Recreating a Hornady 139g SST for 7mm RM

I'm trying to simply copy the 139g factory rounds I use...139g Hornady SST for 7RM.

I just pulled a projectile and measured the charge: 77.5 grains of powder in the factory round.

I've checked and rechecked and I measure 77.5 every time. But on every chart I've seen 77.5 is way into the redline. It looks like you get a compressed load by the time you get to 75 grains.

So does anybody know what powder is this? And how much 2217 or 2213sc do I need to get the same whoomph?

Hoping somebody can point me in the right direction.

Why only use a 139/140gr bullet in a 7RM?

Look at stepping up to a 162gr/168gr bullet and get the performance out of the 7RM that its capable of.

From some of the experiences i had with the 139gr SST in a 7mm-08 i wouldnt be using that bullet in a case that can push them much much faster.

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Originally Posted by GWH

Why only use a 139/140gr bullet in a 7RM?

Look at stepping up to a 162gr/168gr bullet and get the performance out of the 7RM that its capable of.

From some of the experiences i had with the 139gr SST in a 7mm-08 i wouldnt be using that bullet in a case that can push them much much faster.

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Interesting. What happened?

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Originally Posted by YosemiteSam

Interesting. What happened?

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Bullet blew up on front shoulder of a Sika yearling leaving a shallow dinner plate sized flesh wound. Luckily the copper jacket carried on thru and did kill the animal, but it was a bloody mess.

That was only pushed at 2850 fps from a 7mm08.

Sent from my SM-G930P using Tapatalk

This is the surface explosion on entry

Attachment 110988

Another example of why I don't run ssts!

You are not able to re-create the load you want by simply dissembling the Round , for two reasons .
Firstly you cannot get the powder because it is not a commercially sold powder and secondly the powder load is regulated by pressure not a given velocity even though the two follow each other to some degree .

Quote:

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Originally Posted by GWH

This is the surface explosion on entry

Attachment 110988

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Train wreck

Had the same sort of result at close range with 708 sst but ok at 200m

Mate lost a red hind in November with that 139sst out of his 7m08. close range shot ??50_70mtr. Dropped and got up and ran when he was about to get the knife out.
At 100-200mtr it does a good job on smaller eating reds I have seen him shoot.
Z

Quote:

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Originally Posted by YosemiteSam

I'm trying to simply copy the 139g factory rounds I use...139g Hornady SST for 7RM.

I just pulled a projectile and measured the charge: 77.5 grains of powder in the factory round.

I've checked and rechecked and I measure 77.5 every time. But on every chart I've seen 77.5 is way into the redline. It looks like you get a compressed load by the time you get to 75 grains.

So does anybody know what powder is this? And how much 2217 or 2213sc do I need to get the same whoomph?

Hoping somebody can point me in the right direction.

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You might find the the Factory secret powder is more dense than those to powders giving it a greater weight for it's size. I also agree however, You might as well be useing a 708 if you are going to run such a light projectile. I have used the sst in 154 if I remember correctly out of my RM. With very good results, Have now moved on to 162 AMAX,

I'm shooting feral goats out to 500 sometimes. But usually in the 250 - 300 range. I figured the 139 would be AOK for that. I'd get a bigger round for a bigger animal.