Increased ES with increased velocity

[leclairk]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

 

[Benchrest Braxton]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

have you tried switching primers or playing with neck tension?

 

[bozo699]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

The gun will tell you what it likes, you can try different powder bullets primers and even brass and you may eventually get where you want to be. I’ll take accuracy every time over velocity.
Wayne

 

[Allen Corneau]

... At 2715 my ES is about 10 with a great group size...

So, what's the problem again?

 

[leclairk]

So, what's the problem again?

I guess that's the second part of my question, if factory shoots 2750, should I settle for 2715? Seems a shame to reload and end up with a load that shoots slower than factory.

 

[leclairk]

have you tried switching primers or playing with neck tension?

I haven't. I've been using federal 215's but I have some 210's I could try.

 

[Benchrest Braxton]

I haven't. I've been using federal 215's but I have some 210's I could try.

that should help, report back please after you try!

 

[KMart]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

Are you seeing pressure signs at 2850? How much powder are you increasing between loads?

 

[Webster]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

Try a different powder. Check out the load maps on this website for 7MM cartridges.

 

[jelenko]

I guess that's the second part of my question, if factory shoots 2750, should I settle for 2715? Seems a shame to reload and end up with a load that shoots slower than factory.

35 fps? 1%?

 

[searcher]

The dynamics of all loads change with increases or decreases in powder. If it shoots great only 35 fps off what you think better - I'd be pretty happy it is only that small amount.

 

[JFrank]

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are shooting about 2715. At 2715 my ES is about 10 with a great group size and with each powder increase my ES increases to where at 2850ish my ES is 50 with terrible groups. I know there are many factors at play but maybe there is a common issue that creates this situation.

Partly possible for the larger ES may be that your brass is fire forming as your shooting these rounds with increased loads, after forming they may settle down a bit.

 

[Ccrider]

Inconsistencies in your brass and reloading process. The faster the speed, the more the inconsistencies are magnified.

Also, low es does not necessarily mean smaller groups; at least at distances up to 600. You should be looking for the load that consistently shoots small groups, not small es.

And yes, this is coming from someone that will not shoot without having a chronograph on. I just use the information for different reasons.

 

[quest450]

I'm with Frank !!, I'd turn off my chronograph and just fireform brand new brass then you can start gathering data and play with different components but always trust the target !!!

 

[bozo699]

For me es/sd matters a lot in my br rifles
Hunting rifles that are used to make ethical shots on live game with the shooter very experienced and knowledgeable in his load and rifle and shooting abilities is 600 yards and less!… YouTube has made every Tom Dick and Harry capable of 1000 yards and beyond ethical kills on animals and it’s simply just not true!… first of all there’s not many cartridges out there that have the 1800 ft lbs of energy needed at that distance to do the job successfully!… except of course the can do everything 6.5 “CREEDMOOR “. Thats why on a hunting rifle the only thing that really matters to me is cold bore groups period the end!
Wayne

 

[kyreloader]

For me es/sd matters a lot in my br rifles
Hunting rifles that are used to make ethical shots on live game with the shooter very experienced and knowledgeable in his load and rifle and shooting abilities is 600 yards and less!… YouTube has made every Tom Dick and Harry capable of 1000 yards and beyond ethical kills on animals and it’s simply just not true!… first of all there’s not many cartridges out there that have the 1800 ft lbs of energy needed at that distance to do the job successfully!… except of course the can do everything 6.5 “CREEDMOOR “. Thats why on a hunting rifle the only thing that really matters to me is cold bore groups period the end!
Wayne

How does energy kill animals?

 

[Old Navy]

I thought the whole point of the 7PRC was to be the big dog of the 7mm family. You should be able find a good load around 2850 or better. Keep at it.

 

[Jeff Porter]

How does energy kill animals?

Well… it doesn’t. The bullets ability to penetrate into vital organs and disrupt blood flow and cause the animal to loose blood pressure and go unconscious or a shot hits the nervous system near the brain stem is what it takes to physiologically kill game. Shot placement trumps KE of a bullet every time. I have hit 30 pound coyotes with 58 Vmax in the vital areas and the “Bang/Flop” drop where they were standing. Miss that shot placement with the same bullet and they are off to the races for several yards or hundreds of yards until the blood loss is enough to cause unconsciousness and death. Same with white tail. Also pretty sure my 100gr broad head doesn’t have 1800 Ft-LB of energy but the buck I shot through the heart only went 20 yards.

But you need to have the velocity and bullet design to penetrate into those vital areas and cause that damage. That has been historically translated as energy needed.

 

[Doom]

Well… it doesn’t. The bullets ability to penetrate into vital organs and disrupt blood flow and cause the animal to loose blood pressure and go unconscious or a shot hits the nervous system near the brain stem is what it takes to physiologically kill game. Shot placement trumps KE of a bullet every time. I have hit 30 pound coyotes with 58 Vmax in the vital areas and the “Bang/Flop” drop where they were standing. Miss that shot placement with the same bullet and they are off to the races for several yards or hundreds of yards until the blood loss is enough to cause unconsciousness and death. Same with white tail. Also pretty sure my 100gr broad head doesn’t have 1800 Ft-LB of energy but the buck I shot through the heart only went 20 yards.

But you need to have the velocity and bullet design to penetrate into those vital areas and cause that damage. That has been historically translated as energy needed.

Actually it does, but it's not the total energy of the bullet that kills but it's the energy transferred to the animal that determines the amount of damage the bullet does to the vitals. In general the key is to get sufficient penetration to the vitals and then have the bullet expend its energy within the vitals maximizing the damage and blood loss.

When the M16 was initially introduced in Viet Nam the rifles had a 1 in 14 twist that barely stabilized the 55gr FMJ bullet in air. When the rifle entered combat soldiers were amazed at the damage the little bullet inflicted on the enemy. It was much greater than expected. It turned out that the barely stable bullet once it encountered the internals began to yaw, tumble, and break at the cannelure ultimately transferring most of its energy to the target and not passing through as a more stabilized FMJ bullet would tend to do.

The tradeoff between penetration and internal damage is the key issue in the design of hunting style bullets. Lack of penetration and total energy transfer will do little damage to a bear but it's pretty devastating to a prairie dog! And so it goes.

 

[bozo699]

How does energy kill animals?

Well… it doesn’t. The bullets ability to penetrate into vital organs and disrupt blood flow and cause the animal to loose blood pressure and go unconscious or a shot hits the nervous system near the brain stem is what it takes to physiologically kill game. Shot placement trumps KE of a bullet every time. I have hit 30 pound coyotes with 58 Vmax in the vital areas and the “Bang/Flop” drop where they were standing. Miss that shot placement with the same bullet and they are off to the races for several yards or hundreds of yards until the blood loss is enough to cause unconsciousness and death. Same with white tail. Also pretty sure my 100gr broad head doesn’t have 1800 Ft-LB of energy but the buck I shot through the heart only went 20 yards.

But you need to have the velocity and bullet design to penetrate into those vital areas and cause that damage. That has been historically translated as energy needed.

Actually it does, but it's not the total energy of the bullet that kills but it's the energy transferred to the animal that determines the amount of damage the bullet does to the vitals. In general the key is to get sufficient penetration to the vitals and then have the bullet expend its energy within the vitals maximizing the damage and blood loss.

When the M16 was initially introduced in Viet Nam the rifles had a 1 in 14 twist that barely stabilized the 55gr FMJ bullet in air. When the rifle entered combat soldiers were amazed at the damage the little bullet inflicted on the enemy. It was much greater than expected. It turned out that the barely stable bullet once it encountered the internals began to yaw, tumble, and break at the cannelure ultimately transferring most of its energy to the target and not passing through as a more stabilized FMJ bullet would tend to do.

The tradeoff between penetration and internal damage is the key issue in the design of hunting style bullets. Lack of penetration and total energy transfer will do little damage to a bear but it's pretty devastating to a prairie dog! And so it goes.

You are both correct I have dispatched elk with a 22 Rimfire, not much energy there!… a broad head makes a huge wound channel placed in the correct spot. At say 200 yards and you miss your mark and hit it directly in the front shoulder……. Probably not. I realize 200 is a ridiculous distance for a bow but so is say 1200 yds with a 168 gr .284 bullet,.. why?…. Not enough energy in both cases!… it’s long been known that most std hunting,…. Once again HUNTING bullets needs about 1800 ft lbs of remaining energy for the bullet to reliably expand to dispatch an elk , does it need that if you hit it in the spine or heart?… no of course not, can you for certain on your first shot at 1000+ yards hit one in the neck?..
one last thought…… if a 2000 lb car traveling at 1 mph hits you is the probability that your going to die high or low?…..now at 65 mph the same car hits you what’s your probability of death now?…… wait!….. your already typing it was the velocity that killed you….. really?…. If the car was made of styrofoam that weighed 5 lbs at the same speed would your survival rate increase?…..energy does play a factor.
Wayne