How much weight deviation is acceptable for accuracy?

[Wheelguns 1961]

I recently purchased some hi-tek 115gn rnfp’s at .313 for my single seven from acme bullets. These bullets are not very good. I tried to work up a load with them and could not get any accuracy. I am a very detail oriented reloader, and I am aware of all the details that make up an accurate cartridge.

After having problems with all of the cartridges, I came home and started to weigh bullets. The weights ranged from 112.2-116.9. So I decided to weigh all the bullets and separate them according to weight. My question is, how much weight difference is acceptable and still maintain good accuracy?

The problem is all of the bases are concave. I suspect this is the reason for the large weight difference. I realize that this will also negatively affect accuracy. So, what do you guys think? If I wasn’t waiting on a similar mold, I would just melt them all. To me they are not worth the trouble to send them back, however they will be recieving an email expressing my dissatisfaction.

What I am trying to do at this point, is make the best out of a bad situation. I separated them in 1/2 grain increments. Is this too much? Should I bundle them in 1 grain increments. I hope this all makes sense. What do you guys think?

[Smoke4320]

for me personally 1/2 grain difference is the limit ..

[Wheelguns 1961]

Thank you. That is also what I was thinking, especially since I am trying to work up a load.

[Rcmaveric]

I have had some pretty wide weight swings still shoot normal and even sub moa. I would think the base is your issue. You mentioned concave. A hollow base design might not work with how youre shooting it. I would check the size of those bullets also.

Sent from my SM-G925T using Tapatalk

[Echo]

I believe a grain or 2 won't make much difference in 100-yd group size, for most of us, in 165 grain or larger boolits. If we are shooting at 500-yd targets, different story, and samo if we are chasing sub-minute groups.

[Wheelguns 1961]

The bases aren’t supposed to be concave. They were under poured. Some look like they were never sized, and are fat. They are without a doubt the worst cast bullets I have ever bought. The only thing that looked good was the hi-tek coating, and the pretty wooden box they came in. Did I mention the name ACME BULLET company. No wonder the coyote couldn’t get the roadrunner. He was using ACME bullets. Just plain junk!!!!

[GhostHawk]

I'm with Rcmaveric, I've had rounds with 4-5 grain difference from low to high and still had good accuracy.

That being said I think it is easier to do with bigger bore than it is small.

I weighed a batch of 150 boolits for my Mosin once. Between gas checks, lube I would say 50% were within a grain. The other half was roughly evenly split between low and high.

So I matched up 20 accuracy loads that all were within 0.2 grains and could see no difference between those and the ones that varied.

What did make a big difference was lube, applying gas checks with a rubber mallet before sizing. So they were seated flat and solid. And cleaning the bore till all the old copper fouling was out. Then only shooting cast.

That batch I tumble lubed with Bens Red, yeah I heated the boolits and the lube with a heat gun in a stainless bowl and tumbled until it was pretty much all in the grooves. Then gas checked and sized .314, then 2 coats of BLL over the Ben's red.

Was shooting the Lee .312 185 gr beagled up to .314-.315.

Those shot as good as my eyes could hold on iron sights.

[redhawk0]

I try to keep mine at 1% of average weight...example...i shoot 405gr .458"s....I keep 401-405gr. I also shoot 340gr .458" I keep 337-340gr. I have never noticed a difference in accuracy keeping within the 1% range. (I don't typically see bullets over the mold published weight with my alloy) If I did...then I'd make the range around whatever the mean weight is.

redhawk

[CJR]

A couple of comments about bullets and accuracy. If the bullet design is inaccurate (CBs or jacketed) and you have zero weight spread or use trick coatings or use slick lubricants, you will still have inaccuracy. Many years ago, the NRA identified accurate and inaccurate CB designs. After that many inaccurate mould designs were dropped. Based on US Air Force documented research on bullet design, we now know that the greater the spacing between the forward Center of Pressure (CP) and rearward Center of Gravity (CG) of the bullet design, the more accurate that bullet will be. Fortunately, NOE identifies CP & CG on their mould designs to help us make an educated selection of accurate CB designs.

Best regards,

CJR

[Seabee1960]

222865
Several of the other posts are on the right track vis a vis boolit weight.There are many variables and so many lessons that have to be learned form experimentation or even better from learned friends that post here. After much experimentation with a dozen .30 caliber molds, aluminum and steel, nose pour and base pour gas check and plain base I consider the deviation in weight of a batch of bullets cast at the same time to be a secondary cause of poor accuracy. I now use an $15 electronic scale I bought to check the weight of Cub Scout pine wood derby cars set to grams and sort bullets by the 1/10 gram (1.5 grains). A square flat base and a properly seated gas check are much more important to good accuracy then a +/- 1 grain deviation in bullet weight.

I have a tale of woe to tell about the Uberti 1885 High wall in 30-40 Krag I bought 4years ago and the tortuous journey to MOA groups. After dozens of combinations of boolit types, powders, gas check designs etc. I was ready to pull the Unertl off the barrel and hang it on the wall to just look at. I took the rifle to the local shooting range to burn up some lead boolit loads when an old timer seeing my frustration came over and offered to help; this was obviously not the first High Wall he had ever fixed. He asked to borrow a small screwdriver, proceeded to unscrew the forearm screw a couple of turns and then tore the end flap off a box of .22 rim fire ammo I had in my shooting box. He folded the small piece of cardboard and placed it in between the barrel and the fore end and then retightened the screw. The next groups were 1 and 1/2 inches .
Now I was back in the game so I went home, cast up boolits for a load recommended here that I had never seen published anywhere else. (18 1/2 grains of Reloader 7 and a Lyman 311284 sized to .310 using a Lyman gas check) Perfection.
One tool I would recommend to all is the NOE burring tool that you use to rub the flash off the base of a cast boolit. It will not chamfer the base but is designed to remove any anomalies left from the sprue cutting process. This process insures that the gas check will seat squarely on the base. This will help more than fretting about alloy composition and weight deviation I believe. http://noebulletmolds.com/NV/product_info.php?cPath=21&products_id=28

I hope this helps

[John Boy]

Half grain increment for reloads for distances 600 to 1000yds otherwise 4 MOA variance. Under 600yds one grain is acceptable. 50 to 100yds - whatever they weigh

[JonB_in_Glencoe]

I recently purchased some hi-tek 115gn rnfp’s at .313 for my single seven from acme bullets. These bullets are not very good. I tried to work up a load with them and could not get any accuracy. I am a very detail oriented reloader, and I am aware of all the details that make up an accurate cartridge.

After having problems with all of the cartridges, I came home and started to weigh bullets. The weights ranged from 112.2-116.9. So I decided to weigh all the bullets and separate them according to weight. My question is, how much weight difference is acceptable and still maintain good accuracy?

The problem is all of the bases are concave. I suspect this is the reason for the large weight difference. I realize that this will also negatively affect accuracy. So, what do you guys think? If I wasn’t waiting on a similar mold, I would just melt them all. To me they are not worth the trouble to send them back, however they will be recieving an email expressing my dissatisfaction.

What I am trying to do at this point, is make the best out of a bad situation. I separated them in 1/2 grain increments. Is this too much? Should I bundle them in 1 grain increments. I hope this all makes sense. What do you guys think?


The bases aren’t supposed to be concave. They were under poured. Some look like they were never sized, and are fat. They are without a doubt the worst cast bullets I have ever bought. The only thing that looked good was the hi-tek coating, and the pretty wooden box they came in. Did I mention the name ACME BULLET company. No wonder the coyote couldn’t get the roadrunner. He was using ACME bullets. Just plain junk!!!!

Since you are confident in your loading capabilities and I assume the boolit is the proper fit and design for your gun, then I would surely be contacting ACME. There should NOT be a 4%+ weight deviation in commercial cast bullets.

[Seabee1960]

John Boy... This cast boolit shooting at 1000 yards intrigues me... What gun, what cartridge, what load ?

[wv109323]

I recently cast some 200 SWC H&G 68 boolits for the .45 ACP. I picked out the obvious rejects then I picked out the 10 worst boolits I could find. Most were rounded bases or wrinkled noses. I loaded them and then loaded 10 commercial cast 200 SWC. I tested them in an accurate gun in a Ransom Rest. The groups were identical at 3" X 1 1/2" at 50 yards.
I also have a 360156 boolit mold for the .38 special. I can not get any accuracy with that mold. Accuracy is like 3 feet at 50 yards with a RR. I have shot it through different guns and unacceptable accuracy results. Several different loads and velocities. The tested boolits were very nicely cast and very close in weight.
So your problem is most likely boolit design and not quality of the cast. Of course the boolits must fit the bore and not distorted when seated or crimped. The 9mm is one of the tougher calibers to reload for. This has been due to various bore diameters,bullet diameter as cast and leade in the barrel. My CZ chamber would not accept a bullet size that was necessary to fit the bore.I had to go with a .358 boolit and have the leade in the barrel extended.

[kayala]

I shoot commercially cast bullets; just out of curiosity I've got handful of ACME (.313 100 gr) extreme spread was 1.5gr (1.5%), got 300 gr from other manufacturer ES was 3.1gr (almost same - 1%). Full disclosure - I've used pocket size electronic scales not some lab equipment.

[country gent]

Several things come into this when I do sort. the big ones are bullet use , plinking close 25-50 yds, matches at same ranges with handguns, rifle bullits at 100-200 and then bullets for out to 500-600yds. Bullet weight a 1% varience on a 50 grn 22 cal is .5 grn on a 100grn its 1 grn and on a 550 grn its 5.5grns so for me bullet weight plays a part in the process.

I normally drop my big bullets from the mould within .7 grns consistently. On smaller bullets this my increase to 1grn. Also the method I cast ladle bottom pour has an affect here. I normally shoot for roughly .5 grns on my 550 grn bullets for 500-600 yds and pretty much get it from the mould and ladle. on smaller bullets you may want to maintain the .5 grn or even a little less for precision work.

One reason for the variance in purchased cast bullets is the machines used run 3-4 sets of mould blocks and even the same desighn they may vary by a few grains from mould to mould due to how they were cut. Then consider than 2-3 mchines may be running the same bullet and 3-4 different sets of mould blocks in each one. Add in slight variations in alloies when refilling these pots and 3-4 grns is unheard of.

[Grmps]

I've always heard 1% but the final test is what your gun says.

[robg]

1% seems to work for me but good bases at the most important thing for consistent accuracy .

[JonB_in_Glencoe]

SNIP...

One reason for the variance in purchased cast bullets is the machines used run 3-4 sets of mould blocks and even the same desighn they may vary by a few grains from mould to mould due to how they were cut. Then consider than 2-3 mchines may be running the same bullet and 3-4 different sets of mould blocks in each one. Add in slight variations in alloies when refilling these pots and 3-4 grns is unheard of.

The OP bought ACME's 115gn rnfp’s at .313

My 2¢ is, I can't imagine ACME running that uncommon of a bullet on a machine with more than one mold? let alone several machines ...and then to have the inconsistently poorly filled bases...I just don't think they were machine run.

[Jackpine]

I agree with everyone who has posted, that what you have done in a certain situation worked well. HOWEVER, I don't think there is ANYTHING, other than maybe a bullet that is way undersized or any loading technique where there is an obvious difference from load to load, that will always make a difference. Guns, at least the ones that I have worked with, do not read the same forums and technical manuals that I read.

I have loads and rifles where varying bullet weight has an adverse affect on accuracy and have shot others rifles where I compared loadings with the light and heavy culls, where the extreme spread was 4.0 grains and compared against bullets that were sorted + or _ .2 grains, and the culls shot just as well. I agree that bullet design and more importantly, I think, bullet nose design, compared to throat, are good indicators or what should work, again, the theory does not always give the best results.

I remember the first time I used 45-45-10 lube. I was assured by a self anointed expert on another cast bullet site, that 45-45-10 would shoot as good or better, than LLA, in any load or rifle and that it was easier to use. Well, I don't disagree that it is easier, or at least I think it is, but I proved to myself (never did respond there, because it would not have done any good) that in the first comparison that I did, accuracy was measurably better with the LLA. Not saying that 45-45-10 or any other lube is bad, or that in a test tomorrow with another loading or rifle, that it would not do better, just saying that it or any other lube will not always be the best.

That being said, unless I have thoroughly tested a bullet and load, and have proven to myself that sorting does makes no difference, I sort bullets that I am using for serious long range work, to a range of approx + or - .3 grains per total bullet weight of 100 grains, so + or - .5 grains with a 180 grain bullet and + or - 1.5 with 500 grain, altho, in practice, I sort the 500 grain + or - 1.0 on most of my 500 grain bullets, because they get shot at the most extreme ranges. Also, I sort with any new loading, because with a quick recovery electronic scale, hundreds of bullets can be sorted in minutes, and it is faster to eliminate that variable than testing for initial load workup. I am a firm believer, that if you think doing or not doing something, will cause problems or cause you to not shoot as well, you are probably right.

I know my ideas are very good, because my opinions and $5 have purchased many cups of coffee in many cheap restaurants!

Praise the Lord and pass the ammo!

Jackpine

[JSnover]

I still don't see where the OP said what he was actually doing with these boolits. On the weight question, +/- .3 grains may not even be noticeable if the target is close enough.
The real problem is he started with crappy boolits and probably won't get any good data from them, just a bunch of shotgun groups and a trip back to the loading bench.
If I was handing out advice, I'd say to get some recommendations from other members about good quality commercial cast or ask to borrow some well-made boolits from somebody (Sorry, I don't have any cast in that size), then he can get down to some serious load development and accuracy testing.

[Tripplebeards]

I might have to start sorting in .5 gr and give it a try. I have been sorting In 1 grain increments on on my 44 mag, 450 BM, and 35 rems. I shot sub MOA the other day at a 100 yards with my 77/44 doing this and four other loads shot 1.25"- to 1.5". Maybe I can tighten things up a little.

[pls1911]

In my experience casting (35 years +), for anything less than bullseye shooting at rifle ranges, +/- >.5 grain is plenty close for well formed bullets.
Most of the time +/- 1 grain will be unnoticed.