Re#26 and the 7mmWSM

[Iron Worker]

Just returned from the range here in Reno NV 33 degrees here. I'm loving Re#26 . Today pushing Hornady 162gr Amax out of a 26" brux 9"twist bbl. Starting at 66grs avg velocity was 3,033 using a Magneto V3 ...67grs was 3,060 ,68grs was 3,125 69grs was 3,170,70grs was 3,225 with 1 shot 3,362 ? 71grs was 3,270 with one shot 3,310 ? 1/2 MOA -3/4 MOA accuracy with all loads. Using new Bertram brass and W-W LRMP all primers were Flat ,but no ejector marks and zero extraction problems. My previous loads were 69grs of H1000 producing 3,175 AVG with beginning pressure signs. What could've been the cause of the two spiked high velocity loads 3,310 and 3,362 ?

 

[Iron Worker]

No doubt these velocities are out outrageously high ! But I've gotten high velocities using other chronographs as well .

 

[elkaholic]

Just returned from the range here in Reno NV 33 degrees here. I'm loving Re#26 . Today pushing Hornady 162gr Amax out of a 26" brux 9"twist bbl. Starting at 66grs avg velocity was 3,033 using a Magneto V3 ...67grs was 3,060 ,68grs was 3,125 69grs was 3,170,70grs was 3,225 with 1 shot 3,362 ? 71grs was 3,270 with one shot 3,310 ? 1/2 MOA -3/4 MOA accuracy with all loads. Using new Bertram brass and W-W LRMP all primers were Flat ,but no ejector marks and zero extraction problems. My previous loads were 69grs of H1000 producing 3,175 AVG with beginning pressure signs. What could've been the cause of the two spiked high velocity loads 3,310 and 3,362 ?

The cause is over pressure, as you alluded to. You shouldn't be able to run larger charges of RL26 than H1000. Usually, it's 2 grains less! Better be careful or you may be wearing the bolt like a unicorn!

 

[cape cove]

Your #'s arn't that far off the Alliant data. They list 71.2 grs of Rl-26 as max for the 162gr Hornady A-max with a vel of 3171 ft/sec from a 24" barrel. You have a 26" barrel so you could up those figures by 60-80 ft/sec. This would put you close to their #'s using a 26" barrel. As for the 3362-3310 #'s, as was said they are either bad chrono readings or over pressure. JMO

 

[Iron Worker]

Over pressure ! Well the primers are very flat ,but no shinny ejector marks and zero extraction or bolt lift resistance.But I did with 69grs of H1000 My powder burn rate list doesn't have re#26 on it.

 

[Iron Worker]

Just searched latest burn rate chart,it said Re#26 was one step slower than H1000.

 

[elkaholic]

Over pressure ! Well the primers are very flat ,but no shinny ejector marks and zero extraction or bolt lift resistance.But I did with 69grs of H1000 My powder burn rate list doesn't have re#26 on it.

Could be that your powders are a little different burning; it happens. I have a similar case, the SS based on the Saum. In my 7 SS and 6.5., RL26 is always 2 grains less than H1000 although the velocity will be 50' higher. It just seems really odd that you pressured out with H1000 at (2 grains less) than you did with RL26? That is some mighty hefty velocity too! But who knows; I load where I feel ok about it and you should too

 

[Iron Worker]

Could be that your powders are a little different burning; it happens. I have a similar case, the SS based on the Saum. In my 7 SS and 6.5., RL26 is always 2 grains less than H1000 although the velocity will be 50' higher. It just seems really odd that you pressured out with H1000 at (2 grains less) than you did with RL26? That is some mighty hefty velocity too! But who knows; I load where I feel ok about it and you should too

I think I'm going to drop the load maybe a 1.5 grs. It was 33 degrees at range today . I bet a 80 degree weather might blow primers. Also it was a warmer day when shooting the H1000 loads.

 

[highdrum]

Most people have observed .5 psi / degree with RL26. It's not temp stable but predictable. Once temps get above 85° pressure can get excessively high pretty quickly, be aware of that.

 

[just country]

morning, 66.5grs 4831sc, 215 fed. and Winchester brass, and
140gr. accu-bond. .500 all day long. justme gbot tum

 

[Creedmoor shooter]

Over 3300 with a 162? That's 28 nosler territory. I ran my 7mm rem mag to 3150 but stopped because I knew I had to be getting up there in pressure even though my brass looked fine.

 

[cape cove]

Just searched latest burn rate chart,it said Re#26 was one step slower than H1000.

Don't rely too much on burn rate charts. According to Alliant RL-26 is slower than RL-25. This has certainly not been the case in the 4 or 5 chamberings i've tried it in. In fact I feel it is at least 2-3 grs faster than RL-25. Closer to RL-22 than RL-25.JME

 

[Wedgy]

Reloder 26 is in fact slower the RL 25...I had it scientifically explained to me(way over my head) but it acts like it's faster using less in an otherwise equal load. All I can say is that it is a magical powder !
But it does speed up a lot at about ~84 F

 

[elkaholic]

Don't rely too much on burn rate charts. According to Alliant RL-26 is slower than RL-25. This has certainly not been the case in the 4 or 5 chamberings i've tried it in. In fact I feel it is at least 2-3 grs faster than RL-25. Closer to RL-22 than RL-25.JME

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