.
 

Winelover

North Central Arkansas
is that a Hollywood I see there?

That it is............mint condition Senior Turret with eight of the 1 1/2" threaded holes. Also have the full set of Hollywood 12 gauge dies, two powder measures and two shot dispensers. Owned by my BIL's father. He got killed in a motorcycle accident in the early 70's. Sat in their basement, till I got a hold of it, just prior to moving to Arkansas in 2012.