Powder recommend for a 7saum with a 20inch barrel

[softtail103]

I am have a 7saum with a 20in barrel that should be done in 2-3 months. I will be running the Berger 180 Hunting VLD's. I have always used H1000 for my 7mm rifles but they all have at least a 24 or 26 inch barrels. Will I need to move to a faster burning powder to keep the velocity above 3000fps?

 

[RockyMtnUT]

4831sc
RL26 Its been a while but I think you will have a hard time getting 3k without hitting pressure with a 20inch.

 

[BoomFlop]

You might see 2800 with Reloder 26 before you see pressure. I'd guess H1000 to be around low to mid 2700 maybe.

 

[Ucsdryder]

H1000 is what I use in a 20" 7saum. After 150'rounds I started getting ejector marks and backed down. Still fiddling with it but I'm at 2770 right now. Before speed up I was at 2750, and before I dropped powder I was up to 2800 (after barrel speed up).

 

[comfisherman]

Few years back (OK looks like 10... geez that explains the grey in the beard) a friend and I were working on a gs project trying to get better code to predict high energy photons interaction with matter. We decided a fun proof would be to take some overbore cheapy barrels and cut them down inch by inch and see if a similar situation could predict optimum balance between barrel length and speed loss. We needed 2x variables so did bullet weight and powder burn rate.

Our only guidance was ernie bishops threads that expressed the best load long is usually pretty good short. Given his experience with sps we set off.

We found direct links between heavy and light for caliber loosing significantly more than middle weight bullets. In our 270wsm barrel heavies lost more over light, the reverse was true for the 7mm rum. We thought we would see more pronounced speed differences based off powder. We took our numbers to the destroyer of discovery (our statistics person) and they decided it was easier to explain our powder speed findings as system noise than an actual findings. To be fair it didn't point consistently in one direction and basic sig fig elimination made them go away.

Tldr: I'd rock what you know to be a good powder/bullet combo as a starting point.

Footnote... a 16.5 inch 7 rum launching 175 partitions over a full tilt retumbo load makes more fire than Elon musks flame thrower.

 

[lancetkenyon]

7SAUM....20".....180s.....3000fps? You are going to be disappointed. RL23, RL26, Retumbo, N565 will all get you top speeds, but not 3000fps from a 20". More likely 2800-2850 tops.

You should have asked the question BEFORE you opted for a 20" if you are dead set on wanting 3000fps with a 180. Should have gone 20" 28 Nosler to attain those speeds.

 

[Troutslayer2]

I'm not sure you will be able to get 3000 FPS with 168 grain bullets. 180? Wishful thinking imo.

 

[softtail103]

7SAUM....20".....180s.....3000fps? You are going to be disappointed. RL23, RL26, Retumbo, N565 will all get you top speeds, but not 3000fps from a 20". More likely 2800-2850 tops.

You should have asked the question BEFORE you opted for a 20" if you are dead set on wanting 3000fps with a 180. Should have gone 20" 28 Nosler to attain those speeds.

I have a few 7mm's that I push over that number. I knew exactly what I was doing BEFORE I ordered it. This was a simple question if anyone has. I have a 7WSM that hits 2986 out of a 22in. It's not that much of a stretch.

 

[RockyMtnUT]

I have a few 7mm's that I push over that number. I knew exactly what I was doing BEFORE I ordered it. This was a simple question if anyone has. I have a 7WSM that hits 2986 out of a 22in. It's not that much of a stretch.

The WSM has7+ grains more capacity. I hope you can get it.
I show you will be at 2861fps then tune it down to 2836fps for clovers.

Your question was " Will I need to move to a faster burning powder to keep the velocity above 3000fps?"
Answer is Yes. You might have to use the new Hodgdon H1000V2 powder to achieve it or make some Nomra Powder mix?

 

[Longtine88]

N560 hands down. I've loaded it for several short barrels and 180's. Works great in all. Gets the most in velocity for short barrel also but your never gonna hit 3,000 safely for sure

 

[comfisherman]

The WSM has7+ grains more capacity. I hope you can get it.
I show you will be at 2861fps then tune it down to 2836fps for clovers.

My 7 saum data is limited to an older nosler book that goes to 175s. 70% of the powders top out on the shady side of 2900 with load densities well in excess of 100%. Even the fastest 3 powders are near high 90s. All of which are loads in a 24 inch tube at nosler hq elevation...

Even going 3 fingered redneck Ackley would be tough with this....

Curios, if you are close with a 22 inch wsm why did you go 7 grains less powder and a shorter barrel?

 

[softtail103]

N560 hands down. I've loaded it for several short barrels and 180's. Works great in all. Gets the most in velocity for short barrel also but your never gonna hit 3,000 safely for sure

I have not used any N560. I have read that it is a dirtier powder? I know nothing about it, but I may have to try it. Thank you for the info sir.

 

[Longtine88]

I never found it dirty but it is fairly stable and burns hotter double based. I shoot it in 3 different saums.

 

[orkan]

Sure, you can hit 3000fps with a 7 SAUM. ... with a 140gr bullet.