Magpro temp sensitivity

jjohnsonElknewbie

jjohnsonElknewbie

WKR
Joined
Mar 16, 2021
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Location
Western Iowa
Good morning ya'll, I'm doing homework on starting powder/loads for my 6.5 WSM. Magpro seems to provide exceptional velocity along with some others. There are a few Vhitavouri powders as well as H1000 and Retumbo that are slightly slower, but I've had good luck with them. What are folks observations with Magpro regarding temp sensitivity, and is it as bad as the internet says, or would you recommend this powder?
 
I use it in my 280 AI, here in AZ. Have not seen much on the Chrono. But that said I try to shoot below 80 Degrees in the summer and around 40-50 in the winter. Just started some 6.5 PRC stuff, going Friday . It's hot now so we'll go in the am and report
 
Weldor said:
I use it in my 280 AI, here in AZ. Have not seen much on the Chrono. But that said I try to shoot below 80 Degrees in the summer and around 40-50 in the winter. Just started some 6.5 PRC stuff, going Friday . It's hot now so we'll go in the am and report
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Sounds great and thank you. This would be a great option to get right around 3,000 MV or more in an 18" 6.5 WSM if its not too picky.
 
It might be like TAC or Hunter where it spikes at around 85 degrees and above. Which isn't much of an issue when you adjust your loads. My issue is my most accurate loads with the lowest SD/ES are at top end loads (TAC and Hunter). So I have had primers blow when I get closer to 95 degrees. So I have really accurate winter/ spring loads and so so summer loads.
 
I too was wondering! I am fixing to order some to try in my 280AI rifle. Planning on trying 7mm Berger Classic Hunter 150 168 gr bullet.
 
I sent a note to Hodgdon regarding these two powders and they simply comfirmed neither are temperature stable. I asked if there was a threshold on either end of the spectrum where this can be more pronounced and haven't heard back yet.

IF, we assume they are impacted by x FPS with each degree change of temperature, if a guy still wants to use them on the higher temp side it requires caution due to pressure spikes if using max loads in the heat. On the colder temp side it requires additional diligence on potential POI changes compared to warmer conditions when doing load development. Given I always check zero before a hunt regardless of load dev during warmer temps., this really isn't that big of a concern to me. If its really hot I won't do any load dev until it cools off.

If a guy doesn't want to worry about it, the extreme series by Hodgdon (Varget, H4350, H1000, etc...) are the least impacted according to multiple tests. However, they aren't completely insensitive, and still require dilligence, especially as range increases beyond say 500 yards.

The bottom line is YMMV depending on your loads and conditions at the time of shooting. Undertanding these complexities will help explain unexpected results, and possibly keep guys from thowing the baby out with the bath water.
 
jjohnsonElknewbie said:
I sent a note to Hodgdon regarding these two powders and they simply comfirmed neither are temperature stable. I asked if there was a threshold on either end of the spectrum where this can be more pronounced and haven't heard back yet.
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They just got back to me.

"Above 90 degrees will enhance pressure issues and avoid direct sunlight on the ammo/ammo carriers. You could keep ammo in a cooler for temperature control, use a small ice pack to keep the temperature stable."
 
Did some more research today, and it looks like N565 is the closest contender and its much more temp stable than 7828 or Magpro. With the 147 I theoretically should be able to get right around 3,000 MV in a 20" barrel and 3185 MV in the current 24" tube. I won't know for sure until I send some downrange and I'll let you guys know how it goes in a few weeks hopefully.
 
Ok, Got out at zero dark thirty. about 77 degrees H1000 140 Speer sp. 56.5 gr. 2708, 2770,2711 for an average 2725. next up Magpro 140 Speer sp. 59 gr. 2751,2756,2811,2782,2802. ave. 2780. next up H1000 140 Nosler bt 57.5 gr. 2897.2872.2951. ave. 2906. All shot out of a Fierce carbon roque CT 20" CF bbl. with Banish 30 . about 85 when we headed back.
 
Weldor said:
Ok, Got out at zero dark thirty. about 77 degrees H1000 140 Speer sp. 56.5 gr. 2708, 2770,2711 for an average 2725. next up Magpro 140 Speer sp. 59 gr. 2751,2756,2811,2782,2802. ave. 2780. next up H1000 140 Nosler bt 57.5 gr. 2897.2872.2951. ave. 2906. All shot out of a Fierce carbon roque CT 20" CF bbl. with Banish 30 . about 85 when we headed back.
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Thank you for sharing. That really gives me hope that 3,000MV in a 20" should be doable in my rifle
 
I have not reached it yet.(3000 fps) Still looking for the right combo. I know a lighter bullet would probably work, but I want to stay with the 140. Barrel has around a hundred or so rounds through it, hopefully it will speed up. My next bump is Hornady's load 57.7 H1000. I'm going to stick with 59 gr. Magpro for the summer and load some 60 gr for the fall.
 
If a person worked up a load in summer time. How would it do in winter? I live in Arkansas. Our winter isn't too bad.
 
jjohnsonElknewbie said:
Did some more research today, and it looks like N565 is the closest contender and its much more temp stable than 7828 or Magpro. With the 147 I theoretically should be able to get right around 3,000 MV in a 20" barrel and 3185 MV in the current 24" tube. I won't know for sure until I send some downrange and I'll let you guys know how it goes in a few weeks hopefully.
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Lots of luck trying to obtain those speeds. I have been going crazy with his prc. I have found for my gun vel and accuracy does not go together out of my 20" barrel. I might be settling in with 2870 130 grain tgk using 565. Mag pro did seem faster today im going to shoot over got it up to 3060 ish but group was close an inch. Im a 1/2" guy dont care to settle for more.
 
204_ruger said:
If a person worked up a load in summer time. How would it do in winter? I live in Arkansas. Our winter isn't too bad.
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With the powders that aren't temp stable, I would keep load dev shooting well under 90 degrees. Find a load that groups as well as you want and then shoot it again in the fall to verify.
 
Bobcat 33 said:
Lots of luck trying to obtain those speeds. I have been going crazy with his prc. I have found for my gun vel and accuracy does not go together out of my 20" barrel. I might be settling in with 2870 130 grain tgk using 565. Mag pro did seem faster today im going to shoot over got it up to 3060 ish but group was close an inch. Im a 1/2" guy dont care to settle for more.
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Thank you and I'm shooting a 6.5 WSM with significantly more case capacity than the PRC. Hoping this will give me the edge.
 
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