So if I understand your first post, you would like to see the same weight projectile and same powder and getting the same measured pressure to see if one bullet is faster than the others. Not going with signs of pressure but measured amounts of pressure
Why Hammer Bullets Are Always Faster
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Hard rock
Well-Known Member
In the meanwhile he's missing out on Hammer bullets always being faster.
Not really. Just pressure tested data. It will sort itself out what works best with hammers. Just like any other bullet. It may be same or different.
Lou
I will make one more point. Velocity is the only thing we can measure that has a direct correlation with pressure. Velocity is proportional to the area under the pressure / time curve. If you are getting similar velocities as published load data the area under the pressure time curve is the same. It does not mean the shape of the curve is the same though is much more likely if using same compinents (mainly exact same powder). If you are getting higher velocity or lower velocity you have more or less area under the curve.
Primers, primer pockets, che, bolt lift, ejector swipe, etc.. at best are an indirect indicator of pressure. Metal hardness, tolerances and probably other things make these unreliable. Something will probably show up if way above pressure limits in any gun or you may get a surprise and pop a primer
.
Most bullets have pressure tested data. Using similar components (particularly powder due to burn rate) velocity along with conventional pressure signs you at best can assume the area under the curve is similar and similar curve shape
If you do not have pressure tested data you have no idea what the velocity potential is for a bullet with a given powder. You can:
A) Rely soley on traditional signs
B) Rely on velocity of similar bullets (or cases of equiv volume for wildcatters) and conventional pressure signs. This, for ex, is what Hodgdon recommends
Some folks infer that hammers have special design features that there is no "B". That is fine but it still does not make "A" reliable. So, I would recommend folks do "B" until we have real data to compare against.
Lou
Primers, primer pockets, che, bolt lift, ejector swipe, etc.. at best are an indirect indicator of pressure. Metal hardness, tolerances and probably other things make these unreliable. Something will probably show up if way above pressure limits in any gun or you may get a surprise and pop a primer
.Most bullets have pressure tested data. Using similar components (particularly powder due to burn rate) velocity along with conventional pressure signs you at best can assume the area under the curve is similar and similar curve shape
If you do not have pressure tested data you have no idea what the velocity potential is for a bullet with a given powder. You can:
A) Rely soley on traditional signs
B) Rely on velocity of similar bullets (or cases of equiv volume for wildcatters) and conventional pressure signs. This, for ex, is what Hodgdon recommends
Some folks infer that hammers have special design features that there is no "B". That is fine but it still does not make "A" reliable. So, I would recommend folks do "B" until we have real data to compare against.
Lou
I wonder what's the cost of a strain Gauge.
Calvin45
Well-Known Member
Maybe we should all just stop repeating ourselves. I'll go first!I will make one more point. Velocity is the only thing we can measure that has a direct correlation with pressure. Velocity is proportional to the area under the pressure / time curve. If you are getting similar velocities as published load data the area under the pressure time curve is the same. It does not mean the shape of the curve is the same though is much more likely if using same compinents (mainly exact same powder). If you are getting higher velocity or lower velocity you have more or less area under the curve.
Primers, primer pockets, che, bolt lift, ejector swipe, etc.. at best are an indirect indicator of pressure. Metal hardness, tolerances and probably other things make these unreliable. Something will probably show up if way above pressure limits in any gun or you may get a surprise and pop a primer
Most bullets have pressure tested data. Using similar components (particularly powder due to burn rate) velocity along with conventional pressure signs you at best can assume the area under the curve is similar and similar curve shape
If you do not have pressure tested data you have no idea what the velocity potential is for a bullet with a given powder. You can:
A) Rely soley on traditional signs
B) Rely on velocity of similar bullets (or cases of equiv volume for wildcatters) and conventional pressure signs. This, for ex, is what Hodgdon recommends
Some folks infer that hammers have special design features that there is no "B". That is fine but it still does not make "A" reliable. So, I would recommend folks do "B" until we have real data to compare against.
Lou
choprzrul
Well-Known Member
This is from Hodgdon's load data page online for a 25-06 shooting 90gr bullets using H4350
10,000 psi more pressure with 26 LESS fps?
It is being posited that using published load data for same bullet weight and powder charge weight is ok.....but the starting weight for the Sierra is only 1/2 grain away from the listed max charge weight for the GMX. What's going to happen if someone uses the Sierra midpoint data (51.0gr) on some 90gr GMX they have laying around?
I mean, after all, there is published data showing 53.0gr of H4350 is ok in a 25-06 with a 90gr bullet? 51.0 should be fine.....
Not to mention....how in the world is 50,700 psi pushing a 90gr pill to almost exactly the same velocity as 60,600 psi???
Which one of those sets of published data is correct for a 90gr Absolute Hammer? Same weight of bullet, call it the same velocity, but wildly different psi.
At what point do we suppose the Sierra HPBT will show signs of pressure? +1%, +2%, ?? Would we run out of case capacity before ever reaching dangerous levels (65,267 max?) of psi?
Hat tip to Hodgdon....I used their published load data in this post.
.
10,000 psi more pressure with 26 LESS fps?
It is being posited that using published load data for same bullet weight and powder charge weight is ok.....but the starting weight for the Sierra is only 1/2 grain away from the listed max charge weight for the GMX. What's going to happen if someone uses the Sierra midpoint data (51.0gr) on some 90gr GMX they have laying around?
I mean, after all, there is published data showing 53.0gr of H4350 is ok in a 25-06 with a 90gr bullet? 51.0 should be fine.....
Not to mention....how in the world is 50,700 psi pushing a 90gr pill to almost exactly the same velocity as 60,600 psi???
Which one of those sets of published data is correct for a 90gr Absolute Hammer? Same weight of bullet, call it the same velocity, but wildly different psi.
At what point do we suppose the Sierra HPBT will show signs of pressure? +1%, +2%, ?? Would we run out of case capacity before ever reaching dangerous levels (65,267 max?) of psi?
Hat tip to Hodgdon....I used their published load data in this post.
.
One is CUP - copper units of pressure. One is PSI - pounds per square inch. Both ways of measuring pressure recognizes by saami and not same thing. Cartridges have different CUP and PSI limits. For ex 270 is 52k CUP and. 65k PSI. You can web search difference though most newer data is PSI these days
Lou
However though both max pressures with the respective measurement types you can see max velocities similar…
I would start with gmx data and see what it looks like. As noted both are max loads though use a different pressure measurement system
Lou
I would start with gmx data and see what it looks like. As noted both are max loads though use a different pressure measurement system
Lou
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SMHI will make one more point. Velocity is the only thing we can measure that has a direct correlation with pressure. Velocity is proportional to the area under the pressure / time curve. If you are getting similar velocities as published load data the area under the pressure time curve is the same. It does not mean the shape of the curve is the same though is much more likely if using same compinents (mainly exact same powder). If you are getting higher velocity or lower velocity you have more or less area under the curve.
Primers, primer pockets, che, bolt lift, ejector swipe, etc.. at best are an indirect indicator of pressure. Metal hardness, tolerances and probably other things make these unreliable. Something will probably show up if way above pressure limits in any gun or you may get a surprise and pop a primer
Most bullets have pressure tested data. Using similar components (particularly powder due to burn rate) velocity along with conventional pressure signs you at best can assume the area under the curve is similar and similar curve shape
If you do not have pressure tested data you have no idea what the velocity potential is for a bullet with a given powder. You can:
A) Rely soley on traditional signs
B) Rely on velocity of similar bullets (or cases of equiv volume for wildcatters) and conventional pressure signs. This, for ex, is what Hodgdon recommends
Some folks infer that hammers have special design features that there is no "B". That is fine but it still does not make "A" reliable. So, I would recommend folks do "B" until we have real data to compare against.
Lou
I mean no disrespect at all towards anyone but this is beating that same dead horse everyone else has been beating for the last year, just with a different stick. It's like a speed limit sign, thousands upon thousands of dollars spent, decades of research and information gathering to post the safest speed for any stretch of given road for your safety but I'll bet you drive 5 mph over but that's what makes the world go round
Rich Coyle
Well-Known Member
With the above posted, if you are a Christian I expect you to obey the New Testament commands, instructions, injoicings, and requests.
Reverend
What in the world are the last couple of posts? I didnt quite get them, but I think they are cuts at me. If so, sorry if I made you feel bad with a rational discussion. Maybe the moderator will give you a "safe" forum. If not, sorry I took wrong way. Either case you can PM me to not take away from the post on loading hammers if want to trade insults or discuss something else
Lou
Lou
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So I posted a thread about 280AI speeds and the hammer guys were saying they got 3400 with a 140 and H100v. Ok. Now I can maybe get that due to bullet design and engraving forces you can get higher velocity. But 100v is 200 fps slower than every other 140 with R26. So with R26 you can get 3600? No way. So by some mystery of physics hammers are faster with 100v than other powders in 140 class bullets which are known to be faster. That doesnt pass the smell test.
