Bullet setback

[One1]

I’m starting this discussion to have added input on one that I’m having tonight in person. Here is the issue in front of us.....

 

• 38 special
• 158gr hard cast
• large flake powder on low velocity load around 700fps. Very dirty and smokey.
• setback is 0.10 on the cartridge in question

 

So person 1 - it’s a low velocity load and soft cast lead. it’ll slide out like butter with no major pressure spike. Unlike a jacketed round the lead rib on the bullet is more for seating suggestion than as structural as a jacketed round would be Due to it being so soft.

 

And person 2 - because it slightly wrapped around the rib of the projectile at the case mouth it won’t come out as easily and will spike pressure somewhat. Undecided on if it will matter because the case can handle a lot more than what it was loaded.

 

Made up internet person 3 - OmG NoOOoo iT’lL eXplOdE.

 

What do you think? For full disclosure at least 50 of these have been shot already and i do not own them, but do have some set back less than this so I’m interested in hearing opinions.

clickable thumbs:

[RED333]

7 hours ago, One1 said:

low velocity load around 700fps. Very dirty and smokey.

This is what I caught, needs something done to fix "very dirty and smokey".

[Dirtshooter]

7 hours ago, RED333 said:

This is what I caught, needs something done to fix "very dirty and smokey".

I concur, sounds like either the wrong powder or not enough powder. If the bullets are hard cast, put a heavier crimp on it, there shouldn't be any setback.

[Darrell]

Well, the problem with the internet..... that crimp already looks excessive to me.  I've always figured the lightest crimp that keeps the bullet from moving during recoil is the right crimp. 

There's no picture of the unloaded bullet, but it looks to me like the bullet that's seated deepest has the crimp around the body of the bullet. That DOES mean that more pressure is going to build in the chamber before the bullet begins to move. Just as an experiment, seat one or two bullets at each depth in unloaded cases, then use an inertial puller to knock those bullets out. I'm guessing that the deeper-set bullet is going to take considerably more effort to pull than the shallower set bullet.

The deeper you seat the bullet, the higher the pressure will be due to reduced case volume. But so long as you're not compressing the powder AND your cases aren't showing signs of overpressure then you're okay. But crimping that much is going to wear your cases out much more quickly than light crimps. Remember that brass hardens as it's worked. Every time you fire the gun the brass expands to fill and seal the chamber. The more it moves, the sooner the case mouth splits. 

Some powders are dirtier than others. If the smoke and residue are a problem then Red and Dirt are right that you may want to try another powder. Or maybe even a different brand primer.