Acceptable cast bullet weight variation.

[braddock]

I'm casting Lee's LF 309.170, don't know what the lead is, largely range scrap. Boolits are turning out 163.2 grains to 164.1 grains with no real trends. By the time they are aloxed and gas checked the weight has grown to 168.1 to 170 grains.
The alox is bound to cause variations but the base casting weight, is that kind of variation OK?
They are for 30/30 btw in front of 18 grains of 2400 and an S&B LR primer in federal and winchester brass. Velocity is circa 1800 fps, accuracy is 3 shots in a 4" group at 100 yards, resting on a fence post with a williams peep rear sight and a 79 year old marksman(?).

[country gent]

The old rule of thumb was 1% variation but this variance is that a 50 grn cast boollit is allowed .5 grns +/_ while your 170 grn is allowed 1.7 grns +/_ and a 500 grn is allowed 5 gns +/_. I would test and see what your rifle load is affected by. One load 10 rounds at the extreme ends and 10 round that are exactly the same weight, This will tell you what affect it has on your rifle load and give an idea what is allowable
I normally cast bullets in the 360-550 grn range with my technique I throw the first 15-20 back in the pot and then keep them.Normally on a run of 400-500 they will be within .5 grns of each other. Work on your technique you may be able to tighten up the variance by pouring faster or slower, a bigger sprue or a little overflow.Sometimes a mall adjustment in temp can make a big difference

[braddock]

Thanks for that, I'm still learning as I go and wanted to perfect my technique with this mold before I move on to my 6 cavity one and the 357 one.

[country gent]

Keep in mind each mould has its own quirks and may take slightly different things as to technique and temp.

[braddock]

Lot like women, eh? I only have lee's dies, the 357 one is long in the tooth, has no steel alignment pins, just grooves and spigots machined into the casting.

[Divil]

I am happy if my 9mm, .38 and .357 boolits are within 2 grains. If casting .45, I would go to 3 grains variance. I think all of my present molds and alloys have no trouble achieving this standard.

[Digital Dan]

.3 grains for rifles. Cast, weigh and segregate.

[BLAHUT]

I'm casting Lee's LF 309.170, don't know what the lead is, largely range scrap. Boolits are turning out 163.2 grains to 164.1 grains with no real trends. By the time they are aloxed and gas checked the weight has grown to 168.1 to 170 grains.
The alox is bound to cause variations but the base casting weight, is that kind of variation OK?
They are for 30/30 btw in front of 18 grains of 2400 and an S&B LR primer in federal and winchester brass. Velocity is circa 1800 fps, accuracy is 3 shots in a 4" group at 100 yards, resting on a fence post with a williams peep rear sight and a 79 year old marksman(?).

When done casting for the day, say 50 lbs of bullets, I weigh each, and segregate each into its own pile by weight, everyone in the pile weighs the exact same. I am very anal, I shoot long range, every cartage in the box of 50 or 100 or, weighs the same.. This eliminates one possible cause of one leaking out of the 10 ring at distance ????? Velocity at about 1200 FPS. with a Double peep out to 1000yds... Starting and staying subsonic; eliminates one more possibility of leaking out of the 10 ring at distance... As far as what you are shooting; this will put dead dear in the freezer....

[Walter Laich]

as "sorta" mentioned above it depends on what you want from your loads

Shooting cowboy action with the 2x2 ft square targets a whopping 7 yards away is a mite different from precision shooting at 100 yards

. . . and yes, we can still miss those targets at times

[metricmonkeywrench]

For load development with pistol calibers I prefer to stay within 1g (x.1 to .9) which is achievable if you have enough in the pile. Otherwise for general plinking within 2g or so for pistol. Haven't really gone that deep with rifle

[charlie b]

For pistol I never weigh the bullets. Cast, inspect for a filled out base, load and shoot.

Rifle I am like BLAHUT. Weigh and inspect. Sort into 0.1gn batches. Toss back any with visible flaws of any type.

[mehavey]

1%
and unless you're in the heavy bench rest
game you'll never know the difference.
https://castboolits.gunloads.com/sho...=1#post5014895

[quilbilly]

I'm casting Lee's LF 309.170, don't know what the lead is, largely range scrap. Boolits are turning out 163.2 grains to 164.1 grains with no real trends. By the time they are aloxed and gas checked the weight has grown to 168.1 to 170 grains.
The alox is bound to cause variations but the base casting weight, is that kind of variation OK?
They are for 30/30 btw in front of 18 grains of 2400 and an S&B LR primer in federal and winchester brass. Velocity is circa 1800 fps, accuracy is 3 shots in a 4" group at 100 yards, resting on a fence post with a williams peep rear sight and a 79 year old marksman(?).

I suspect yours is not a mold or lead problem if you are getting 4" clusters. Using the same mold, that is nearly the same load (19 gr), same primer, and same boolit I use in my 308 for sub MOA groups at 100 yds but my 30/30 doesn't like it at all. My 30/30 prefers a lower MV (around 1600) with a powders like Unique, 5744, or RE-7 which give me 1-1/2" groups or sometimes less using a Skinner sight plus handheld with a rest. Of course my 73 year old eyes have to be fresh in the morning when I can actually see the center of the target. I would try a load of 19 gr of either RE-7 or 5744, and possibly even a Unique that would get you to around 15-1600 fps mv. Just so you know, besides rifles, I have a T/C Contender 10" barrel in 30/30 and it likes even faster powders.

[Winger Ed.]

Unless I'm going to compete for the Bianchi Cup:
I keep batches separate since different alloys can have pretty big variances.
After weighing several batches from my Iron molds and not finding any variances big enough to really worry about-
if they look good, I shoot 'em.

[huntinlever]

No real logic behind it but the fact it's a 45-70, and I'm only using it to hunt to 150+/-, so I accept 390.0-391.9 out of my Accurate 46-406VG. I used to sort in 1 gram lots, but no longer see the point - worked up a load for this weight, it works, the rest get returned to the pot.

[Harter66]

Ok a couple of things.
1 1% is a standard. I don't know who came up with it but it makes sense I guess . It's a goal and goals are good .

2 I have had rifles that would throw 18" off over there for 2 gr of case weight . One would open from a .750 , 5 shot group to 1.5 for .3 gr of 4350 in an 06' case . I've had 2-3 that were just straight up garbage disposals . The 308 that would shoot 2.5" with 7.62 NATO ball that ran 145-151 gr in 80's Argentine surplus .

3 I have "better" 2c moulds that almost drop 2 different bullets and a couple of Lee 6 cav moulds that if I don't stay right in the groove will drop 2@-2 , 3@nominal , and 1@ +2-3 gr on 158-175 gr bullets . Then I have an 8cav H&G that drops inside 6/10 gr for all 8 at 196 gr 45 cal SWC and an NOE 461-535 @3 cav that has no identifiable difference in the 3 holes .

Last . Consistency is everything. Stable temperature throughout the pour lot . Stable cycle times including how long the mould is open and how long it takes to fill it.

[country gent]

I ladle pour my bullets I dont pour for sprue but pour the whole ladle into the cavities letting the excess flow over and back into the pot. My sprue plates are vented so the lead flow is controlled.
I cast with 2 moulds fill the first as above set aside and fill the second. Pick up the first cut sprue drop and refill. I run 20-1 around 700-725* in a 20 lb pot.
I put the first 15-20 casts back in the pot.
When done sort for visual defects ( not many) and weights are within .5 grn
This keeps bases hotter longer allowing for better fill and off gassing.You want to keep the mould cooling from the bottom up so gasses are released and the molten puddle can fill any voids as it cools. One other thing that is a help is I have several sets of cabin tree locking handles that close the blocks under the same pressure every time

[Shopdog]

Don't want to get too deep into it;

Been milling bases off N on for a cpl years. Shortening the overall length to drop a whole drive band sort of thing. Recently got it about perfected....

As it pertains to the weights; it has been a real eye opener. In a nutshell,most of the weight variance is caused by the sprue cutting. The "cheaper" the sprue plate,the worse the bases are about affecting the weights. And it's plain as day,meaning... you don't need reams of data and statistics.

Now whether you and/or the rig can shoot the difference?... that's on y'all. Get your bases "clean" and watch your weights get more consistent.

[stubshaft]

My criteria for culls is .5% based on total weight. I used to use a cupcake pan to separate all of the different weights, from lightest to heaviest.

This was for competition loads in my Sillywett guns. For plinking +/- 5 grains was good enough.

[Bigslug]

I went down the uber-precision rabbit hole years ago when competing in Highpower rifle. Eventually, I learned that there's a place for that kind of anal-retentiveness, and once you leave competition circles, you can set many of the practices that add significantly to production time aside.

The best way to start is to ask yourself the following question: "What is this tool FOR?" It sounds like you're running a .357 lever action with iron sights. This is not a long range competition gun. It is not a police sniper rifle. If the bench is only for load development, and you're primarily shooting standing or from field expedient positions, there's a practical limit to the accuracy YOU will be able to wring out of even the world's best rifle shooting the world's best ammo. That goes quadruple for handgun blasting ammo. It's basically a case of perfection becoming the enemy of good enough.

You can really do most of your culls based on visual cues - wrinkles, rounded edges on the base, unfilled bands, bad sprue cuts leaving and "outy", obvious voids or inclusions, etc... Weigh some of the duds and some of the pretty ones and you'll start to get a feel, but a sub-1% spread while you're learning the game ain't bad at all.