GlockTalk.com
Home Forums Classifieds Blogs Today's Posts Search Social Groups



  
SIGN-UP
Notices

Glock Talk
Welcome To The Glock Talk Forums.

 
  
Reply
 
Thread Tools Display Modes
Old 04-18-2010, 13:48   #1
n2extrm
Senior Member
 
n2extrm's Avatar
 
Join Date: Feb 2009
Posts: 1,915
More Chrono data

As some of you may remember I posted some chrono data back in December and some problems I may have had.

http://glocktalk.com/forums/showthread.php?t=1155094

I finally got back to the range today and made some adjustments to the load trying to get SD, ES and velocity where I wanted it. I tried increasing neck tension and varying the charge to see where I would head.

The book data is for .308 winchester, 168g sierra match kings bthp, large rifle primer, 42.0g re15, seated to 2.800 inches should yield 2600 fps.

My loads and data is as follows. I have included high low es sd and velocity to keep it simple.

1st string 7 shots. Federal brass full length sized, 168 SMK, fed 210m primer, 42.0 grains RE15, seated @ 2.800"
High 2502
Low 2441
ES 61
SD 20

2nd 10 shots. Hornady Match Brass, neck sized with .335 bushing, 168 SMK, fed 210m primer, 42.1 grains RE15, seated 2.800
High 2468
Low 2316
ES 152
SD 41.7

3rd 10 shots. Hornady match Brass, neck sized with .335 bushing, 168 SMK, fed 210m primer, 42.4 grains RE15, seated 2.945"
High 2466
Low 2372
ES 94
SD 28.3

4th 10 shots. Hornady Match Brass, neck sized with .331 bushing ( better neck tension) 168 SMK, fed 210m primer, 42.6 grains RE15, seated 2.945"
High 2475
Low 2414
ES 61
SD 22.6

The groups are close in size, but the best group at 100 was probably #1 then # 3 by #4 I think I was spent and it was useless to measure it. I was also more worried about hitting the chronograph then perfect shooting!

My thought is to leave the smaller bushing and longer length, bump the charge up to 43.0, 43.2 and 43.4 and see what numbers are revealed. 43.6 is max published, but I am bellow velocity and I am longer then published length so I think I will be safe even a little above the max published.

Suggestions or thoughts?

Last edited by n2extrm; 04-18-2010 at 13:49..
n2extrm is offline   Reply With Quote
Old 04-20-2010, 21:56   #2
dougader
Senior Member
 
dougader's Avatar
 
Join Date: Apr 2004
Location: OryGun
Posts: 3,384
If you're shooting for both group size and velocity at the same time I don't think you'll get your best groups because you're thinking tooo much about blasting your chronograph. Shoot for velocity first, then shoot the same load for group size.
__________________
Doug

"In St. Louis, armed Homeland Security agents monitored Tea Party members protesting the IRS. Good idea. When people think their government is out to get them, the best response is to send the government out to get them." -Fred Thompson
dougader is offline   Reply With Quote
Old 04-21-2010, 05:29   #3
srd
Senior Member
 
Join Date: Apr 2009
Posts: 284
I load 11 rounds of each test round. I mark the holders as to what is in each along with each target before i leave fror the range. Shoot for group size first and then chrono the last round after all the loads have been shot. . I have learned over the years that you can have a lousy SD and accuracy can be excellent.
srd is offline   Reply With Quote
Old 04-21-2010, 16:45   #4
n2extrm
Senior Member
 
n2extrm's Avatar
 
Join Date: Feb 2009
Posts: 1,915
Quote:
Originally Posted by dougader View Post
If you're shooting for both group size and velocity at the same time I don't think you'll get your best groups because you're thinking tooo much about blasting your chronograph. Shoot for velocity first, then shoot the same load for group size.
Yeah I see that can be a problem. I actualy thought of just buying the spare screens now. Groups have been good till I get past 200 yards. That is why I started to play with the chronograph.

Quote:
Originally Posted by srd View Post
I load 11 rounds of each test round. I mark the holders as to what is in each along with each target before i leave fror the range. Shoot for group size first and then chrono the last round after all the loads have been shot. . I have learned over the years that you can have a lousy SD and accuracy can be excellent.
Trying this actualy. I know what seemed to group better and worse, then was looking at the chrono data. Just trying to get the most out of the load.

Thanks guys, I have been reading and re-reading and I think the Hornady cases may be an issue. It seems they have a larger capacity then most, I think that may be the slower numbers and higher ES and SD. I plan to go up a little and see where it heads. No pressure signs on the brass and primers, easy bolt lift, so I will bump it up and see where it goes.

Thanks again.
n2extrm is offline   Reply With Quote
Old 04-21-2010, 17:54   #5
GLShooter
Senior Member
 
Join Date: Jan 2006
Location: Phoenix, AZ
Posts: 404
Send a message via AIM to GLShooter
I like to load to at least 90% on my rifle cases. It seems to help for consistency. The closer to 100% density the better for me.

I always shoot for group as I chrono my ammo. I use a Millennium CED Chrono and have not hit any screens yet. 10 feet from muzzle to screen. The big area is plenty big enough to steer around.

Greg
__________________
The best gun for self defense? Any loaded one will do.
GLShooter is offline   Reply With Quote
Old 04-21-2010, 18:15   #6
WiskyT
Malcontent
 
WiskyT's Avatar
 
Join Date: Jun 2002
Location: North Carolina
Posts: 11,755
Your accuracy beyond 200 yards is probably off due to paralax. That is an issue that is a thread in and of itself. The short version is, if you don't have a scope with paralax adjustments, and you don't make 100% certain that your eye is totally centered in the lense, you can move your point of impact easily as much as a foot on each shot. That is the trouble I was having with my regular bubba deer hunting scope. A guy showed me a trick and it fixed it right up, but it's not the right way to do it. It's just a field expedient that works. You have to move your eye forward or backward until you have a very small area to sight through. That small area will be in the center of the scope. To see what I'm talking about, rest your rifle on bags so it will stay still without you touching it and it is sighted on a 300 yard target. Move your head left and right and see how the reticle moves the opposite way.

If your gun/load shoot a good group at 100 yards, it will shoot a good group at 300, you just have to find a way to make it work. The bubba scopes are set to be paralx free at 100 yards, they have a lot of error at 300 and beyond.
__________________
Drugs are bad because if you do drugs you're a hippie and hippies suck.
Eric Cartman


"If you kill enough of them, they stop fighting."-General Curtis E. LeMay

Last edited by WiskyT; 04-21-2010 at 18:15..
WiskyT is offline   Reply With Quote
Old 04-21-2010, 18:20   #7
n2extrm
Senior Member
 
n2extrm's Avatar
 
Join Date: Feb 2009
Posts: 1,915
Quote:
Originally Posted by WiskyT View Post
Your accuracy beyond 200 yards is probably off due to paralax. That is an issue that is a thread in and of itself. The short version is, if you don't have a scope with paralax adjustments, and you don't make 100% certain that your eye is totally centered in the lense, you can move your point of impact easily as much as a foot on each shot. That is the trouble I was having with my regular bubba deer hunting scope. A guy showed me a trick and it fixed it right up, but it's not the right way to do it. It's just a field expedient that works. You have to move your eye forward or backward until you have a very small area to sight through. That small area will be in the center of the scope. To see what I'm talking about, rest your rifle on bags so it will stay still without you touching it and it is sighted on a 300 yard target. Move your head left and right and see how the reticle moves the opposite way.

If your gun/load shoot a good group at 100 yards, it will shoot a good group at 300, you just have to find a way to make it work. The bubba scopes are set to be paralx free at 100 yards, they have a lot of error at 300 and beyond.
Thanks Wiskey. Almost all of my scopes have paralex adjustment only one does not a 3-9X for the woods. I just seem to get looser and alot more drop then I would like at the longer rangers. It could be 100% THE IDIOT AT THE TRIGGER. I am just trying to learn and enjoy while getting the most out of it. What do you think of the velocity I am getting out of a 26" barrel remington 700?
n2extrm is offline   Reply With Quote
Old 04-21-2010, 18:31   #8
WiskyT
Malcontent
 
WiskyT's Avatar
 
Join Date: Jun 2002
Location: North Carolina
Posts: 11,755
Regarding paralax, I see that you have that covered.

Regarding velocity, the numbers look a bit slow. My older Hornady manual doesn't have data for R15, but with a 22" tube and numerous powders with their 168BTHP, they get higher velocities, 2600-2700. I'm not saying boost the R15 charge, because I don't know what the max is, but you might be better off with a different powder. You should be able to get more along the lines of 2800-2900 with a 26" bbl.
__________________
Drugs are bad because if you do drugs you're a hippie and hippies suck.
Eric Cartman


"If you kill enough of them, they stop fighting."-General Curtis E. LeMay
WiskyT is offline   Reply With Quote

 
  
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump




All times are GMT -6. The time now is 03:45.




Homepage
FAQ
Forums
Calendar
Advertise
Gallery
GT Wiki
GT Blogs
Social Groups
Classifieds


Users Currently Online: 595
140 Members
455 Guests

Most users ever online: 2,244
Nov 11, 2013 at 16:42