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Joined: Feb 2010
Posts: 17,927
Campfire Ranger
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Campfire Ranger
Joined: Feb 2010
Posts: 17,927 |
I believe there's already a thread about how difficult it is to manage an extra 12oz or rifle.
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Joined: Jul 2001
Posts: 60,052
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,052 |
smokepole,
General Hatcher mentioned the unreliability of primer appearance as a pressure indicator in HATCHER'S NOTEBOOK, first published in 1947. He knew a thing or two about pressures in rifle ammo, since he was one of the U.S. military's top ordnance officers for many years, the reason he was Technical Editor of AMERICAN RIFLEMAN after his retirement.
Unfortunately, he didn't go into any detail about why primer appearance is so unreliable, apparently thinking the reasons were obvious--such as varying thickness in primer cups, added to variations in headspace. I've got a collection of old issues of AMERICAN RIFLEMAN and am slowly going through them, among other things looking for details to his statement about primer appearance. Will post them if I find any, though among many Campfire members the opinions of dead guys don't matter, because their post-count is so low.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Jul 2012
Posts: 50
Campfire Greenhorn
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Campfire Greenhorn
Joined: Jul 2012
Posts: 50 |
Pushing a 120 TTSX another 200 FPS gets you 7" less drop, 2" less drift, and an additional 154 FPE at the 500 yard line.
Not even worth the [bleep] effort...
16 Sure.....advantage is small. Point being it isn't worth chasing it in the little case just to show you can reach velocities with it that you won't see anywhere else credible.(pressure tested). You aren't breaking any new ground or proving a thing....just stuffing more powder in and it doesn't take any brains to do that. If we want it,then we can have it.....just buy a bigger cartridge.  Of course this may require compromises like a longer or fatter case,a slightly heavier rifle, etc. Part of the game. Wasn't chasing anything. Started below published load data. Not sitting here saying hey look at me. Not trying to take any credit. I did not design the powder or the rifle. Just posted what I saw and considered interesting. Quit reading so much into it, it makes you look like you have a complex about it!  just kidding, I know most of you guys are concerned about the safety aspect. On a side note, here's a hypothetical. You try this new powder. 7-08, 120 ttsx. You are not seeing any pressure sign. Velocity is very high and you are not near max. Exactly what velocity do you stop at?
60 percent of the time, it works every time
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Joined: Jun 2006
Posts: 45,993
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2006
Posts: 45,993 |
.... among many Campfire members the opinions of dead guys don't matter, because their post-count is so low. Yep, and they also never post pics.
A wise man is frequently humbled.
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Joined: Jun 2006
Posts: 45,993
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2006
Posts: 45,993 |
You try this new powder. 7-08, 120 ttsx. You are not seeing any pressure sign. Velocity is very high and you are not near max. Exactly what velocity do you stop at? Personally, if I had data for the bullet I was shooting (not a different 120-grainer) I'd stop at the max "book" velocity, regardless of the powder charge, taking into account any difference in barrel length. Based on the theory that my rifle is at max pressure when I see max velocity.
A wise man is frequently humbled.
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Joined: Jul 2012
Posts: 50
Campfire Greenhorn
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Campfire Greenhorn
Joined: Jul 2012
Posts: 50 |
Slim,
As noted in my first post on powder, nothing is free. The tests in Hodgdon's data are shot inside temperature-controlled rooms at 70 degrees. Yes, Hybrid 100V is the "fastest" powder with 90-grain bullets (by exactly one fps over H4831), but H100V is also one of the less temperature-resistant powders I've ever tested. In a trial a few years ago with several powders and 165-grain bullets in the .30-06. H100V lost 176 fps between 70 degrees and zero Fahrenheit.
Since H4831 is one of Hodgdon's Extreme powders that are very cold-resistant, it doesn't normally lose any velocity between 70 and zero, which means that the "advantage" of oh-so-modern H100V would disappear with a drop of about half a degree in temperature. I've found this sort of temp-sensitivity to be common among newer powders designed to produce top velocities at 70 degrees.
The REAL advances in powders haven't been extra velocity as much as other characteristics, such as consistent velocities over a wide range of temperature. Did you notice the h100v load had less pressure as well. Varget was a leap and not very temp sensative. LVR in the 30-30 was a big leap. I agree a lot of these new powders are not perfect, but I fail to see how they are not getting faster. That was my only point.
60 percent of the time, it works every time
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Joined: Jan 2007
Posts: 35,900
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2007
Posts: 35,900 |
On a side note, here's a hypothetical. You try this new powder. 7-08, 120 ttsx. You are not seeing any pressure sign. Velocity is very high and you are not near max. Exactly what velocity do you stop at?
Basically what Smokepole said. I'd look at as many sources as i could for that bullet,and even others of the same weight noting barrel lengths, etc. I'd likely back off to to roughly the top velocity,give or take. Watch accuracy.I'd be looking for a weighted average in terms of velocities and consider anything I didn't see in a manual as an aberration or goof up on my part from going too high....kind of an "OOPS!". I'd take 5-10 cases, fire them several times,and watch velocities and check for primer pockets opening. If the load passed all these touch/feely tests I'd say I'd be good to go.Not the most scientific of methods but maybe the best we can do as basement hand loaders. I'd also compare powder capacities of cartridges a step up, in size....say a 280 and 280 AI in the case and see what they are doing.If I am equalling or exceeding the velocities of those cases I'd be looking for the reason.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Feb 2010
Posts: 17,927
Campfire Ranger
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Campfire Ranger
Joined: Feb 2010
Posts: 17,927 |
My concern is always mono's vs jacketed of the same weight. But it aint my rifle.
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Joined: May 2004
Posts: 779
Campfire Regular
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Campfire Regular
Joined: May 2004
Posts: 779 |
It'seems scary that you think magic powder makes a 7/08 into a 7mm RM.
Look at the velocities in the book for your load, and the quick load figures above.
Once again, either your chrony is jacked or you're about to blow yourself up.
Please realize chamber, brass, and throat can cause your rifle to reach pressure way before book max.
S
Reload for velocity not weight and capacity.
Slim, Take the above to heart. This is the point everyone is making.
Only a fool would sell an accurate .30-06
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Joined: Dec 2004
Posts: 20,379
Campfire Ranger
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Campfire Ranger
Joined: Dec 2004
Posts: 20,379 |
You try this new powder. 7-08, 120 ttsx. You are not seeing any pressure sign. Velocity is very high and you are not near max. Exactly what velocity do you stop at? Personally, if I had data for the bullet I was shooting (not a different 120-grainer) I'd stop at the max "book" velocity, regardless of the powder charge, taking into account any difference in barrel length. Based on the theory that my rifle is at max pressure when I see max velocity. Bam.
I replace valve cover gaskets every 50K, if they don't need them sooner...
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Joined: Nov 2011
Posts: 30,895
Campfire 'Bwana
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Campfire 'Bwana
Joined: Nov 2011
Posts: 30,895 |
My concern is always mono's vs jacketed of the same weight. But it aint my rifle. Yep. Or any other variable that will change the bearing surface.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
You cannot over estimate the unimportance of nearly everything. John Maxwell
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Joined: Mar 2010
Posts: 1,980
Campfire Regular
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Campfire Regular
Joined: Mar 2010
Posts: 1,980 |
Pushing a 120 TTSX another 200 FPS gets you 7" less drop, 2" less drift, and an additional 154 FPE at the 500 yard line.
Not even worth the [bleep] effort...
16 Sure.....advantage is small. Point being it isn't worth chasing it in the little case just to show you can reach velocities with it that you won't see anywhere else credible.(pressure tested). You aren't breaking any new ground or proving a thing....just stuffing more powder in and it doesn't take any brains to do that. If we want it,then we can have it.....just buy a bigger cartridge. Of course this may require compromises like a longer or fatter case,a slightly heavier rifle, etc. Part of the game. On a side note, here's a hypothetical. You try this new powder. 7-08, 120 ttsx. You are not seeing any pressure sign. Velocity is very high and you are not near max. Exactly what velocity do you stop at? I will generally load to book maximum velocity if I can get there with no obvious signs of pressure. If that is the case I will proceed carefully until I do notice pressure then back off accordingly The main thing I am looking for is incremental increases in velocity, as soon as this diminishes I believe an over pressure situation is occurring, often noticed just before bolt lift comes into play.
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Joined: Jan 2007
Posts: 35,900
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2007
Posts: 35,900 |
The main thing I am looking for is incremental increases in velocity, as soon as this diminishes I believe an over pressure situation is occurring, often noticed just before bolt lift comes into play.
Good strategy...... but with the double based propellants I've worked with the velocity doesn't flatten out (diminish at top end); with double based powders like RL22,you add more powder and you continue to get more velocity even in the red line zone. Meantime you are already over the top and don't know it but velocities are atypical but we think they are OK. You hang out on the ragged edge of pressure and performance.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Feb 2010
Posts: 17,927
Campfire Ranger
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Campfire Ranger
Joined: Feb 2010
Posts: 17,927 |
I go the way of my BR bretheren and let the groups decide, not the chrono. Load data is a hoot.
How much powder?
"2 more clicks than last time"
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Joined: Jan 2006
Posts: 2,977
Campfire Regular
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Campfire Regular
Joined: Jan 2006
Posts: 2,977 |
What are the specifics on your 2000mr load? Sorry, didn't see this earlier. 49.0 gr using 120 gr TTSX in a 24" barrel gave cloverleaf groups and 3130-3150 fps. I went up to 49.5 gr and velocity went up as you would expect (3160ish) but accuracy suffered. Hornady lists 50.0 gr as their max for 120 gr bullets with 3188 fps in a 22" barrel. I had zero pressure signs with either of these loads.
Last edited by bludog; 04/23/15.
"Blessed is the man whose wife is his best friend - especially if she likes to HUNT!"
"Love the Lord your God with all your heart, soul, mind and strength, and love your neighbor as yourself. There is no commandment greater than these."
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