Vertical bullet stringing

sewwhat89 · #1 08-21-2005, 02:41 PM

What causes bullets to string vertically, inconsistent meplats or velocity variations? I shot a group at 500 m and the bullets are within a quarter inch horizontally, but vary 4 inches vertically. Any suggestions?

11B2CV · #2 08-21-2005, 06:48 PM

Your breathing! [img]/ubbthreads/images/graemlins/grin.gif[/img]

7Rumloader · #3 08-21-2005, 07:15 PM

Velocity variations will definitly cause it and I would think the inconsistent meplats would too. I would check velocities and get the load with the smallest spread for long distance work.

sewwhat89 · #4 08-21-2005, 07:32 PM

I am shooting 175 gr SMK in 300 SAUM. The bullet's meplate seem to vary greatly to the naked eye. The load I am shooting varies from 2946 to 2954 at 15 ft. I have shot it several times, and in the East Tx humidity and heat the loads have always shot the same. I shoot the 500 m targets early am to avoid the wind and mirage, but the bullets ALWAYS string vertically on me. These do at least. The 150 AB always put two touching then one flier, so I shoot the SMK. I never (knock on wood) have fliers with the SMK out to 300 yds, but at 500 the group goes vertical.

1doug · #5 08-21-2005, 07:40 PM

You might want to read this, taken from the 6mmbr site
www.6mmbr.com/verticaltips.html

(jb1000br where were you?)
d-a

royinidaho · #6 08-21-2005, 08:13 PM

[ QUOTE ]
I am shooting 175 gr SMK in 300 SAUM. The bullet's meplate seem to vary greatly to the naked eye. 500 yds is most probably too close for meplates to make that much difference. The load I am shooting varies from 2946 to 2954 at 15 ft. That seems pretty good so shouldn't be a problem I have shot it several times, and in the East Tx humidity and heat the loads have always shot the same. I shoot the 500 m targets early am to avoid the wind and mirage, but the bullets ALWAYS string vertically on me. These do at least. The 150 AB always put two touching then one flier, so I shoot the SMK. Is this ALWAYS the case. How far away is the flyer? I never (knock on wood) have fliers with the SMK out to 300 yds, but at 500 the group goes vertical.

[/ QUOTE ]

What is the symetry of your SMK groups at 300yds? If there is no vertical stringing @ 300 there should be no stringing @ 500. If your groups are good @ 300 and vertically sting @ 500 the first thing I'd check is the parallax. What are your scope details? AO adjustment etc? If an AO then make sure you adjust from 300 to 500.

Next I'd check the front rest. If too hard vertical stringing can occur. If its a pedestal rest and sandbag make sure the stock doesn't stick to it. Should slide easily. Also make sure that the sling thing is not recoiling back into the sand bag. That'll drive ya nuts plus mess up the stock sooner or later.

sewwhat89 · #7 08-21-2005, 09:40 PM

The scope is a Zeiss 4-14x44. The gun slides in the rest, but the swivel stud does whack the bag pretty good. It has a nice channel gouged in it.

At 300 yds, the SMK dont really group well, and the AB put 2 touching and the other about 3 inches away up and left. Every group fired has done that. Its either the first or last shot that is the flier. The SMK group 0.25" at 100, 2" at 200m, 3.5" at 300 yd, and 4.2" at 500 m. I am beginning to think I am the problem. I have limited experience shooting "long" range, and it is a new gun.