cast bullet wieght variance

[Olsherm]

Question for you experienced caster/shooters?
How much effect will a bullet a couple of grains over stated mold weight have on pressure ect?

Question:My cast bullets 45LC 454190 Lyman mold
came out of the mold weighing from about 254gr to 258gr.Will they make much of a difference on impact at target/low or high per weigh?I assume they would?I also assume I would need to lower powder a little to allow for extra weight on the heavier ones?I am weighing them and sorting them from 254gr to 256gr and 256gr to 258gr respectivily.I guess my alloy mix was not correct?? I have shot a few already with light loads of Trailboss ect and they seem ok so far. Thanks

 

[Iron Mike Golf]

The 258 gr bullets are 1.6% heavier. That's not a huge variance.

Things that can cause variance (weight and dimensions) when casting:

Alloy composition (Lyman nominal weights are based on using Lyman #2 alloy)
Mold temperature
Mold not completely closed

 

[anachronism]

You're okay. Go ahead and use them. Like Mike said, there are a lot of variables.

If you were shooting competition, or at long range, you might be dismayed at the accuracy, but for for daily shooting you're fine. No need to adjust your loads or anything.

 

[Jimbo357mag]

The 45 colt is a low pressure round. Unless you are loading near the top of the 'Ruger Only' loads or using an inferior gun there should be no problems.

 

[Olsherm]

Thanks for the input. olsherm

 

[GP100man]

Mine usually drop a little heavy also , but as mentioned it`s because my alloy has more lead than Lyman #2 alloy .

If I have good fill out (of the correct dia.) & a good base / +- 2% I shoot em !

I rarely load to MAX ,so I have enuff wiggle room with boolit weight .

 

[Rick Courtright]

Hi,

Since SAAMI max pressures represent an "average" based on untold numbers of rounds, I'd think there's enough safety margin to account for a couple of grains +/- w/ cast bullets. As a general rule, I've found cast loads in the books are usually quite a bit below the max for a given caliber, adding to that margin.

Most of my bullets are cast w/ wheelweights, and it's interesting that certain molds cast "light" while others cast "heavy" (all from the same mfr) even when cast from the same pot so the alloy, temp and all are as equal as can be expected.

I weigh my bullets, out of the mold, and segregate them into weight groups. Depending on the bullet, the weight range for the group usually runs from 2-4 gr w/ bullets I'm trying to make accurate, and that's enough to make them better than I am! "Blasting bullets" may be in a 5 gr range...

Rick C

 

[Iron Mike Golf]

Oh, and the cavities in the mold might be a little different, too.