7RM 131 HH load data

[mn_hntr]

My dad has a MK-II in 7RM that's been a finicky gun to find a load for. He just drew his first antelope tag (doe) and I'd like to get his rifle dialed as he's never shot much over 150 yards. I purchased the sample pack of 131 HH and have the following powders:

H4350
N165
Superformance
IMR 4831
H4895

What powder would you recommend trying out? and at what initial powder load?

 

[Bob Wright]

Based on those powders, assuming you have them and specified in loading data, the 2 Hodgdon powders.
I have used Retumbo with 140 grain Sierras. Without load development, I was fire forming brass after annealing. I was surprised how well that load grouped just picking a book middle of the road charge. So go with your slowest burn rate powder. Do a 300 yard ladder. You have 5 foulers and 10 for record. Good luck. Report back.

 

[Kmccord]

My dad has a MK-II in 7RM that's been a finicky gun to find a load for. He just drew his first antelope tag (doe) and I'd like to get his rifle dialed as he's never shot much over 150 yards. I purchased the sample pack of 131 HH and have the following powders:

H4350
N165
Superformance
IMR 4831
H4895

What powder would you recommend trying out? and at what initial powder load?

Use Hodgdon load data center, it will give you starting loads for the weight class of bullet and cartridge. You do not have much to test with, however great thing Hammer Bullets are generally in stock, but I would not waste time since hunting seasons is just around the corner.

 

[GLTaylor]

See where you pressure out with 4831, then see if you need faster/slower powder for good case fill (90+ %). You are going to be pleased with speed and accuracy. Use .003 or more neck tension for best ignition.

 

[ButterBean]

Based on those powders, assuming you have them and specified in loading data, the 2 Hodgdon powders.
I have used Retumbo with 140 grain Sierras. Without load development, I was fire forming brass after annealing. I was surprised how well that load grouped just picking a book middle of the road charge. So go with your slowest burn rate powder. Do a 300 yard ladder. You have 5 foulers and 10 for record. Good luck. Report back.

Retimbo will be way too slow, and that's the wrong load work up procedure for Hammers

 

[ButterBean]

See where you pressure out with 4831, then see if you need faster/slower powder for good case fill (90+ %). You are going to be pleased with speed and accuracy. Use .003 or more neck tension for best ignition.

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X-2, Start at 65g and work up til you find pressure

 

[mn_hntr]

Thanks for your input I'll start with the 4831. In general is it okay to use the starting load data for lead bullets of the same grain weight when using HH?

 

[GLTaylor]

I would go up to mid-range to start. Hammers are more "slippery" than traditional bullets. You may also find you can go slightly above listed max charges. Just depends on your rifle bore. If you're comfortable, start by going up in whole grain increments til you get near listed max charge. Then go to 1/2 gr increments - and watch your brass for pressure signs (ejector marks, increased bolt lift, Etc.)

 

[ButterBean]

Thanks for your input I'll start with the 4831. In general is it okay to use the starting load data for lead bullets of the same grain weight when using HH?

Start at 65g and you'll be fine

 

[Bob Wright]

Retimbo will be way too slow, and that's the wrong load work up procedure for Hammers

We're not talking about absolute hammers here, right?
What powder he has on hand is what he listed.

 

[mn_hntr]

Start at 65g and you'll be fine

I will start there, I just ordered a competition electronics chronograph yesterday too. Hopefully I can view velocities with the HH as well.

We're not talking about absolute hammers here, right?
What powder he has on hand is what he listed.

Just the standard HH. https://hammerbullets.com/product/284-cal-133g-hammer-hunter/

 

[ButterBean]

We're not talking about absolute hammers here, right?
What powder he has on hand is what he listed.

That's correct so why even mention Retumbo? and the thread title is
"7RM 131 HH load data" and "So go with your slowest burn rate powder." would be a total waste of time and components

 

[Bob Wright]

The chronograph is indespensible for reloading.

 

[Huntfly]

I load for two 7 mags, have had good luck with imr 4350 in both rifles. Nosler partitions, 150 grainers.