Sighting In My 9MM Upper W/ 5" Tros Barrel

[Tango2249]

I just sighted in my RRA 9MM Upper yesterday for the first time. It has a 5" Tros barrel and I was shooting 147gr SS ammo using an Aimpoint H1 and Trident9 can.

After shooting about 15 rounds and shooting a very nice group at 20 yards, I let the suppressor cool down for a few minutes. After I loaded another may, all of my shots were hitting about 3" to the left an about 1-2" low.

Do you guys see any POI change when the suppressor heats up and cools? It seemed like after it heated up again, the shots were back in the center of the target. Any info would be appreciated.

[joshrunkle35]

I haven't seen that with a suppressor. I have seen that with barrels, but usually only the first cold bore shot, and not that much of a difference. Did you loctite down your optic? Sometimes they can move slightly.

[Tango2249]

I bought the H1 from Larue Tactical along with the mount. The optic came with the mount already mounted. I'll take the mount off the receiver and check the screws. They said the are loc tighted when they mount the optic but I'll double check it.

[David Hineline]

Does the point of aim change when you shoot without the silencer? A 5" barrel should be pretty stiff and would not notice a lot of poi change silencer on/off, if you see much point if impact change silencer on/off I would triple check the alignment.

[Kramer]

I just sighted in my RRA 9MM Upper yesterday for the first time. It has a 5" Tros barrel and I was shooting 147gr SS ammo using an Aimpoint H1 and Trident9 can.

Does the Tros barrel have the three lug mount or screw on?

[Tango2249]

I was shooting with the 3-Lug adapter. All of my shots were with the suppressor attached.

[joshrunkle35]

I bought the H1 from Larue Tactical along with the mount. The optic came with the mount already mounted. I'll take the mount off the receiver and check the screws. They said the are loc tighted when they mount the optic but I'll double check it.

I was referring to loctiting the optic mount to the rail, not just the optic to optic mount. The entire mount can move slightly on the rail causing a poi shift. Think about this, the post that fits down between rail spaces, do you have to pound it in, is it a tight fit? Of course not. There's a bit of play between rail spaces, and if your mount isn't practically welded on, it can move. It would be even worse if you removed the optic. You need to re-zero each time you remove an optic.

Seeing as how you're taking the mount off the receiver, I can almost guarantee that's your problem.

[Tango2249]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

[joshrunkle35]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

[yamatitan]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

BS I have multiple larue mounts and every single one of them returns to zero every time I take it off and put it back on.

[Tango2249]

My other Larue mounts also return to zero when taking them off. That is one of the reasons I stick with Larue. I have never heard of putting Loc Tite on the rail with a Larue mount. I do Loc Tight the Optic to the mount but not the Mount to the rail.

[joshrunkle35]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

BS I have multiple larue mounts and every single one of them returns to zero every time I take it off and put it back on.

What's your zero capable of? 4 moa at 100 yds? sub-moa at 100 yds?

[joshrunkle35]

My other Larue mounts also return to zero when taking them off. That is one of the reasons I stick with Larue. I have never heard of putting Loc Tite on the rail with a Larue mount. I do Loc Tight the Optic to the mount but not the Mount to the rail.

That has nothing to do with larue, it has to do with any type of removeable mounts. Send larue an email. I'd wager they'd say the same thing.

[yamatitan]

What's your zero capable of? 4 moa at 100 yds? sub-moa at 100 yds?

It stays around 1.5 moa at 100 yards, doesnt matter how many times I take it off. EDIT to add that this is just a ruff average like I siad I have many (4 larue mounts) Some are a little more some are a little less.

[JasonAAC]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

I've got no love for LaRue, but this is not at all the OP's problem.

You do not loctite any part of the mount itself, just the screws that hold the optic to the mount.

The LaRue mounts will not shift during firing. They WILL return to very close to your original zero if removed.

It sounds like something is not right with the 3-lug mount, either the spring is not holding it tight enough, or the 3-lug on the barrel or the sleeve inside the mount is out of spec.

Did you then shoot a bunch to heat it back up, then shoot a group? Then let it cool down again and shoot another group to compare?

ETA- Like David said, do some zeroing (hot and cold) without the can to eliminate that variable.

[goteron]

Nothing of value to add to this conversation other than Jason is a true Professional.

I agree, its not the optic.

[Bowen1911]

Send larue an email.

But don't let him know where you work

[Tango2249]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

I've got no love for LaRue, but this is not at all the OP's problem.

You do not loctite any part of the mount itself, just the screws that hold the optic to the mount.

The LaRue mounts will not shift during firing. They WILL return to very close to your original zero if removed.

It sounds like something is not right with the 3-lug mount, either the spring is not holding it tight enough, or the 3-lug on the barrel or the sleeve inside the mount is out of spec.

Did you then shoot a bunch to heat it back up, then shoot a group? Then let it cool down again and shoot another group to compare?

ETA- Like David said, do some zeroing (hot and cold) without the can to eliminate that variable.

I did notice after I made some adjustments that the 3_Lug mount loosened up a little on the suppressor? I then started shooting another group and I was back on target. If the mount loosens during firing, would that effect the accuracy? I am going back to the range tomorrow and will see how it is shooting. Thanks for all of the relpies.

[JasonAAC]

...If the mount loosens during firing, would that effect the accuracy? I am going back to the range tomorrow and will see how it is shooting. Thanks for all of the relpies.

Absolutely that will affect it.

You will get shift from unsuppressed to suppressed, but it should not move around. If you have wandering shift with the can mounted, you are either getting slight baffle strikes or something in the can/mount is loose.

Shoot a couple groups from a rest (or at least a bench) unsuppressed to make sure the optic and gun holds groups first.

[JasonAAC]

Another thing, and I don't mean to be insulting, is make sure the can is fully mounting to the 3-lug.

it should push on, then turn 1/3rd of a turn, then snap back away from the muzzle a little. That is locked on.

[Kramer]

...If the mount loosens during firing, would that effect the accuracy? I am going back to the range tomorrow and will see how it is shooting. Thanks for all of the relpies.

Absolutely that will affect it.

You will get shift from unsuppressed to suppressed, but it should not move around. If you have wandering shift with the can mounted, you are either getting slight baffle strikes or something in the can/mount is loose.

Shoot a couple groups from a rest (or at least a bench) unsuppressed to make sure the optic and gun holds groups first.

That's why I asked earlier if it had a three lug, it could be the problem.

[Tango2249]

Another thing, and I don't mean to be insulting, is make sure the can is fully mounting to the 3-lug.

it should push on, then turn 1/3rd of a turn, then snap back away from the muzzle a little. That is locked on.

When I go and shoot tomorrow I will make sure the mount and suppressor are on nice and tight. I didn't want to put it on too tight the first time I shot it, not knowing it could loosen up. The suppressor did lock correctly I'm place.

I'll shoot a group first without the suppressor and then with the suppressor and see how it shoots.

[Schulze]

My Larue mount has the throw lever on it and is set with a lot of tension. I don't see how the mount could have shifted. I would have to really pry it off to remove it.

That's your problem. You should loctite the mount down. That should fix your problem. (and use the high temp stuff) Those mounts are not intended to be removed at all, and they can and will shift slightly during firing. The throw lever is there in case your optic goes down in the middle of a fight and you need to remove the mount to use your buis. The quick remove/attach is just a sales pitch.

Every statement in your post is devoid of truth. I award you no points, and may God have mercy on your soul.