TTSX Velocity

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I am in the process of working up a load for my 24" barreled 7mm Rem Mag using 150 TTSX. I am referencing Hodgdon's Load Data website. My load components are Federal 215 primers, and Remington brass, and I'm seating >.050" off the lands. I have tried H1000 and Retumbo, but am still ~150 fps short of the Barnes Vor-Tx factory ammo which I have chronoed. Also, I have absolutely no pressure signs at max load using the Retumbo; it gives me the most velocity, and very acceptable hunting accuracy. Are these results typical of hand loads? I have read elsewhere that the 7RM is a widely under-loaded caliber as far as load data is concerned (although i have not been tempted to go above max, as I don't have the experience to make that judgement call). SAAMI maximum average pressure for the 7mmRM is 61,000 psi, and Hodgdon's data shows 57,200 psi for a max load of Retumbo.
I know barrel length is a factor, but Barnes and SAAMI uses a 24" barrel as the standard for this caliber.
What does the factory use to achieve such blistering velocity? I want it too.
Any input is appreciated, especially from those who load for a 7mm Remington Magnum.
 
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Are you using the same chronograph to compare factory loads and your own loads? What was the factory ammo chronographing at? Hogdgon's max load for 150gr TTSX and Retumbo is 73.5gr and that is already a compressed load - it is probably a bit too slow for that bullet weight. Their H1000 max load is 73.8gr, which is well above what Barnes gives as a max load - 68.0gr.

I have had good results with 7mm RM and IMR 7828 (mostly in heavier weights) and RL22, RL17 and IMR4350 with lighter weight bullets. Also keep in mind that you are using Reminton brass as opposed to Winchester, which is used in both the Hogdgon and Barnes data. I use W-W and Nosler brass, so i don't know how case capacity of the R-P compares.

http://www.barnesbullets.com/Copper_Manual4/7mm%20Remington%20Magnum.pdf
 
I loaded that bullet in my 24" barrel 7 mag and was barely able to sqeeze out 3000 fps with re 25, retumbo wasn't far behind. I found the slow burners to work best, kept getting pressure signs near max load and lower velocity with the other usual powders. The 7 mag seems to be a funny duck, I hear about a lot of people having trouble getting book velocity with that cartridge, escpecially in 24" barrels. I never should have bought that chronograph, it can make you hate your rifles
 
hookedonblacktail said:
The 7 mag seems to be a funny duck, I hear about a lot of people having trouble getting book velocity with that cartridge, escpecially in 24" barrels. I never should have bought that chronograph, it can make you hate your rifles
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I have read that a 7mm RM with a tight spec chamber will allow loading higher velocity without pressure signs as well. Maybe the 7RM suffers from large tolerances in factory rifles, and lawyers are killing the max load data for the slow powders? I know I could easilyload more Retumbo, as I don't have any pressure signs at max.
Yes the chrono is causing me grief. The elk will die at 2900 or 3100 at 200 yards, so why do I care? I guess it's like buying a 500hp sports car and finding out it is governed to 100mph.
I could have bought a .270 win, but it's often barrelled 22".
 
Try a faster powder like IMR 4350 0r IMR 4831, with lighter bullets (140- 150 grains) in my rifle and a 24 inch barrel I had trouble reaching the listed velocities with slower powders like retumbo, Re 22 and H1000 . With bullets 160- 168 grains I had the best results with Retumbo.
 
I have read that a 7mm RM with a tight spec chamber will allow loading higher velocity without pressure signs as well.
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It's more like a tighter chamber generally produces more pressure with the same load. You may have an oversized chamber in your rifle. Personally, I have found R-22 to provide the best results with 140-150gr bullets in the 7mm remmag.
 
The highest velocity attainable in the 7 RM is with IMR7828 in my experience, which is extensive with the big 7. The 7mm RM is capable of over 3200 fps with 150gn bullet and 7828 safely.
 
c-fbmi said:
The highest velocity attainable in the 7 RM is with IMR7828 in my experience, which is extensive with the big 7. The 7mm RM is capable of over 3200 fps with 150gn bullet and 7828 safely.
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I have noticed that "book" loads with 175gr Partitions/Game Kings/Deep Curls with IMR7828 give much lower than book velocity in two 7mm RM that I have tested lately - Steyr Luxus S and Rem 700 with a Krieger 5R 8.5 twist barrel. The 64.5 to 66.0gr loads are giving between 2725 and 2800fps. By way of example, I believe 65.0gr in Nosler #4 is listed at 2950fps. I have zero indication of pressure, so I am comfortable working up from those loads still. On the other hand, Ramshot Magnum was pretty much spot on at just over 2900fps.

I do have a bunch of 7828 left so I will work with that a bit more, but Ramshot Magnum has piqued my curiosity, and I may very well change over. Have you given that powder a try?
 
I have done a fair bit of reloading for the 7mm Rem mag. RL22 is the way to go in my brothers A bolt. 140 grain TTSX .030" off the rifling, fed 215 primers, 69.2 grains RL22 at 3200 F.P.S. with a 24 inch barrel. That load groups at just around an inch. Hope this helps.
 
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