Does the 1:7 twist require harder alloy?

[lawboy]

Hi, all. So I has an experience this weekend that I want to share and see if others have seen similar.
I had some free time so I cast a mess of LEE 312-155-2R bullets. I loaded 200 rounds using my tried and true load.
I took them to the range along with some leftover rounds from an older batch of bullets cast a few weeks ago.
The old ones shot as expected which is to say, just fine.
The ammo wit the new bullets shot like an cylinder bore shotgun. Seriously awful.
I was perplexed. I loaded both batches of ammo exactly the same ... or so I thought.
Then I remembered that I had fixed harder alloy for the first batch of bullets than I did for the second.
I think the softer alloy could not take the kick in the pants. BUT, no leading.
I have use the softer alloy for bullets to shoot from other rifles chambered for cartridges other than 300 BLK and with slower twist rates. I n
never had a problem.
Anybody experience this or have any thoughts?

[r.tenorio671]

...you might want to weight the bullets from each batch and see if there is a difference. I've seen the weight difference occur when I used to cast handgun bullets and changed the antimony percentage in the mix.

EDITED: ...also, the softer alloy may be compressing / deforming more once it enters the forcing cone/lands.

[lawboy]

...you might want to weight the bullets from each batch and see if there is a difference. I've seen the weight difference occur when I used to cast handgun bullets and changed the antimony percentage in the mix.

EDITED: ...also, the softer alloy may be compressing / deforming more once it enters the forcing cone/lands.

The softer bullets that won't shoot are just a little over one grain heavier than the harder ones that do shoot.
I have cast a new batch of harder bullets and loaded a few with the same load. Will test when I can get back to the range this weekend.
Also loaded some rounds with the Lyman 31141 bullet for a ladder test with both 4227 and 1680.

[reloader64]

Did you get to the range yet?

Also, do you water drop your bullets?

[Dolomite_Supafly]

There are so many variables with cast bullets that they can be very difficult to find consistently accurate loads. It is possible but it generally takes more time to find an accurate cast bullet load compared to a jacketed bullet load. But when you do find an accurate load using a cast bullet it is so satisfying knowing you are now self sufficient and not subject to the markets bullet availability. In 2008 it was nearly impossible to find anything related to guns, including reloading supplies. When my friends were unable to shoot I didn't miss a beat because I had the ability to make my own.

When I start out casting a new bullet I use the alloy I use most, clip on wheel weights. And how I make sure they are consistent, lot to lot, is I cut each weight with pruning shears. This serves two purposes, first I do it to ensure I am not putting zinc into a pot full of lead. Second, even within clip on weights there are differences between hard and soft alloys so when I am cutting the weights to ensure they are lead I separate the weights according to how hard or soft they are to cut. Then I cast about 100 bullets using the hard clip on alloy and test them. If they are good to go I will cast 1,000+ using the same alloy so I have plenty of bullets that were cast at the same time, with the same alloy, so they should be the same. But as time goes on those bullets will become harder which can change how the bullets shoot. The only way to mitigate that is either shoot all those in the batch rather quickly or you have to watch for changes on the target and adjust accordingly. Loads that shoot great on one day may not shoot as well on another day because of changes in the weather.

I have talked to people who are so worried about lead aging and hardening that they sort the bullets according to when they were cast. That is as they are cast they are sorted so they can be loaded oldest to newest. And when they are shot that are shot oldest to newest. And I don't mean lots but individual bullets. They cast them in order then load them in the same order and then they shoot them in the same order. That is overkill to me but some competitors swear it helps with shot to shot consistency and being consistent is what wins.

[Rooter pig]

My cmmg barreled 300 bo pistol would not shoot air cooled ww's any good. 4 inches at 25 yards. Shoots the same load but with water dropped ww's.75 at 25 yards.

[Dolomite_Supafly]

Just because YOUR gun shoots water dropped better does not mean others will have the same problem. I shoot pure lead and with load development it will match your results.

Every gun is different.

[yondering]

Just because YOUR gun shoots water dropped better does not mean others will have the same problem. I shoot pure lead and with load development it will match your results.

Every gun is different.

Remember, you're shooting pure lead for subsonics, not for supers. You really do need harder alloy for higher pressure supers, if you expect any accuracy. When someone posts about the Lee 155gr bullet, I generally assume they are shooting supers, unless otherwise specified.

[Dolomite_Supafly]

I was trying to say that all guns are different.

[yondering]

Very true, and even more so because everybody's loads and cast bullets are different too. Some guys swear by pure lead for best accuracy, other guys (like me) find better accuracy with harder bullets. To each their own, that's why we experiment.