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I need some group diagnostic help
Posted: Fri Apr 24, 2009 3:02 pm
by ACLakey
I have been working up loads for my new .223AI and I am having a heck of a time with 5 shot groups. I have not had this type of problem with any other rifle so I could use some help figuring out what is going on. The problem is I have been getting three rounds in a very good group with two consistent fliers.
I have been measuring every load so I know the charges are accurate. I am not getting any barrel to stock contact, conditions are fair for shooting. I am using the same Win brass and CCI 200 primers as well. I usually shoot from bags but today I used a lead sled but it did not help any. Here are some samples of what I am talking about.
Any thoughts or suggestions???
I did try some H4895 and had by far the most consistent results and the best velocities with no signs of pressure. The wind started to pick up a bit while shooting these groups. I need to work around this load and shoot some more of it....still not giving up.
Re: I need some group diagnostic help
Posted: Fri Apr 24, 2009 4:24 pm
by surfclod
All of my previous serious range sessions were plagued by fliers as well, most groups had 3-4 holes under 1/2 MOA and a flier or two that ruined an otherwise impressive group.
Just last weekend I did some load development and I have greatly reduced my occurrence of fliers. Here is what I have changed over my previous groups.....
-Bedded action in stock with new recoil lug
-More brass prep, trim to 1.840" flash hole deburred, primer pocket uniformed, neck turned, (about 25-50% material removal)
-Concentricity check, those over 0.0015" were used for foulers
-Match grade primers (CCI BR-4)
I am not sure which was most important, (I suspect the bedding) but I have also noticed, now that I have a chronograph, that often (but not always) a group with a flier also had the larger spread in velocity. My record keeping does not indicate if the flier was the one with the deviant velocity but next time I will note the velocity with each bullet hole to see how well this corresponds.
Do the fliers occur near the end of the group or do they occur at random???
Re: I need some group diagnostic help
Posted: Fri Apr 24, 2009 5:22 pm
by ACLakey
Thanks for the information.
The fliers occur at random which is why I am baffled. I have been very careful to let the barrel cool between shots. I did not think to check the velocity against the fliers, next trip I will keep better notes on the shots. Thanks for the insite.
Re: I need some group diagnostic help
Posted: Sun Apr 26, 2009 3:01 pm
by giterdone
surfclod is on the right track with his recommendations. I would sort the cases by weight after fully prepping them. Also if you want to go further, sort your bullets for uniform base to ogive length. I had a similar problem and it was corrected by outside neck turning and using bushing dies.
Re: I need some group diagnostic help
Posted: Mon Apr 27, 2009 6:12 pm
by ACLakey
Ok, I performed some of the checks mentioned above prior to another frustrating trip to the range this morning. I checked the bedding and it seems good. I took the scope off and made sure the bases and rings were tight. I picked up a second scale to verify the loads were consistent. I went to the range with the load that showed the most potential and the first four groups I varied the primer.
What is up with this group?
It defiantly did not like the CCI 450
Next I tried moving out the seating depth in .010 increments.
Lastly I did not try any hotter load with H4895 so I gave that a go....not so good.
I ran the bore snake down the tube and revisited another load that showed promise. I varied the primers again with not so good results.
I am going to try and borrow a better scope before the next trip out. If that does not show any improvement I will look at re crowning. I know I have not shot anything heavier yet but I really don't know what else to do at this point. Any more information would be appreciated.
Re: I need some group diagnostic help
Posted: Mon Apr 27, 2009 9:44 pm
by acloco
Don't change anything on the rifle yet....change targets. This one is too busy with lines and color.
Some may not believe or consider this as an option...but I am nearsighted. So, add that with scope magnification, targets are sometimes not friendly to me.
Check for yourself - while sitting in shooting position, adjust your scope however you believe it provides the clearest picture, close your eyes, count to ten, open them, and check clarity again.
The orange dots tend to bleed color onto the surrounding target area, thereby, not giving you a true spot to hold on, the dot actually is "floating" on the target. (like the sign test at the driver's license examiner - pick which sign is closer to you - same concept)
See here:
http://www.gunloads.com/modules.php?nam ... itemId=254
I use this one if the cross hairs do not fill up the + in the target:
http://www.gunloads.com/modules/gallery ... itemId=589
Another:
http://www.gunloads.com/modules/gallery ... itemId=689
The following two I use at longer distances. The white center is nice.
http://www.gunloads.com/modules/gallery ... itemId=493
http://www.gunloads.com/modules/gallery ... itemId=497
This works well at 100 yards if the cross hair is not thick.
http://www.gunloads.com/modules/gallery ... itemId=477
And...lastly, use this one. Don't aim at the dots, but use groups of 4 to align the posts of your crosshairs - works well with duplex reticles:
http://www.gunloads.com/modules/gallery ... itemId=637
Re: I need some group diagnostic help
Posted: Tue Apr 28, 2009 7:16 am
by Lenard
Contrary to what has been said so far, my experiences show most problems are with bedding. Even though the bedding of the action may look good, it is a misnomer to believe everything is fine with it. If there is any binding of the action, groups like yours are the norm. I use a dial indicator mounted to the barrel and indexing off he stock. Anytime one has over .005 of movement when loosening the action screws, groups like yours are the norm.
There may be other problems that are causing you to have fliers, of which have been noted.
Lenard
Re: I need some group diagnostic help
Posted: Tue Apr 28, 2009 6:05 pm
by stevecrea
I do not believe you indicated what the rifle is, did you?
Have you experimented with the overall length, and seating the bullet just slightly off the lands?
Have you examined the muzzle to determine if the crown may have been nicked or cut offcenter?
Re: I need some group diagnostic help
Posted: Tue Apr 28, 2009 6:10 pm
by stevecrea
Is the barrel freefloated, or does it have a pressure point near the forend?
Is your ammo sitting in the sun, getting hot? Or are you letting a cartridge sit in a hot chamber?
Re: I need some group diagnostic help
Posted: Tue Apr 28, 2009 6:21 pm
by ACLakey
The barrel is free floated and there is no contact. I am shooting under a shaded awning and the ammo is single fed prior to each shot.
Re: I need some group diagnostic help
Posted: Fri May 01, 2009 9:47 pm
by broncsandwhiskey
How are you doing with your groups now. Well here is something you can do that always works for me and that is fire lapping. Now this may get some flack from some members but it has worked for me. Go to cabelas and look for the David tubb final bore finish and get the .224 kit and follow the directions to the letter and you should see good results. Ride Up.
Re: I need some group diagnostic help
Posted: Sat May 09, 2009 3:28 pm
by ACLakey
Thanks for the information. Through my trouble shooting with the rifle I took the scope off and checked the bases. The front base screws felt loose so I attempted to remove them to find they were stripped. It seems the screws were too short and only grabbed with about 1/16" of thread which gave way. I replaced with longer screws and will try to get to the range in a week...busy with home improvements this weekend. Thanks for the information and I will post results. I will also have a buddies Leupold VX III on had to try as well.
Re: I need some group diagnostic help
Posted: Sun May 10, 2009 8:57 pm
by Ryan S Albright
It sounds like you are doing your home work. I had a windage screw on my scope mount that was cracked but not visable to the necked eye untill I checked the torque and it fell apart. That was about a month back. I was getting funny groups also. I put in a post about it. I bet you found your problem. Good work and thanks for the post. It helps.
Re: I need some group diagnostic help
Posted: Sun May 17, 2009 10:39 am
by ACLakey
An update for those still interested.
After checking the bedding, replacing the screws in my front base and cleaning up the crown I finally made it back to the range. Groups are more consistent than before but I am still seeing the same three in one hole and two in another phenomenon.
I am going to work with the loads of H4895 in the 28.4-28.6 gr range and play with seating depth a little. The horizontal stringing that I was getting is now gone and I will be putting better glass on the rifle at the end of the month. There is hope yet.
Re: I need some group diagnostic help
Posted: Sun May 17, 2009 4:42 pm
by Rambler
Hello, I'm just wandering what is the twist rate on your barrel? I may have missed it but you might have to change bullets,and also its kinda hard to get all 5 shots to go into one hole,I seem to get excited or whatever and probably pull the trigger instead of squeezing it and flowing thur with it,also wind flags, even if its simple like servey tape in a stick.