Lee Chapter 10 Question - re gas checks?

[Daryl]

Hi,

Based on C.E. Harris' couple of articles on cast bullets for military loads, I've used gas checks for the 7.62x39 and 7.62x54R. I'm curious about when gas checks are actually required.

When reading Chapter 10 in the Lee 2nd edition, he talks about matching bullet strength (i.e. harndess) to pressure, but never mentions gas checks there.

So, I'm wondering if gas checks substitute for the required hardness, or even if you had the hardness as indicated by Lee, you should use gas checks?

For example, his chart on pg 134 would show 34.8BHN for about 45,000PSI. Yet, Harris suggests just WW is ok with gas checks which is what I do - so that is maybe 12-14 with GC and it seems just fine. But, is Lee saying that 35BHN and no gas check? or his his chart suggesting you should still be at much higher BHN with the GC?

And, most people use PB bullets with handgun cartridges such as the 9MM, which I do also. That is a 28K to 32K load with just WW.

Comments? Thoughts? Just don't worry about it?

thanks

[swheeler]

Daryl; all I can say is I don't believe the "numbers" expressed by Lee's formula. Way too many variables are not factored in. Many conditions affect the amount of pressure an alloy can take before leading occurs, like bullet fit, bore condition, powder speed, lube,temperature and on and on. I can tell you that caliber/bore diameter/bullet dia has a lot to do with how much pressure an alloy can take. If you are loading the slowest usable powder for each caliber,a 22 and a 35, bullets are both cast of ACWW and gas checked, the 22 caliber bullet will take 25% more pressure than the 35 before failing- WITH ALL OTHER THINGS BEING EQUAL. So we are talking a 22 GC bullet at say 40Kpsi and a 35GC bullet @ 30Kpsi with a BHN of 12. So for me the formula doesn't work GCed or not.