7mm rem mag speed

[bstomper]

It's a Winchester model 70 stainless 24" (I think) barrel 7mm rem mag. Only thing I have done to it is pillars bed and action bed in a Boyd's thumbhole stock. I can't remember the exact length to the lands off the top of my head but There is still plenty room. The 3.370" is the max that will fit my magazine.

 

[David Lindler]

My 7mm mag likes 168 grain Berger's with 68 grains of retumbo at magazine length bullet seating a federal match primers 2860 fps

 

[Backcountry sports]

I have done the first portion of the Scott Saterlee 10 round load development for my 7 mm rem mag. I am using H1000, federal case, federal 215 primers and 175gn Accubond LR. I found a real nice node with speeds of 2719, 2722, and 2715 at 63.8, 64.0 and 64.2 grns and they grouped sub MOA. Is 2700 FPS a considered a slow speed for the 7 mm in 175 grain bullet.

 

[Backcountry sports]

3067 retumbo 71.5 on my 7mm cooper 26 inch barrel that the load arron at gun works gave me years ago

 

[David Lindler]

3067 retumbo 71.5 on my 7mm cooper 26 inch barrel that the load arron at gun works gave me years ago

My mag only has 24 inch barrel and will tolerate 70 grains of retumbo without pressure signs. 68 in my gun was more accurate.

 

[Creedmoor shooter]

2700 seems pretty slow. I'm running the 180 eld at 2959 in my 26in with rl-26.

 

[Bdubose]

My experience with my 7Mag & H-1000 on 168 grain ABLRs is that the harmonics start troubling you at higher speeds and you may not get past it before pressure becomes an issue.

If terminal ballistics are still good at your desired max distance then go with what shoots well! More speed is not always the answer.

 

[David Lindler]

My experience with my 7Mag & H-1000 on 168 grain ABLRs is that the harmonics start troubling you at higher speeds and you may not get past it before pressure becomes an issue.

If terminal ballistics are still good at your desired max distance then go with what shoots well! More speed is not always the answer.

I agree. Every rifle barrel is different. Some are faster than others just cause its fast, doesn't make it accurate.
I take sub-moa groups over speed any day.

 

[vancewalker007]

Per the IMR web site you're right near their measured max. They show 64.5gr at 2692. They list several other powders that may give you a little better velocity. The highest one they show is IMR 8133. This is a slower powder than H1000. I've used it in a 7LRM and a 6.5 PRC with good results. But, to your original question, you're right in the wheel house for youre powder bullet combo.

Note, I've found the IMR data to typically be very conservative.

 

[JJMoody]

Per nosler book data
With h1000, their data shows around 2850 max. Your particulars in your rifle will vary. Yadda yadda.... iiwm, I'd find where you find pressure using a chrono, Monitor velocity as well as pressure signs, observe flat spots in velocity as powder increases and focus on those nodes for your testing, then mess with seating depth to tighten up grouping. Please call me out if I'm reading this wrong. Longer seating depth than book will yield different pressure/velocity, sure, pressure equals speed. I think you're low, but could be wrong. I don't always shoot for speed if accuracy is there, but feel you can do better on this.

 

[WYO300RUM]

My load is 69.5grains of Retumbo pushing 175gr ELDX and I am able to get 3035fps

What length barrel do you have ?

 

[bstomper]

Thanks for all the info guys. This is great. If I just neck size the cases, I assume that will follow same theory as the longer seating depth and also make more in the case which in turn will take more powder to create the pressures to get the faster velocities.
I will keep working on this in .2grain increments and stop at the first signs of pressure. I'm still pretty new at the reloading thing so I have been very cautious when I start getting to the higher end of what the manual says for powder charges. But knowing that the extra case volume because of the longer coal will take more powder to get the same result, I will keep going. I have always figured that was the case but just needed to hear it from some experienced reloaders.

 

[WYO300RUM]

Thanks for all the info guys. This is great. If I just neck size the cases, I assume that will follow same theory as the longer seating depth and also make more in the case which in turn will take more powder to create the pressures to get the faster velocities.
I will keep working on this in .2grain increments and stop at the first signs of pressure. I'm still pretty new at the reloading thing so I have been very cautious when I start getting to the higher end of what the manual says for powder charges. But knowing that the extra case volume because of the longer coal will take more powder to get the same result, I will keep going. I have always figured that was the case but just needed to hear it from some experienced reloaders.

What length barrel do you have also ?

 

[vancewalker007]

Thanks for all the info guys. This is great. If I just neck size the cases, I assume that will follow same theory as the longer seating depth and also make more in the case which in turn will take more powder to create the pressures to get the faster velocities.
I will keep working on this in .2grain increments and stop at the first signs of pressure. I'm still pretty new at the reloading thing so I have been very cautious when I start getting to the higher end of what the manual says for powder charges. But knowing that the extra case volume because of the longer coal will take more powder to get the same result, I will keep going. I have always figured that was the case but just needed to hear it from some experienced reloaders.

Neck sizing only has nothing to do with the seating depths you choose. For better long term results with your cases you should be FL resizing to make sure you keep the shoulder bumped back, but that's a whole different ball of wax. If this is a stock SAAMI chamber you may not have a ton of room to push the bullet out unless it's a Weatherby. You'll have to do the max length measurements to the lands of the bullet you want to use then work back in 5 thou ish steps to find that sweet spot jump.