Bullet Setback Overpressure Calculation

Yes and no. I work in the medical field as a programmer analyst. We’re VERY WELL funded. To the tune of billions - as an industry. Me personally not so much. 🤣

When dealing with diseases like MD and cancer - where the patient is the variable - the number of corrective measures for data set is staggering.

My dad was a physicist with the space program. He’s told me many times they were just guessing about so many assumptions made and they got lucky more often than not.

I can only imagine!
 
Even when I don’t understand, I enjoy hearing or reading someone discussing their work (or hobby) with enthusiasm. Your’s passed every test.

I similarly enjoy reading reloading discussions here about things I’ll never begin to understand.

Yeah, it’s sort of amusing when someone attempts to call out a person on a certain post, and that person spits out a response like @rhino465 did……………..crickets….!!!! :rofl:

Interesting work, Rhino….. nice job…
 
Yeah, it’s sort of amusing when someone attempts to call out a person on a certain post, and that person spits out a response like @rhino465 did……………..crickets….!!!! :rofl:

Interesting work, Rhino….. nice job…
I got it - and even understand most of the details - but explosives? that’s not my field. I wrote my dissertation on the recovery of vanadium salts from oil-fired power plant slag. Those old fuel oil boilers are a treasure trove of recyclable toxins.

Back then the idea of recovering those toxins for industrial use was cost prohibitive. But I still graduated so, it’s cool.
😎
 
I got it - and even understand most of the details - but explosives? that’s not my field. I wrote my dissertation on the recovery of vanadium salts from oil-fired power plant slag. Those old fuel oil boilers are a treasure trove of recyclable toxins.

Back then the idea of recovering those toxins for industrial use was cost prohibitive. But I still graduated so, it’s cool.
😎
Most of what alot of you peeps do is wayyyy over my pay grade….
I admire you folks for that kind of determination…
I just think it’s amusing when you back up your posts with authorization to those who try and call you out….. :thumbup:
There are a few here who do this as an antagonistic way, like it when they get shut down…
 
You knew I had to do it.

> To guarantee the secrecy of grand jury hearings, Federal Rule of Criminal Procedure 6(e)
> prohibits most persons present during the proceedings from disclosing what transpired
> inside the grand jury room; however, the proscription does not apply to witnesses.

. . . . now that's interesting.
Thank King George and colonial era secret trials for our lack of total secrecy (Or openness to put it another way).

Prosecutors do try and intimidate everyone in the room from blabbing. Mostly it works.
 
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Nail on the head! But I better stop now:)
Well, bringing this back to the OP, lots of things happen that shouldn’t and it sure does help to be prepared for when they do - things like a grandstanding prosecutor with Congressional aspirations or a loose necked cartridge that catches on the feed ramp. Either one can ruin your day; both are to be avoided as much as possible.
 
I guess I could have started a separate thread, but this question is closely related to the original post.

I have a new 9mm pistol and am starting to work up a load for it. The bullets I am using are Berry's 124-grain heavy plated HBFPs and I would like to use Universal powder. I can find data for those bullets but not with that powder, and vice versa. The shortest COL listed for these bullets is 1.060", but in order to plunk in my barrel they need to be seated to 1.020". The lowest starting charge for a 124-grain bullet I can find is 3.5 grains. That is the starting charge Lyman #50 indicates for a Hornady HP/XTP, also seated to 1.060".

My question is this: is it safe to start my load development at 3.5 grains seating the bullets to 1.020", or is that 0.040" difference enough to increase the pressure to a dangerous level? GRT does not have the Berry's bullet in its library, but substituting the 124-grain Hornady shows a pressure difference of 5100 psi between the two seating depths. Max pressure at 1.020" is shown as 27k, 7k below SAAMI max, but that's not for the bullet I'm using.

I think I'm probably on safe ground, but it's always good to ask and see if there's something I'm missing.
 
I guess I could have started a separate thread, but this question is closely related to the original post.

I have a new 9mm pistol and am starting to work up a load for it. The bullets I am using are Berry's 124-grain heavy plated HBFPs and I would like to use Universal powder. I can find data for those bullets but not with that powder, and vice versa. The shortest COL listed for these bullets is 1.060", but in order to plunk in my barrel they need to be seated to 1.020". The lowest starting charge for a 124-grain bullet I can find is 3.5 grains. That is the starting charge Lyman #50 indicates for a Hornady HP/XTP, also seated to 1.060".

My question is this: is it safe to start my load development at 3.5 grains seating the bullets to 1.020", or is that 0.040" difference enough to increase the pressure to a dangerous level? GRT does not have the Berry's bullet in its library, but substituting the 124-grain Hornady shows a pressure difference of 5100 psi between the two seating depths. Max pressure at 1.020" is shown as 27k, 7k below SAAMI max, but that's not for the bullet I'm using.

I think I'm probably on safe ground, but it's always good to ask and see if there's something I'm missing.
Yes, you are on safe ground. Here’s why:
Berry's 124-grain heavy plated HBFPs
Hollow Base. You’re adding gap - airspace - into the equation. The bullet you’re comparing to has a solid base. If you are concerned, lower the charge another 5% and single load (no magazine or an empty magazine if your pistol has a magazine safety). It’s harder to have a catastrophic event resulting from a stuck bullet if you single load and visually check the barrel after each round.
 
Yes, you are on safe ground. Here’s why:

Hollow Base. You’re adding gap - airspace - into the equation. The bullet you’re comparing to has a solid base. If you are concerned, lower the charge another 5% and single load (no magazine or an empty magazine if your pistol has a magazine safety). It’s harder to have a catastrophic event resulting from a stuck bullet if you single load and visually check the barrel after each round.
Makes perfect sense. But then I went into overthink overdrive, and thought if they're the same weight, the mass displaced by the hollow base had to go somewhere, probably resulting in added length. But no. I checked their respective lengths (which I should have thought to do before) and the XTP is 0.571" and the Berry's is 0.550". How can that be? Maybe the Hornady copper jacket, being thicker than the Berry's plating buy less dense than lead, takes up more space? More likely it's a difference in the nose taper of the bullet. Either way, the shorter bullet, combined with a hollow base gives me confidence that I'm not going to create over‐pressure hazards by seating deeper.

I do like the suggestion of single loading, and will do my testing that way.
 
Makes perfect sense. But then I went into overthink overdrive, and thought if they're the same weight, the mass displaced by the hollow base had to go somewhere, probably resulting in added length. But no. I checked their respective lengths (which I should have thought to do before) and the XTP is 0.571" and the Berry's is 0.550". How can that be? Maybe the Hornady copper jacket, being thicker than the Berry's plating buy less dense than lead, takes up more space? More likely it's a difference in the nose taper of the bullet. Either way, the shorter bullet, combined with a hollow base gives me confidence that I'm not going to create over‐pressure hazards by seating deeper.

The nose shapes are different, which is why the XTP is longer. Don't get too distracted by the hollow base. The hollow base does not create more space in the case. If you compare two bullets with the same weight and nose shape and construction, the hollow base bullet is longer, but when seated to the same OAL, the space they occupy in the case is the same.
 
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