405 gr - plus or minus how much?

[Yellow Fang]

I purchased 200 bullets (405 gr HiTek coated for 45-70) from a well known commercial entity.

Weighing them shows what seems to be high variability, from 395 to 406 grains. More than half weigh between 401 and 405, with about a third weighing between 399 and 401.

Is this weight variation typical? With IMR4198, they print 3-4 inches @ 100 yards.

I've separated the rest by weight, and will try some more loads when I can get to the range.

Thanks for any feedback.

[Wardo1974]

That seems like a lot to me...there's a local guy near my hometown of Kingston who casts many boolits, and the recent batch I got from him of about 500 ranged between 413-415 grains (it's a 405 mold, but these are 99% lead, so they drop heavier.)

Your spread seems really high to me and seems to suggest it would affect accuracy.

[Duckdog]

They should shoot just fine. I do not buy them but there is a bit of variance in the weights on my cast bullets, and I get cloverleafs at 50 yds and not much bigger at 100.

Remember that 5 grains at 405 grains is just about a .8% variance, which is a much lower percentage if you were talking a 200 gr bullet, which would be closer to 4%.

I get pretty good consistence if I am weighing bullets from the same melt and given alloy, and I would guess they achieve the same thing, so you probably have bullets mixed form different melts and slightly different alloys.

If you have any Unique or 5744, give those a try and see if the groups tighten up a bit. 30 gr of 5744 is a good load with 45/70 and 405 gr bullets. With that bullet, I am assuming that's what you are working with???

Good luck!

[KYCaster]

Plus or minus 2% is pretty much the accepted standard.....depending on what you paid. If the price was comparable to other sources, then you probably can't find a better deal.

If your tests show a preference for a particular weight then use the better ones for serious work and the culls for practice.

The alternative is to pay a higher price for a guaranteed target weight. You can probably sort them yourself much cheaper than paying someone else to do it for you.

Been there, done that......from both sides of the deal!

Jerry

[Outpost75]

Agree with KyCaster that +/- 1% or 2% total variation is normal and expected. With larger diameter, longer bullets it is more difficult to cast bullets without internal voids due to shrinkage porosity. Professional casters using the Magma and similar machines usually slow down the production rate as bullets get larger and heavier to help mitigate this condition. Machine cast bullets from a properly set up Magma machine will be more uniform in weight than all but the most expert, experienced hand casters.

The key to uniform bullets is to cast a large sprue, overflowing the mold, and keeping the gate through which metal is poured liquid as long as possible to continue to feed metal into the cavity to compensate for shrinkage as it cools.

The common commercial casting alloys such as 92-6-2 PB-SB-Sn have a well defined solidification point which lends itself to machine production, but depending upon machine casting rate, block size and pot temperature it is likely in larger bullets that the sprue will harden before shrinkage voids can be mitigated by a longer pour time. Machine casters want to produce clean sprue cuts with sharp clean bases for their customers. But if you mount, section and etch commercial cast bullets for metallography you will find tiny shrinkage voids which are apparent under a microscope. In a properly designed casting machine these voids will be small, uniform and aligned closely to the longitudinal axis of the bullet, located forward of the bullet's center of gravity, where they do least harm in terms of accuracy.

[Yellow Fang]

Great responses, thank you, gurus!

[fredj338]

The larger the bullet the greater chance for variation. 401-405gr is about the right spread, under 1%. The bullets well under could have internal voids near the base that will mess with accuracy.

[hickfu]

When I first started casting with my 430gr mold. I was getting variances of 12 grains and was going to throw anything over or under back in the pot to try again. It was suggested that I load and shoot them as is to see how they would do. I loaded 1 of each weight (12 boolits) with the same powder charge and took them to the range.

At 100 yards I could not see the difference as I was knocking out a circle about the size of a silver dollar. My 45-70 wont be used for shots on game animals over 150 yards so I dont even bother weighing them any more.

[Toymaker]

When casting my 405 grain bullets I allow 1% variance but set them up in 0.5 grain groups for shooting. This is mostly to eliminate bullets with large voids in them. At 500 yards I haven't noticed a real difference. Most of my shooting is at 200 yards. Someone suggested 30 grains of 5744. I think that's a bit stiff and something around 23 grains is going to be more appropriate. 5744 behaves like 4759 which has been discontinued. Fortunately I laid in a good supply before it got hard to find. But I'd like to know what rifle, action, barrel length, twist rate, etc.
Don't disregard heavier bullets either. These are 5-shot groups at 100 yards. The group size holds pretty consistent at 200 yards too.
161122 161123

[Duckdog]

I hate to differ, but 23 gr of 5744 is well below the starting load of 26 Gr in the Lymans 49th for 1873 type rifles. The max is 29 gr. 26 gr is listed, without chronographing of course, at 1189 FPS. 29 gr is at 1313. I think 23 gr would be pretty slow, but I have dropped nearly that low.


I shoot a lot of 5744, with a lot going through my NEF, and 30 gr with a 405 gr bullet chronographs at 1425 FPS and is actually pretty mild. To each his own, but why limit this caliber to that of a lesser caliber.
The starting load of 5744 for 1886 Win and 1895 Marlins in the same manual is 32 GR with a max of 36 GR.


I know guys who hotrod this caliber and I think they mainly just end up with a sore shoulder. I have yet to find anything I have shot with mine with my load that has not dropped like a sack of potatoes!

[Kraschenbirn]

I purchased 200 bullets (405 gr HiTek coated for 45-70) from a well known commercial entity.

Weighing them shows what seems to be high variability, from 395 to 406 grains. More than half weigh between 401 and 405, with about a third weighing between 399 and 401.

An 11 grain range of weight variance, to me, seems a bit much. You've stated that these are 'commercial' so they were most likely 'machine-cast' which might account for some variance but the number still seems awfully high. A few years ago, a friend gave me about three hundred moly-graphite coated 45-70 RNFPs which had been cast on a Magma 'Master Caster' using Magma molds. At one time, his company had provided the cast boolits for a major ammo manufacturer's 'cowboy' cartridge line and these were leftovers from an R&D project. I weighed random samples (approx. 10%) of these before loading and MAX. variance was +/- two grains (1/2%). Day before yesterday, I cast a short run of 400 gr .40 cals. from a David Mas SC mold and max. variance (random samples, again) was less than 3/4 gr.

Bill