8208 question

[bheadboy]

I received my 700 back from the Harts with the bbl. re-chambered to 222m, from 223 which had a loose chamber and shot poorly. trued, crown, bedding etc. they scoped the bbl and said I did not need to change it, I would have if they thought so.

it now shoots .5moa or less as I do my work using 4198, 2015 and h335. weather down here is a bummer - hot humid windy flags flapping etc. - so one cluster under .500 is fine as far as I am concerned until conditions improve.

the problem prompting this post is this -- I tried 8208 in the 222m and all charges were dropped in a culver then weighted on a scale to confirm, trickled if needed. all cases +/- .3 gr and all using the same box of 7 1/2 primers the other loads used. Sierra 50gr bk used on all test.

now the weird thing, the 8202 had velocity (Oehler 35) ranging from 3225 to 4013fps -- WH??? the hang!!!!

I am sized to set the shoulder back .002 and the jump is .020 per Sinclair and Hornady gages.

I have never had a 5 shot string with a 700 fps spread with carefully weighted charges.

help????/

Bob

 

[CJ6]

Chrono issues. Even the best have them.

 

[rcw3]

700 fps spread - - hmmm - - either - - -

A. Chrono malfunction; or
B. Some form of oops at the reloading bench.

My suggestion - - try another round of chrono testing with 8208. I have done a lot of work with that powder (admittedly not the 222M) but it generally yields very tight ES numbers across the chrono in most cartridges I have tried.

 

[CatShooter]

It is a chrono issue - you can not get 4,000 fps with a 50gr bullet, from a 222 Magnum, no matter how hard you squeeze the trigger...

 

[Webster]

I had the same Chrono problem. It seems that if the sun is at a low angle light reflecting off the bullet affects the start/stop triggering of the Chrono. This problem is documented in literature. A sun screen doesn't help because the sun is at an angle under the screen. My range faces the North and the sun is always from behind at a low angle. I seem to get more bad readings about 3 o'clock in the afternoon? Try using the Chrono when it's cloudy or a cloud passes over the sun?

 

[bheadboy]

I have to clarify, -- I was shooting north to south, - I had fired fowlers -4198, 2 loads/groups, 2015 2 loads/groups for a total of 24 fired shots over the Oehler - all velocities consistant

then I went to the 8208 and fired 2 loads/groups - both have the erratic velocities -

then I went to H335 2 loads/groups - not a single problem,

it was only 8208 that did this -- all shooting within 1 1/2 hours in partly cloudy sky with wind varing 8-15mph

based on comments above the only possible though is the sunscreens did not work --but why on only one powder???

again all loads individually weighted and no way a double charge re case capacity.

Bob

 

[amlevin]

based on comments above the only possible though is the sunscreens did not work --but why on only one powder???

Because that's the powder you were shooting when the malfunction occurred.

I'm guessing that if it was truly a powder problem those cases that fired the +700 fps rounds would show some pressure signs or at least look a whole lot different than the ones that shot the slower rounds.

I've had chrono issues where some rounds only recorded sub 1,000 fps and the next almost twice the average speed usually expected for that load. It's all about light, how the bullet triggers the sensors, and also the stability of the internal clock in the chronograph. Fluorescent lights on covered ranges and cell phones can be a problem too.

 

[bheadboy]

thanks for your comment I will give 8208 a try again.

Bob

 

[bdale]

Was the chrony sitting with part of it in the shade and the other in the sun , I've had this happen when shadow was cast across one of the censors

 

[tdogg]

I've had similar issues when my pro chrono batteries got weak. Worth checking prior to your next trial.

Cheers,
Toby

 

[lpreddick]

Bolt lift should have been HARD! with the 4000 fps loads? If lift was same as slower loads, chrono problem.

 

[bheadboy]

new batteries, out in the open, no shade. bolt lift modestly firm, not hard - case head no burnish

chrono must be the source.

Bob

 

[joshb]

Maybe God wants you to stick with the 335?

 

[mshelton]

Maybe God wants you to stick with the 335?

Agging for Jesus.

 

[Ledd Slinger]

It is a chrono issue - you can not get 4,000 fps with a 50gr bullet, from a 222 Magnum, no matter how hard you squeeze the trigger...

+1