Casting Session, NOE 310-165-FN (30 XCB)

[Bret4207]

Multiple definitions of "jam", makes sense. Multiple ways of getting the bullet aligned, makes sense. I think at some point some drawings of some sort would be needed to outline the differences. But just knowing there is no "one way" to success is oddly encouraging to me.

Fiver, I'm surprised the K31 isn't in the 2500 plus club. I got one back when they were going for $119.00 or so and it has to be among the finest target milsurps ever. I have a SAECO RG4 with a skinny nose that should be just the ticket for it, if I ever get time.

358156- Absolutely right on this applying across the spectrum. Even though these guys are talking rifles with fixed chambers and bullets with pronounced noses, I see it also applying to revolvers and SWC or WC! It doesn't matter if it's a 223 at 2850 fps or a 32 S+W at 650fps, the concepts are the same. It's the variables that add up as the pressure increases...I think anyway!

 

[L Ross]

the key is the transition from one to the other.

From proper static fit transitioning into dynamic fit?
I am going to have to start to pay attention to my alloy and it sounds like I'll have to water quench. Not something I look forward to.
Are you simply plopping them from the mould into a bucket of water? Are you heating in an oven then quenching? How long do I have to then get to the Star and size before they get too hard to push through? I am seeking advice from all of the High Velocity experimenters here and thank you all in advance.

 

[L Ross]

We have all read for years and years from various authorities that 1800 was the threshold for accuracy with cast in most Rifle calibers.
Some experiment with coatings and alloys and have been able to achieve better velocity.
But at the same of aggravation, there is little I need to shoot with a cast that requires more than 1800 FPS. IF I had to have more power just take the black powder theology and use a bigger bore/ heavier projectile at same 1800 FPS. Only other I can think of is get game Closer.

Last choice IF more is still needed, I’ll load a jacketed bullet.

At least that’s this mans opinion.

Yeah that's right where I was, until I put together a really nice wood stocked, bedded, triggered, scoped, Charlie Milazzofied, (of MK-II trigger fame), Model 700 .308. Suddenly plinking steel at 200 was way too easy compared to a bunch of Mil-Surp 03A3's and Springfield deer hunter sporters I had been satisfied with. Then because the deal I found on two Leupold Mark AR Mod-1's for less than the MSRP of one, led me to trying to understand milliradians, and ranging, and getting serious about wind and suddenly I want to shoot steel at 500 yards like Waco.

 

[waco]

I want to shoot steel at 500 yards like Waco.

It's easier than you might think. You should just give it a try. If I can do it...

 

[fiver]

from the mold into the water works fine.
now.. this gets them all within 1-2 final BHN points but you have to wait at least a month for them all to settle down into the same 18-19 BHN area.

going from the oven into the water does a couple of things for you.
1. you get to visually sort them and/or weight sort them into groups of your choosing.
2 this lets you toss back the outliers without hurting your feelings or having 2 cups full of lubed and sized bullets your never gonna shoot.
3 you know they all got the same heat treatment
4 you can adjust the heat treatment.

I just toss the starting bullets, then when I'm sure I'm in the 'middle of a run' I go to the little bucket on the stool next to me.
all I'm looking for is consistent quality bullets within a little window.

as far as sizing, I try to not really size my bullets.
anything over having enough resistance to seat the gas check is more sizing than I want.
the 165-A doesn't tolerate sizing anyway, so if I get one that IS being sized I'm wiping the drive band down from convex to flat sided.
not what I want.

the goal is to get the bullet from the mold to the target with as little change as possible.
if there is to be a change let the rifle do it, work your way around that change so the bullet comes out the barrel the same changed shape each time.

 

[Will]

from the mold into the water works fine.
now.. this gets them all within 1-2 final BHN points but you have to wait at least a month for them all to settle down into the same 18-19 BHN area.

going from the oven into the water does a couple of things for you.
1. you get to visually sort them and/or weight sort them into groups of your choosing.
2 this lets you toss back the outliers without hurting your feelings or having 2 cups full of lubed and sized bullets your never gonna shoot.
3 you know they all got the same heat treatment
4 you can adjust the heat treatment.

I just toss the starting bullets, then when I'm sure I'm in the 'middle of a run' I go to the little bucket on the stool next to me.
all I'm looking for is consistent quality bullets within a little window.

as far as sizing, I try to not really size my bullets.
anything over having enough resistance to seat the gas check is more sizing than I want.
the 165-A doesn't tolerate sizing anyway, so if I get one that IS being sized I'm wiping the drive band down from convex to flat sided.
not what I want.

the goal is to get the bullet from the mold to the target with as little change as possible.
if there is to be a change let the rifle do it, work your way around that change so the bullet comes out the barrel the same changed shape each time.

This makes a lot of since. I have noticed when messing with the 30 silhouette recently that when I size to .310 and get the bullet down in my Lyman 4500 enough to fill the lube groove I’m wiping some of the taper off in front of the lube groove.
Gonna have to figure out a way to make that not happen.

 

[Ian]

Will, my 30 SIL bullets come out nearly .312" on the bands if I add tin to balance the antimony in COWW alloy. This is exactly the size they are supposed to cast. Fun fact: this bullet was originally designed for the bore/groove/throat dimensions of the K31 Swiss rifle, so the nose is a bit small for the normal .30s. Due to the nature of the two tapers it works suprisingly well in the larger bores (it is NOT dependent on the tops of the lands for alignment), especially with a mild alloy and lots of pressure that will push metal up into the base of the nose and bump it up to fill the grooves anyway.

We powder coat this bullet and that adds another 1.5 to 2 thousandths to the diameter which helps the nose but doesn't help our already oversized driving bands if we want to have a final size around .309-10" as the coating seems to prefer in .30-caliber rifles.

But!

This bullet has a very deep, steep-sided lube groove, fairly narrow main driving band, and a tapered shoulder for the forward driving surface. These support points are engineered to be able to squeeze down .004" plus displace the extra metal from the land engraves. The front shoulder folds back like an umbrella and the main drive band easily draws down in girth as the bullet is pushed through the throat taper.

What I'm trying to say is that the bullet will get drawn down smaller whether the rifle does it or your sizing die does it, the only difference is how concentrically that operation is achieved and how the structure of the alloy is affected.

I like to seat the gas checks and lush the bullets through a .309" Lee sizer, then powder coat to re-anneal the alloy and restore the dendrite structure. Then, as soon as they cool and are still soft, size them nose-first in a form die which does very little except true the base perfectly square, smooth any bumps on the nose from the coating, and take them back down to .3095" on the driving surfaces while holding the nise true and straight. The precipitation hardening can then take effect over the following couple of weeks and the bullet's internal structure is like you never sized them at all.

 

[L Ross]

It's easier than you might think. You should just give it a try. If I can do it...

You bet I'm going to! Absolutely. This forum is a collection of the best thinking bullet casters and loaders I have ever seen! I almost hate to tell others about it for fear some knuckleheads will ruin it.

 

[Ian]

Don't worry about that. We have had a few knuckleheads join here but for some reason they don't seem to stay very long

 

[freebullet]

The same methods fiver layed out can be used to "fix" underperforming non high speed loads. We get away with more at low speed but all those tips come in handy for slow stuff to.

 

[fiver]

correct.
I try not to lay out any rules, because there really isn't too many.
the only 'RULE' I really follow is to find the centerline of the barrel and put the centerline of the bullet in it the best you can.
if your afraid of failing your not gonna try exactly the opposite of what you been doing, or something that you've never tried before.
not everything is gonna work [chuckle] I got a pretty looooong list of things that didn't work for me.

 

[Ian]

I tend to speak from my primary interest which is usually working near the full potential of both accuracy and velocity of production sporting rifles. It can be a real challenge because there's so much working against you a lot of the time. Sloppy chambers, rough rifling, throats that are less than ideal in shape, finish, or dimension, and so forth. Sometimes a barrel lapping, throat polish, and crown job is in order to get it spiffed up for cast bullets. Once the rifle is in decent form, the measuring and head scratching begins. What moulds do I have, or can be had, to fit this thing and what challenges am I going to have to think through to achieve Job #1?

A discussion of static and dynamic fit from my point of view is to look at what you have and are trying to do, then go to the chapter in The Big Book of Experience that describes methods that worked out in that situation in the past, and apply them. If the throat looks like so, then try to pick a bullet that fits these certain parts and size it to the size it needs to be. Cast it from an alloy that will work the right way for the bullet/throat combination and loading techniques you think you need to use (span a gap, self guide, engrave easily, resist slump, or whatever the priorities are), pick a suitable powder, put it all together and go get some trigger time. Adjust various things to tune the load to be as accurate and effective for its purpose as is reasonable.

The thing is how do you know how to make these decisions?

THAT is what I want to try and shed some light on.

 

[fiver]

well I work from the bullet design backwards.
x-bullet= x alloy.
y-bullet= y alloy.
kind of a rule of thumb.

from there I move to powder and gentle or hard launch.
manipulate the launch with length.
then go back and re-work the alloy for diameter or taking up the punch if necessary.
and then slightly re-work the load [powder speed] or continue up the ladder with what I'm using.

that usually finds me an accuracy node I'm happy with or one I can see that needs a little more sumthin, and try to zero in on that one thing.
neck tension, anneal, primer change, maybe one more/less .001 in diameter.
sometimes I'm just so far down the line I need to break the chronograph out just to see if I'm not exceeding jacketed velocities without realizing it.

 

[Bret4207]

When I stopped trying to over size/over work my cast bullets, things got a lot easier. I don't recall what I was working with for sure, but it seems like I was trying to take something around .312 down to .309 or so because I'd been told in countless articles that you needed to match the groove size BEFORE you loaded the bullet. I think it was Al Miller in Handloader that had an article saying that was pure hogwash and that if it would chamber the barrel would do the sizing, within reason of course. I tried the as cast diameter and my groups tightened right up. After that I pretty much stayed with the idea of using bullets that would chamber "as cast" and any trips through the sizer were for lube/GC application with the die touching the bullet no more than possible. It seems to work for many guns and loads.

OTOH, I have used a sizer to "bump" noses, so I suppose that's definitely under the heading of "over working" my castings! Then Ian starts discussing "dendrites"...way above my knowledge level. Keep it going though, you don't learn by staying ignorant.

Getting things lined up is about as far as I've gotten in Ians list. I'm probably darm lucky to have had what success I have had. I've done some work on finding bullets that fit a particular throat, but I simply don't know enough to do more than guess. Thats the kind of thing that makes this thread so interesting to me. I read and re-read and ponder and hope the brain can process it. Fivers last X=Y process is rocket science for me. Great stuff!

 

[Ian]

The unsized bullet might shoot better just because it's bigger and has less room in the chamber neck to wallow around. I think someone mentioned base-first sizers tending to move more metal on one side of a bullet than the other, distorting the center of form, so there's a another reason that as-cast bullets shoot better.

Dendrites are the crystalline lattice formations of the metal molecules that form in lead or lead alloy when (or as) it freezes. The formations tend to be random and planar, causing a tendency to shear under stress. Tin, sulfur, and arsenic break up these planes into much smaller units which resist long shear fractures. Antimony is like rebar with very strong dendrites. Being a LEO I know you've seen a mountain of broken glass. Think of pure lead like plate glass; it's homogenous and fractures in large, long lines. Think of binary lead/tin alloy like tempered glass that shatters into tiny, uniform bits. Think of ternary lead/antimony/tin alloy like laminated safety glass.

I tend to smaller sizings with powder-coated, self-aligning bullets in my .30-calibers because that's what Mr. Target says is best, but there is a much different dynamic there than with uncoated bullets which do indeed like to be as large as will function (most of the time).

 

[Rick]

I think someone mentioned base-first sizers tending to move more metal on one side of a bullet than the other, distorting the center of form, so there's a another reason that as-cast bullets shoot better.

Without doubt yes. I did a comparison of bullets sized in straight thru sizers and in & out sizers at a friend's machine shop using a comparator, if I remember right it was 50x magnification. Across the board the in & out sized bullets were sized off center (non-concentric), some remarkably so and the straight thru sized bullets were considerably more concentric.

I've little experience with the LEE sizers but logic would say the results should be similar to the Star straight thru sizer.

 

[fiver]

the problem is you have a very sensitive area on the bullet.
right along in there where the nose and the front drive band meet.
this is the most critical part of the bullet and the diameter/shape right there is where I tend to spend my time.
if that means more/less stuff in the alloy or a small amount of time spent with a drill and some lapping compound then that's what needs done.

either way your using that part of the bullet more than any other part to do all of this stuff we are talking about.
miss the body diameter by a thou?
that's a lot better than having that shape and diameter not help the bullet find it's way into the little hole smoothly.
if it's undersize right there,, well there goes the front edge of that drive band.
except,, [man yep I love using that word] when the design doesn't have a 'band' or a scraper like they used to call them in the old days.
now what happens?
well,, the same thing happens of course.
we can't change the what so much as the where and the how, aaand the how much.
what we can do is change how much lead is displaced, how far into the hole the bullet is before any lead is displaced, and we can give that lead someplace to go.
now we have to balance all of that out with enough lead to hang on to the rifling during it's journey.
we can't just have 3/4's of an inch of bore ride nose length and a short 1/4"neck length stopper on the base.
that's kind of what Mann was doing and those type of bullets can shoot accurately [very stupidly accurately] up to a point of forward speed then the whole system is overwhelmed and it doesn't.
which is too bad those type of bullets are soo easy to deal with every where else in the supply chain.
anyway remember that whole slam into the funnel with the front drive band thing, and the part about controlling shape changes to the bullet/
well we just pushed all of that to the back of the bus.

 

[popper]

happy combination first time out, but not at 2500fps. I got the AR10-308 rifle - shot some jax and then from recommendations got the 31-165A and loaded for 2700 from it -LLA or Recluse. Changed to PC but found the alloy was the biggest factor - Slightly above WD nuke med PB with some As and touch of extra Sb. Got there pretty fast. Changed to the C version, added a carbine upper, a tad of Cu in the alloy. Pretty much done deal. Are there better designs? Maybe but the C does what I want.

 

[Bret4207]

Fiver, good post. Got any theories on the lead dispalcement you spoke of and whats good and bad? I always just sorta figured it would squash into the lube grooves and do not harm, but no you got me thinking I was wrong...again.

 

[fiver]

me and Ian both do.
that's something we have discussed [actually quite a bit] over the years.
i'll let him take that one since it will tie into my and his above thoughts.
if he doesn't touch on it I will come back and talk about how lube works in the lube groove/s/ and the influence lead displacement has/can have on it.