When real world shooting does not correspond with JBM, does one have to figure the B.C. given by the manufacturer is in error? While playing at the range last Friday, 8/8/14, I fired almost thirty rounds across an Oehler 33 to establish the velocity of 3,638 feet per second. With a 300 yard zero the printout called for 1.7 to hit at 400 yards. Today, with some firing I discovered I needed only 4 clicks in the Swarovski z5 5-25X52 to get there. JBM suggested 3.7 minutes to hit at 500 yards. The rifle needed only 8 clicks for correct hits. At 600 yards it called for 7.3 minutes. Again I fired a few, letting the barrel cool after two shots each time. I settled on 14 clicks to hit consistantly at 600. Am I see something like .35 -.40� for each click?

What do you guys think?

By going with manufacture info, you relied on it for your trajectory.

shoot without adjusting the scope at different ranges, then measure from the point of aim to point of impact. Assuming you chronied the loads, work back to figure a BC.

By adjusting the scope, you have introduced another variable if you had concerns/questions about the trajectory to start with.

Get a big piece of cardboard or paper and measure out 20 MOA in all four directions in increments of 5 MOA or so from your POI (which would ideally be your POA).

Then crank it up, down, left, right. That will eliminate or affirm a very large variable.



Travis

Boy Oh Boy!!

Thanks, guys, for the suggestions. These activities sound like a lot of fun and very informative.

Swaro's don't track for schit,but as a "saving grace",their Owner's don't shoot for schit either.

Congratulations?................

I just had deja vu

Seen it again...myself...............(grin)

Ringman, give this a whirl. This target was shot at 100 yards. Verticals are 1 MIL, horizontals are 1.5 MIL. Had stiff left to right wind gusts that I did not adjust for. Shot it impatiently at lunch one day recently. Even so, this rig is good to go. The final return to zero was the shot touching the point of aim. I use Litz BC's with assurance. If off at distance it has to be velocity and is a breeze to determine.

I'd want to see 10 Mils and/or 40 MOA of tracking "ability",looonnnnggggg before I was "comfy" in a system's abilities..............

Big Stick,

My personal experience with Swarovski is rather limited. It did take four before I kept the one I have; which shows poor quality control. And the one I kept needed a new spring in the vertical turret before 200 rounds were fired.

Whether the majority of Swarovski shooters are not good shooters, I don�t know. I�ve seen only two other guys at the range with Swarovskis. I don�t remember their shooting, so can�t disagree with your experience.

Lovely Story.

Shoot the come-ups and report back.................(hint)

ctsmith,



That looks good and didn't take many rounds or a long time.

Cut the cardboard, drew it off, shot it, ate lunch, and back at the office all in an hour. It helps to have a rig that does what it is suppose to.

What's JBM ?

Also what bullet are you using?

Wow.................

Spotshooter,

This is a fun tool.

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

I chose the G.S.Custom because of penetration and accuracy testing. They smoked the others.

http://www.gscustomusa.com/contact.html

+P+

Anyhow - if you bullets not spinning fast enough the in stability in-stability will drop the B.C.

Read this from Bryan Litz.... It may explain your issue .

BTW - ya'll have no sense of humor. And I'm not from Texas Either!

WOW!


Ha- I forgot the link, look for his testing post half way down the page.
http://forum.snipershide.com/range-...ler-lr-accubonds-bc-testing-results.html


He has put up a link in that post to a stability calc as well.

Stabilizing should not be a problem. I�m firing an 85 grain bullet in a 10 twists.

Today�s shooting seems to indicate the B.C. is WAY better than advertized.

These guys forget they learned at one time or another also. Only God is omniscient.

Ok.... Maybe I should have read the whole post.



Either way scope testing is a good thing.

Ringman,

I would extend the courtesy of pointing out where they are mistaken...unless of course they ain't.................

You truely are too kind.

I know.

PS and by the way...it's "truly"..............(hint)