Groups opened way up in 25 shots. From 1/2" to 3"

[zimm17]

I have a new Howa 1500 in 6.5CM, Nightforce SHV 4-14, on a Harris/Laure bipod. SDN-6 Suppressor with 51T muzzle break. I know a direct thread is better, but it's what I got.

I completed the Howa break in procedure on my last range outing. This was the first time firing suppressed. First shots were 3" low @ 100 yards, guess it's the suppressor. 10 shots to get it dialed in. Shot first 5 shot group- .48". Looking great. Move to the next target, things are heating up. It was 92 degrees and humid. The barrel and suppressor got pretty darn hot. The suppressor cover I have flies off and goes downrange 20 feet. The group is now 2". Shoot another 5, and now it's 3".

Heat mirage was killing my vision through the scope. Scope screws are tight. Suppressor must have jumped a tooth because I can rotate it back and forth. Maybe that's it? I didn't have enough time to remove it (it was too hot anyway) and try un-supressed.

Maybe it's too dirty from 20 shots? I was taking my time- the range has 10 minute firing intervals to change targets so it was 25 shots over 45 minutes.

Now I need to go back for another range session as I'm not happy with this mystery. I think the first step is remove the suppressor and try again.

 

[hafejd30]

Very easily something could have warped due to heat or more likely loosened up on the suppressor Mount, which seems from your post is what happened.

I’d definitely start inspecting everything in regards to the suppressor and muzzle device to start. If that was loose it would throw rounds. But launching a shield off a suppressor is pretty hard to do unless of course you didn’t pay attention and it slid off the end. Look for baffle or end cap strikes

I’d check for damage and confirm everything is tight. Shoot a group without the suppressor. Confirm it’s good. Reattach suppressor (obviously A bit tighter) shoot another group. Not letting it heat up like you did the first time.

Just FYI I would have stopped at the shield flying off to inspect. And really examined things after the first 2” group. Some guns do foul quick and shoot really shitty when fouled. But loose can and launching mirage shields may indicate something else.

Simplistic/possible outcome:
- suppressor loosened during fire
- mirage shield slid enough to cause the pressure from the barrel to strip it from the suppressor
- suppressor still loose and inconsistent as you continued shooting, therefore resulting in the 2-3” groups.

It never hurts to make a mark with a sharpie on the suppressor and barrel for a quick reference to make sure it hasn’t loosened. Or keep an oven mit etc to periodically check it if it has a tendency to come loose

Or it could be something completely different which shooting Unsuppressed would hopefully indicate.

 

[zimm17]

Baffles are fine. The cover just slipped off the front. I think it was backwards so the paracord wasn't grabbing the muzzle break and it just flew off due to recoil. It was only loose enough to rotate back and forth one tooth on the AAC brake. I'll keep investigating as I clean it.

 

[hafejd30]

I want to say there was a thread where a guy had similar issues with that mounting system. Chances of me finding it are next to zero but I remember something about not tightening the suppressor enough and it caused issues. I really want to say it was a similar mount to yours

 

[hafejd30]

I think this is it. I don’t have time to read through it but I’ll post for you anyways

https://www.snipershide.com/shooting/threads/aac-adapters-causing-accuracy-issues.182788/

 

[skipjack]

Mirage could have killed your groups too.

 

[spife7980]

Shoot it without the can and see how it does. When it shoots better you will have your answer.

 

[chevy_man]

Of all the stupid things I bring to the range, I started bringing my cordless Milwaukee fan. Set it to the side and aim at the barrel/can to blow the mirage away on the calm days. Helps cool the barrel quicker when it's dead calm too.



I'd guess it's a combination of mirage and the loose can.