7 Rem mag powder with 143 gr Hammer?

[Wedgy]

I also run H-1000 with the 143, maybe could get faster mv with a faster burning powder but the accuracy and consistency is very good. Very low es and sd in my rifle. I get 3220ish mv in a 26 inch barrel. cheers, Jason

I was 69.0 grains of H1000 209M for 3,210fps 143 grain HH with a 22" barrel

 

[Mark37082]

What twist are you running?

 

[junior71]

H4831sc

 

[Wedgy]

What twist are you running?

8 twist

 

[targetsmoker]

I have good luck in my 7mm rem mags with IMR 4350 with 150 gr and 140 gr bullet weights.

 

[Mark37082]

I wish I had a faster twist in my 7RM. It won't stabilize the HH 143. Went with an 8 twist in an upcoming 280ai for this very reason.

 

[Hardware]

Started a load with good results so far with Retumbo

 

[fire814]

How much Retumbo?
I have had good results using Retumbo with 168-180 gr Bergers, but have not tried it in lighter bullets.
Appreciate everyone's reponse!

 

[Hardware]

We have settled on 71.5g in Federal cases.

 

[Len729]

Running 72g Retumbo @ 2998 .75 MOA in Federal cases and CCI250

 

[The Badger]

RL23 was a good match in mine with the 143HH's. Has a 1 in 9 Brux barrel at 26".

 

[fire814]

Running 72g Retumbo @ 2998 .75 MOA in Federal cases and CCI250

Isn't that very slow for a 143 gr bullet? I got those speeds with less Retumbo and 180 gr bergers.

We have settled on 71.5g in Federal cases.

What speed and group size?

 

[Hardware]

We were getting right around 3200fps with a 26" 1-8 barrel 71.5g Retumbo, Fed 215 Federal brass

 

[Veteran]

Varget, H1000, H4350, and H4831(extreme series pow
are among the top for heat. The issue is the the rise in FPS per degree is not linear, meaning some powders, like Reloder 26 (in MY EXPERIENCE yours may vary,) are very stable from say 20F to 85F but above that they increase very rapidly. If you are within the stable range of temperature you will be fine. Some of the VV powders such as N570, N560 have shown to be very heat tolerant.

Powder Temp Stability — IMR Enduron vs. H4350 and Varget « Daily Bulletin

A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451.

bulletin.accurateshooter.com

View attachment 359833View attachment 359834

Great Data. Nice Chart. I noticed you and another poster both alluded to RL 26 becoming unstable over 85 deg F. I have personally seen that.
I developed some loads in Michigan in moderate temps, and was shooting them in Texas in 95 plus temps in .338 LM. Velocities were very scary. 250 gr scenars at 3300 fps.....Im pretty sure that the psi was 70,000 plus.....scary.....shut that down quick of course.

Of the Vihtavuori powders, I believe that only N565 and N568 and maybe N570 are advertised as temp
stable. They may say N560 is temp stable but in 90 plus weather it does not act stable.

My experience.