Seating depth for cast bullet in 308

[Tubs]

Hi All,

Noob question but if Im not compressing the powder is there any issue with a shorter overall cartridge length?

I bought some Black Widow 165gr cast RNFP .30 bullets for my 308. I have been seating them low with a COL of 2.61 inches, it isnt compressing the powder (I ca hear the powder shaking around). Im making both light loads using Trailboss and standard loads using 2206H.

These 165gr cast bullets are a bit odd as they are aprox the same length as my 130gr Speer HP's ie: they are short.

Thanks,

[InisBineest]

Hi All,

Noob question but if Im not compressing the powder is there any issue with a shorter overall cartridge length?

I bought some Black Widow 165gr cast RNFP .30 bullets for my 308. I have been seating them low with a COL of 2.61 inches, it isnt compressing the powder (I ca hear the powder shaking around). Im making both light loads using Trailboss and standard loads using 2206H.

These 165gr cast bullets are a bit odd as they are aprox the same length as my 130gr Speer HP's ie: they are short.

Thanks,

They mate, i have done the same with my own cast 165 gr projectiles.

One thing to note immediately... DO NOT COMPRESS TRAILBOSS!! Bad things can happen. In regards to other powders, no idea.

My Loads were for a Ruger No. 1 and as such I had to seat them way deeper than anyone normally would, just to be able to load them into the chamber (no bolt or lever to push them in) and that worked jsut fine! Accuracy was good. It was over a 70% capacity case load of trailboss... never weighed it as I was going by volume and results. Was a nice soft load, great for plinking, but a lot of drop past 100m.

[Tubs]

Thanks, Im not compressing the trailboss but am stretching out the load a little to 15 grains, which should get me around 1500 fps hopefully. A good small game round...

[LawrenceA]

As stated above no compression on TB.
For the normal loads 2207 would probably burn better as cast bullets create less pressure than copper jacketed.
Not familiar with the Black Widow pill but most cast are designed for the 30-30 and as such there will be a crimping groove.
Basically there is no issue going shorter.

It is worth noting that many guns shoot best with the bullets just off or touching the rifling.

I think Black widow are hard cast and powder coated so you should be able to drive them hard enough to hunt with if you desired.

[Tubs]

As stated above no compression on TB.
For the normal loads 2207 would probably burn better as cast bullets create less pressure than copper jacketed.
Not familiar with the Black Widow pill but most cast are designed for the 30-30 and as such there will be a crimping groove.
Basically there is no issue going shorter.

It is worth noting that many guns shoot best with the bullets just off or touching the rifling.

I think Black widow are hard cast and powder coated so you should be able to drive them hard enough to hunt with if you desired.

Thanks, Ive got plenty of 2206H, these trailboss loads are just for cheap plinking and some bunny busting. Black Widow rated up to 3000 fps apparently, ie a hot load....

[bladeracer]

Hi All,

Noob question but if Im not compressing the powder is there any issue with a shorter overall cartridge length?

I bought some Black Widow 165gr cast RNFP .30 bullets for my 308. I have been seating them low with a COL of 2.61 inches, it isnt compressing the powder (I ca hear the powder shaking around). Im making both light loads using Trailboss and standard loads using 2206H.

These 165gr cast bullets are a bit odd as they are aprox the same length as my 130gr Speer HP's ie: they are short.

Thanks,

No problem at all, as long as it still cycles through the action.
You don't _need_ to compress the charge, but it can sometimes help make a more efficient burn.

[bladeracer]

As stated above no compression on TB.
For the normal loads 2207 would probably burn better as cast bullets create less pressure than copper jacketed.
Not familiar with the Black Widow pill but most cast are designed for the 30-30 and as such there will be a crimping groove.
Basically there is no issue going shorter.

It is worth noting that many guns shoot best with the bullets just off or touching the rifling.

I think Black widow are hard cast and powder coated so you should be able to drive them hard enough to hunt with if you desired.

I wouldn't get too tied in knots about compressing TB, but you'll likely hit a velocity limit before you reach that point anyway.

Some bullets prefer a long jump, some prefer to be near the lands. Secant designs are more likely to be jump-sensitive, tangent designs are less sensitive, hybrids combine the two with a tangent ogive to the depth of the rifling, then a secant ogive to the tip. But this only matters for optimum accuracy, loaded to magazine length is generally fine.

Tangent means the curve is a continuation of the bearing surface, secant means the ogive meets the bearing surface at an angle.

[bladeracer]

Thanks, Ive got plenty of 2206H, these trailboss loads are just for cheap plinking and some bunny busting. Black Widow rated up to 3000 fps apparently, ie a hot load....

3000fps is a very hot load for a cast bullet, even powder-coated or plated.
I have fired a soft cast 180gn bullet in 8x57mm at 2544fps just to see what happens, not powder-coated, just checked.
It went through 8mm steel plate at 50m, but it took a long time to clean the bore afterwards
That was on 40gn of AR2206H.

[Tubs]

Thanks, Ive got plenty of 2206H, these trailboss loads are just for cheap plinking and some bunny busting. Black Widow rated up to 3000 fps apparently, ie a hot load....

3000fps is a very hot load for a cast bullet, even powder-coated or plated.
I have fired a soft cast 180gn bullet in 8x57mm at 2544fps just to see what happens, not powder-coated, just checked.
It went through 8mm steel plate at 50m, but it took a long time to clean the bore afterwards
That was on 40gn of AR2206H.

Funny you say that mate, I just loaded a few mags worth with 41gr of 2206H. Running it through the heavy barrel on Friday.... Ive got it 3000fps in writing from the manufacturer so if it blows up and I survive Im off to small claims lol.

[Blr243]

I’m curious , not that I ever intend to push cast fast, but other than leading barrels , what negative things happen when u push cast lead too fast, firstly checked, unchecked, and powder coated ?

[Tubs]

Ill tell u after Ive done it:)

[bladeracer]

I’m curious , not that I ever intend to push cast fast, but other than leading barrels , what negative things happen when u push cast lead too fast, firstly checked, unchecked, and powder coated ?

Leading is the biggest problem I think. Lead is softer than copper or brass, so when it hits the rifling it tends to push through it instead of immediately beginning to rotate. This can shear the rifling off the bullet, leaving the bullet undersize, allowing gas cutting, where the gas flows past the bullet, and ruining accuracy until it is cleaned out, usually accomplished by firing some reduced jacketed-bullet loads. Tighter twist rates exacerbate the problem.

[boingk]

Once again, the answer is in the past.

Black powder runs into a wall around the 1400fps mark. Not universally, but generally.

The logic of that era, with that limitation, was therefore to make the projectile larger to give impart more energy to the target. You needed more powder to make the larger projectile leave the barrel at a useful speed, but overall it was projectile mass that gave you your final result.

So where am I going with this?

You're running the equation in reverse.

Instead of pushing the pill faster, you need a bigger pill. You may be able to get something like a 300 Blackout pill in the 200 - 230gn range which a 30-30 or 308 will be able to easily push along at a useful speed without leading. A quick search of Blackwidow shows they do indeed make this sort of projectile.

Click here for BlackWidow link

Now the other thing here is that running a 230gn projectile from the 308 will give some interesting loading options. Running 2206H, ADI only lists projectiles up to 208gn with a 35gn charge as minimum load. I'd be tempted to load at 10% under that for starters, call it 31.5gn of 2206H at 230gn. It'll likely be around the 1700fps range, so 1450 foot pound muzzle energy. Thats a lot of heat for a hard-cast pill at 30 cal, so it'll probably punch straight through whatever you hit with it!

The 165gn pills have a much better flatpoint type nose, though, and obviously better case volume available. You'll find them shorter than comparable spire-point pills due to lack of a lighter copper jacket and also a denser overall section with no longer, narrower nose. I'd load to the same outline characteristics - hold it against a spire point round and roughly match the outline of the spire to the rounded flatpoint pill.

I'd stick with a minimum load of 2206H and the 165's so you don't have to worry about leading. You'll still have plenty of energy on target, even at a relatively slow 2000fps the 165gn will yeild about 1400 foot-pound. Plenty for pretty much anything.

See how your leading goes and let us know!

[Blr243]

Blade that was a very good answer/ explanation .... I had never given any thought to the initial push , and rifling being stripped/ undersize result

[boingk]

Its like the opposite of driving a jacketed pill too fast, resulting in centrifugal destruction after exiting the barrel. Except this time its shear forces inside it.

- boingk

[LawrenceA]

Blade that was a very good answer/ explanation .... I had never given any thought to the initial push , and rifling being stripped/ undersize result

This is why we:
- powder coat,
- add gas checks
- use harder lead
- use gain twist rifling
- Paper patching or even cloth patch
- struggle with shallow rifling and cast bullets

Kinda why it is just about impossible to get cast pills to work in a 6.5 Swede and yet you can paper patch a 300 win mag. Some claim to use cast bullets to 4,000rpm with patching.


Apart from stripping the rifling, which only really happens on heavy loads and long bullets, the biggest problem is gas cutting. As mentioned above it when the ultra hot gases rush past the projectile while it is still in the barrel.
This has the effect of stripping lead and depositing it inside the barrel and damaging the base of the bullet. This leads to bad fouling and bad accuracy.
By using a bullet a couple of thou over the bore you go a long way to prevent this blow by. By powder coating or patching you limit this even further if not eliminate it. By adding a gas check you also pretty well eliminate it.
Powder coat and gas check and you have a bullet that you can drive to about 2,400fps or a bit faster.
Paper patch and go as hard as you like. No leading as the bullet does not touch the rifling.

Personally I'll stick with gas checks and powder coating.

[InisBineest]

Personally I'll stick with gas checks and powder coating.

I do this with my 165gr, I don't even thing about leading with that combo. That all said, Ive sold my Ruger and am waiting on a 300blk upper for my WFA1L. Planning on running the same pills in that and crossing my fingers that I don't get feeding issues!

[bladeracer]

Paper-patching is great, but also very fiddly, especially with smaller bullets like .224" and .243", and time consuming. I think most people are wanting to shoot cast bullets so they can shoot a lot of them, cheaper than jacketed bullets, or even for free with recovered bullets. Paper-patching a couple hundred rounds every month wears thin very quickly.

With PC you can cast 200 bullets in an hour, toss them in a tub with the powder, give it a shake, dump them onto a silicone sheet, and stick them in the oven for 20 minutes, while you throw some powder charges into some brass. It's very quick and easy.

You can also paper-patch jacketed bullets to increase their diameter to fit a larger bore diameter, .243" up to .270" for example, for the 6.5x52mm Carcano, or .308" up to 325" to fit 8x57mm.

[Blr243]

Good info guys. I’m lapping it up.

[bladeracer]

Good info guys. I’m lapping it up.

If paper-patching is of interest, you might enjoy Paul Mattews' book "The Paper Jacket".
Local library might be able to get it for you, before lashing out $40-50 for a copy.

[LawrenceA]

Good info guys. I’m lapping it up.

If paper-patching is of interest, you might enjoy Paul Mattews' book "The Paper Jacket".
Local library might be able to get it for you, before lashing out $40-50 for a copy.

An excellent book

[Tubs]

I went from getting 1/2 MOA @ 200 using Sierra MatchKings to 2 MOA @50 using coated lead.

Accuracy with trailboss at short ranges ie: low velocity was better. The full load (41gr 2206H) cast RNFP's kicked like a mule and were way off.

Time to start gas checking maybe? and yes Ill reduce the load of 2206H for the next batch.

At least I know what a gas check is now:)

[LawrenceA]

I went from getting 1/2 MOA @ 200 using Sierra MatchKings to 2 MOA @50 using coated lead.

Accuracy with trailboss at short ranges ie: low velocity was better. The full load (41gr 2206H) cast RNFP's kicked like a mule and were way off.

Time to start gas checking maybe? and yes Ill reduce the load of 2206H for the next batch.

At least I know what a gas check is now:)

Make sure your weights are correct and even more important is diameter.
Good luck and have fun.

[bladeracer]

I went from getting 1/2 MOA @ 200 using Sierra MatchKings to 2 MOA @50 using coated lead.

Accuracy with trailboss at short ranges ie: low velocity was better. The full load (41gr 2206H) cast RNFP's kicked like a mule and were way off.

Time to start gas checking maybe? and yes Ill reduce the load of 2206H for the next batch.

At least I know what a gas check is now:)

That would be about what I'd expect switching from a high-quality jacketed competition bullet to cast lead.
It is possible to improve the accuracy, but it can take quite a lot of work. Gas checks come in bags of 1000 or more, and are not expensive. I prefer to order gas-check moulds whenever possible, even if I don't intend to run checks. I don't know if it's fact, but I think a nice symmetrical gas check can really help accuracy, the base of the bullet contributes significantly to accuracy, but is hard to keep symmetrical when casting due to cutting the sprue. Some moulds and check combinations might be easier to seat through a sizing die, but I generally don't size the bullets if I don't have to and just seat the checks by hand. Then I lube or PC and go shoot them. Lube takes time to dry, PC doesn't.

You can try different bullet alloys, different bullet diameters, different coatings and/or lubes. I use lead shot and/or 60/40 solder sticks to adjust my alloys, but most of my lower-velocity bullets are just cast from recovered .22LR bullets (I keep the .22 bullets separated from recovered unknown alloy bullets). Pure lead can be bought at Bunnings, bullet alloys can be ordered from Northern Smelters. If you are practicing somewhere private there's no reason you can't keep recycling the same bullets forever.

When you're ready to invest in casting yourself, I'd suggest at least trying PC. The outlay is a bag of powder, a silicone oven tray, and a small toaster oven - under $100 for the lot. It also allows you to increase the size of a bullet if you think it might be under-size for your bore.

Did you measure your velocities?
If the velocities are all over the place, hundreds of fps differences, you almost certainly have gas-cutting issues. If you can recover the bullets you can see if the rifling is clean and sharp as well.