Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels and Ballistics


Reply

Ladder test and scientific method question for the ballisticians.

 
LinkBack Thread Tools Display Modes
  #1  
Old 03-21-2007, 01:14 PM
Platinum Member
 
Join Date: Jun 2007
Posts: 1,515
Ladder test and scientific method question for the ballisticians.

Hey guys 4key's back. I've been in a bit of a hovering pattern recently with the long range stuff but I am hitting the reloading hard and heavy with some new wildcat bullets that recently found their way into my mailbox.

Heres the background: Richard sent me some 169.5 gr rbbt .30 cal open meplat j4 jacketed bullets. I put them on top of my standard loads of 41.4 gr of h335 in once fired brass and the groups were phenominal. 1 to 1.5 inch range at 300 yards.

Heres the procedure: I ordered 100 169.5 gr rbbt tapered jacket .30 cal bullets. They were the same uld shape but did not have the open meplat. I loaded them the the same distance from the lands and did a ladder test at 300 yards with a .3 grain increment using varget.

The ladder test showed a clear and consistent "peak and valley" pattern. at the bottom of the valleys there were 3 shots then the string would peak again within 1 shot. the velocities would also climb consistantly.

I chose to load six 3 shot test loads around the 2 loads in the highest velocity valley with each 3 shot group loaded in .1 grain increments. Basically trying to tune in on the highest velocity accuracy node.

Heres the results: The 300 yard groups were unsatisfactory. There were groups that strung out sideways. There were groups that strung verticaly. The smallest group was a symmetric triangle that was 3.5 wide by 1.5 inch high. Nothing consistant from one group to the other where I could say "these 3 groups are OK but this is where they start falling appart."

As a control to this I also loaded three 3 shot groups with the h335 powder that had worked so well with the test bullets. I loaded 41.3 41.4 and 41.5 gr to see if I had the same good results I had before. These loads were the worst of all. I couldn't believe what I saw.

The question: What do I do next? The variables changed were a change in powder (except in the control test), a change in jacket design and a change in new brass from once fired and neck sized.
I don't know if I should try the same 3 shot groups from once fired brass? Should I scrap my hopes of using varget? Should I throw away the data from the ladder test and use a conventional 4 or 5 shot group test with loadings in .2 gr increments starting 10% below max load?
__________________
GRAVITY. It's not just a good idea. It's the LAW!
Reply With Quote
  #2  
Old 03-21-2007, 06:03 PM
Platinum Member
 
Join Date: Jan 2004
Location: Blackfoot, Idaho
Posts: 8,058
Re: Ladder test and scientific method question for the ballisticians.

I stated to respond in a very detailed manner but....got lost in my own thinking [img]/ubbthreads/images/graemlins/confused.gif[/img]

After reading the post a couple of times; do you have any of the older open meplate bullets left? I'm betting the answer to that one is no. [img]/ubbthreads/images/graemlins/grin.gif[/img]

You may want to check COL from base to ogive w/the new bullets [img]/ubbthreads/images/graemlins/confused.gif[/img] and compare to the older bullets.

Changes you stated should not have made as much difference in your results as you observed. The standard load that shot so well w/the open meplate bullets indicates that the limiting variable is the bullet. [img]/ubbthreads/images/graemlins/confused.gif[/img]
__________________
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
Reply With Quote
  #3  
Old 03-22-2007, 01:01 AM
Platinum Member
 
Join Date: Jun 2007
Posts: 1,515
Re: Ladder test and scientific method question for the ballisticians.

Hey Roy. I actually do have some of the bullets left. In fact I fired two of them at the 300 yard target first to make sure I was on paper. Those two bullet holes were exactly 1 inch apart stacked almost straight up and down. [img]/ubbthreads/images/graemlins/frown.gif[/img] base to ogive is the same. I want to get in touch with Richard and pick his brain on the matter as well.

Good to hear from you again. I'm going to let this topic soak for a while before loading anything for a return trip to the desert. I'm hoping to hear from Kirby the resident wildcat factory rep, Abinok my ladder test mentor and the Utah boys just because they know their stuff and I havent had a chance to strike up a conversation with them in a while. There is alot of other knoledge here as well so anyone with a thought on the matter please speak up. Dont be bashful, I really don't have any decent plan at this time and I see rock chuck season coming just around the corner.
__________________
GRAVITY. It's not just a good idea. It's the LAW!
Reply With Quote
  #4  
Old 03-22-2007, 07:27 AM
Platinum Member
 
Join Date: Jan 2004
Location: Blackfoot, Idaho
Posts: 8,058
Re: Ladder test and scientific method question for the ballisticians.

send me your email, I've lost it,rrrrr I can't find it. [img]/ubbthreads/images/graemlins/mad.gif[/img]
__________________
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
Reply With Quote
  #5  
Old 03-22-2007, 04:13 PM
Platinum Member
 
Join Date: Jun 2007
Posts: 1,515
Re: Ladder test and scientific method question for the ballisticians.

4kedhorn@gmail.com
__________________
GRAVITY. It's not just a good idea. It's the LAW!
Reply With Quote
  #6  
Old 03-22-2007, 04:50 PM
Platinum Member
 
Join Date: Sep 2004
Location: on the rifle range in Utah
Posts: 2,723
Re: Ladder test and scientific method question for the ballisticians.

Good to see you're back 4key! Glad to hear you are out shooting again.

Try repeating the ladder with once fired brass and Varget. Forget that dirty, temperamental H335. Other than that, I'm afraid I don't have any more advice. I'm not too keen on the ladder tests because of problems as you mention so I'm probably not the best guy to help you with them since I never use them. Perhaps Abinok can help?

Rockchucks are out now but are still either nursing or are pregnant so just a little longer and they're fair game. Yippeee! [img]/ubbthreads/images/graemlins/wink.gif[/img]
__________________
Find it
Range it
Click it
Pull it
Dump it

If it's not far, it's boring.
Reply With Quote
  #7  
Old 03-22-2007, 09:49 PM
Platinum Member
 
Join Date: Jun 2007
Posts: 1,515
Re: Ladder test and scientific method question for the ballisticians.

10-4 on the chucks. Make sure to say hi to Unk and Roland. I still talk about you guys and your pink and blue cannon. How is the .338 thunder? I was going to read up on it but I am too far behind to read the big post about it. What ranges are you hitting fur with that gun.

I agree that I should still give the Varget another fair shake. I did call Richard Graves and I'm glad I did. He gave me some advice that I remembered Kirby giving a long time ago once I heard it again. Basically it was to kiss the lands and kick 'em in the butt. I am going to try increasing the velocity and getting them as close to the lands as I can and still keep them mag length. I know that getting the rounds .005 or less from the lands is best but this is a hunting gun and not a BR so I insist on having the rounds fit the mag. I would sooner spend the $$$ to have the pipe rechambered to bring the lands back toward the bullet.

If you have the time, tell me what you would would do with the remaining 51 bullets to find my best (reasonable) load. I have Varget powder, fed match primers, once fired brass, new brass and a pact chrono. Should I load 3 shot groups in .2 gr increments? Should I shoot another ladder and sneak past max looking for pressure signs? Let me know.

If anyone else has a thought let me know.
__________________
GRAVITY. It's not just a good idea. It's the LAW!
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: Ladder test and scientific method question for the ballisticians.
Thread Thread Starter Forum Replies Last Post
Ladder Test Question coues7 Reloading 4 11-19-2010 04:40 AM
Ladder test result question rugerdog5 Reloading 9 06-15-2010 08:57 PM
Ladder Test Results & "Sweet Spot" Question. FullCurlHunter Reloading 1 04-14-2006 08:24 AM
Ladder Test Question ??? GO-FASTER Reloading 15 01-29-2006 09:20 AM
ladder test question. Sasquatch Reloading 9 06-08-2005 10:33 PM

Current Poll
Do You Think Slingshots Should Be Legalized For Hunting Brown Bear?
Yes - 47.09%
890 Votes
No - 52.91%
1,000 Vote
Total Votes: 1,890
You may not vote on this poll.

All times are GMT -5. The time now is 10:26 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC