M1a suppressed please help

Alexs15

Private
Minuteman
Dec 21, 2020
19
5
Oregon
Hello everyone I’m looking for some answers here I’m lost.

I bought an M1a and I’ve been on a mission to suppress it. I got an adjustable gas plug, and a smith enterprise thread adapter. I also have a keymo adapter for my sandman L.

I timed everything it seems solid I went to fire it through my suppressor and now we have a problem. Unsuppressed my groups are tight. Suppressed my rifle won’t group. Upon inspection it appears there is a glance on my end cap there is also copper flakes on my keymo adapter.

To be clear there are no markings or glances off my smith enterprise or my keymo muzzle brake. Just on my end cap.

Photos are attached.

Thanks
 

Attachments

  • 6C761A50-FF84-433D-A168-43CDC85AF709.jpeg
    6C761A50-FF84-433D-A168-43CDC85AF709.jpeg
    201.7 KB · Views: 445
  • D0F1858C-C182-4B72-8D53-91D44AB1E786.jpeg
    D0F1858C-C182-4B72-8D53-91D44AB1E786.jpeg
    330.8 KB · Views: 260
  • E8F6DA2F-B73C-4E4A-AAB8-4BD04AFFA2CF.jpeg
    E8F6DA2F-B73C-4E4A-AAB8-4BD04AFFA2CF.jpeg
    274.5 KB · Views: 241
  • 03C8C372-761B-4EFA-95AF-832E86519461.jpeg
    03C8C372-761B-4EFA-95AF-832E86519461.jpeg
    433.3 KB · Views: 227
  • CE57B603-29C3-42E4-AEB1-54CAB0C3B8E3.jpeg
    CE57B603-29C3-42E4-AEB1-54CAB0C3B8E3.jpeg
    524.6 KB · Views: 238
I ran a cleaning rod through and I didn’t have any issues. I also had a bore light and checked. didn’t see any reason to have a concern.
A cleaning rod is not the right tool to use to check bore alignment; it's not precise enough for the task. You should use a precision ground bore alignment rod to check.
 
In this case the muzzle end is the most important location.

The alignment rod must fit snug with very little - no play.

For a suppressor to be effective on this platform it will be best to have the gas system off and cycle by hand.

Kind of defeats the purpose of an M14 or SA version of it.
 
Also how affective is an alignment rod when you can’t go through the breach. You have to go through the muzzle end ?
Yea man just slide it in with and without the can on and then push the road flush with the muzzle/end cap. I use the Surefire rods on my stuff and I’m glad I did rather than risk using a cleaning rod.

My M14 is tits on with the stock flash hider but I’m about to grab an SEI in a week to see how it goes with the rod and then my mount.

Personally I wouldn’t trust a cleaning rod after using the right tool for the job.
 
  • Like
Reactions: Evintos
Yea man just slide it in with and without the can on and then push the road flush with the muzzle/end cap. I use the Surefire rods on my stuff and I’m glad I did rather than risk using a cleaning rod.

My M14 is tits on with the stock flash hider but I’m about to grab an SEI in a week to see how it goes with the rod and then my mount.

Personally I wouldn’t trust a cleaning rod after using the right tool for the job.
Yeah I’m gonna talk to my local gun store and see if they have one to barrow. Otherwise I’ll just. Buy one.

I’m trying to avoid spending several hundred dollars chasing something that I can’t pin point. At this point it could be the way springfield cut the end of the barrel, it could be the smith enterprise adapter. It could be something going on with the thread pitch of dead airs adapter.

If I get a delta p thread adapter it’s like 210$

I’m about to just drop it off at a gunsmith have them check alignment and trouble shoot before I start randomly dropping money on things that may or may not be broken.
 
On both of my M1A's I got rid of the front sight/castlenut assembly entirely. It's difficult to get that castlenut tight enough and too much variance imho when using a suppressor. I'm using a Hughes Precision thread adapter and then my YHM qd muzzle device is threaded directly to it. I only shoot them scoped, so I don't care about the front sight, maybe you do. And you absolutely need a bore alignment tool to check concentricity, a cleaning rod won't do. I ordered steel rods from McMaster Carr that fit perfectly at a fraction of the cost.
 
On both of my M1A's I got rid of the front sight/castlenut assembly entirely. It's difficult to get that castlenut tight enough and too much variance imho when using a suppressor. I'm using a Hughes Precision thread adapter and then my YHM qd muzzle device is threaded directly to it. I only shoot them scoped, so I don't care about the front sight, maybe you do. And you absolutely need a bore alignment tool to check concentricity, a cleaning rod won't do. I ordered steel rods from McMaster Carr that fit perfectly at a fraction of the cost.
I'll add some info on the McMasters option.
8893K219 is the part number for a 0.2969" (+/- 0.0005") rod that many use for 30cal. It should be checked for straightness by rolling on a perfectly flat surface, but a granite countertop is probably the closest most have to do that. McMasters is also business to business, but varies on how strictly they enforce that.
 
I'll add some info on the McMasters option.
8893K219 is the part number for a 0.2969" (+/- 0.0005") rod that many use for 30cal. It should be checked for straightness by rolling on a perfectly flat surface, but a granite countertop is probably the closest most have to do that. McMasters is also business to business, but varies on how strictly they enforce that.
Pretty sure that's the one I ordered. It's a 36" rod that I cut down to the appropriate sizes. Make sure to bevel the ends as they will be sharp/jagged. They had no problem shipping to my residential address.
 
  • Like
Reactions: Evintos and msgriff
On both of my M1A's I got rid of the front sight/castlenut assembly entirely. It's difficult to get that castlenut tight enough and too much variance imho when using a suppressor. I'm using a Hughes Precision thread adapter and then my YHM qd muzzle device is threaded directly to it. I only shoot them scoped, so I don't care about the front sight, maybe you do. And you absolutely need a bore alignment tool to check concentricity, a cleaning rod won't do. I ordered steel rods from McMaster Carr that fit perfectly at a fraction of the cost.
That’s actually a great point on the castle but tightness that I didn’t think about. I’m going to order one of those HP adapters instead of the SEI. Thanks for the tip.
 
  • Like
Reactions: Arc Light
Gonna add more to the directions with alignment rods. Make a small mark with a sharpie or marker. Insert the rod with the can on and the mark in a known location (example 12 o'clock or 6 o'clock). Note any concentricity issues and at what location. Take rod out, rotate the rod so the mark is 180* degrees of where you had it before. If the concentricity issue (if any) is at the same location, the rod is straight and now you know if there are concentricity issues. If the rod is bent or has other issues (could be damage due from shipping), the location of where the rod touches the end cap will change.

If you want more affordable alignment rods, I do however suggest the 8890K prefix W1 tool steel McMaster-Carr rods rather than the 8893K prefix. So for a 308 win, either a 8890K227 (0.295" diameter) or 8890K228 (0.2968" diameter). You do have to cut them to length and chamfer the edges.

Diameter Tolerance-0.000500" to 0.00050"
Straightness Tolerance0.005" per ft.

The 8893K prefix (01 tool steel) rods don't have a straightness tolerance however, they do have a diameter tolerance of
Diameter Tolerance-0.0005" to 0.0005"
 
Last edited:
  • Like
Reactions: msgriff
Alright guys the saga continues!!!!

Hughes adapter is a work of art wish I would’ve went this way off the get go.
20BE122F-F683-4932-B978-D98FD94E2B9B.jpeg


This is beautiful and centered at least it looks that way to me. Yes I did buy the over priced alignment rod. But it is the perfect tool for the job. So here I’m excited and thinking all is well and I have been saved by Hughes precision but then….


D9224B5D-ACB0-4052-934A-0CBD0AE8F237.jpeg

This made me a little nervous with the dead air muzzle break……
7BB60BBC-02AC-4889-B8A8-D4928A8F0E7B.jpeg

This is the can on. This is what it looked like before when I got my end cap strike. Any thoughts?

My conclusion is that it is either a thread issue with Dead Airs brake, or it’s something wrong with the rifle itself. (Barrel cut incorrectly?threaded barrel is out of spec?) ?????

I’m back to square one. But I’m glad to have you guys here to help.

Save me from this madness!!!!! 😭
 
My conclusion is that it is either a thread issue with Dead Airs brake, or it’s something wrong with the rifle itself. (Barrel cut incorrectly?threaded barrel is out of spec?) ?????

I’m back to square one. But I’m glad to have you guys here to help.

Save me from this madness!!!!! 😭
Wouldn't be the first time there were issues with Dead Air brakes but just to rule out something simple, you are using shims and not a crush washer to torque the brake on, correct? If so, contact Dead Air for a replacement and if the replacement has issues as well, then the evidence points more towards barrel thread/shoulder issue.
 
Stupid question sorry! Do these thread on the factories existing threads on the Springfield or ? Do I need to have the barrel threaded ?
If you have the time, money, and know a very competent gunsmith with a lathe, then I would honestly have the barrel cut back 1" and then recrowned and bore-centric threaded 5/8-24 and have the smith check his thread concentricity and suppressor alignment with an alignment rod when done. Think of it like this... It only has to be done right once, and then it's good to go forever. So, IMO, it's worth having it redone, and done 100% right this time. 👍🏼

I just read the rest of the thread and see your ongoing saga... I would checkout using a JMac Customs KeyMo for your can. Their products are extremely precise, and top-tier quality. I run more of the JMac KeyMo's than I do dead air KeyMo's. JMac also makes a short 360º radial style KeyMicro that will work just fine with your rifle. I run these on several of my short AR pistols where I want to keep OAL down.

 
Last edited:
On both of my M1A's I got rid of the front sight/castlenut assembly entirely. It's difficult to get that castlenut tight enough and too much variance imho when using a suppressor. I'm using a Hughes Precision thread adapter and then my YHM qd muzzle device is threaded directly to it. I only shoot them scoped, so I don't care about the front sight, maybe you do. And you absolutely need a bore alignment tool to check concentricity, a cleaning rod won't do. I ordered steel rods from McMaster Carr that fit perfectly at a fraction of the cost.
Tell me more about this Hughes Precision mount please and thank you
 
If you get all the alignment figured out, you’re going to want a blank firing adapter for the shield to help keep gas out of your face. I run a gas lock front sight, Area419 Hellfire adapter, and Ecco modified AAC 7.62 SD. It’s fun, but lots of gas to the face without that shield.
 
If you get all the alignment figured out, you’re going to want a blank firing adapter for the shield to help keep gas out of your face. I run a gas lock front sight, Area419 Hellfire adapter, and Ecco modified AAC 7.62 SD. It’s fun, but lots of gas to the face without that shield.
I have an Arms # 18 scope mount that does a good job and I have an adjustable gas plug and it seems to help a lot.
 
  • Like
Reactions: KYAggie
Alright guys for the conclusion of this rifle. It will have to go back to Springfield for the barrel to be recut. After switching every single part out and trying a whole different mount system. I’m still seeing the same issue. It appeared to be very close with the alignment rod. And after firing a round I received another light end-cap strike.

Thanks for all of your help.
 
  • Like
Reactions: M8541Reaper