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  1. #1
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    Effect of suppressor on performance of a given load...

    I am thinking very seriously about getting a suppressor with two bushes so will fit my 22-250 and my 7mm08. Not so much a question of if but when...

    How much is the suppressor likely to affect the accuracy of my current load?

    Not an issue for my 7mm08 as I have done next to no load development. But my .22-250 has a load that shoots bughole groups... The reliability of this load is such that I have around 200 loaded rounds that I put together one wet day. I don't really want to compromise the performance of said rounds...

    How much have people had to modify their loads for putting a suppressor on?

  2. #2
    Caretaker Wildman's Avatar
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    Mine shot better after suppression(x2).

  3. #3
    R93
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    It would be rare for a suppressor to cause a rifle to shoot worse. Due to added length they essentially give your barrel and depending on load you could get a velocity increase. By being quieter and softening recoil by design, people tend to shoot better with them fitted. Apart from a barrel harmonics influence, the rifle has always been capable shooting the same without a supp, its the firer who has improved in most cases.
    You will never know unless you fit one.

  4. #4
    Member sneeze's Avatar
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    Quote Originally Posted by R93 View Post
    It would be rare for a suppressor to cause a rifle to shoot worse. Due to added length they essentially give your barrel and depending on load you could get a velocity increase. By being quieter and softening recoil by design, people tend to shoot better with them fitted. Apart from a barrel harmonics influence, the rifle has always been capable shooting the same without a supp, its the firer who has improved in most cases.
    You will never know unless you fit one.
    You hit a purple patch there mate I would generally agree with all the above but I did have a T3 some years ago that was outstanding with the 120 vmax.Against my mates advice I had it suppressed and it was never as good. still ok but it definatly went backwards. Could have been the 1/2" thread, dont know.
    Rules are for the obedience of fools
    and the guidance of wise men” Sir Douglas Bader.

  5. #5
    R93
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    Quote Originally Posted by sneeze View Post
    You hit a purple patch there mate I would generally agree with all the above but I did have a T3 some years ago that was outstanding with the 120 vmax.Against my mates advice I had it suppressed and it was never as good. still ok but it definatly went backwards. Could have been the 1/2" thread, dont know.
    I did say it was rare. I cant shoot 60gr projectiles with my suppressor in my .223 buy they shoot bloody well without it. 55's go better with the supp fitted than without.

  6. #6
    Member sneeze's Avatar
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    Yeah Im a bit of a jynx when it comes to supressors ,ask Tuiman2 . Heres a thought though, the harmonics theory has puzzeled a me a little. If a suppressor changes the harmincs of the barrel why do most tuned loads continue to be well tuned loads? and why generally do they shoot lower when fitted? that seems a little odd if its harmonics. I can see it having a damping effect maybe so it dosnt change it as such just reduces but Iwonder if its more of a weight issue as well making it more stable like a heavy barrel.
    Rules are for the obedience of fools
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  7. #7
    Terminator Products Kiwi Greg's Avatar
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    Quote Originally Posted by sneeze View Post
    Yeah Im a bit of a jynx when it comes to supressors ,ask Tuiman2 . Heres a thought though, the harmonics theory has puzzeled a me a little. If a suppressor changes the harmincs of the barrel why do most tuned loads continue to be well tuned loads? and why generally do they shoot lower when fitted? that seems a little odd if its harmonics. I can see it having a damping effect maybe so it dosnt change it as such just reduces but Iwonder if its more of a weight issue as well making it more stable like a heavy barrel.
    I guess they shoot lower because of the weight on the barrel bending it down a wee bit ?
    A couple of mine move up & left significately, 1 so much so that using it without, say in the bush, requires dialing the scope, which is more hassel than it's worth as far as I'm concerned.
    My 7-08 POI hardly moves with the big Maximus on or off or a T2 brake, go figure, on a 33" barrel ????

  8. #8
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    when you have a gun that shoots bug hole leave it the fuck alone.
    It was months of heart ache and a new trueflight barrel to get what was an ubsurdly accurate 243 .5 inch groups at 100m consistantly. to new barrel fitted and suppressed, now it shoots only about a .9 inch group.
    Fuck that learn from my mistake. suppress the 7mm08 leave the 22-250 alone.
    or be prepaired to take a step back in accuraccy

  9. #9
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    Quote Originally Posted by sneeze View Post
    Heres a thought though, the harmonics theory has puzzeled a me a little. If a suppressor changes the harmincs of the barrel why do most tuned loads continue to be well tuned loads? and why generally do they shoot lower when fitted? that seems a little odd if its harmonics. I can see it having a damping effect maybe so it dosnt change it as such just reduces but Iwonder if its more of a weight issue as well making it more stable like a heavy barrel.
    You need to look at the barrel like a cantilever. In terms of vibration most things tend to measure their vibration against their natural frequency (i.e. the frequency at which an object will vibrate itself to death at). For an object as simple as a cantilever its natural frequency is based on its weight, the objects stiffness and the distribution of that weight. Increasing the weight reduces an objects natural frequency and would almost certainly increase the difference between the excitation frequency generated by the bullet flying/bouncing/spinning down the barrel and the barrel’s natural frequency. The bigger the difference between the excitation frequency and the natural frequency the less the amplifying affect of the vibration. Increasing the overall weight of the barrel (i.e. heavy barrel) would also do this.

    Because the weight of the suppressor is not a large percentage of the weight of the whole barrel its effect of the grouping performance of any individual load is often very small.

    Tiny variations in the barrel dimensions and within the barrel material I think accounts for the direction of the suppressor “flick”. This would explain its consistency as well I think i.e. it always flicks shots to about the same location.

    I have a theory about the size of the suppressor “flick” but not one I feel like trying to write down. Also all of the above are simply my theories on it and they are certainly not backed up by my own research. Feel free to pick them to pieces and together we might come up with something believable!

    Also actual results will be much better than my crackpot theories so go and try it out!

  10. #10
    Member sneeze's Avatar
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    Yeah thats pretty much where I was going with the damping effect like a heavy barrel. Im probably being a bit pedantic but its the " shoots to a different poi due to changing the harmonics" I see quoted. I supose damping the effect is "changing" but I dont think thats why it shoots to a different poi. Im more along the flick line you mentiond but on the surface i thought it could be simply weight affecting muzzel jump and tourqe. To be honest Its not something I'v given a lot of thought. Like barrel harmincs Iv read a few theroys giving different ideas on why and how but believing one or the other won't change what needs to be done. Supressors are in the same boat with me really,I put it on, I have to dial up 2 moa. Knowing exactly why wont change the 2moa Im basicly a lazy bugger.
    Rules are for the obedience of fools
    and the guidance of wise men” Sir Douglas Bader.

  11. #11
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    I've found my suppressor makes the 243 with 20" barrel shoot 2 inches high!!

  12. #12
    R93
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    IIRC the muzzle brake used to be removed and hung off the muzzle and droop was measured with a clinometre for the 105mm L118's in service now. It was called the droop measurement and had to be calculated and solved for different angles of barrel elevation. The brakes weighed over 30 kgs iirc at the end of a 19 foot barrel. The difference in barrel droop with and without the brake was amazing.
    So IMHO harmonics or whatever of said barrels must be influenced as you are adding a weight that can have a couple of different contacts along the barrel.
    Especially in the case of an overbarrel supp.
    It is however a consistent weight and contact, therefore it stands to reason once POI is adjusted for, it should, on most occasions shoot said load as well.
    If not it has to be an influence the supp or machining has caused that has effected the barrel adversely. Or it has effected the way the gases are influencing the projectile. No?
    Last edited by R93; 10-07-2012 at 10:28 AM.

  13. #13
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    The length of the barrel has a large effect on its natural frequency. Does anyone want to start with say a 26" barrel with a suppressor and progressively shorten the barrel and refit the suppressor shooting groups at each reduction in length? Done to examine the difference in location of the groups. Would be an interesting experiment to do I think.

  14. #14
    Member sneeze's Avatar
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    IIRC BunneyBuster spent some time rotating a suppressor with a lock nut or something and the poi moved around quite a bit.I think he got it to zero where he wanted it quite well. But memorys a bit fuzzy ,Ill ask him next time Im talking to him.
    Rules are for the obedience of fools
    and the guidance of wise men” Sir Douglas Bader.

  15. #15
    LJP
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    Quote Originally Posted by sneeze View Post
    IIRC BunneyBuster spent some time rotating a suppressor with a lock nut or something and the poi moved around quite a bit.I think he got it to zero where he wanted it quite well. But memorys a bit fuzzy ,Ill ask him next time Im talking to him.
    Hmmm i had an interesting discussion with Robbie Tiffen a while ago about the possibility of setting up a suppressor to act as a tuning device. A bit off topic but can you imagine being able to load tune by using your suppressor indexed at different points. Just like some Benchrest shooters

 

 

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