Suppressor problems - would you cut the bbl?

[Ocnandmtns]

Need advice from people with more experience in this area than I have.

- I bought my first suppressor(zero experience with them before this)
- bought a 30 cal Banish backcountry Ti(reputable manufacturer and light)
- Planned to run it on my 2 rifles: a Kimber Mtn Ascent in 300WSM w/ a facotry threaded 24" barrel and on a Barret Fieldcraft w/ non threaded barrel that I'd cut
- Planned to see how it shot and felt on my Kimber before deciding how much to cut it back.

My Kimber shoots terrible with the can on! It was driving me nuts trying to figure out what the problem was. After burning through about a 80 rnds I realized that w/o the can it would group fine at 200 yds and then I'd put the can on and it would immediately be off paper, about 12" or more off and not really grouping. Shot several different factory rnds all with similar results. Checked can for baffle strike and not seeing any. Talked to Silencer Central who i bought from and to Kimber. SC says all signs point to barrel harmonics. Kimber says they've never heard of this issue.

I have very reputable local gunsmith that I planned to have cut both barrels so I took rifles to him to discuss. He immediately said it was prob barrel harmonics and that the super thin and fluted Kimber barrel is prob the issue. Since I wanted to cut the barrel back 4" anyway I asked if it would be likely to fix the issue- he said he can't guarantee it and that I might just end up with a shorter barrel with the same issue. Of course he doesn't want to guarantee it and I wouldn't ask him too. But, do any of you with more experience have thoughts on whether this will likely address the issue? I'm not a long range hunter, I'd like to be able to shoot out to 500 but prefer shots <300 yds. So, if I lose a little velocity but end up with a little lighter and easier to carry rifle it's not the end of the world, but if I knew it wouldn't fix the issue I'd probably leave the barrel unmolested.

Cutting will allow us to go from 7/16 threads to 1/2" which the gunsmith says is the min dia he likes to run for a can. Fieldcraft has a heavier barrel that shouldn't be an issue.

 

[KyleR1985]

If the rifle shoots at stock length, it’ll almost certainly shoot cut down.

You can guess pretty easily with searches here and google on velocity expectations at whatever length you’re cutting to. Then you’re just doing ballistics calcs to see if that satisfies whatever you’re going for.

Fluted barrels sometimes can’t be threaded.

Not exactly what you’re looking for, but some things to consider.

 

[Ocnandmtns]

Thanks. Yep but this barrel can be threaded- front 10" or so is non fluted so we'd be in there. Mainly looking for thoughts on whether cutting is likely to help w/ harmonics issue.

 

[HNTR918]

Need advice from people with more experience in this area than I have.

- I bought my first suppressor(zero experience with them before this)
- bought a 30 cal Banish backcountry Ti(reputable manufacturer and light)
- Planned to run it on my 2 rifles: a Kimber Mtn Ascent in 300WSM w/ a facotry threaded 24" barrel and on a Barret Fieldcraft w/ non threaded barrel that I'd cut
- Planned to see how it shot and felt on my Kimber before deciding how much to cut it back.

My Kimber shoots terrible with the can on! It was driving me nuts trying to figure out what the problem was. After burning through about a 80 rnds I realized that w/o the can it would group fine at 200 yds and then I'd put the can on and it would immediately be off paper, about 12" or more off and not really grouping. Shot several different factory rnds all with similar results. Checked can for baffle strike and not seeing any. Talked to Silencer Central who i bought from and to Kimber. SC says all signs point to barrel harmonics. Kimber says they've never heard of this issue.

I have very reputable local gunsmith that I planned to have cut both barrels so I took rifles to him to discuss. He immediately said it was prob barrel harmonics and that the super thin and fluted Kimber barrel is prob the issue. Since I wanted to cut the barrel back 4" anyway I asked if it would be likely to fix the issue- he said he can't guarantee it and that I might just end up with a shorter barrel with the same issue. Of course he doesn't want to guarantee it and I wouldn't ask him too. But, do any of you with more experience have thoughts on whether this will likely address the issue? I'm not a long range hunter, I'd like to be able to shoot out to 500 but prefer shots <300 yds. So, if I lose a little velocity but end up with a little lighter and easier to carry rifle it's not the end of the world, but if I knew it wouldn't fix the issue I'd probably leave the barrel unmolested.

Cutting will allow us to go from 7/16 threads to 1/2" which the gunsmith says is the min dia he likes to run for a can. Fieldcraft has a heavier barrel that shouldn't be an issue.

I'd run 1/2x28.
Pencil barrels will never shoot good with more than 3 rounds at a time. Get a barrel cooler from magneto speed.
I have a kimber at 19'' and it shoots 10 shots, 2 shots then cool between, under 1.5''.

 

[HandgunHTR]

Pencil barrels will never shoot good with more than 3 rounds at a time.

That is a fallacy. Shitty barrels won’t shoot good. Neither will shitty shooters.
Good barrels will shoot good regardless of how many rounds are shot before letting the barrel cool.
90% of the time when I hear this, it is based on someone shooting a light rifle chambered in a medium to heavy recoiling cartridge and the group opening up isn’t the rifles fault.

OP, cut the rifle down to 20”. If it still doesn’t shoot to your liking, try to borrow a DT can of another make to see if it really is an issue with the weight of the can, or if it is just that suppressor.
I shoot multiple cans on “pencil barrel” rifles and don’t have that issue.

 

[ResearchinStuff]

It's probably not harmonics. Companies love blaming stuff on mythical things that can't be proven.

The low impact is because your barrel is now bending due to the added mass at the front. Poi shift with the can on vs off is normal, a stiffer barrel will typically be less affected. Likewise, the bend in the barrel is probably showing either insufficient free float, poor bedding loose action screws, or some combo of those 3 things.

Cutting my tikka barrels had no accuracy effects. Unless your barrel has a fat or narrow spot, it should affect yours either.

 

[AZ_Hunter]

It's probably not harmonics. Companies love blaming stuff on mythical things that can't be proven.

The low impact is because your barrel is now bending due to the added mass at the front. Poi shift with the can on vs off is normal, a stiffer barrel will typically be less affected. Likewise, the bend in the barrel is probably showing either insufficient free float, poor bedding loose action screws, or some combo of those 3 things.

Cutting my tikka barrels had no accuracy effects. Unless your barrel has a fat or narrow spot, it should affect yours either.

That is most likely. Also sometimes strikes aren’t obvious because it’s an ever so slight kiss, that doesn’t show up until eventually there is a little copper deposit. Been there done that.

Get an alignment rod and check your can alignment.

I have been a can convert since 2015, have a couple dozen and have built a few.

 

[False_Cast]

Regardless of what you're observing can-on/can-off, the FIRST thing I'd be doing is checking/cleaning/Loctiting all fasteners, especially ring & base mounts and action screws. Many Kimber "barrel issues" were cleared up when base and/or action screws were found to be too long and bottoming out or loose. The easiest fix of all time.

 

[Maverick1]

TLDNR.

Doesn’t matter what you typed, anyhow.

The answer to your question or issue is: Tikka.

And the answer is - and always will be: Tikka.

 

[Ocnandmtns]

Thanks everyone! What I learned today: This rifle stuff is a beast and I should just go back to archery. Kidding, shooting right out of the box would have been nice but I don't mind a good technical challenge. I'm feeling better about cutting the barrel and I'll also look into all the other suggestions you guys gave.

 

[HNTR918]

That is a fallacy. Shitty barrels won’t shoot good. Neither will shitty shooters.
Good barrels will shoot good regardless of how many rounds are shot before letting the barrel cool.
90% of the time when I hear this, it is based on someone shooting a light rifle chambered in a medium to heavy recoiling cartridge and the group opening up isn’t the rifles fault.

OP, cut the rifle down to 20”. If it still doesn’t shoot to your liking, try to borrow a DT can of another make to see if it really is an issue with the weight of the can, or if it is just that suppressor.
I shoot multiple cans on “pencil barrel” rifles and don’t have that issue.

Completely False.

Go buy a Kimber mountain ascent, and show me a respectable 10 shot group shot consecutively with a can on it!

That same rifle will print great 10 round groups if allowed to cool after 2-3 shots. If 10 shots are shot consecutively, then the 10 round group will be 4-5X larger.

If the rifle barrel contour is thick enough, then laying down prone, getting set, and shooting a one good 10 round group is far easier than laying down getting set, shoot two, get up, walk around, move rifle, then repeating 5 more times.

 

[HNTR918]

Regardless of what you're observing can-on/can-off, the FIRST thing I'd be doing is checking/cleaning/Loctiting all fasteners, especially ring & base mounts and action screws. Many Kimber "barrel issues" were cleared up when base and/or action screws were found to be too long and bottoming out or loose. The easiest fix of all time.

I agreed with this. Undo the action bolts, place action in stock, make sure recoil lug is against the back wall, snug the front action screw, put in rear action screw loosely, torque front screw, then torque rear screw.

I've also glass bedded Kimbers and seen the groups cut in half.

Lastly, open up the stock barrel channel. This can cause issues if shooting off a bipod. I like a good 0.100''-0.200'' of clearance, not the good old dollar bill rule.

 

[HandgunHTR]

Completely False.

Go buy a Kimber mountain ascent, and show me a respectable 10 shot group shot consecutively with a can on it!

That same rifle will print great 10 round groups if allowed to cool after 2-3 shots. If 10 shots are shot consecutively, then the 10 round group will be 4-5X larger.

If the rifle barrel contour is thick enough, then laying down prone, getting set, and shooting a one good 10 round group is far easier than laying down getting set, shoot two, get up, walk around, move rifle, then repeating 5 more times.

You should read this thread.

Cold bore zero versus (very) Hot bore zero “test”

Discussions around “cold bore shifts” and “cold bore zeroes” versus “warm or hot barrel zeroes” are constant. So is the belief that barrels “walk” when they heat up or that groups open when they heat up. After having multiple discussions, @Ryan Avery and Jake @Unknown Munitions and I set up a...

rokslide.com

In your example of using a Kimber Mountain Ascent rifle, do you suppose that the difficulty in shooting a tight 10-round group may be due to the fact that it is a sub-5# rifle and that lighter rifles in medium to heavy recoiling chamberings are hard to control during recoil, thereby making it harder to be consistent during shooting? Or is the barrel expanding that much due to heat that it is fundamentally changing the point of impact of the bullet?

Your second paragraph pretty much answers the question. Why do you think it is easier to shoot a 10-round group in one sitting with that rifle rather than getting up and moving around after each shot or small string? Could it be that it is hard to get back into the exact position again and that shooter consistency plays a much bigger role in the group size than barrel heat does?

 

[HNTR918]

You should read this thread.

Cold bore zero versus (very) Hot bore zero “test”

Discussions around “cold bore shifts” and “cold bore zeroes” versus “warm or hot barrel zeroes” are constant. So is the belief that barrels “walk” when they heat up or that groups open when they heat up. After having multiple discussions, @Ryan Avery and Jake @Unknown Munitions and I set up a...

rokslide.com

In your example of using a Kimber Mountain Ascent rifle, do you suppose that the difficulty in shooting a tight 10-round group may be due to the fact that it is a sub-5# rifle and that lighter rifles in medium to heavy recoiling chamberings are hard to control during recoil, thereby making it harder to be consistent during shooting? Or is the barrel expanding that much due to heat that it is fundamentally changing the point of impact of the bullet?

Your second paragraph pretty much answers the question. Why do you think it is easier to shoot a 10-round group in one sitting with that rifle rather than getting up and moving around after each shot or small string? Could it be that it is hard to get back into the exact position again and that shooter consistency plays a much bigger role in the group size than barrel heat does?

The thin barrel is heating up, and changing the point of impact.

This is proven when a 10 round consecutively shot group measures 6”.

And a 10 round group, cooled between every 2 shots measures 2”.

This has been repeated many times with several rifles with #1 & #2 barrel profiles.

“Good barrels will shoot good regardless of how many rounds are shot before letting the barrel cool.” - Completely False

 

[HNTR918]

You should read this thread.

Cold bore zero versus (very) Hot bore zero “test”

Discussions around “cold bore shifts” and “cold bore zeroes” versus “warm or hot barrel zeroes” are constant. So is the belief that barrels “walk” when they heat up or that groups open when they heat up. After having multiple discussions, @Ryan Avery and Jake @Unknown Munitions and I set up a...

rokslide.com

In your example of using a Kimber Mountain Ascent rifle, do you suppose that the difficulty in shooting a tight 10-round group may be due to the fact that it is a sub-5# rifle and that lighter rifles in medium to heavy recoiling chamberings are hard to control during recoil, thereby making it harder to be consistent during shooting? Or is the barrel expanding that much due to heat that it is fundamentally changing the point of impact of the bullet?

Your second paragraph pretty much answers the question. Why do you think it is easier to shoot a 10-round group in one sitting with that rifle rather than getting up and moving around after each shot or small string? Could it be that it is hard to get back into the exact position again and that shooter consistency plays a much bigger role in the group size than barrel heat does?

In the post you shared, my point is perfectly demonstrated.
These are both factory Tikka's and both show a larger group shot between cold and hot.
This will be exaggerated with a thinned barrel, such as a Kimber!
#7 is what I see very often.

 

[mxgsfmdpx]

I'd run 1/2x28.
Pencil barrels will never shoot good with more than 3 rounds at a time. Get a barrel cooler from magneto speed.
I have a kimber at 19'' and it shoots 10 shots, 2 shots then cool between, under 1.5''.

Weird. I’ve shot Tikka and Sako lite contour barrels so hot that you can’t keep your hand on the barrel and they still keep on stacking bullets.

What brand barrels have you seen needing to be “cooled down” to continue to shoot accurately?

 

[HNTR918]

Weird. I’ve shot Tikka and Sako lite contour barrels so hot that you can’t keep your hand on the barrel and they still keep on stacking bullets.

What brand barrels have you seen needing to be “cooled down” to continue to shoot accurately?

Kimber, Remington, Winchester.

Tikka & Sako lite contours have much more mass than a #1 or #2.
Thus, the reason Tikka & Sako chose those profiles over going super lightweight.

 

[mxgsfmdpx]

Kimber, Remington, Winchester.

Tikka & Sako lite contours have much more mass than a #1 or #2.
Thus, the reason Tikka & Sako chose those profiles over going super lightweight.

I would see “stringing” with a couple different brand carbon barrels and a couple savage blued barrels going back about 8-10 years. I also had some issues with higher priced aftermarket steel barrels not being as consistent when shot very hot.

I think more so than the barrel profile with Tikka and Sako, my guess is that the cold hammer forging and properly stress relieving is what allows them to perform in the way they do. A friend of mine who is a product manager at Sako also seems to think this is what makes a difference.

I shoot them so hot that the only reason I switch rifles is because of the mirage in the scope. Usually 3-5 days a week minimum at home in AZ.

With these barrels I haven’t seen any measurable and repeatable correlation with accuracy discrepancies in very hot versus ice cold barrels.

Always curious to learn which brands suffer from this.

 

[HandgunHTR]

The thin barrel is heating up, and changing the point of impact.

This is proven when a 10 round consecutively shot group measures 6”.

And a 10 round group, cooled between every 2 shots measures 2”.

This has been repeated many times with several rifles with #1 & #2 barrel profiles.

“Good barrels will shoot good regardless of how many rounds are shot before letting the barrel cool.” - Completely False

As someone who has quite a bit of experience regarding how metals react to heat, I stand by my statement that if a barrel is deforming enough when heated to significantly change the point of impact at 100 yards, it is a shit barrel.

Again, you are ignoring the biggest factor when it comes to group size. The shooter. In almost all cases, the reason the super-lightweight guns have larger group sizes when shot consecutively is because of the shooter, not the gun.

I have more than one sporter-contoured rifles that will shoot consistently small groups, even when rapid fired, including a Remington 700 with a #1 contoured Pac-Nor, several factory Tikkas (which btw have a very similar profile to Remington and winchester factory profiles), and a Remington XP-100 with a super lightweight profile barrel.

 

[Okie_Poke]

Thanks everyone! What I learned today: This rifle stuff is a beast and I should just go back to archery. Kidding, shooting right out of the box would have been nice but I don't mind a good technical challenge. I'm feeling better about cutting the barrel and I'll also look into all the other suggestions you guys gave.

I don't have any qualms about cutting the barrel, but I'll be surprised if that by itself is going to be the fix. Maybe, and I'm not a gunsmith, but I doubt cutting the barrel in an effort to improve harmonics is a panacea. I don't have a ton of experience here, but my first reaction to your OP was "something is loose or rubbing that shouldn't be as a result of the can." Personally, I would check all of the things others have suggested regarding the can and rifle before I spent the money to cut the barrel down.