300 Blackout Zero Issues

[DocJekyll]

Hello all,

I'm trying to solve a problem with my SBR, and I'm not 100% sure what else to try. I recently completed my SBR and managed to get out to the range to begin zeroing it. I have the L/R adjustment done and there is no issue with that, however I have managed to bottom out my red dot and I'm still nearly 5in too high. I've removed a spacer but it still isn't there. I thought I would reach out to you guys and see if there is something I've missed that could bring me in the rest of the way.

Here's what I've got on my gun:

300BLK Spikes 10.2 barrel
Troy BUIS
Aimpoint T1 4MOA
KAC T1 Mount (One spacer installed, one has been removed from previous zero attempt)

 

[padawan]

What is your distance?

Factory loads or hand loads?

 

[DocJekyll]

What is your distance?

Factory loads or hand loads?

Sorry, factory Remmy 120 OTM supersonic

Zero is 50yds

Also to clarify, the dot is 5 to 6in above my point of impact.

 

[padawan]

You might try changing the mount and optic out for a 2nd rig if you have something handy just to start ruling things out.

Maybe one of the optics guys will be by. We have a 16" 300Bk temporarily set up with a old Nikon Prostaff 4-12 and it is on at 100 yds. Running various Sierra and Hornady 110 to 125g loads.

We initially zeroed at 50 but 100 was either 2 or 3" too high or low (I don't remember). We then zeroed it at 100 and 50 was closer.

 

[The Bubba Effect]

I am trying to get this right in my head.

The point of impact is approximately 5-6" below the point of aim (the red dot) at 50 yards.

You say that you have "bottomed out" the optic's elevation. Do you mean that the optic's elevation has been turned "down" to it's maximum bottom elevation (you have turned the elevation adjustment clockwise until there is no more adjustment).

Is this correct?

 

[DocJekyll]

I am trying to get this right in my head.

The point of impact is approximately 5-6" below the point of aim (the red dot) at 50 yards.

You say that you have "bottomed out" the optic's elevation. Do you mean that the optic's elevation has been turned "down" to it's maximum bottom elevation (you have turned the elevation adjustment clockwise until there is no more adjustment).

Is this correct?

Thats correct. The optic's dot is as low in the adjustment plane as it can go, and the bullet impact is still about 5in lower than the dot at 50yds. Perhaps using a different zero?

 

[The Bubba Effect]

Thats correct. The optic's dot is as low in the adjustment plane as it can go, and the bullet impact is still about 5in lower than the dot at 50yds. Perhaps using a different zero?

I might be way off, so forgive me if I am. This is why I asked specifically whether you had adjusted the elevation adjustment clockwise to the limit.

Turning the t1's elevation adjustment clockwise "down" brings the point of impact down relative to the point of aim [the dot].

Is it possible that you have spaced out on this and turned the elevation "down" (bringing the point of impact "down" relative to the point of aim), when you should have been turning the elevation adjustment "up/counter-clockwise", bringing the point of impact "up" relative to the point of aim/dot?

I only ask this because it is common for me to make exactly this mistake.

http://www.aimpoint.com/uploads/tx_pxaaimpoint/Manual_Micro_T-1_ENG_12034-4_Folded_LoRes.pdf

If this is the case, you would need about 12 moa adjustment up/counterclockwise. That should be 24 clicks on the T1.

Again, if I misunderstand the situation and you have turned the elevation adjustment counterclockwise/up to it's limit, and the point of impact is still 5-6" low at 50 yards, then that is something else and hopefully someone else will have the answer that we can both learn.

 

[DocJekyll]

I might be way off, so forgive me if I am. This is why I asked specifically whether you had adjusted the elevation adjustment clockwise to the limit.

Turning the t1's elevation adjustment clockwise "down" brings the point of impact down relative to the point of aim [the dot].

Is it possible that you have spaced out on this and turned the elevation "down" (bringing the point of impact "down" relative to the point of aim), when you should have been turning the elevation adjustment "up/counter-clockwise", bringing the point of impact "up" relative to the point of aim/dot?

I only ask this because it is common for me to make exactly this mistake.

http://www.aimpoint.com/uploads/tx_pxaaimpoint/Manual_Micro_T-1_ENG_12034-4_Folded_LoRes.pdf

If this is the case, you would need about 12 moa adjustment up/counterclockwise. That should be 24 clicks on the T1.

Again, if I misunderstand the situation and you have turned the elevation adjustment counterclockwise/up to it's limit, and the point of impact is still 5-6" low at 50 yards, then that is something else and hopefully someone else will have the answer that we can both learn.

The impact when I began zeroing was actually quite a bit further below the dot when I began zeroing the rifle. In the course of zeroing I reached the maximum adjustment bringing the dot and point of impact together. I removed a spacer and was able to get it slightly closer but it isn't where I want it yet.

I guess what I'm really trying to see is if perhaps it could be an issue of a misaligned barrel or something else. I've never had an issue running out of adjustment on a red dot sight before and it has me quite perturbed. I believe Chapter 4.2 on the Aimpoint T1 says to check that.

 

[Bfish]

Have you ever successfully used this sight on another rifle?

 

[The Bubba Effect]

The impact when I began zeroing was actually quite a bit further below the dot when I began zeroing the rifle. In the course of zeroing I reached the maximum adjustment bringing the dot and point of impact together. I removed a spacer and was able to get it slightly closer but it isn't where I want it yet.

I guess what I'm really trying to see is if perhaps it could be an issue of a misaligned barrel or something else. I've never had an issue running out of adjustment on a red dot sight before and it has me quite perturbed. I believe Chapter 4.2 on the Aimpoint T1 says to check that.

Gotcha. I sometimes do things backwards, so that was my first thought. Good luck!

 

[DocJekyll]

Have you ever successfully used this sight on another rifle?

My 14.5 556 gun was perfectly zero'd with the optic.

 

[Bfish]

My 14.5 556 gun was perfectly zero'd with the optic.

Good, you know it's not the optic then... You can cross that off. Mount or rifle now.

 

[DocJekyll]

Good, you know it's not the optic then... You can cross that off. Mount or rifle now.

Agreed. I did remove one spacer and it seemed to help a little but I am going to get the upper in a vice, and check the level of both the barrel and upper. It's possible the extension or the barrel may be misaligned. It's also worth noting that I'm having the same issue with the BUIS as well.

 

[Light]

Agreed. I did remove one spacer and it seemed to help a little but I am going to get the upper in a vice, and check the level of both the barrel and upper. It's possible the extension or the barrel may be misaligned. It's also worth noting that I'm having the same issue with the BUIS as well.

Then its most likely the rail or the rifle/barrel itself.

 

[Bfish]

Well good luck man, let us know what you figure out!