Long Range Hunting Online Magazine


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


Reply

How do I get my extreme deviation or spread DOWN?

 
LinkBack Thread Tools Display Modes
  #22  
Old 08-26-2013, 09:05 AM
Silver Member
 
Join Date: Dec 2006
Posts: 336
Re: How do I get my extreme deviation or spread DOWN?

Thanks Mikcr! That's incredible, now I have another excuse to experiment/shoot&load.
If you don't mind me asking, how tight is the neck on the rifle you're shooting?
Thanks again!
Steve
Reply With Quote
  #23  
Old 08-26-2013, 11:47 AM
Platinum Member
 
Join Date: Aug 2003
Location: NC, oceanfront
Posts: 3,234
Re: How do I get my extreme deviation or spread DOWN?

I have only one factory gun right now, a Cooper in 223. This one gives me 4thou total clearance over loaded necks. But it doesn't get easier to load than with a 223.
My other guns (in 6br, 6xc, 6.5wssm) have aftermarket barrels chambered with my reamers. Well I just sold the 6xc, but it provided 2.5thou of clearance. The 6br is tight, and I turn necks for 1.5thou total clearance. The 6.5wssm is fitted, I turn the necks for 1thou total clearance with it (does not require neck sizing at all).
The 6.5wssm provides for learning truths about some things assumed around here.
Related to annealing, I learned from it, and my measure, that firing does not harden brass -ever.
It is sizing cycles that hardens brass. Sizing being an amount that actually causes yielding(it's beyond spring back).
Reply With Quote
  #24  
Old 08-26-2013, 04:21 PM
Silver Member
 
Join Date: Dec 2006
Posts: 336
Re: How do I get my extreme deviation or spread DOWN?

Thanks Mikecr! This is very interesting; especially that you're able to actually measure neck tension. Have you ever had a neck crack on you? If so, how many firings did you get before that happened?
Thanks again for the valuable information!
Steve
Reply With Quote
  #25  
Old 08-26-2013, 07:53 PM
Platinum Member
 
Join Date: Aug 2003
Location: NC, oceanfront
Posts: 3,234
Re: How do I get my extreme deviation or spread DOWN?

I've never had a case problem of any sort. My brass will last the rest of my life, and/or as many barrels, cut with my reamers, that I use.
This makes the cost of any brass meaningless to me.

I don't measure neck tension(grip). There is currently no tool that does this.
I measure seating force with a hardened mandrel from necks that are consistent in friction (carbon film present). When hardness changes(from initial lead dip stress relieving) I get a big step change from normal. I get necks that are weak in springback. But that's alright, a few fireforming/sizing cycles, and all settles to normal.

Now the 223 brass for my cooper is not turned, and there is a small bit of thickness variance there. ~1/2thou total. I'm sizing it pretty good and I see small variances in seating force measure with a few out of 50 I reload at a time. SO far I've been able to adjust to match by tweaking length of neck sizing. No problem yet, but maybe I'll tire of this if it turns into a problem trend.
I'll either lead dip to start over, or go to Lapua's newer brass at that point.

I have never tried frequent annealing, as I don't picture any good in it over my approach. But I can picture bad in it easy enough.
Annealing takes the stored springback out of your brass. Springback is all that grips bullets(not interference fit). When you reload you WILL expand necks, but bullets make terrible expanders. So necks should be pre-expanded to proper interference prior to bullet seating.This also pushes thickness variance outward, allowing straighter seating. When your seating forces to get too high, due to downsizing annealed necks without follow-up pre-expansion, seater stems wedge onto bullet noses and your seating depths go all over the map.
But, pre-expanding annealed necks for proper interference may not leave enough bullet grip, because there is lower springback to grip bullets with. Adjustments for this mean over sizing, under expansion, and the tail chasing begins..
Now you can develop a load with very light neck tension, caused by frequent annealing, but you won't have as many options to the tuning. Good for benchrest -when you don't need many options, bad for hunting cartridges, where you usually do.

I fine tune loads with tension adjustment(length of neck sizing), as set through seating force measurement -vs- results. Frequent annealing would mean giving that up at least, and for no more reason than a bandaid on poor planning up front.
Reply With Quote
  #26  
Old 08-26-2013, 09:02 PM
Silver Member
 
Join Date: May 2013
Location: Elkhorn Idaho
Posts: 344
Re: How do I get my extreme deviation or spread DOWN?

I built a 6.5-284 for one of my return valued customers 5 yrs ago. I knew the man knew how to shoot and how to load. He had a Weatherby MK5 action, Bartlien bbl, etc. When it left my shop it would print a .118 ctc group. He came back in 2 yrs and it opened up to a 2in group and upon closer examination his deviation was over 250 fps! He wanted a new barrel. With only 450 rds I knew something was wrong. After pushing him and questioning him he admitted he had listened to the internet and installed a David Tubb firing pin spring and had a titanium firing pin installed. The strikes on the primers were indicating this.I Installed a factory spring that I modify a steel firing pin and he was back in business. Moral of the story,, sometimes its not the obvious as the previous 4 pages point out, The internet is a danger place, and do not fix it if its not broke!
Reply With Quote
  #27  
Old 08-26-2013, 11:25 PM
RTK RTK is offline
Silver Member
 
Join Date: May 2012
Location: Left coast, kalifornia
Posts: 330
Re: How do I get my extreme deviation or spread DOWN?

Not doubting you, but how could something like that cause that big of variance.
Reply With Quote
  #28  
Old 08-27-2013, 08:21 AM
Platinum Member
 
Join Date: Aug 2003
Location: NC, oceanfront
Posts: 3,234
Re: How do I get my extreme deviation or spread DOWN?

You wouldn't think it would, given a primary explosive in primers.
But I've tested myself and discovered that different striking of primers absolutely changes results from them.
I also found there are a lot of things affecting primer strike.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Current Poll
Spot & Stalk or Ambush For Western Deer?
MOSTLY - Spot & Stalk - 73.55%
1,029 Vote
MOSTLY - Ambush - 26.45%
370 Votes
Total Votes: 1,399
You may not vote on this poll.

All times are GMT -5. The time now is 12:18 AM.


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