Question on Rimfire Barrel Length With Suppressor And Accuracy Problems

[Longshot231]

This is a long story and a little difficult to get to the point so forgiveness is begged for in advance.

A couple of years ago, I purchased a .22LR upper from Rock River Arms with a 16 inch barrel.

.22LR Tactical Carbine

Rock River Arms, Inc. offers a complete line of American made, custom built AR15 style rifles.

www.rockriverarms.com

I put it on a lower and scoped it with a Vortex Viper PST. On the end of the barrel, I put a SIG rimfire suppressor. For a semi-auto the accuracy was phenomenal.

Later on, I removed the daylight scope and put on a Burris Thermal scope. The accuracy was still great with all sorts of ammunition.

Then one day, I got a borescope. This is where the tail of woe began with this rifle. Now I know that there are all sorts of comments I will get about why I should not have purchased the borescope but let's try to stay on topic as I'm curious about accuracy issues when it comes to barrel length and suppressors on rimfire rifles.

Anyway, I looked in the bore with the scope and discovered that the barrel was severely pitted. It looked like a 100 year old rifle barrel. Yet it still shot great. I had a 1917 Enfield that was like that. It was one of the better shooting WWI rifles that I owned.

I have several other AR-15 uppers from Rock River with pristine barrels. They are all amazingly accurate. So this particular barrel is an exception.

I was not content with the condition of the barrel and contacted Rock River. They were nice enough to offer to install a new barrel.

So I asked them if I could get a stainless barrel which was 20 inches instead of 16. I was willing to pay the difference but they didn't charge me.

I received the upper back with the new 20 inch barrel back in a couple of weeks. Everything was reassembled; lower, thermal scope and suppressor.

The thermal scope allows for the use of six different "models" when it comes to changing reticles for six different types of ammunition. In other words if I wanted to use CCI standard velocity for one "model," I could switch to another "model" for CCI mini-mags. I could choose between 10 different reticles for each "model."

So off to the range I went to rezero the rifle. At first the accuracy was great. These are the brands and types if ammo that I shot in order: CCI SV, CCI 45 grain Suppressor, CCI Mini-Mag, CCI Stinger, American Eagle 40 grain and Federal Auto Match.

I didn't have to fire a lot of rounds to zero each type of ammo and didn't experience any accuracy issues until the CCI Mini-Mag which would have been with "model" #3. After about 10 rounds fired, I started noticing extreme fliers.

We're talking about 1 foot high to 1 foot low at 50 yards. Sometimes the rounds would go left or right about 6 inches!

Initially, I thought that the Mini-Mags weren't the best round for that barrel. The CCI stinger didn't group too bad but it has never been considered match ammunition.

The American Eagle and Auto-Match didn't group to bad either but not tack-driver quality. So I ended the range session with the intent to come back the next day and try some Norma target ammunition for use with "model" #3 of the thermal scope.

I cleaned the rifle but because I probably shot less than 200 rounds I decided not to clean the suppressor.

I had shot the Norma ammunition out of the 16 inch barrel with the daylight scope before and accuracy was exceptional for a semi-auto rifle. So I thought it should work with the 20 inch barrel.

The Norma ammunition was all over the place like the mini-mag the day before. So I decided to see what the CCI SV would do.

Keep in mind that I was getting excellent results the day before at the beginning of the previous range session. During this second range session, the CCI SV bullets were all over the place!

I examined everything on the rifle. Everything was tight! So I removed the suppressor to see what would happen.

You guessed it, without the suppressor the accuracy was excellent. No fliers at all! Even the Norma ammunition grouped better.

I experimented with and without the suppressor. Everytime I shot with the suppressor the rounds produced groups the size of a soccer ball. Without, I was able to hit 3/4" rimfire steel swingers consistently!

BTW, there isn't anything wrong with the suppressor. Everything is concentric and there are NO baffle strikes.

Now for my theory bout barrel length/stiffness. I have three other rimfire rifles that I shoot with the same suppressor. Two of them have 16.5 inch barrels and the other has a 22 inch barrel.

The rifles with the shorter barrels are a Savage B22 ane Ruger American Rimfire. Both guns have gone through extensive makeovers, with laminated stocks, triggers, picatinny rails, etc...

The rifle with the 22 inch barrel is a Vudoo 360. I ordered the heaviest barrel possible. Accuracy has always been excellent with and without the suppressor.

Keep in mind that accuracy issues with the newer, longer Rock River barrel didn't show up until more fouling had accumulated in the suppressor. Also remember that I cleaned the barrel prior to the start of the second range session.

My guess is that because of the longer barrel any harmonic anomalies are going to be magnified compared to a shorter barrel of the same diameter. The Vudoo doesn't have any accuracy problems because everything about it has been manufactured with perfection in mind. I also think that the heavier barrel would be less susceptible to harmonic anomalies with a suppressor.

Another issue with the harmonic theory with the accumulation of carbon fouling in the suppressor. My problems didn't start until I shot a little less than a hundred rounds. That would not have caused a lot of fouling but still put enough weight in the can to add to the moment/arm with the longer barrel.

A shorter barrel has a shorter moment/arm and less prone to harmonic problems.

I suppose that I could leave the suppressor off of the rifle but this defeats the purpose that I had in mind for the thermal to hunt at night. I hunt on a couple of farms and don't like disturbing the owners with gunfire at 2 AM.

So my plan is to remove the suppressor and thermal scope. I have another good scope and mount to put on the rifle to use for daylight fun.

Now I can look on the bright side. This gives me an excuse to get another Rock River rifle with the 16 inch barrel to use with the thermal scope and suppressor.

So what are your thoughts? Is there any validity to my theory about barrel length and stiffness when in comes to suppressors in the rimfire world?

Thanks in advance.

 

[NighthawkCG]

Have seen cans throw off accuracy when they are not totally concentric. Not enough off to cause a baffle strike, but enough to cause what I suspect is some uneven turbulence as the bullet passes through. Have also seen rimfire cans with a ton of crud/buildup in them.

Lastly, not a rimfire expert, but many say you should season the barrel when switching ammo types. I have 2 rimfires and do believe they settle down after a few mags of the new ammo. Prob won't matter within the brand (CCI SV vs Suppressor) unless they are the specialty temp stuff (diff lube for diff temps/conditions) but may be something to consider.

All of that being said, rimfire guys sometimes love their harmonic tuners so I don't think your theory could be too off either.

 

[Longshot231]

Have seen cans throw off accuracy when they are not totally concentric. Not enough off to cause a baffle strike, but enough to cause what I suspect is some uneven turbulence as the bullet passes through. Have also seen rimfire cans with a ton of crud/buildup in them.

Lastly, not a rimfire expert, but many say you should season the barrel when switching ammo types. I have 2 rimfires and do believe they settle down after a few mags of the new ammo. Prob won't matter within the brand (CCI SV vs Suppressor) unless they are the specialty temp stuff (diff lube for diff temps/conditions) but may be something to consider.

All of that being said, rimfire guys sometimes love their harmonic tuners so I don't think your theory could be too off either.

I agree with all of that but for the fact that during the second range session the accuracy changed with installing and removing the suppressor.

You also gave me something to think about. I have a barrel tuner. So I wonder if it would make a difference using it. On the other hand, I would probably also have to change the settings of the tuner everytime I changed ammunition.

 

[308pirate]

This is a long story and a little difficult to get to the point so forgiveness is begged for in advance.

A couple of years ago, I purchased a .22LR upper from Rock River Arms with a 16 inch barrel.

.22LR Tactical Carbine

Rock River Arms, Inc. offers a complete line of American made, custom built AR15 style rifles.

www.rockriverarms.com

I put it on a lower and scoped it with a Vortex Viper PST. On the end of the barrel, I put a SIG rimfire suppressor. For a semi-auto the accuracy was phenomenal.

Later on, I removed the daylight scope and put on a Burris Thermal scope. The accuracy was still great with all sorts of ammunition.

Then one day, I got a borescope. This is where the tail of woe began with this rifle. Now I know that there are all sorts of comments I will get about why I should not have purchased the borescope but let's try to stay on topic as I'm curious about accuracy issues when it comes to barrel length and suppressors on rimfire rifles.

Anyway, I looked in the bore with the scope and discovered that the barrel was severely pitted. It looked like a 100 year old rifle barrel. Yet it still shot great. I had a 1917 Enfield that was like that. It was one of the better shooting WWI rifles that I owned.

I have several other AR-15 uppers from Rock River with pristine barrels. They are all amazingly accurate. So this particular barrel is an exception.

I was not content with the condition of the barrel and contacted Rock River. They were nice enough to offer to install a new barrel.

So I asked them if I could get a stainless barrel which was 20 inches instead of 16. I was willing to pay the difference but they didn't charge me.

I received the upper back with the new 20 inch barrel back in a couple of weeks. Everything was reassembled; lower, thermal scope and suppressor.

The thermal scope allows for the use of six different "models" when it comes to changing reticles for six different types of ammunition. In other words if I wanted to use CCI standard velocity for one "model," I could switch to another "model" for CCI mini-mags. I could choose between 10 different reticles for each "model."

So off to the range I went to rezero the rifle. At first the accuracy was great. These are the brands and types if ammo that I shot in order: CCI SV, CCI 45 grain Suppressor, CCI Mini-Mag, CCI Stinger, American Eagle 40 grain and Federal Auto Match.

I didn't have to fire a lot of rounds to zero each type of ammo and didn't experience any accuracy issues until the CCI Mini-Mag which would have been with "model" #3. After about 10 rounds fired, I started noticing extreme fliers.

We're talking about 1 foot high to 1 foot low at 50 yards. Sometimes the rounds would go left or right about 6 inches!

Initially, I thought that the Mini-Mags weren't the best round for that barrel. The CCI stinger didn't group too bad but it has never been considered match ammunition.

The American Eagle and Auto-Match didn't group to bad either but not tack-driver quality. So I ended the range session with the intent to come back the next day and try some Norma target ammunition for use with "model" #3 of the thermal scope.

I cleaned the rifle but because I probably shot less than 200 rounds I decided not to clean the suppressor.

I had shot the Norma ammunition out of the 16 inch barrel with the daylight scope before and accuracy was exceptional for a semi-auto rifle. So I thought it should work with the 20 inch barrel.

The Norma ammunition was all over the place like the mini-mag the day before. So I decided to see what the CCI SV would do.

Keep in mind that I was getting excellent results the day before at the beginning of the previous range session. During this second range session, the CCI SV bullets were all over the place!

I examined everything on the rifle. Everything was tight! So I removed the suppressor to see what would happen.

You guessed it, without the suppressor the accuracy was excellent. No fliers at all! Even the Norma ammunition grouped better.

I experimented with and without the suppressor. Everytime I shot with the suppressor the rounds produced groups the size of a soccer ball. Without, I was able to hit 3/4" rimfire steel swingers consistently!

BTW, there isn't anything wrong with the suppressor. Everything is concentric and there are NO baffle strikes.

Now for my theory bout barrel length/stiffness. I have three other rimfire rifles that I shoot with the same suppressor. Two of them have 16.5 inch barrels and the other has a 22 inch barrel.

The rifles with the shorter barrels are a Savage B22 ane Ruger American Rimfire. Both guns have gone through extensive makeovers, with laminated stocks, triggers, picatinny rails, etc...

The rifle with the 22 inch barrel is a Vudoo 360. I ordered the heaviest barrel possible. Accuracy has always been excellent with and without the suppressor.

Keep in mind that accuracy issues with the newer, longer Rock River barrel didn't show up until more fouling had accumulated in the suppressor. Also remember that I cleaned the barrel prior to the start of the second range session.

My guess is that because of the longer barrel any harmonic anomalies are going to be magnified compared to a shorter barrel of the same diameter. The Vudoo doesn't have any accuracy problems because everything about it has been manufactured with perfection in mind. I also think that the heavier barrel would be less susceptible to harmonic anomalies with a suppressor.

Another issue with the harmonic theory with the accumulation of carbon fouling in the suppressor. My problems didn't start until I shot a little less than a hundred rounds. That would not have caused a lot of fouling but still put enough weight in the can to add to the moment/arm with the longer barrel.

A shorter barrel has a shorter moment/arm and less prone to harmonic problems.

I suppose that I could leave the suppressor off of the rifle but this defeats the purpose that I had in mind for the thermal to hunt at night. I hunt on a couple of farms and don't like disturbing the owners with gunfire at 2 AM.

So my plan is to remove the suppressor and thermal scope. I have another good scope and mount to put on the rifle to use for daylight fun.

Now I can look on the bright side. This gives me an excuse to get another Rock River rifle with the 16 inch barrel to use with the thermal scope and suppressor.

So what are your thoughts? Is there any validity to my theory about barrel length and stiffness when in comes to suppressors in the rimfire world?

Thanks in advance.

You could have avoided all that bullshit and hassle if you had ignored what you saw inside the first barrel and instead believed what its targets were telling you.

When will people ever learn?

 

[Longshot231]

You could have avoided all that bullshit and hassle if you had ignored what you saw inside the first barrel and instead believed what its targets were telling you.

When will people ever learn?

Remember that I addressed that in the original message.

Then one day, I got a borescope. This is where the tail of woe began with this rifle. Now I know that there are all sorts of comments I will get about why I should not have purchased the borescope but let's try to stay on topic as I'm curious about accuracy issues when it comes to barrel length and suppressors on rimfire rifles.

Regardless of that, your comment is well taken.

 

[Mr. Wolf]

One thing I noticed shooting suppressed 22lr, make sure that the threads are spec’d to the correct length and the shoulder is square. My Thunderbeast 22 Takedown didn’t play nice with my CZ457 thread specs so I mainly run it on my plinkers. Once corrected, it shot much better but needed to be cleaned after 200 rounds to avoid being out of tune.
YMMV, happy shooting

 

[Zak Smith]

One thing I noticed shooting suppressed 22lr, make sure that the threads are spec’d to the correct length and the shoulder is square.

Check these. A fair number of 22's have threads that are not correct, or not "correct for the suppressor being used."

 

[kl3309]

I know you said you checked for baffle strikes but did you check the end cap for any smears around the exit hole? And did you shake the can to see if any chunks came out?
I've got an old Huntertown Arms can that shoots fine when absolutely clean but will get big flyers like you about 100 rds. in. No evident baffle strikes but I'll see some smears around the exit hole. My guess is that crud is knocked loose and falls into the path of the bullet as it flies through the can (I used to see this all the time when I had radial comps on my TacSol uppers, with big chunks of lead falling out of the comp as you shoot). None of my other rimfire suppressors do this.

 

[B y r o n]

So how is the accuracy if you clean the suppressor before your shooting session with ammo that grouped poorly?

 

[Longshot231]

I know you said you checked for baffle strikes but did you check the end cap for any smears around the exit hole? And did you shake the can to see if any chunks came out?
I've got an old Huntertown Arms can that shoots fine when absolutely clean but will get big flyers like you about 100 rds. in. No evident baffle strikes but I'll see some smears around the exit hole. My guess is that crud is knocked loose and falls into the path of the bullet as it flies through the can (I used to see this all the time when I had radial comps on my TacSol uppers, with big chunks of lead falling out of the comp as you shoot). None of my other rimfire suppressors do this.

So how is the accuracy if you clean the suppressor before your shooting session with ammo that grouped poorly?

I can take the can apart. It's a SIG suppressor with "M" baffles. There were no smears on the end cap.

When I shot the rifle with the clean suppressor the first day the accuracy was great. No flyers until I tried shooting the CCI Mini Mags. Then the rounds went everywhere.

I took the rifle home and cleaned it that night but not the suppressor.

The next day, despite a clean barrel, the results were the same. So I removed the suppressor and fired 20-30 rounds with fantastic accuracy with CCI Standard Velocity and Norma target ammo.

Everytime I replaced the suppressor, the accuracy sucked. Remove it and there are no problems.

Recall that this barrel was a replacement for the original barrel that was pitted. The original barrel was chrome-moly 16 inches. The replacement is a 20 inch stainless barrel.

When I had the old barrel with a daylight scope on it, the accuracy for a semi-auto, was fantastic. One day, about a year ago, a grandfather was at the range with his left-handed grandson who was also left-eye dominant. He had a difficult time with a right handed bolt action rifle.

So I let the kid shoot several hundred rounds of CCI standard velocity at golf balls suspended on mason line from 100 yards away! He was hitting them about 75% of the time! His misses were even close! There were NO fliers.

Again, this was accomplished with the older, shorter barrel! He did all that shooting with the same suppressor.

Your theory about crud getting knocked loose has a lot of merit. Because of the different lengths of barrels, I'm inclined to believe that crud is enough to cause harmonic anomalies in the longer barrel because of the longer moment-arm.

I will take the rifle out tomorrow with a daylight scope on it to see how it does with CCI SV.

I put the thermal on a S&W M&P 15-22 and will see how it does. This rifle has a 16.5 inch barrel but accuracy wasn't it's strongest quality.

However, I tightened the barrel nut today to see if that makes a difference for getting tighter groups. If that doesn't work then I have the perfect excuse to buy another rifle with a 16 inch barrel

 

[B y r o n]

Or you could simply clean the suppressor!

 

[Longshot231]

Or you could simply clean the suppressor!

That is always the option and I do keep them clean. However, after about 100 rounds that would become impractical when one considers the volume of shooting in a day with rimfire ammunition.

I have the same rimfire suppressor on other rifles and pistols which have been shot a lot more in one range session without any problems.

 

[FuhQ]

I have a Mask HD and 2x TBAC 22TD’s… No issues with accuracy with any of them.

My thoughts lean towards the Sig can. They’re never mentioned amongst the top-tier cans for a reason…

 

[Longshot231]

I have a Mask HD and 2x TBAC 22TD’s… No issues with accuracy with any of them.

My thoughts lean towards the Sig can. They’re never mentioned amongst the top-tier cans for a reason…

That's true. SIG had a few promotional events at the LGS over several years, where they would pay for the tax stamp. It was too good an offer to pass up. After the next three get out of jail I will have seven of them. The ones that I have, so far, haven't given me any problems until now.

 

[NateVA]

I have a Mask HD and 2x TBAC 22TD’s… No issues with accuracy with any of them.

Are you using them on precision-style rigs and if so, how often are you cleaning them?

 

[Emerson0311]

Not a suppressor, but I have a factory Ruger muzzle brake on a 16” 10/22 that quickly builds up carbon and I get flyers from strikes on the carbon build up. Without the brake the accuracy is poor, with it great.

 

[chevy_man]

I have a Mask HD and 2x TBAC 22TD’s… No issues with accuracy with any of them.

My thoughts lean towards the Sig can. They’re never mentioned amongst the top-tier cans for a reason…

They don't pay the right people. Kevin might be a dick, but he can design a can.


I have shot a ton of them. Never an issue.


The barrel is picky. That is the problem. Something about it is borderline, and a slight change tips it passed where it's accurate.

 

[FuhQ]

Are you using them on precision-style rigs and if so, how often are you cleaning them?

Yes. And I clean my cans every 350-500 rounds. Or if I plan on letting them sit for a while.

 

[FuhQ]

They don't pay the right people. Kevin might be a dick, but he can design a can.


I have shot a ton of them. Never an issue.


The barrel is picky. That is the problem. Something about it is borderline, and a slight change tips it passed where it's accurate.

Kevin designed them for Sig? That explains why they’re not very quiet and have bad looking welds and why if you flip them upside down, they resemble a 8====> .

 

[chevy_man]

Kevin designed them for Sig? That explains why they’re not very quiet and have bad looking welds and why if you flip them upside down, they resemble a 8====> .

Kevin sold out to Remington, went to work for SIG, threw a tantrum and left, and started Q.

Mine is solid. It's also from their first design as are all of them I've shot. I haven't talked to anyone that owns one that's disappointed.

There's plenty of trash talking sig for plenty of other good reasons though. I'm just that lucky guy that everything I buy works.

 

[FuhQ]

Kevin sold out to Remington, went to work for SIG, threw a tantrum and left, and started Q.

Mine is solid. It's also from their first design as are all of them I've shot. I haven't talked to anyone that owns one that's disappointed.

There's plenty of trash talking sig for plenty of other good reasons though. I'm just that lucky guy that everything I buy works.

I completely forgot about his little stint at Sig and then he pitched a fit and left. I honestly never even think any the douche until his name or Q gets brought up.

And yeah, you’re right about the plenty of other reasons… I was going to buy one of those P322 (or whatever it is) .22LR pistols, but after all the problems got even worse, I was like, “Nah, I’ll wait on the Ruger MK-IV SSH from Silencer Shop…” Glad I waited on it.

Saw this posted on IG the other day…

 

[Longshot231]

Not a suppressor, but I have a factory Ruger muzzle brake on a 16” 10/22 that quickly builds up carbon and I get flyers from strikes on the carbon build up. Without the brake the accuracy is poor, with it great.

Is that the birdcage flash hider? If so, does it have the enclosed or open bottom?

If it's not the birdcage, can you provide a picture?

 

[Oldguy03]

I believe you should probably clean the suppressor!

 

[Longshot231]

I took the rifle out today with a birdcage flash hider that was factory issue. Instead of the thermal, I mounted a daylight scope.

Rimfire ammunition has always proven finicky in cold weather. Today was no exception. Regardless, I didn't get any fliers that were more than a half inch with CCI SV. I shot a couple of thirty round groups that measured an inch and 1 1/4 inches at fifty yards.

That's with a semi-auto, cold weather and ammunition that isn't really match grade. So I'm satisfied.

The rifle is accurate enough. Everything points to the suppressor, or the threads being a little off on the barrel.

I will try the suppressor and thermal scope on the S&W M&P 15-22 tomorrow.

 

[FuhQ]

I took the rifle out today with a birdcage flash hider that was factory issue. Instead of the thermal, I mounted a daylight scope.

Rimfire ammunition has always proven finicky in cold weather. Today was no exception. Regardless, I didn't get any fliers that were more than a half inch with CCI SV. I shot a couple of thirty round groups that measured an inch and 1 1/4 inches at fifty yards.

That's with a semi-auto, cold weather and ammunition that isn't really match grade. So I'm satisfied.

The rifle is accurate enough. Everything points to the suppressor, or the threads being a little off on the barrel.

I will try the suppressor and thermal scope on the S&W M&P 15-22 tomorrow.

Accuracy Solutions makes a .22LR alignment rod. A regular .223/5.56 rod is too large to fit in a .22LR bore, since .22LR is made tight for the lead projectile to press into the grooves.

Suppressor Alignment Rod To Check .22 LR 16" | Accuracy Solutions

Precision machined in USA from Stainless Steel. Bore specific and guaranteed straight to .001." In most cases, damaged stainless steel alignment rods can be sent back to us for straightening. Engraved with logo and caliber size for easy identification. Packaged in clear PETG storage tubes that...

accuracy-solutions.com

I have a couple of their rods, and they're nice quality and really nice fit (minimal play).

 

[Longshot231]

Accuracy Solutions makes a .22LR alignment rod. A regular .223/5.56 rod is too large to fit in a .22LR bore, since .22LR is made tight for the lead projectile to press into the grooves.

Suppressor Alignment Rod To Check .22 LR 16" | Accuracy Solutions

Precision machined in USA from Stainless Steel. Bore specific and guaranteed straight to .001." In most cases, damaged stainless steel alignment rods can be sent back to us for straightening. Engraved with logo and caliber size for easy identification. Packaged in clear PETG storage tubes that...

accuracy-solutions.com

I have a couple of their rods, and they're nice quality and really nice fit (minimal play).

Thanks! I've been looking for one of these. Ordered one now!

 

[Emerson0311]

Is that the birdcage flash hider? If so, does it have the enclosed or open bottom?

If it's not the birdcage, can you provide a picture?

It’s the weird one that comes on the 10/22 Competition. I end up cleaning it with a drill bit. The holes are at lots of different angles.

 

[FuhQ]

Thanks! I've been looking for one of these. Ordered one now!

Glad to help. They're also the only ones that I could find that make a 7mm rod, so I have one of those and one of their 6mm rods. I hope they make a .257 rod someday...Then I'll have one for all my different calibers.