Armory Sponsor
Posted: 1/25/2017 12:44:01 AM EDT
|
I have a Remington 700 LTR that I decided to get threaded for my suppressor (AAC 762 SD). After the thread I noticed the threads were shorter when compared to my other 30 cal guns and my muzzle brake wouldn't time right. The guy that threaded it told me it was the standard for 5/8x24 but I'm no machinist so what do I know. He took it back and trimmed a small portion from the front of the barrel so he wouldn't have to cut them off and start over and he installed the brake for me. The crown is recessed and he said he didn't get near it.
So now that it's threaded it shoots as it should without the suppressor on it but once I put it on I can't even hit a 2'x2' plate at 100 yards! Take the suppressor back off and it hits zero again. When I try to adjust the scope I run out of adjustment. There are no baffle strikes and I'm using factory FGMM 168gr. Any suggestions would be greatly appreciated! (You guys told me to thread it so I'm blaming you!  )
|
|
Adding anything to your barrel, especially something big and long and heavy like a suppressor, will usually change your POI.
Start out at a shorter distance, like 25yds, to see where the rifle prints with the suppressor installed, and if it holds a group. If you thought you could just add a suppressor and have the rifle hold the same zero, you were clearly mistaken, though I admit 10" at 100 (to move it off your target plate) seems like an awful lot. |
|
At home you would typically have to use shims to time the muzzle brake. It would be pure luck to have it time properly with no shims. A competent gunsmith can time the brake without shims but it has to be done with the brake in hand and the barrel on the lathe. The muzzle/crown shouldn't bottom out on the brake. The shoulder of the brake should seat squarely on the barrel shoulder with no gap.
Are you seeing a random shotgun like pattern of hits? I know you said you are missing the plate but are you seeing impacts on any type of backstop/berm? It can be very difficult to see where bullets are grazing the ID bore of the endcap. A light discoloration may be all that is there. My Mini-30 had rounds that were grazing the ID of the endcap of my SDN-6 and were grouping in about an 8 foot circle. There was no visible damage or copper marks. I had to clean the ID of the endcap, fire a single round, and inspect by removing the can and fully rotating it in good bright light to see what was going on. The carbon fouling was hiding the slightest rub that was enough to send the rounds all over the place. I sent it to Morgan at Class 3 Machining to get the factory threads fixed and all is well now. |
|
Remove the bolt and look straight down the can. You'll easily be able to tell if it's not concentric.
What do you mean when you state it wouldn't time correctly? Do you just mean the orientation where it stops rotating when you screw it onto the mount? If so, there's no incorrect orientation. It just stops somewhere. You can "time" that somewhere by shimming the mount, if preferred. There are different 51T mounts. With the 100209 Deep Socket Blackout FH (left), you can't see the shoulder when it's installed. 
If you could remove the mount and check the barrel threading with dial calipers, you'll notice if it's significantly out-of-spec. Pages 12 & 13. Circuits is correct. You will unquestionably experience POI shift when adding/removing a can, but 10 MOA is not normal. |
|
That's a nice pdf to have I hadn't seen that before. Going off of that and all the other threaded 30 cal rifles I have its definitely not to the industry standard but it's to a different maybe older standard? From the muzzle to where the threads end is only maybe 1/2 or a little more.
I'm using their brake so it had to be timed with the ports to the side. I really liked this gun before hand and wish I wouldn't of threaded it now. I may just have to have him or someone else cut the threads off and start over. Hopefully he knows how to recrown  . Plus the LTR barrel is fluted so there's only so much up front to work with before you get to where it starts.
|
Armory Sponsor