New guy, 6mm creedmoor Q's

[BigdaddyWSM]

Hello everyone from South Dakota. I am a new member but have been shooting for awhile. I built a 6mm CM on a Savage action, 1-8 Shilen 26" barrel to use as a long range coyote/antelope rifle.
I have been working up a few loads with the 95 gr Berger VLD hunting bullet & am having wierd results. this is a 1 round scott satterlee thing trying to find a level in graph to start with. OAL is .020 off lands with comparetor. using Whidden dies. necks are .270 bushing. 1-1.5 th runout. only about 50-60 rounds through rifle so far. using a Lyman gen 6 scale backed up with Gempro 250 both calibrated first.
Started out with 41.4 -43.2 gr H4350.
1. 3050
2. 3080
3. 3029
4. 3049
5. error
6. 3194
7. 3163
8. 3157
9. 3226
10. 3206
Kind of jumping all over place but everything in center of 1" dot. Any reason on the up/down velocities?

 

[davere]

What chrono are you using?

 

[BigdaddyWSM]

I am using the Caldwell , fresh batteries & always seemed to work pretty good. and using Starline LP brass 2nd firing.

 

[BigdaddyWSM]

What chrono are you using?

#3
I am using the Caldwell , fresh batteries & always seemed to work pretty good. and using Starline LP brass 2nd firing.

 

[XLR308]

You say it is a brand new barrel, if so it would most likely need to be broke in before it will settle in and give more consistent velocities.
Your #9 velocity may also be were you topped out. Do you have any pressure signs on your brass or primers on your mid to top end loads?

 

[davere]

#3
I am using the Caldwell , fresh batteries & always seemed to work pretty good. and using Starline LP brass 2nd firing.

Optical chronos can be a real PITA sometimes - they want light to be within a certain narrow range, or they cough out weird values. In addition to XLR308's comments, I'd double check your chrono setup - make sure that the light is consistent and well diffused (like, the chrono is fully in the shade, with no direct light striking it or the skyscreens), and that it's an appropriate distance from the muzzle. I've seen similar issues in the past - inconsistency, and weird readings - when chrono'ing with an optical chrono in non-optimal lighting conditions. My fix for that was to use IR skyscreens (CED chrono) and always have the chrono fully in the shade - short of building a box for it (which is heavy to lug around), that usually got me consistent results.

You might have already done all of those things, but if not, it's good info to know/use.

 

[RTH1800]

Make sure chrono is not too close to the muzzle.

 

[GIXXER2000]

Not a big fan of those Chrono's . I use a Magneto Speed reads every shot.
I don't even bother trying to chrono my loads until I have min 50 round down the tube as the barrel changes so much. Get some rounds down the tube then see if you AVG FPS become more stable.

 

[BigdaddyWSM]

You say it is a brand new barrel, if so it would most likely need to be broke in before it will settle in and give more consistent velocities.
Your #9 velocity may also be were you topped out. Do you have any pressure signs on your brass or primers on your mid to top end loads?

No pressure signs at all.

 

[BigdaddyWSM]

Optical chronos can be a real PITA sometimes - they want light to be within a certain narrow range, or they cough out weird values. In addition to XLR308's comments, I'd double check your chrono setup - make sure that the light is consistent and well diffused (like, the chrono is fully in the shade, with no direct light striking it or the skyscreens), and that it's an appropriate distance from the muzzle. I've seen similar issues in the past - inconsistency, and weird readings - when chrono'ing with an optical chrono in non-optimal lighting conditions. My fix for that was to use IR skyscreens (CED chrono) and always have the chrono fully in the shade - short of building a box for it (which is heavy to lug around), that usually got me consistent results.

You might have already done all of those things, but if not, it's good info to know/use.

I was in sun with shades on, facing East around 10:00 am. I will try an overcast day next & also I was 8 ft from Chrono, maybe too close?

 

[XLR308]

No pressure signs at all.

I would just continue to do whatever your barrel break in process is and load work up. If you feel confident that your chrono is not giving you erroneous readings I wouldnt worry to much about it. I have a Beta Master chronograph that has irritated me to the point that the only reason I still have it is so I can shoot the damn thing when I replace it with a Magnetospeed. It works great when I'm all by myself but as soon as the are others shooting near me it starts throwing error codes.

 

[Rangemaster]

Hello everyone from South Dakota. I am a new member but have been shooting for awhile. I built a 6mm CM on a Savage action, 1-8 Shilen 26" barrel to use as a long range coyote/antelope rifle.
I have been working up a few loads with the 95 gr Berger VLD hunting bullet & am having wierd results. this is a 1 round scott satterlee thing trying to find a level in graph to start with. OAL is .020 off lands with comparetor. using Whidden dies. necks are .270 bushing. 1-1.5 th runout. only about 50-60 rounds through rifle so far. using a Lyman gen 6 scale backed up with Gempro 250 both calibrated first.
Started out with 41.4 -43.2 gr H4350.
1. 3050
2. 3080
3. 3029
4. 3049
5. error
6. 3194
7. 3163
8. 3157
9. 3226
10. 3206
Kind of jumping all over place but everything in center of 1" dot. Any reason on the up/down velocities?

Keep working on a load, it took me about 150 to 200 rounds before I settled on 41.7 gr h4350 at 3060 fps.
your velocities might be in your powder measurements or neck tension. My scale reads down to the hundreds .001.

 

[BigdaddyWSM]

Keep working on a load, it took me about 150 to 200 rounds before I settled on 41.7 gr h4350 at 3060 fps.
your velocities might be in your powder measurements or neck tension. My scale reads down to the hundreds .001.

I will do that, thanks. Got some RL16 been wanting to try anyway. I'll keep you guys posted. Thanks for all the advice.

 

[davere]

I was in sun with shades on, facing East around 10:00 am. I will try an overcast day next & also I was 8 ft from Chrono, maybe too close?

Usually with an optical chrono, they tell you to be at least 12 feet away from the muzzle. So, you could potentially have some blast effect interfering.

Definite +1 on the Magnetspeed being a better option.

 

[Codiekfx400]

It’s probably not your powder charge method I throw mine with a lee perfect powder measure (different powder) and I have the same chronograph and my velocities are more consistent than that.