1/2 moa to 3-4 moa. Help

[DogDown338]

Hello Everyone,

Rifle Specs:
Seekins SP10M 6.5CM
March 4.5-28
Area 419 1 piece cantilever.
TBAC Bipod

Ammo.
135 Berger Classic Hunter
2.810 oal
Don’t remember BTO off top of my head
42.1gr h-4350
Alpha LRP 1x fired brass NOT annealed
Fed 210M
Heavy Taper Crimp
1/2-3/4 moa
SD typically 7-8 fps
2,850 FPS


I’ve been putting a lot of time behind my SP10M in 6.5CM lately. The rifle was absolutely hammering. Outshooting bolt gun buddies out to 1,300 yards. It’s literally the most fun I’ve ever had behind a rifle.

Anyways over the weekend I took the rifle out, checked zero. Shot 3 inside of a quarter. Adjusted scope right .2 and down .2 Another quarter sized group. All velocities recorded via garmin while zeroing 2848fps average. 6.5sd

Rifle is zeroed

Then i dialed for 700 and sent it. Miss right, correct for wind, miss farther right, correct further for wind miss way left.

Hmmm. Let’s step back to 500
Miss way high, miss way way low, left, right. Extremely erratic.

Getting nervous now. Back to 100 yards

Same ammo 3 shots about 1.5-2 moa group.
Uhhh ohh. Grab some factory loaded 142 smks from Defender ammo. 5 shot group 3-4 moa

Okay, scope must be loose.
Check mount with torque wrench
All screws correctly torqued.

Put fresh paper up at 100 yards
Anchor rifle down tight on metal bench
Dial up 20 Mils, then down 20 Mils, back to same spot. This isn’t a proper tracking test but it’s what I got.

What the hell has happened to my baby?

 

[Old Man with Gun]

Carbon maybe? How do you clean the barrel?

 

[DogDown338]

Hoppes #9 soaking then nylon brush then repeat 2-3x

followed by CU+2 soaking wait 15 minutes dry and repeat until all patches are clean

Finish with 1 wet #9 patch followed by dry patch.

 

[Im2bent]

Even a March can shit the bed?

 

[Tictacticaltimmy]

doubt this is the issue but make sure none of your attachments are touching the barrel or gas block.

also check that the muzzle device has not loosened.

 

[hafejd30]

First thing I’d do is swap the optic to a known reliable one and at least rule that out

 

[DogDown338]

Alright. I will give the barrel a good cleaning and try another optic on it. Think i can get my hands on a razor. Will shoot this weekend and report back. Any other suggestions before next outing are appreciated.

 

[diggler1833]

Different optic and even mount would be my first test as well. Best of luck.

 

[Coffee_and_Pipes]

Any chance you could also bring the March and test it out on a different rifle when you go back? That way you could isolate and test the Seekins and the scope mount in similar conditions?

 

[DogDown338]

Any chance you could also bring the March and test it out on a different rifle when you go back? That way you could isolate and test the Seekins and the scope mount in similar conditions?

Great idea, i will test the march on my ol trusty 308 and throw its gen 2 pst on the seekins and shoot em both.

 

[BCP]

Then i dialed for 700 and sent it. Miss right, correct for wind, miss farther right, correct further for wind miss way left.

If dialing I'd think the scope took a shit if holding I'd think wind