Suppressor increasing group size?

B

BigOhio

Sergeant
Full Member
Minuteman
Jan 4, 2011
143
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Ohio
#1
Not sure which thread is correct for this question, but just purchased a new to me 308 from a well known smith and had the barrel cut back to 18.5". I sighted it in at 100 yds. yesterday and was not happy with the groups with either FGMM308 and FGMM7.62 175s. Before drawing conclusions I decided to take it out to my a 300 yd. range today and see what happens. My first 5 shots at 200 yards was a vertical sting of about 4 inches with the first and second shots being the extremes. I then tried 300 yds. and had a group of about 5 inches and really disappointed. At this point I pulled the suppressor (Tigershark) and shot a group at 200 yds with 2 shots touching and the third about 1/2" out with the FGMM308. Shot another 3 shot group with the FGMM7.62 and wasn't as good but not bad. Then put the suppressor back on and the groups opened back up to 3-4". Pulled the suppressor again and next 3 shots of FGMM308 went into a cloverleaf at 200 yards.

I checked the suppressor and see no signs of baffle hits or keyholes so don't think that the bullets are hitting the baffles. I expected a POI change with the suppressor but expected the group size to remain about the same and or be better. To me, the rifle shows much potential but with the suppressor the consistency seems to go to hell. At this point I'm thinking that the barrel harmonics are screwed up by the suppressor but interested in other thoughts.
 
#3
From your first post you say you purchased from a well known smith, then had it cut back, or at least that's the way it reads. Did you have it cut/crowned/threaded locally or did the smith that built it thread it? If it was local, they may have not threaded it concentric with the bore. That could be causing a slight baffle strike that causes your groups to open up. It could be VERY minimal contact and that's all it takes to upset the stability if the projectile. Keep us up to date.
 
#4
Same smith that build the rifle cut, crowned and threaded it for me. I guess it could be slight hits on the baffles but sure didn't see any sign of it and the bullets holes at 100, 200 and 300 do not show any signs of instability.
 
#5
Big,

I have a Shark (.30 cal) also. I bought it because alot of guys I shoot with said they were the best. To make a long story short, it turns my match rifles into shot guns......These are .25"-.50" rifles that turned into 3"-4" groups at 100yds. I experimented with it on 5 different match rifles before sending it back. I also adjusted loads as well to make sure the suppressor wasn't pushing me out of my accuracy node. It was inspected and a new base cap put on. Unfortunately, it still was not any better. I wrote it off as a loss and it now sits on my AR as a plinker.

I know that adding a suppressor will change the recoil pulse of the rifle and it does take some folks a little while to adjust to it. However, I let a few "can shooters" shoot my rifles and the results were the same.

I know many people have and are very happy with Shark suppressors. I'm sure they are a overall great product. I just didnt have the best of luck with mine. I'm not upset about it and have no ill intent towards Shark.
 
#6
It is usually the threads on the barrel or the threads on the suppressor that are the problem. It is difficult to make happen but the threads should be cut on both the barrel and the suppressor by the same smith.
 
#7
the can is usually never the problem, I would say its the smithing work on the threading, in the past I have taken cans apart and painted the inside diameter surfaces of the baffles, then fired on round through it and then disassembled the can again and inspected the baffles for any spots where a possible strike would have scraped paint off, is so it was back to the gunsmith with the barrel.
 
#8
Gone firefighting)What center fire cans can you disassemble ? I know 22 rim fire cans come apart, but I am unaware of any center fire cans that the OP could take apart and inspect.
 
#9
Jmilera said:
Gone firefighting)What center fire cans can you disassemble ? I know 22 rim fire cans come apart, but I am unaware of any center fire cans that the OP could take apart and inspect.
Click to expand...

most every manufacturer will make one or two units that are user serviceable. there is always a bunch of coffee shop talk about the pros and cons of each but there is probably another thread for that.
 
#11
If you suspect it's your threads we recommend all our customers use ADCO in ohio... fast turn around, good prices. They have probably threaded hundreds of customer barrels and I've never heard a single negative remark. I've probably had 30 or so threaded by them They actually have two of my barrels right now.

Otherwise any of the purist machinists on this site like Mark @ Short Action Customs I'm sure would give you impeccable threads.
 
#12
Thanks for the responses. Since getting the suppressor I hardly ever shoot unsuppressed and have noted accuracy issues with other rifles, just not to this extreme. In the past I thought that the issues were probably rifle or load related and never gave the threading a thought. The same gunsmith has done the threading on most of my rifles so I will contact him and see if he could check out the suppressor threads and go from there.
 
#13
BigOhio said:
Thanks for the responses. Since getting the suppressor I hardly ever shoot unsuppressed and have noted accuracy issues with other rifles, just not to this extreme. In the past I thought that the issues were probably rifle or load related and never gave the threading a thought. The same gunsmith has done the threading on most of my rifles so I will contact him and see if he could check out the suppressor threads and go from there.
Click to expand...

Who is the smith? Are they 07FFL/02SOT......? I would sent the suppressor back to the manufacture and have them check.....probably send the barreled action to them too and have them check the threads.
 
#14
BigOhio said:
Thanks for the responses. Since getting the suppressor I hardly ever shoot unsuppressed and have noted accuracy issues with other rifles, just not to this extreme. In the past I thought that the issues were probably rifle or load related and never gave the threading a thought. The same gunsmith has done the threading on most of my rifles so I will contact him and see if he could check out the suppressor threads and go from there.
Click to expand...

Make sure he is zeroing off the bore not the OD of the barrel.
 
#17
Shooters,

Short Action Customs is the original builder of the rifle, as well as the company who installed the EFR, shortened the barrel and redid all the muzzle work. Its easy to always think that we could never do anything wrong, so I'm trying to not assume that it could never be on our end, however I would like to explain how we thread muzzle devices for suppressors that way people can become educated on how we do things here at Short Action Customs.

The videos below show the reader not only our attention to detail and pursuit of perfection when it comes to our machine work, but also that we are clearly doing our best to co-axially indicate the barrel in to give the most concentric threads/machine work possibly attainable with our machines. The first video would be the best showing how we indicate our barrels in for chamber work and muzzle work. We guarantee our threads to be concentric to the bore within .0001-.0002" of an inch. I'm confident that I can take any barrel we have threaded and dial it back in the lathe with our indicator on the bore in two separate points and then measure the thread runout and achieve our goal of .0001-.0002". I have done it multiple times in the past and that is why we have our guarantee.

Check a bone stock Remington 700 AAC-SD's threads for squareness and runout. It hast most likely 10 times the runout, and they will shoot suppressors with out baffle strikes. Furthermore, measure any suppressor bore diameter. You will find most to be in the .360" (Thunder Beast Arms Corp 30BA) and .355" (AWC ThunderTrap Ti. 30). So something would have to be insanely wrong for a barrel thread/shoulder to cause baffle strikes inside a suppressor, especially a baffle or so in from the exit baffle.

Furthermore, the Shark suppressor has stacked components in the equation. You are first relying on a barrel thread adapter to be secured to the suppressor main body in a concentric/square fashion and then threaded on to a muzzle. To magnify things further, with a suppressor like the Shark that can be disassembled and reassembled, if its not put together 100% right, it can cause issues. A personal friend of mine has a Shark and he thought he put it back together and he started getting the same symptoms and even a baffle strike.

At Short Action Customs, we always stand behind our work because we believe we do very solid machine work. I'm happy to dial the barrel back with with witnesses to verify the workmanship, however to me it seems clear its a suppressor issue. I have TBAC and AWC suppressors in stock that are proven shooters, I'm happy to test fire the rifle at my personal 400 yard range with the customer to help with trouble shooting. I also have a stash of FGMM 175 and some 168 as well as Corbon and Black Hills Match we can try.


Locating the curvature of bore - YouTube

Thunder Beast Arms Corp 30P-1 Suppressor test - YouTube

Thunder Beast Arms Corp. 30BA concentricity test. - YouTube
 
#18
I and at least one other had the same issue with our tigershark/shark cans, and were told it was us causing theissue. My rifle at the time was a trg22 and his was a custom build off a m2008 action from a good builder. I noticed after each group they slowly tightened from a dinner plate down to almost moa after about 50 or 60 rounds, that was with fgmm168's, I later did handloads that were never tried with the can but shot extremely well and the rifle was sold, the hide member that bought the rifle seems to be happy.
 
#19
BigOhio- RUN dont walk to take Mark up on the offer above to test a different can. He may even be able to assist in checking the Shark for proper assembly after reading through the post. Be sure to take a thank-you gift too ;-)
 
#20
Sharks can be problematic if not reassembled properly. It is not as easy as it sounds to reassemble the can. If the end caps are not fully screwed on, and I mean FULLY, the baffles will move inside the can. If you take a can with a partially screwed on end cap and roll it in your hands back and forth quickly, you can hear the baffles spinning. This is not what you want. Even leaving a gap of a couple of thousandths of an inch can cause this. Make sure the can is properly reassembled before proceeding. If it is not, take it apart, clean out as much carbon as you can, then try it again. The grit buildup can cause some spacing when putting it back together.

I had baffle strikes with mine on a Sako TRG, which dumbfounded me, because it shot fine on many occasions before that. The variable that changed is that the end cap was not fully on. When I cleaned and reassembled it, the strikes went away. It is better to lock at least the aft end cap on the can with some red loctite to minimize the possibility of loosening.
 
#21
One more thing: baffle strikes are not overtly evident to an untrained eye. And what I mean by untrained, is that you have never seen a true baffle strike before. The term "strike" is a strong term, and leads us to logically assume that there is some powerful force "striking" metal; and surely we would be able to point out an area that a bullet going 3000 fps is "striking". While in some cases, this may indeed be happening, it is not always the case. A term, "baffle brush" or "baffle wipe" would be more commensurate to what is actually happening. In this case, the bullet is gently touching a baffle or end cap on its exit, and it diverts its trajectory. This does NOT always result in keyholing. I was having end cap "strikes", and they were not obvious at all. The areas of rubbing made no deformity to the metal, and they simply looked like just a small area of uneven cerakote application with powder burn. I missed it myself the first time I looked at it. So just because you don't see baffle strikes on your can, it doesn't mean they are not happening.
 
#22
While anyone can make a mistake, I highly doubt Mark's threading could be to blame. (Not emplying anyone is blaming him)

I've seen and handled Marks work multiple times between my own rifles and others. His work is extremely precise and disciplined. I would definitely take him up on his offer to check it with another can.
 
#23
That's pretty much the same thing that was relayed to me from Shark. After returning it, my ability to shoot properly was called into question. The whole experience pretty much ruined me on ever wanting to shoot suppressed.
 
#26
trevor300wsm said:
That's pretty much the same thing that was relayed to me from Shark. After returning it, my ability to shoot properly was called into question. The whole experience pretty much ruined me on ever wanting to shoot suppressed.
Click to expand...

I will bring my can down the next time I am in town. Let's see if it is the can or rifle.
 
#27
trevor300wsm said:
That's pretty much the same thing that was relayed to me from Shark. After returning it, my ability to shoot properly was called into question. The whole experience pretty much ruined me on ever wanting to shoot suppressed.
Click to expand...

Trevor, read what I said about the shark. Screw it together nice and tight, with zero gaps, and it should work fine. If you are having trouble disassembling it, soak the end cap in some hoppes no. 9 and try again. I cleaned my baffles in my thumlers tumbler for about 5-10 minutes, which removed most of the grit. The can should then be able to be assembled properly. I would recommend sealing the aft end cap to minimize the variables of possible loosening in the future
 
#28
Thanks for the responses and a special thanks to Mark at SAC. I was able to make it to the shop today and we ended up getting the suppressor apart and cleaned up. I did have a rattle in it before and re-assembled it with the instructions from mijp5 and now have no rattles. Can't wait to get it out again and see if this helps.
 
#29
Managed to get to the range this morning and tested the Tigershark now that it is cleaned up and put back together with no rattles. Didn't get all the testing that I wanted before my hands got numb and I was chilled (32 & freezing rain) but tested it with a new SAC DTA 7RM barrel and factory DTA 308 barrel. At 200 yards both shot a little less than an inch group and the suppressor tightened them up a little. I then pulled out the 308 which is the reason I started this thread and my unsuppressed group was about 2.5" (compared to 1/2" last week) but the suppressed group was about the same at which point I could barely feel my fingers and was starting to shiver so decided to pack it up and try again when the weather decides to cooperate a little more.
 
#30
BERTMAN77MK2 said:
It is usually the threads on the barrel or the threads on the suppressor that are the problem. It is difficult to make happen but the threads should be cut on both the barrel and the suppressor by the same smith.
Click to expand...

I have never seen a suppressor with out threads, is there a way to order one like that or are you talking about having a smith oversize and true the existing threads on a can?
 
#31
BERTMAN77MK2 said:
It is usually the threads on the barrel or the threads on the suppressor that are the problem. It is difficult to make happen but the threads should be cut on both the barrel and the suppressor by the same smith.
Click to expand...

I've got 4 cans, and a variety of hosts, and the threads were cut by about a dozen different 'smiths.

I've had no problems with any of them.

YMMV.
 
#32
Bottom line for this thread is that there are more variables in the equation when dealing with a Shark. When my Shark wasn't assembled properly, and I mean the end cap was loose by about 2-3 thousandths of an inch, the baffles were loose. In effect, when shooting at a target 800 yds away, the bullet was hitting the grass at about 500 yds. NOTHING to do with the threads. Just wasn't assembled correctly. When I tightened it up, it worked fine again.
 
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