284 Shehane vertical issue

[JamesnTN]

I took the 284 Shehane out yesterday to give it a whirl at 1000 since all my testing has only been done at 500 yards. Before I took it to 1000 I shot two five shot groups with it at 500 that yielded groups of 1.5". Once I was zeroed I dialed up 16 MOA and went to 1000 yards. The mirage late was rough and after getting zeroed I went to paper and shot two five shot groups one using the 210m primers and the other with the BR2 primers my best group was 10.5" and all verticle. I never measured the other but I'm guessing at least 12" if not more. The best group was usng the BR2 even at 500 yards. So I'm puzzled at how can a rifle shoot so well at 500 go to crap at 1000?
I admit I did run them pretty fast as I was running out of daylight. But still I felt I shot them accurately.
My load on this is 57.5 grains of H4831sc and a 180 Berger hybrid HBN coated. I've only ran it across a chronograph to get a avg velocity and I don't remember the ES but I know it wasn't near as good as my Dashers are.
So any advice on how to get this verticle down. I've been up to 58.5 grains in testing and I'll say the brass didn't like it. No hard bolt lift but I could definitely feel the difference in sizing the cases back.

 

[savageshooter86]

Mirage was rough. That is probably the issue

 

[Terry]

James

I think you said it... The mirage late was rough

I'd re-shoot in better conditions.

 

[JamesnTN]

Mirage was rough. That is probably the issue

Yea I couldn't believe the mirage at near dark. I dialed the scope way back after I shot those groups and put a shot on a 10" plate then I moved down to the 4" plate and put two shots on that one. I caught the edge of it both shots but verticle on that was less than 2" but again I dialed the scope back and took more time on those shots.

 

[Terry]

Can't wait to see your next groups!

 

[JamesnTN]

Can't wait to see your next groups!

Hopefully I can reshoot in the morning if the wind isn't too bad.

 

[noload]

If you have at least .0035" neck clearance, I don't think thats your vertical issue. My Shehane would not like 57.5gr..... It might shoot good ?? Don't think I could afford the brass..

 

[savagedasher]

Simple check put a target up at 100yds . Put a aim point 28'' below the target and shoot 2 shots . If you have any vertical at 100 it wont get better at 1000. Larry

 

[JamesnTN]

Simple check put a target up at 100yds . Put a aim point 28'' below the target and shoot 2 shots . If you have any vertical at 100 it wont get better at 1000. Larry

Larry,

The rifle is near water lined at 500 it shoots 1.5" five shot groups at that distance. I've never seen verticle at loads while shooting at 100 yards. That's why I do most my load developing at 300 and then move out to 500 and tweak it.

 

[savagedasher]

Simple check put a target up at 100yds . Put a aim point 28'' below the target and shoot 2 shots . If you have any vertical at 100 it wont get better at 1000. Larry

Larry,

The rifle is near water lined at 500 it shoots 1.5" five shot groups at that distance. I've never seen verticle at loads while shooting at 100 yards. That's why I do most my load developing at 300 and then move out to 500 and tweak it.

Some time it pays to read all that you said . My Bad Larry

 

[JamesnTN]

Well I went back out today and shot once more this time no mirage and I also dropped powder .2 and upped it .2 of a grain the charge of 57.3 shot 9" verticle the 57.5 shot just under 5" of verticle (this is my original load) and the charge of 57.7 grains shot just over 6" verticle. Horizontal on all groups were less than 1" I just have find a way to get that verticle out.

I was suggested to go up to a 215m primer and that's my next test is try a hotter primer, or do I use a tighter neck bushing?

Any suggestions?

 

[Tommie]

Nornally I'd suggest chronographing to sniff out an ES gremlin, but those 1.5" groups at 500 yards kinda blow that theory. If there a chance the issue is environmental? Some sort of updraft thing happening down range? And just thinking out loud: could a parallax problem affect 1000 yard shots but not half that distance?

 

[JamesnTN]

Nornally I'd suggest chronographing to sniff out an ES gremlin, but those 1.5" groups at 500 yards kinda blow that theory. If there a chance the issue is environmental? Some sort of updraft thing happening down range? And just thinking out loud: could a parallax problem affect 1000 yard shots but not half that distance?

I checked the parallex that's good to go. Now the other theory I don't know it's possible. Today was windy 4-6 mph switched 3-11 and a tail wind. Another theory brought to my attention that I need to test is maybe I'm not putting enough shoulder into the rifle or my front bag is too hard. I'll work on that one the conditions I have no control over I'll just have to test more when there's no wind.
I'm not expecting 2" groups from this rifle but I'd like to at least move another 2" of vertical. I feel I'm in my node since powder upped by .2 grain added more vertical. This 1000 yard accuracy is new to me as I normally only shoot 600 yards so I am aware setup is more critical and holding the gun the same each time also is as critical. I'll get it figured out and thanks for those sending me emails and private makes ages on this.

 

[Tommie]

James,

I didn't want to suggest a possibility of inconsistent bench technique because some people get insulted. But since you brought it up, yes, it's something to consider.

 

[Terry]

Someone told me what can't come back comes up. For what its worth.

 

[1shot]

James,
Have you tried Wolf/Tula primers? I watched a series done years ago by Bob Jenson and German Salazar. The most mild primer gave the lowest ES/SD the opposite of what logic would tells us. In addition to a chronograph they had a strain gauge attached to the receiver. The Wolf was the clear winner. I would give it a try. At this point, what do you have to loose?
Lloyd