Can a shooter's mechanics and form influence velocity E.S.?

[dfitz7604]

Wow! I learn something new every day. I wouldn't of ever thought of this. But the more I think about it the more it makes sense. Thanks for opening my eyes to yet another factor.

 

[DMP25-06]

Bullet seating depth is critical, should be way ahead of a lot of things when reloading for precision!!

Bigngreen ,

I did initial rough seating depth tests at -.010" , -.040" , -.070" away from lands with low power loads , 3 shots each to determine which depth shot smaller group .
But , I have not yet tried smaller increments of seating depth changes .

Thank You ,
DMP25-06

 

[DMP25-06]

The Chrongraph you are using could easily be causing as much variation as anything else. I use Shooting Chrony products but they are extremely sensitive to setup, light and shooting angle. Unless your shots are going across the Chrono at exactly the same angle and spot on the pickups with consistent light you can easily get 100 FPS variation in a load that should have an ES of 5. This is far more likely to be inducing high ES than your shooting style, given all the other quality and appropriate prep work you have done to get ES in line.

If you have access try running some rounds through a Lab Radar and see what you get for ES without changing anything else. Other option is to test your Chronograph. Take some Eley Tenex ammo and shoot it across your Chrono. This is very high quality RF ammo and should show an ES of well under 10 FPS. If you are getting more than that it is the Chrono.

,

Dean2 ,

Thank you for the suggestion of using the Eley Tenex .22 RF test . That is a very good idea .
I will try that , but it may be 2 weeks before I am able to do so .
I am currently using a Magnetospeed , first generation chronograph .
I do not know anyone with a LabRadar .

By the way , my name is Dean .

Thank You ,
DMP25-06

 

[Dean2]

Wow! I learn something new every day. I wouldn't of ever thought of this. But the more I think about it the more it makes sense. Thanks for opening my eyes to yet another factor.

Your welcome. Some troubleshooting info direct from Chrony. If your bullet has to travel even 1/4" more over the 12" of a typical length of a Chrony that is .020833 percent or 62.5 fps at 3000 fps nominal. That is wasy to have happen iof hte Chrono is not perfectly level and completely open.

PROBLEM: No reading after shooting. Cause & Remedy:

1. not using diffusers on blue sky, sunny day; add diffusers;
2. using diffusers on a cloudy day; remove diffusers;
3. unit too close to muzzle; move unit farther away;
4. not shooting directly over photocells; aim more carefully;
5. unit not properly aligned with bullet path; realign rifle to point directly at target; and,
6. shooting too early or too late (poor light conditions); wait for better light, or end chronographing session.

D) Err 1 shows on screen; the first sensor did not detect the passage of the bullet. This means either that the shot was not fired directly over the centre of the first sensor, or, that there are poor light conditions. Be sure that the Chrony is aligned with the line of fire.

E) Err 2 shows on screen; the second sensor did not detect the passage of the bullet. Same as above: poor light or poor alignment.

F) Err 3 through Err 8 shows on screen; the exact number relates to internal codes, and is of no significance to the user. May indicate poor light condition. Installation of Diffusers may help.

G) Low velocity reading. Light conditions not right; try diffusers. You may be shooting during poor light conditions.

H) False reading (usually high); can result from very strong light, or by operation near electric motors, radar, powerlines, electric fences, static electricity, radio transmitters, etc. It may also be caused by the Chrony being too close to the gun's muzzle. Remedy: try using diffuser, moving away from electrical interference, moving unit farther from the muzzle, or all of these.

I) Very high velocity readings: 1) can result from muzzle blast; move Chrony farther from muzzle; 2) Chrony is not fully open; check for interference from tripod or base.

J) Dead display in cold weather; replace battery with a warm battery.

OTHER TIPS AND HINTS

Make allowances for temperature differences between chronographing your loads and their use in competition. In cold weather, powders burn more slowly and will produce lower velocities than they will at higher temperatures. Different altitudes may also affect velocity. Loads developed which are near maximum velocity during cold weather may produce dangerously high pressures and be unsafe during hot weather. Always try to match conditions while chronographing with those conditions you will face when shooting or hunting. That is, if you hunt in late autumn, do the chronographing in late fall.

ALWAYS WEAR EYE AND EAR PROTECTION WHEN CHRONOGRAPHING.

On sunny days, at certain angles, light may reflect from the bullet and cancel the bullet's shadow. Mark the bullets all the way around with a dark-coloured felt marker if this seems to be happening.

On sunny days, the Chrony may be tilted sideways toward the sun, so that the Diffusers are between the sun and the photocells. Be sure that the Chrony unit remains fully open, and that it is perfectly aligned with the target. Using diffusers on cloudy days may shut out too much light.

Using diffusers on cloudy days is not necessary, since you have the clouds as a white background for contrast.

 

[Dean2]

,

Dean2 ,

Thank you for the suggestion of using the Eley Tenex .22 RF test . That is a very good idea .
I will try that , but it may be 2 weeks before I am able to do so .
I am currently using a Magnetospeed , first generation chronograph .
I do not know anyone with a LabRadar .

By the way , my name is Dean .

Thank You ,
DMP25-06

Just to be clear on the ELEY ES, match rifle that likes the ammo ES will be under 10, normal 22 like a Ruger or typical bolt gun that doesn't have a match chamber ES can be as high as 35, just so we don't incorrectly accuse the Magneto speed of being inaccurate.

 

[jbs2014]

Hello jbs2014 ,

Yes , I have tried the Satterlee method , but I have not tried changing the bullet seating depth to see if that has an effect on E.S.

I have a flame-type annealing machine made by Mike's Reloading Bench ,
( mikesreloadingbench.com ), that I use with Tempilaq to achieve proper temperature .

I use an RCBS Chargemaster Combo to dispense the powder charge , and then I transfer that charge to my RCBS 10-10 Balance beam scale , to which I then trickle powder into pan until the beam perfectly zeros-out . If the trickler happens to drop 2 kernels of powder on it's final trickle , and the beam goes over zero , I will use a pair of tweezers to remove 1 kernel of powder , thereby balancing exactly at zero for the charge weight that I need . After I have filled all of my cartridge cases by this method , I will use an electric toothbrush touching the side of cartridge cases to vibrate and settle the powder inside the cases . Final inspection is to use a flashlight to visually inspect all cases to verify that they are equally charged before seating the bullets . After seating the bullets , I check the runout to verify straightness .

The cartridges that I load and shoot most often are :
6.5CM - Peterson Brass , CCI BR-2 primers , H4350 and RL26 powders , 147 gr. Hornady ELD-M bullets .

.308 Win. - Federal GM brass , Winchester LR primers , Hodgdon Varget and IMR 4064 powders , Sierra Match King 175 gr. bullets .

.300 Win. Mag. - WW brass , Winchester LR Magnum primers , Hodgdon H1000 and Retumbo powders , Berger 215 gr. Hybrid and Hornady 208 gr. ELD-M bullets .

And new toy , 7mm-.300Win.Mag. , that I am currently working on load development .
SIG .300WM brass , necked down to 7mm in 3 steps with neck bushings , Federal 215 Gold Medal match primers , Hodgdon H1000 powder , Berger 180 gr. Hybrid and Hornady 180 gr. ELD-M bullets .

Thank you for your interest ,
DMP25-06

DMP25-06

The only thing I could think of that may help would be to try some different primers, at least in regards to the 6.5 CM, 308, and the .300 Win. I had issues loading 5.56, then I switched to the Federal AR Match primer and I have an ES of 13 FPS with a 77 grain TMK at 2910fps.

Are all the barrels on your weapons at the 100 round mark? How often do you remove copper fouling?

What is the best ES that you have gotten so far?

 

[DMP25-06]

DMP25-06

The only thing I could think of that may help would be to try some different primers, at least in regards to the 6.5 CM, 308, and the .300 Win. I had issues loading 5.56, then I switched to the Federal AR Match primer and I have an ES of 13 FPS with a 77 grain TMK at 2910fps.

Are all the barrels on your weapons at the 100 round mark? How often do you remove copper fouling?

What is the best ES that you have gotten so far?

jbs2014 ,

On the 6.5 CM I have tried Fed 210M , Fed 210 , CCI BR-2 , and Fed 215M , and the BR-2 was most accurate and lowest ES @30+ .
On the .308 Win , I tried Fed 210M , Wolf , CCI 200 , Fed 210 , and Win LR primers , and the Win . Large Rifle primers were most accurate with ES @ 24FPS .
On the .300 WM , I tried Fed 215M , Fed 215 , CCI 250 , Fed 210M , and Win LRMagnum primers . The Win LRM primers gave best accuracy and lowest ES at 25 FPS.

All 3 of these rifles have 500+ rounds through them .

I give them a thorough copper cleaning when accuracy begins to leave ( 200 - 250 shots , sometimes less ).

The 7mm-.300WM is just now at 115 round count , and it has only had Fed 215M primers thus far .
It's ES is the worst , at 40-60 FPS during load development .
But , as I explained in my opening post , 1st shot is usually fastest , #2 , 3 , 4 , are almost identical , and #5 will usually be slower .

Thank You ,
DMP25-06

 

[Dmagna]

When it comes to velocity, Es, and sd that's all made at the Reloaders bench. Holding a rifle a certain way will not effect these components unless you shift the powder away from the primer in a weird way. It sounds to me like your loads just need adjustment.

 

[Dmagna]

Also have to remember that in the summertime your load can change. Keep your ammo out of the sun, don't let a round sit in a hot chamber. Rl 26 acts funny when getting above 85 degrees.

 

[Bstick]

SD and ES is based on the velocity node in the rifle. You have to fine the node. It doesn't matter how OCD you are on the bench, if you haven't found the node. I have consistently had SDs under 5 using just a chargemaster without another scale. I have also had the same SDs using a lab grade scale.

Your chrono isn't the issue. The issue is you are on the edges of the node. Free recoil can effect velocities. It's science.

 

[woodnut]

You have received some good intel, and I sure learned a thing or two myself! One of the best is that it's not so much you or your loading, but the chrony! I have shot over one a lot, and one day I get one set of es and sd, next time different numbers, and the same loadings from one day. The chrony is more sensitive than we give it credit for. If the screens are set at slightly differing distances, angled differently, battery getting low, sky not the same, bullets crossing at different spots, etc.,etc. And there's the shooter holding the rifle differently. Yeah, you can go bonkers trying to find the answers, but if your loads shoot well (pressures, etc.), velocities average is good, and accuracy is good, smile!

 

[DUSTY NOGGIN]

i could see slight sd/ed change but 50fps !! .. no way.. i would have to see that in person to believe it with a rifle i know shoots better ..

solve your neck tension problem and find a powder that gives close to 100% capacity would be my guess for the cure

i have never used a old school chronograph . magneto speed user

 

[DUSTY NOGGIN]

i have a question .. is this fully formed to chamber brass ? and how far off the lands are you seating ???

 

[jbs2014]

DMP25-06

Were you able to get the lower ES?