Extreme ES caused by barrel?

[LongBomber]

If you have fairly consistent 1/2moa accuracy you are at or near the right seating depth. Then it becomes making sure you are in the right powder node, and neck tension is consistent.

 

[whirlwindjml]

I wish that was it but hard to imagine that when I can shoot other rifles through it the same outing without issues. Unless the small 6mm bullet at those speeds are causing a chronograph issue? Like I said I hope your right. Guess I need to round up another graph to know for sure

What chrono? I went to a magnetospeed and all my mystery speed bull crap went away. The lighting on the optical chrono really messes with things at times. I gave the the other chrono s away and kept 1 for arrows.

 

[DJ Fergus]

What chrono? I went to a magnetospeed and all my mystery speed bull crap went away. The lighting on the optical chrono really messes with things at times. I gave the the other chrono s away and kept 1 for arrows.

I fully agree with you about the optical chronos being mysteriously finicky.

 

[DJ Fergus]

I've got a TC venture in 243 Win that is giving me fits with ES. Ive ran different powder/bullet/brass/primer combos but this particular rifle has ES of around 150fps(sometimes higher) regardless. Its shoots 1/2moa groups @100y but of course with those ES it would probably string at longer ranges. It will normally start out high and the velocity will decrease with every shot, not always but common. Same powder scale and same chronograph used with diffrent rifles that have low ES. Is there something with the chamber/barrel that could be causing this?

You could still try shooting your most accurate load out to 300, 500 , 600 yards or so while shooting through your Chrono. If your impacts show lower on the target for the lower velocities on the Chrono, then you know your reading is good. If not, then you know your Chrono reading is probably not correct.

 

[whirlwindjml]

Another thing I was wondering is what size die. If your not controlling your neck tension it can give you funky speed jumps. The lee collet may help get that closer.

I shoot for 1 thousandth tension now. (Bushing die) I also graphite the necks and with the appropriate powder dose I get single digit ES with the Hodgson powders.

Frustrating sometimes isn't it

 

[Cookie114]

You could still try shooting your most accurate load out to 300, 500 , 600 yards or so while shooting through your Chrono. If your impacts show lower on the target for the lower velocities on the Chrono, then you know your reading is good. If not, then you know your Chrono reading is probably not correct.

That's a good idea. Hadnt really thought if test it that way.

Another thing I was wondering is what size die. If your not controlling your neck tension it can give you funky speed jumps. The lee collet may help get that closer.

I shoot for 1 thousandth tension now. (Bushing die) I also graphite the necks and with the appropriate powder dose I get single digit ES with the Hodgson powders.

Frustrating sometimes isn't it

I'm using a rcbs fl but I'm going to pull my Lee collet die out and try neck sizing some of the once fired and see what happens.

 

[Cookie114]

What chrono? I went to a magnetospeed and all my mystery speed bull crap went away. The lighting on the optical chrono really messes with things at times. I gave the the other chrono s away and kept 1 for arrows.

Caldwell and I agree with you. Ill only use it on overcast days or it's all over the place with all my loads. Yesterday when I was using it I was also shooting 6.5 over it and wasn't getting crazy readings. But maybe the 6mm projectile running appox 3200fps is harder for it to read correctly vs a 6.5 projectile running 2800?

 

[whirlwindjml]

Caldwell and I agree with you. Ill only use it on overcast days or it's all over the place with all my loads. Yesterday when I was using it I was also shooting 6.5 over it and wasn't getting crazy readings. But maybe the 6mm projectile running appox 3200fps is harder for it to read correctly vs a 6.5 projectile running 2800?

Unfortunately my caldwel was most finicky of them all. I bought it because it had pretty good reviews at the time I looked at it but I was severely disappointed.

 

[Cookie114]

Unfortunately my caldwel was most finicky of them all. I bought it because it had pretty good reviews at the time I looked at it but I was severely disappointed.

Mine has always seemed to be accurate as long as I don't use while the sun is out. LABRADAR is what I want but $500 is good chunk

 

[slikmrc]

Shoot some factory loads thru the rifle for a baseline. Could also weigh out and segregate some cases to see if that helps.

 

[Tiny Tim]

Never had much trouble with optical chrony other than during rapidly changing lighting conditions or from day to day set-ups (ie level, distance from muzzle, boreline distance to optical pick-ups etc...)

 

[Tikkashooter]

Might be the chronograph, if the barrel was so erratic that it gives you150 es, it shouldn't be sub moa

 

[Stgraves260]

Pop a 500 yard target, maybe a 12" x 12" something easy to hit, and check your groups. If they are tight then it's your chronograph. I have a few chronograph I just never use them anymore. Chronographs lie. Holes in paper don't.

 

[parker33]

You could still try shooting your most accurate load out to 300, 500 , 600 yards or so while shooting through your Chrono. If your impacts show lower on the target for the lower velocities on the Chrono, then you know your reading is good. If not, then you know your Chrono reading is probably not correct.

Yes, what he said. Quick easy check on chronological readings