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I just loaded a set of charge test loads for my friend's 22-250. We were using 55 grain Hornady V-Maxs. I had four charges between 37 and 40 grains of H380 (37, 38, 39, 40), which was within what two manuals suggested. We used brand new brass (I did not FL resize it, though.)

The 37 and 38 grain loads fired just fine (and produced great groups as well). The 39 grain loads showed pressure signs, though (flattend and pierced primers). We did not try the 40 grain loads because the 39 showed pressure signs.

It shouldn't be possible to get enough H380 in a 22-250 case firing 55 grain bullets because the max load (I believe it is listed as 41 grains) is a compressed load. Any more powder would overflow the case.

Is this something that happens occasionally? What is the cause? A gun with a chamber on the small side of specs causing more pressure?

My friend was worried that something was wrong with his rifle (its a new Savage), but I assured him that this happens sometimes and we'll just use the lower loads, which shot really well anyway.


Red C.
Everything I say is fully substantiated by my own opinion.
 
Posts: 909 | Location: SE Oklahoma | Registered: 18 January 2008Reply With Quote
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I have the exact same problem with one of my Savage 22.250s. 38 grains of H380 with a 50-55 grain bullet is the absolute maximum load for that gun. I haven't tried the load in my other 22.250 because of this problem.


Frank



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Posts: 12826 | Location: Kentucky, USA | Registered: 30 December 2002Reply With Quote
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I just got off the phone with Midway USA ordering a few new parts for a Savage Bolt...

blew a primer testing a load out on a working up route... using BLC2... the Savage blew the primer at 3 grains below Max load...

the Caliber? 22.250

Savages have tight chambers in that caliber evidently...this waa a brand new case also..
Rem 9 1/2 Mag Primer...
 
Posts: 16144 | Location: Southern Oregon USA | Registered: 04 January 2005Reply With Quote
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Sure, it's why yo uhave to work loads up. Barrel specs, chamber specs, short throat, long throat, ita all matters.


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Posts: 7752 | Location: kalif.,usa | Registered: 08 March 2001Reply With Quote
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quote:
Originally posted by fredj338:
Sure, it's why yo uhave to work loads up. Barrel specs, chamber specs, short throat, long throat, ita all matters.


Exactly! Manuals are just references. All manuals say to work up loads and to stop when obvious pressure signs are reached. That doesn't mean that all max loads in all the manuals are safe and under psi in your rifle. There are a lot of things that affect the psi in individual rifles. Your start loads were safe and accurate and the heavier loads proved 'hotter'...exactly why working up loads is important.

You do not mention any fps so I assume a chronograph was not used(?). Had one been used and the velocity of your start loads was in the expected fps range or higher then that would have told you the loads were approaching max also. In other words if the manual said the 41 gr load was giving 3650 fps and your 38 gr load was giving the same 3650 fps then it would be likely a heavier charge than 38 gr in your rifle would be pushing pressures.

One of the benifits, contrary to some opinions, of the information a chronograph can provide, especially when working up loads.

Larry Gibson
 
Posts: 1489 | Location: University Place, WA | Registered: 18 October 2005Reply With Quote
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Sorta puts the lie to those who stoutly proclaim that today's loading manuals are all "lawyered up." There are solid reasons ALL book makers ALWAYS say to start low and only work up to their max UNLESS you experience signs of excess pressure earlier.
 
Posts: 1615 | Location: South Western North Carolina | Registered: 16 September 2005Reply With Quote
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I agree with all the "work up" post but for what it's worth, I looked at my notes and for several 22-250s, my final load was between 37 and 39grs of H380. I didn't have any comments about pressure signs above that. It's just where my sweet spot fell.
Do you have a chrony? It would be interesting to see where your velocity fell compared to the book velocities.


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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I use a similar load in my 22-250. It's VERY sensative to changes in brass. 39gr is fine with Winchester brass, but don't try it with Rem brass. Eeker
 
Posts: 3034 | Location: Colorado | Registered: 01 July 2010Reply With Quote
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quote:
...if the manual said the 41 gr load was giving 3650 fps and your 38 gr load was giving the same 3650 fps then it would be likely a heavier charge than 38 gr in your rifle would be pushing pressures.
Maybe and then again maybe not! That theory is based on "Pressure = Velocity" which has been proven Totally Wrong so many times that it is amazing anyone would still quote it.

quote:
One of the benifits, contrary to some opinions, of the information a chronograph can provide, especially when working up loads.
The only thing a chronograph will tell a person is Velocity. And if you do a search on this Board using the "Find" feature, you will quickly discover chronographs cause more confusion than not. Lots of CRYBABY and whinning about being 50-250fps too slow in comparison to Velocities shown in a Manual from a Lab environment.

Yet, some folks got suckered into spending $3-$5k on a totally worthless HSGS and constantly try to fool people into thinking they did not waste their $$$money$$$. rotflmo animal rotflmo
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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quote:
Sure, it's why yo uhave to work loads up.


+1

1 gr. increments is not working up loads.


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Posts: 3065 | Location: Hondo, Texas USA | Registered: 28 August 2001Reply With Quote
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HC, why is factory ammo loaded to PRESSURE??

And just because you can't understand what those numbers acrost the front of a Chrony mean, doesn't mean we are all befuddled by the additional KNOWLEDGE that a chronograph brings to our hobby. Smiler


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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I think the title of the thread ought to be, don't load a Savage 22.250 to max load manual data... start REAL low..

three of use having a problem with the Same rifle and caliber...having the same problem..
 
Posts: 16144 | Location: Southern Oregon USA | Registered: 04 January 2005Reply With Quote
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Ho hum, Hotcore demonstrates his lack of knowledge once again.

Larry Gibson
 
Posts: 1489 | Location: University Place, WA | Registered: 18 October 2005Reply With Quote
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quote:
Originally posted by wasbeeman:
HC, why is factory ammo loaded to PRESSURE??
Actually "Factory Ammo" is loaded while watching both Pressure and Velocity in a Lab environment where they can "change the Powder Blend", prior to a Production Run, to optomize both.

quote:
And just because you can't understand what those numbers acrost the front of a Chrony mean, doesn't mean we are all befuddled by the additional KNOWLEDGE that a chronograph brings to our hobby. Smiler
yuck rotflmo animal rotflmo
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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quote:
Maybe and then again maybe not! That theory is based on "Pressure = Velocity" which has been proven Totally Wrong so many times that it is amazing anyone would still quote it.

You aren't actually inferring that velocity has NO relation to pressure? What do you think pushes the bullet out of the barrel? Magic?
Obviously the relationship is not lineal, but certainly, you must agree that high or maximum velocities are only obtained with higher pressure loads, DUUH?
And certainly a chronograph is a helpful tool for the veteran handloader in working up loads, as once the desired accuracy and velocity level is achieved, it might be a good place to stop adding powder before primers start blowing and bolts lock up. How do you work yours up, HC/ With a Ouija Board?


Bullets are pretty worthless. All they do is hang around waiting to get loaded.
 
Posts: 515 | Location: kennewick, wa | Registered: 18 May 2004Reply With Quote
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pressure doesn't equal velocity ..

the area under the presure/time curve = work. work that can be applied to a bullet, its mass, Friction co-e, barrel roughness, length, twist, and how consistent the barrel bore, groove, lands, and straightness.

I hope to give you food for thought, gents, and disband this myth

IF pressure = velocity, then a 308 win loaded to 60,000 psi should have exactly the same velocity as a 30-378 loaded to 60,000 psi - they don't

IF pressure = velocity, then barrel length would have minimal difference in vel -- yet we all KNOW any reasonable load is likely to be faster in a longer barrel, within reason

IF pressure = velocity, then reloading books would supply you identical max loads, for identical speeds, for each cartridge/bullt combo .. they dont

IF pressure = velocity, then we'd all load are cases with unique to max pressure, never using any other powders, to max pressure AND acheive the same max vels as all other powders - aint true

IF pressure = velocity, then reloading books would be very boring, as all max vels would be the same per cart/bullet, and ALL .XXX caliber bullets would go the same speed if loaded to the same pressure .. just aint the truth

in short, ya'll, pressure is one variable and not a direct relationship to vel ...

proof? open ANY reloading manual, turn to any cart, and see if all powders used have the identical max vel ...

its right there, guys .. pressure is a SAFETY issue - don't exceed max pressures ... but max pressure does NOT mean max vel.


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
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Posts: 40234 | Location: Conroe, TX | Registered: 01 June 2002Reply With Quote
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My factory Savage barrel on my 22-250 bbl would reach max pressure early too. As it happens, 38.0 grs of H-380 was it's "sweet" load also. I never pierced any primers in load development, but 39.0 grs was noticeably flattening the primers, plus the groups opened up significantly.

As an aside, when I rebarreled that rifle with a McGowen pre fit bbl in 22-250, I could load the same components to 40.0 grs of H-380, which was it's new sweet spot.

Not trying to hijack the thread, but my factory Savage barrel was noticeably rough as hell in the bore, which is why I swapped it out. I know this has been gone over before, but maybe the rougher bore is a factor in the pressure coming on early in some of the Savage factory bbls.

+1 to each rifle being an individual, and load development for each should start low.


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Posts: 1147 | Location: Bismarck, ND | Registered: 31 August 2006Reply With Quote
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like was stated alot of things effect pressure. Some brass has more capasity then otheres. Some primers will give you more pressure then others and some will even show pressure signs (flattend primers) sooner then other brands. Differnt lots of the same powder can vary in speed. Bullet seating dept has a big effect on pressure as does what bullet you pick. Ever wonder why some manuals list powder charges heavier then others for there bullets that weight the same as a competitors. Bullet shape and jacket thickness will drasticaly effect pressure. Then theres the fact that every rifle is a bit differnt some have tighter chambers then others some have a longer throat and some even had slightly tighter bores. Even two rifles out of the same production run can vary quite a bit.
 
Posts: 1404 | Location: munising MI USA | Registered: 29 March 2002Reply With Quote
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Excellent posts by Jeffe, Slim and Lloyd.

quote:
Originally posted by 2ndtimer:
You aren't actually inferring that velocity has NO relation to pressure? What do you think pushes the bullet out of the barrel? Magic?
Obviously the relationship is not lineal, but certainly, you must agree that high or maximum velocities are only obtained with higher pressure loads, DUUH?
Big GrinSome Pressure is indeed needed. tu2 The problem is that not all Pressures(from different Powders) are the same. Nor are the Chambers, Bores, Grooves, Lands, Cases, Primers, and Bullets.

To destroy your argument quickly, if a person uses a Fast Powder, like IMR-3031 or H4895 in a 30-06 with a 165gr Bullet, the Pressure gets WAAAAAAY tooo HIGH before it gets close to the same Velocity available with H4350 or H4831 at a SAFE Pressure. So, as has been said, the larry theory of "Pressure = Velocity" is not only WRONG, but has the potential to be Dead Wrong.

quote:
And certainly a chronograph is a helpful tool for the veteran handloader in working up loads, as once the desired accuracy and velocity level is achieved, it might be a good place to stop adding powder before primers start blowing and bolts lock up.
The problem is that you can not look at the Velocity and know what the Pressure is. Just continuing to dump in Powder until some randomly selected arbitrary Velocity is reached, is not the SAFEST way to Reload.

quote:
How do you work yours up, HC/ With a Ouija Board?
Glad you asked. Big Grin I use the never improved upon, always reliable, inexpensive, easy to learn, time tested, venerable, totally repeatable, never fail methods used by the greatest Reloaders OF ALL TIME - good old CHE & PRE! tu2

Don't need a chronograph at all. Used them for 25 years or so and finally realized they told me nothing useful. Knowing the actual Velocity can, at the least, be misleading to the "Pressure = Velocity" believers and dangerous at worst.

Nor is there any need to totally waste $3-$5k on a Haphazard SGS that only works reliably inside a Lab when it has been properly Calibrated.

However, if you are Big Grin happy Big Grin using a chronograph, that is just what you should do. tu2

Best of luck to you.
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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Factories do not blend their own powder. They buy it by the ton and specify a burn RANGE. Once they get the powder, the guys with the white coats find the exact burn rate and then tells the working folks how much to dump in the cartridges. They do this by extrapolating pressure to velocity.
I'm no scientist but it doesn't take a lot of IQ to figure that if a load book sez xx amount of yy powder (bullet, case, etc) gives you zz velocity, and that's what you get, it's pretty easy to assume (correctly) that your pressure is the same as the book. It also works that if the load book sez a certain powder gives xx velocity and it is not near the max pressure, if you add powder, you'll find that your return isn't worthwhile. You can also find a working max for your rifle by simply shooting a series of cartridges with assending powder until you see the velocity gain start to flatten out. Try that with your see and pee. Smiler
Parse how you would like but simply stated, IF ALL OTHER THINGS ARE EQUAL, more pressure means more velocity. There is no way it cannot.


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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Lots of "apples to oranges" arguments that pressure does not = velocity. In those arguments most are basically correct. however in this case, the case in which all reloaders find themselves, that premiss is not correct. The case is working up a load in one rifle with the same cases, the same powder, the same bullets and the same primers.

In RedC's example at hand the max load was listed at 41 gr of H380 with the 55 gr VMax bullet. That listed max load was still within SAAMI specs. at lets say 3600 fps. Red hit a max load (pressure signs) at 39 gr of powder. Now lets say Red was using a chronograph and the 37 gr load showed 3520 fps, 38 gr load showed 3600 fps and the 39 gr load (pressur signs) showed 3645 fps. It is the increasing pressure that pushes the bullet fast. It is also safe, at least for me and most everyone but a few here, to assume that given the same cartridge, the same powder, the same cases, the same primers and the same bullets in a comparable rifle that the pressure will be reasonably close to the same with the velocity at 3600 fps. This, even though the powder charge was not the same.

Thus is safe to assume if the velocity is equal to or higher than that with a listed load that the pressure is also equal to or higher.

In a given rifle with a given powder using the same cases, primers and bullets more ppwder = more velcocity which also equates to more pressure. By monitoring the velocity with load development we can know when we are getting into high pressures. No, the chronograph does not measure pressures but it does let us know when we are getting here.

Larry Gibson
 
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quote:
Originally posted by wasbeeman:
IF ALL OTHER THINGS ARE EQUAL, more pressure means more velocity. There is no way it cannot.


sorry. . wrong
just plain and simple WRONG ..
150,000 PSI results in ZERO MV .. the bullet doesn't exit the gun

65K psi for .00001 sec does NOT equal the velocity of 65kpsi for .0001 second.. nor is the later 10X more vel ...

please, stop the "can't be" mental approach ... as if you feel it can't be done, you are probably "right" but NOT correct.

and not even more powder in a case ALWAYS means either more pressure OR more vel .. we've ALL seen a point where there's NO difference or a vel LOSS with adding powder ... doesn't mean you aren't doing SOMETHING but it doesn't mean more+better pressure

its SIMPLE .. the concept is WORK ... the area under the pressure|time curve ....

i've explained this to you, serveral times .. you have a reloading manual .. go open ANY cartridge ... and you'll find different vels for different powder .. all are loaded to the SAME pressure level (except reduced loads) on that page ..

if that can't be any more clear, then i can't even begin to talk to you about it ...


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
 
Posts: 40234 | Location: Conroe, TX | Registered: 01 June 2002Reply With Quote
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I'm a little confused about this pressure/velocity issue. I was just sure that if nothing else changed and one powder produced more pressure than another, then the one with the higher pressure would also have the higher velocity. However, I just jumped over to IMR's load data and ran across something confusing. In the 22-250 data the max load of IMR4320 with a 55 grain bullet produced a velocity of 3689 fps at a pressure of 62,200 psi. However, the max load of IMR4064 produced a velocity of 3713 fps at a pressure of only 62,000 psi. The IMR4064 produced more velocity at a lower pressure than the IMR4320! As I began to dig dipper into the load data, I found things like this all over the place.

What is the cause of this? Does one powder produce its pressure quicker than another, or what is going on?


Red C.
Everything I say is fully substantiated by my own opinion.
 
Posts: 909 | Location: SE Oklahoma | Registered: 18 January 2008Reply With Quote
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Red,
if you goto the hodgedon loading data, you'll see it exactly! pressure doesn't equal vel


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
 
Posts: 40234 | Location: Conroe, TX | Registered: 01 June 2002Reply With Quote
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This whole discussion about pressure=velocity is besides the point here, I believe. Red, you have to cronograph something in that rifle, and compare the velocity you get with the load in the manual. Now I know some of you will smirck, some will turn up thier nose, but there is a relationship to the charge of powder loaded, and the condition of the chamber, throat, and barrel. If the velocity is considerably higher, with your rifle, than the manual lists, could just be a tight bore, etc. In that case back off the load. You may even wind up below minimum!!

Here's my experience: I bought a DPMS Barrel for my AR15. A stainless match 1-8 DCM target barrel. Now I figured, I'd screw the nut down, and go shoot. The previous handloads, which were perfect, in the old barrel, were ripping rims off, and leaving me with a cartridge in the chamber in the DPMS, and the velocities were 300=400 fps faster than the book showed. After much todo and screwing around, I finally kept reducing the loads, until the velocities were in line with Sierra, and viola' .5" groups at 100 yds, and excellent performance. Moral of the story, use a cronograph, and don't be afraid to reduce the loads. Anything else, send the gun back to Savage, and bitch.

Regards

Jerry


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Posts: 1297 | Location: Chandler arizona | Registered: 29 August 2003Reply With Quote
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quote:
Originally posted by jeffeosso:
its SIMPLE .. the concept is WORK ... the area under the pressure|time curve ...
Completely agree with Jeffe. tu2

As you noticed Red, Pressure does not equal Velocity. The Duration of the Burn for each Powder(of the exact same amount) is different. That is why some Powders give Higher Velocity in a specific Cartridge than other Powders with the same components.

The old Hodgdon #26 Manual was(still is) the best Manual for explainign this issue that I've seen. Anyone can flip it open, look at the 30-06 and immediately understand that Pressure does not equal Velocity.

The most recent Hodgdon Magazine Style Manual I have is from 2004 and it still lists the Pressures. If any of you do not have one, I can recommend them highly. It only takes a couple of minutes comparing Pressures and Velocities for you to quicly understand what Jeffe and I are try to get across.

Best of luck to you all.
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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quote:
Originally posted by Red C.:
What is the cause of this? Does one powder produce its pressure quicker than another, or what is going on?
It is just as Jeffe described it - "Work under the Pressure Curve" created by the different "Burn Rate Durations" with the various Powders.

Nothing complicated about it, just as Jeffe said. The confusion begins when people incorrectly believe you can look at a Velocity and know what the Pressure is. Just doesn't work that way.
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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quote:
Originally posted by jeffeosso:
Red,
if you goto the hodgedon loading data, you'll see it exactly! pressure doesn't equal vel


Throw some time into the equation & it becomes meaningful though.
 
Posts: 610 | Location: Cumbria, UK | Registered: 09 July 2007Reply With Quote
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quote:
Originally posted by Oddbod:

Throw some time into the equation & it becomes meaningful though.


yes, I've been saying like a jillion times
quote:
Originally posted by jeffeosso:
its SIMPLE .. the concept is WORK ... the area under the pressure|time curve ....


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
 
Posts: 40234 | Location: Conroe, TX | Registered: 01 June 2002Reply With Quote
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You know you guys are throwing a lot at Red here. he needs some help. One or all of you may be right with your technical banter, but I doubt that is helping him fiugure out what the problem is.

Of course I know it is F---in A important, that you are right.

Jerry


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Posts: 1297 | Location: Chandler arizona | Registered: 29 August 2003Reply With Quote
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I really appreciate the help. I've been reloading for quite awhile, but not as long as most of you guys. Most of what has been said on this thread makes since too me and I really appreciate it. I can see that I have to get a chronograph to really see what's going on with my loads. I've been able to develop many good loads and the trajectories, to some extent, confirm that the velocity for a stated charge is, at least, in the ballpark (but its a big ballpark). However, to really know what my loads are doing I need a chronograph.

As to my original post, I'm encouraged to know that others have the same problem with the same rifle and loads. My guess, from what I've read, is that if I had a chronograph, the highest load I'm able to shoot in the rifle without pressure signs woulds probably produce a velocity similar to the velocity listed for max load in my manuals.


Red C.
Everything I say is fully substantiated by my own opinion.
 
Posts: 909 | Location: SE Oklahoma | Registered: 18 January 2008Reply With Quote
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quote:
Originally posted by Red C.:
I can see that I have to get a chronograph to really see what's going on with my loads. ...
Then you have totally missed the point.

Best of luck to you.
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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quote:
As to my original post, I'm encouraged to know that others have the same problem with the same rifle and loads. My guess, from what I've read, is that if I had a chronograph, the highest load I'm able to shoot in the rifle without pressure signs woulds probably produce a velocity similar to the velocity listed for max load in my manuals.



Not necessarily.

Some rifle will digest higher charges and give higher velocity than manuals. In some cases quite a lot more.

Others will never reach the maximum charges in the manuals, and will give a correspondingly lower velocity.


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Red C., if it helps you any, a parallel to what has been stated about pressure and velocity:

Just think of blood pressure. The speed which your blood flows doesn't necessarily mean it relates to your blood pressure. You can have a hypertensive person with a relatively low or high heart rate and cardiac output. Not sure if that helps or not.


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Posts: 7906 | Registered: 05 July 2004Reply With Quote
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The confusing part here is comparison of pressures with different powders. In that comparison higher pressure does not necessarily mean higher velocity.

That is not what we are discussing here. What we are discussing is higher pressures with the same powder. In that case the higher the pressure the higher the velcocity. It is as simple as that.

Larry Gibson
 
Posts: 1489 | Location: University Place, WA | Registered: 18 October 2005Reply With Quote
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Funny how that worked out fjold considering how the powder got its name



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Challenge your limits


 
Posts: 4271 | Location: TN USA | Registered: 17 March 2002Reply With Quote
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quote:
Originally posted by Larry Gibson:
The confusing part here is comparison of pressures with different powders. In that comparison higher pressure does not necessarily mean higher velocity.

That is not what we are discussing here. What we are discussing is higher pressures with the same powder. In that case the higher the pressure the higher the velcocity. It is as simple as that.

Larry Gibson


+1


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Posts: 1297 | Location: Chandler arizona | Registered: 29 August 2003Reply With Quote
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quote:
As to my original post, I'm encouraged to know that others have the same problem with the same rifle and loads. My guess, from what I've read, is that if I had a chronograph, the highest load I'm able to shoot in the rifle without pressure signs woulds probably produce a velocity similar to the velocity listed for max load in my manuals.



I've seen loads differ as much as 500 fps from the book. That's why I call chronographs "de-liars". Variables such as primer, brass and barrel length can have much larger then expected effect, so until you chronograph it, you are just guessing.
 
Posts: 3034 | Location: Colorado | Registered: 01 July 2010Reply With Quote
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I've seen too many chronos set up so they were reading the muzzle blast and not the bullet.

Setting the ogive of the bullet against the lands in the chamber will spike pressure. Remington "lawyered up" this concern by putting a long leade in their chambers -- which significantly affects accuracy.

I've never had a published load in any manual create any sorts of pressure signs, and I've been loading about three decades in a lot of different calibers.

I'm betting it's a chamber thing and the bullet against the lands.
 
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Jeffeosso,
quote:
pressure doesn't equal velocity ..

the area under the presure/time curve = work. work that can be applied to a bullet, its mass, Friction co-e, barrel roughness, length, twist, and how consistent the barrel bore, groove, lands, and straightness.

I hope to give you food for thought, gents, and disband this myth

IF pressure = velocity, then a 308 win loaded to 60,000 psi should have exactly the same velocity as a 30-378 loaded to 60,000 psi - they don't

IF pressure = velocity, then barrel length would have minimal difference in vel -- yet we all KNOW any reasonable load is likely to be faster in a longer barrel, within reason

IF pressure = velocity, then reloading books would supply you identical max loads, for identical speeds, for each cartridge/bullt combo .. they dont

IF pressure = velocity, then we'd all load are cases with unique to max pressure, never using any other powders, to max pressure AND acheive the same max vels as all other powders - aint true

IF pressure = velocity, then reloading books would be very boring, as all max vels would be the same per cart/bullet, and ALL .XXX caliber bullets would go the same speed if loaded to the same pressure .. just aint the truth

in short, ya'll, pressure is one variable and not a direct relationship to vel ...

proof? open ANY reloading manual, turn to any cart, and see if all powders used have the identical max vel ...

its right there, guys .. pressure is a SAFETY issue - don't exceed max pressures ... but max pressure does NOT mean max vel.


I am impressed! This shows at least a good basic comprehension of internal ballistics aka rocket science!

To be anal though work is not the area under the pressure/time curve.

Again to be anal the work done to the bullet is the area under the (pressure*bore cross sectional area) / (bullet distance traveled down bore)curve

Remember work = force times distance.

Force = pressure times bore cross sectional area

Distance = simply the distance the bullet travels down the bore.

Velocity will be directly related to the power of the load.

Power = time rate change of work or = work / time.

Velocity will have a direct relationship to power.

Perhaps it would be easier for many here to understand this concept if one were to post pressure vs distance curves from say Quickload. One curve with a "slow" powder and another with a "fast" powder both for the same cartridge/bullet combo and exhibiting the same peak or maximum pressure.

Again I am impressed with the level of Newtonian physics comprehension! Carry on!!
 
Posts: 1662 | Location: USA | Registered: 27 November 2003Reply With Quote
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