Key to low ES on reloading

[Mikecr]

It might not be the primer, but seating and striking of it instead.
Counter to popular merchandising, primers should not be seated to the same depth. They should be seated to the same crush.
With this, you can adjust firing pin release/striking to produce results similar to those Woods posted.

Bullet seating does not normally directly affect ES -unless you're on the edge of a powder node at the same time as seating testing. That's really what Woods is showing. That's why you should do seating testing far away from a known powder node.

 

[jsthntn247]

Since I started using one of these, I have no problem getting ES under 15fps with sd's around 5 or less. I work a load up as normal with powder charge first then seating depth. Then lastly shoot it over a chrony at different seating pressures. 5lbs can make all the difference in the world.
Hydro Bullet Seater

 

[dig]

Ambient temp can make a big difference when shooting in summer months. Is the ammo constant temp, has some been sitting in the sun, did you take it from a cool vehicle to the bench and most important have times varied that rounds sits in a hot chamber. This is often very over looked. In our 100 degree weather my spread/sd always open up. I go from the 20s in the 60-70 temp range to over 40 in my 300 wby and that's being very careful.

 

[Mikecr]

I agree with contributing temps and for accuracy testing/hunting I go a couple steps further to manage it.
- Load develop at barrel temp the gun will be field needed for. That is, if it's a summer varmint gun, load develop in the summer, and pack the cabinet with that summer ammo.
- Acclimate ammo in pants pocket regardless of outside temps, range shooting, or hunting. I shoot only single shot, as each is pulled from my pocket, and only when completely ready for the shot. Don't let any heat or cool in a box, magazine, or chamber.

_________________________
Pecker-Temp(patent pending)

 

[Pdvdh]

The one thing you did not mention is what chronograph you are using and how absolutely 100% confident you are in your chrony numbers on your ES.

I would stretch your load out to the farthest distance you have available and shoot 5 rounds, measure your vertical spread. If you are say dead on in your vertical spread I would say you are either good to go or good to shoot your lying chronograph. I've seen way too many chrony's that should not be used as reliable 100% data. I always let my field test shooting override my chrony data.

All of your efforts to reduce ES will be wasted if the instrument you use to measure bullet velocity doesn't provide the precision required to measure the ES/SD within the limits you desire. So which brand/model velocity measuring device are you using? And what assurance do you have that the values it records provide the necessary precision?

My comment is based in the knowledge I've gained from operating duplicate and triplicate light sensing chronographs for measuring velocity for a number of years now. I currently receive four recorded velocities for each bullet fired. This provides me with the data required to identify bad velocity data from any of the units, because the bullet speed over the skyscreens is the same. When I obtain an outlier from one of the units, I know that unit failed to provide good velocity data. Every one of my units will occasionally produce errant velocity data.

Trying to reduce ES/SD based on faulty velocity measurements is equivalent to a dog chasing its tail. A guy can invest a lot of time and resources, and never succeed. Or expressed another way, a guy could succeed, yet be unable to measure/identify/realize that success.

 

[Pdvdh]

One thing that I've learned recently is that coating bullets with hexagonal boron nitride (HBN) will reduce ES. HBN coated bullets reduce the friction between the bullet and the bore. Folks shooting HBN coated bullets pretty much universally agee they experience lower ES from any load they shoot. I believe that the science/physics involved supports this benefit. A bullet with reduced bore friction will produce lower ES than that same bullet with greater bullet to bore friction.

This is a primary reason I've HBN coated all of my bullets this past winter. I haven't yet put in the time to document a reduction in ES from my rifles, but I have no doubt that the reduction in bullet to bore friction will reduce the range of chamber pressure for a given load/bullet, which will also reduce the range of velocity.

The reason I've gone to HBN coated bullets is that I've never enjoyed the pursuit of reduced ES/MV data. It can take a lot of time and effort, without any certainty of reaching any set goal. I believe the HBN coated bullets will reduce the ES of each of my loads in every single rifle. And the HBN coating process is reasonably pain free. So I went all-in.

The reason I mention the importance of the velocity measuring equipment in the prior post? I learned I had wasted a lot of time chasing reduced ES after I started shooting each bullet over duplicate/triplicate velocity measuring instruments.

 

[Pdvdh]

Forgot to mention another benefit of HBN. HBN coated bullets will also provide more uniform bullet seating/bullet release forces. In addition, it will reduce the tendency of bullets to bond to the case neck over time. Bare copper bullets seated into bare brass cartridge necks can have a tendency to bond together over time. The HBN separates the two and prevents this bonding. Some additional reasons to expect lower ES with HBN coated bullets.

 

[flashhole]

Interesting, where does one buy HBN?

To the OP, have you tried Retumbo?

 

[Pdvdh]

Some HBN-related information available in this Thread:

http://www.longrangehunting.com/forums/f19/hexagonal-boron-nitride-151457/

 

[martyj]

We shot 4 rounds this morning and even tried a new batch of H1000 which appears different of at least E.S was way off


#1 es - 10.98 SD-5.47 Nosler case (once fired-full resized) 215 primer Nos. 300 bullet

#2 es- 16.73 SD-9.21 same as above but with Berger OTM

#3 es-16.83 SD-871 same as above but with Sierra 300 SMK

New batch H1000 same brass Nosler bullet 215 primer
es-75.72 sd-37.49 this one was way off. Velocity of one shot was 2828 all the rest ranged from 2782-2807fps

All are same load and same COAL
63 degrees outside and Chronograph was 8 yards down the range
Appreciate all the help and advice

 

[martyj]

Im sure smaller es and sd would be better.
Going to try 250 primers next and maybe bullet coating

 

[bruce_ventura]

... New batch H1000 same brass Nosler bullet 215 primer es-75.72 sd-37.49 this one was way off. Velocity of one shot was 2828 all the rest ranged from 2782-2807fps All are same load and same COAL 63 degrees outside and Chronograph was 8 yards down the range Appreciate all the help and advice

What was the MV for the same load/bullet using the old lot of H1000? You may need to adjust the charge to get back to the same MV.

Nothing wrong with the first three strings. What did you do to get the ES down from 50 fps?

 

[martyj]

What was the MV for the same load/bullet using the old lot of H1000? You may need to adjust the charge to get back to the same MV.

Nothing wrong with the first three strings. What did you do to get the ES down from 50 fps?

Old h1000 Mv are
1-2789 2-2794 3-2800 ES-10.985 sd-5.47

I measured everything including bullet length and what I could not measure I weighed.
Trimmed the cases to the same length even though they didnt need it just make sure they were all the same length.
It was also cooler out today which I think might of helped some.
Im going to retry the new lot of powder that was probably and error on my part some how.

Will all rifles shoot well .020 off the lands? I have this one backed off .100 and it will it did shoot a dime size group at 200 with this load.
At .060 off the lands it shot 1.100.

 

[barefooter56]

Old h1000 Mv are
1-2789 2-2794 3-2800 ES-10.985 sd-5.47

I measured everything including bullet length and what I could not measure I weighed.
Trimmed the cases to the same length even though they didnt need it just make sure they were all the same length.
It was also cooler out today which I think might of helped some.
Im going to retry the new lot of powder that was probably and error on my part some how.

Will all rifles shoot well .020 off the lands? I have this one backed off .100 and it will it did shoot a dime size group at 200 with this load.
At .060 off the lands it shot 1.100.

Martyj,
No. All rifles do not like the bullet seated .020 off the lands. Every rifle has its own "sweet spot". Your rifle likes .100 off the lands as you testing has shown.