Hammer bullet question for Elk

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Ronin75

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Feb 29, 2012
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I have a 7mm RM which has been rebarrel with a Hells Canyon Armory carbon barrel. Currently I'm shooting 155 Hammer Hunter bullets. Because I ordered a shorter barrel to compensate for a muzzle brake I'm only getting a muzzle velocity of 2800 FPS before I start seeing pressure signs. I'm using Nosler brass and Retumbo powder. The rifle shoots my reloads into 3/8"- 5/8" @ 100 yds.
My question is with that bullet and muzzle velocity what should I consider my maximum shooting distance on elk should be. I understanding shot placement is always very critical. Thanks for any input.
 
Ronin75 said:
I have a 7mm RM which has been rebarrel with a Hells Canyon Armory carbon barrel. Currently I'm shooting 155 Hammer Hunter bullets. Because I ordered a shorter barrel to compensate for a muzzle brake I'm only getting a muzzle velocity of 2800 FPS before I start seeing pressure signs. I'm using Nosler brass and Retumbo powder. The rifle shoots my reloads into 3/8"- 5/8" @ 100 yds.
My question is with that bullet and muzzle velocity what should I consider my maximum shooting distance on elk should be. I understanding shot placement is always very critical. Thanks for any input.
Click to expand...

2800 sounds way low unless your barrel is 16". If it us accurate then you're good to go but 2800 with a 7 Rem Mag with at least a 22" barrel is 200FPS slow. 3100 is a cinch from a 24" barrel. I suspect you're seeing something else but I couldn't believe it's pressure related to your charges.
 
To answer your question: depends on where you hunt elk, what altitude? Even at sea level I think it would be good to around 700 yards as the velocity should be high enough to initiate expansion (or Hammer's version which is petals fragmenting off). Possible you may just have an exceptionally slow rifle. I had a 7mm RemMag that was about like this, would only do 2850 fps with a 162SST from a 26" barrel. Should have been at or above the 3000 fps mark. However each rifle is different and my max load was a couple of "book" starting loads. How is the case fill? If you aren't getting good case fill I sure wouldn't go with a faster powder.
 
You said you are hitting pressure signs. That doesn't sounds right with Retumbo. If you go with a faster powder you will just hit pressure sooner. Something is off if you are hitting pressure with Retumbo and are at 2800 FPS on the 22" barrel. I can get over 3150 same bullet and powder in a 24" barrel and a short action. So something isn't right
 
I agree that something seems very amiss with that velocity... Borescope that rifle and see if you have a carbon ring or something that is pressuring you up too soon.
 
Ronin75 said:
I have a 7mm RM which has been rebarrel with a Hells Canyon Armory carbon barrel. Currently I'm shooting 155 Hammer Hunter bullets. Because I ordered a shorter barrel to compensate for a muzzle brake I'm only getting a muzzle velocity of 2800 FPS before I start seeing pressure signs. I'm using Nosler brass and Retumbo powder. The rifle shoots my reloads into 3/8"- 5/8" @ 100 yds.
My question is with that bullet and muzzle velocity what should I consider my maximum shooting distance on elk should be. I understanding shot placement is always very critical. Thanks for any input.
Click to expand...
Your using the wrong powder, H4350, H100V
 
Plug it into the Berger app and see where you hit 1800 FPS. That would be limit.

What kind of pressure signs are you seeing? Do you have pics of the cases?

I have barrels (factory and custom) that just don't shoot fast too. Disappointing yes, however it is the case. I too run into low book charge weights and cannot get to top end with them. I would agree you may want to look to another powder. As mentioned RL22,23 H4831, maybe even H1000. I have shot the 195 with RL23 in my long throated 7RM and was seeing about 2900 FPS for where I would shoot it safely.
 
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Either go to a heavier bullet or a little faster powder. A heavier bullet will help burn more of the powder before the bullet leaves the barrel. You probably won't gain any velocity, but the energy of the heavier bullet will carry downrange further. The pressure build curve on the powder you are using is good for barrels over 24" long and is extremely effective in barrels 26" and longer. And, as others have already said, that setup should have gotten 3000 FPS or more. Maybe check against another chrony?
 
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