Seen this posted over on the Glock board.

They have a 200gr also.

https://www.bengalbullets.com/shop/p/10-401-200-grain-wfngc-bb2m6

Interesting, any ideas in the BHN for this bullet? I did contact them regarding hardness, but nothing back yet

Received this from Bengal Bullets regarding the BHN of their 240gr bullets

Hello Ken,

Thank you for reaching out. I utilize an alloy of 92.5% lead, 2.5% antimony, and 5% tin. I heat treat my bullets by quenching them at 400 degrees. This produces a BHN of approximately 20 (it does take some time for the bullets to come up to hardness, of course). I can also forgo the heat treating process for a BHN of approximately 12.

Thanks,
James 

I wonder how fast you can push that 240.

Considering Underwood is getting aprx 1,200 fps with their 220gr hard cast, I would guess somewhere in the 1,175 range. My concern would be the bullet length, the additional 20gr has to go somewhere

Quote from: Kenk on June 29 2023 05:45:44 AM MDT
Considering Underwood is getting aprx 1,200 fps with their 220gr hard cast, I would guess somewhere in the 1,175 range. My concern would be the bullet length, the additional 20gr has to go somewhere

1175 is very optimistic IMHO.  Heavy bullets tend to give you a free lunch in velocity to a point.  180 grain bullets to 200 grain bullets, you loose 100 fps.  200 to 220 costs you only another 50.  But at some point the encroachment into the free powder space turns a corner and velocity drops way off.  For 10mm 220 is about where the party ends.

With a 220 grain bullet your free powder column space is at most .420", and maybe less if you had to load short to get function due to tipping angle concerns.  Another 20 grains of lead in the case will reduce your powder stack by .055", which is 13% of the available space.  That puts you in the 1000-1100 fps range before you account for the extra mass of the bullet.

I can't find any data at all for a bullet this heavy and would love to see some.  In the absence of data I would probably stop load development at 1050fps and then see about getting the lab tested for pressure.

sqlbullet I agree as the bullet gets a little longer the powder space is less.  The newer cannelure less cast bullets tend to help keep them shorter for the weight.
As you mentioned the nose profile can cause feeding issues and the slightly deeper seating may help with the tipping angle in some firearms as designed.

It would be great for someone with access to actual pressure testing equipment could test various loadings we have documented and found in some loadings.
We sure could use a member/friend in this area to help us all realize just where the true potential lies from a safety standpoint!
If Michael Willard of SwampFox ammo was still alive, he would likely have shared some of his pressure testing.

However, knowing that each 10mm firearm can have differences in chamber quality (tight/lose), feed ramp vs. case support and recoil system setups can all play a role in what we can safely be able to get performance wise.

I for one have pushed the limits as part of the testing and documentations form my own 10mm firearms so I could further understand my limits.