Another suppressor question

Hey team, not sure if this has been discussed before.

I have two different makes of suppressors. Without disclosing the brands, for obvious reasons.

The rifle groups exceptionally well with one suppressor and the groups opens up with the other one. Exact same hand loads.
And no, the projectile does not clip on the second suppressor.

The first one weighs a lot more than the second one. That tells me the harmonics of the barrel changes due to more weight on the front vs less weight.

What's the easiest way, without doing load development all over again to get the gun to group with the second suppressor?

how much of "opening up" are you talking????
in effect you have ,as you suggest,changed barrel harmonics so all bets are off.
luckily my rifles havent done this.
have you double checked the bedding???

From a tight clover to 2" at 100m. Nothing to do with bedding as it groups excellent with the heavier suppressor.
Group is 5x shots at 100m with heavier suppressor.

POI also changes between the two. The heavier shoots +- 80mm lower at 100m. The barrel is a heavy varmint profile, so wouldn't expect that sort of difference, but it does.

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Originally Posted by DELTA NZ

From a tight clover to 2" at 100m. Nothing to do with bedding as it groups excellent with the heavier suppressor.
Group is 5x shots at 100m with heavier suppressor.

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I have exactly the same problem, my old supressor groups a lot better than my new (heavier) supressor. And groups best with no supressor

I seem to have tracked it down to a spot on my tikka where the barrel touches, i suspech more weight on the barrel increases the effect of said spot.

Im gonna cut said spot out and see if it fixes it.

My barrel is slightly thicker than the factory and its cerakoted so i geuss that makes it touch a bit more.

But yeah, your one is the other way around so maybe random harmonics

Quote:

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Originally Posted by DELTA NZ

POI also changes between the two. The heavier shoots +- 80mm lower at 100m. The barrel is a heavy varmint profile, so wouldn't expect that sort of difference, but it does.

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Thats wierd, the abovementioned Tikka (308 sporter has a shilen barrel) has less than 0.5moa diffrence between no supressor and the light supressor. The heavy supressor about 1.5moa from the no supressor impact.


I had an old mossberg ATR that was 12moa between supressor on and off haha.

so your sort of seeing what I am pointing towards......how does it group WITHOUT suppressor??? if its worse or similar to the light one...MAYBE the downward pressure of heavier can is helping somehow... are you shooting both suppressors using the hugyourself/offhand on toe of stock??? if so try offhand on forstock...JUST BECAUSE MAYBE its jumping around a bit more with less weight up front.
what Im driving at is trying to find the why its different....might be the weight forward,might be harmonics,might be rifle moving.... try it and see.

I'd be checking whether the bush at the back of the suppressor is touching the barrel one one of these vs the other. Some say contact is Ok. I think there should be clearance.

Different mass. different harmonics. different poi/grouping.

Why do you think barrel tuners are a thing?

Yep what zeropak said I would be checking that too [emoji106]

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The heavier one is a over barrel, not touching the bush at the back. The lighter one is forward only.

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Originally Posted by STC

Different mass. different harmonics. different poi/grouping.

Why do you think barrel tuners are a thing?

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100% agree. What's the easiest way to get it to group without going through load development again?

I don't think Harmonics would make that much difference. There's something else going on with that barrel forward suppressor. Not sure what, Maybe alignment, I know you said there was no bullet contact with the suppressor but in my experience even restricted travel can cause muzzle blast to upset the projectile.

One is weight shift on barrel harmonics other will be volume of the suppressor and gas pressure difference especially on the projectile leaving the end.

Are both threads equally tight and lock the suppressors hard against the barrel, or is there a gap? I would have placed my bet on harmonics, but that seems less likely on a varmint weight heavy barrel. Puzzling indeed.

Do they both have the same sized hole on them

Quote:

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Originally Posted by DELTA NZ

100% agree. What's the easiest way to get it to group without going through load development again?

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I don't think you can I have 2 different brands and had to redo load development as each one liked a different load.
It's no different to changing bullets or powder.

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Just out of curiosity. Why do you want to run 2 different cans?. If one works well just use that one. Or, Sell the other one and replace it with a duplicate of the one that works?

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Quote:

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Originally Posted by zeropak

I don't think Harmonics would make that much difference. There's something else going on with that barrel forward suppressor. Not sure what, Maybe alignment, I know you said there was no bullet contact with the suppressor but in my experience even restricted travel can cause muzzle blast to upset the projectile.

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Ever done load development?

what causes some loads to do cloverleavs while others don't even remotely group?

same thing. harmonics.

A suppressor adds a large mass at the end of the muzzle. changing that mass will have a large effect. It then comes down to how large your particular accuracy node is.

Quote:

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Originally Posted by DELTA NZ

100% agree. What's the easiest way to get it to group without going through load development again?

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just using the one suppressor that shoots.

If you feel like tinkering around give the other one a good clean.

Pad under the barrel at the tip of the foreend - experimenting with different locations and different pad thickness (changing the amount of upward pressure and the location of it) can reduce the gap. But in this case, one option works rather well so if that does it for you why stuff with it?

Although it would be interesting to note the grouping with the cans off - and see what the difference is. It could well have some form of bedding dislike given that the heavier option improves things over lighter or the action screw tension or stock stability could be factors. There's lots that could contribute to this, how much ammo do you want to burn up and how many notebooks do you want to fill up experimenting which is really the only way to get a handle on whats going on.

we had a new 243 suppressor that had one baffle in it that was smaller than the others It didnt contact the bullet but it did upset it and make it group like a shotgun
the suppressor maker dropped a drill bit down the end that was .5mm bigger than the projectile to demonstrate that it would fall thru all the way and was very surprised when it stopped half way haha

Found the issue. Cheers everyone for the help.

After closer inspection, found that the projectile was ever so slightly touching the suppressor on the inside. Very disappointing as this is a very expensive suppressor.

Please update us when it's been fixed....hopefully maker will do so ASAP for you

Hi all to be fair on the suppressor maker when you fitted the suppressors to your barrel
were they done as a match set ie barrel off in a good lathe and thread /face checked [runout etc ] and the same with the supp. on
if aligned right to the best one can do then a tighter tolerance [smaller hole inside supp ] can be used
even then a to small amount of clearance will affect out come
Aim Small Miss Small

Quote:

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Originally Posted by DELTA NZ

Found the issue. Cheers everyone for the help.

After closer inspection, found that the projectile was ever so slightly touching the suppressor on the inside. Very disappointing as this is a very expensive suppressor.

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So a few things to check, before you necessarily jump on the suppressor.

The thread on the muzzle is quite often the biggest variable.

Is the thread in good condition.
Is it perfectly true to the bore.
How wide is the shoulder that the suppressor screws up against (I like to have 1mm min, so 2mm more than thread diameter)
Is the face of the shoulder clean, a bit of crap or a bur can tip the can.
Is the crown good.

So now to the suppressors

Does the one which is playing up have a smaller bore than the other, if so it might well be that both are tipped slightly but just the tighter one shows it.
Are both rear over barrel end caps a good clearance on the outside of the barrel, I have many barrel offcuts here (from established brands) where the bore is over 1mm eccentric to the O/D, so if the rear over barrel end cap is tight it will tip the can.
Are the barrel to suppressor shoulder faces clean in both suppressors, if not again you can tip the can.

So just a few ideas to look at.

Cheers

Darren