Thread: Supressors.

Originally Posted by Mike H

So to those who are of the opinion that thread diameter doesn't matter what do I tell the guy whose gun now shoots worse than before it had a 1/2" thread cut into it? He's the same guy with the bulging suppressor. Did I mention the rifles twin took the GD approach with a 14 x 1 thread and shoots the same/better as before?

When he sends back his suppressor the rifle will be going also and he'll be rightly asking for a new thread to be cut because the 1/2" one definitely affected his accuracy.

could just need hand loads tweeking as some do after been suppressed, harmonics etc

Your in denial too tui_man2 of the effect?

Maybe if he went S/S he wouldn't have had so much trouble. Weak shit that it is.

Better expand on that. If you thin the barrel (ie: the thread) THEN put a weak component around that thread, well, good luck. If however you put something around it like S/S that has a bit of guts to it then it is going to be inherently stronger.

So your saying if the barrel opens up due to threading, screwing stainless on will close it up again. If so Id reckon theres less shit on a faggots finger than there is on this thread.

My Guess is that when he had the barrel threaded for the suppressor, the crown may have had some damage or the threading is not concentric to the bore. Just depends on how gunsmith/engineer held the barrel for threading

Originally Posted by Chicken

So your saying if the barrel opens up due to threading, screwing stainless on will close it up again. If so Id reckon theres less shit on a faggots finger than there is on this thread.

Gold

Didn't say that though chicken did I. Read again, take note, then come back to me.

Originally Posted by Wirehunt

Why don't people understand fluting does nothing apart from looks. Weight loss is irrelevant as your only talking grains. Strength loss is a much bigger cost.

If you really want to loss weight from the rifle then work out what the diameter of the barrel after fluting then machine the whole barrel to that dimension. And by the way, the barrel will cool much quicker doing that than fluting, yes it will heat faster too.

Not so - I've been working on something for a little while - got enough done to summarise here. albiet it may not make much sense to those that havnt done a Eng deg dealing with the theory.

This stemmed from some of my AR barrels I'm playing with.
Used my Senderos as reference - here goes - I used imperial measurements as thats what we mostly deal with in gunstuff

30 cal Sendero measures 0.840" just back from the end of the fluting.
The flutes are close enough to 0.1875" (3/16) - 100% radius - 6 of them
Forgetting about the rifling - as this is a constant in comparison
A non fluted barrel in 30 cal with the same minor diameter would have to be 0.70" diameter.
We assume the same material of each barrel in the above 2 comparisons.
The 1st moment of inertia of the fluted barrel is 0.014, the solid barrel is 0.011
The minor diameters are equal as stated above, however the fluted barrel is ~27% stiffer than that solid barrel.

This can be proven again by doing a calc with a weight at the end of the barrel.. 100gms, 100kgs.. makes no difference - the fluted barrel will deflect ~27% less

Simple Physics

I will post the example of weight for weight later

Originally Posted by Greg Duley

Well said Gimp. Spanners, you in particular as a moderator I would have thought, should be setting an example on the tone of this forum?

A different example was being made Greg, a reality check maybe - I'll leave for a while before explaining if its required - nothing to do with you though - so no need to stress

I'm a straight shooter, I say what I think - might not always go down well, but if I think you're a knobend, I'll tell you on the net, in the street or at the pub - I dont hide behind a keyboard, nor do I put up with mindless dribble from others or in my industry 'Noel'

Spanners, have you dealt or communicated with any of the top USA barrel makers?

I've dealt with all sorts of barrel makers.. the 25 barrels I got earlier this year all have 1/2 x 28tpi threads on them (0.71 muzzle) , and at least 5 guys I know pulled their barrels from 'top USA makers' as these shot ALOT better.
My 'worst' shooting gun (thats not over 70 years old) has a barrel from a 'top USA barrel maker' - your top barrel mfg is quite possibly different to mine.. button, cut, pre contoured, pre lapped, pre fitted, cyro, heat relieved.. there is so many variables that there is obviously not a perfect formula.

KiwiGreg, please do not misrepresent what I said. You are trying to make black and white what is not. I never said threading or fluting will always detrimentally affect accuracy. I went to great length to explain the issues and the large variables at play here, which are real whether you accept them or not. By all means believe what you will, but we will be trying to do the best for our own rifles and those of our customers. This means using common sense and the commonly accepted best practise by the most recognised accuracy barrel makers and gunsmiths in the world. And that may well mean at times publishing the "inconvenient truth" which may well annoy some internet experts and NZ professionals set in their ways. So be it.

Im not sure exactly what KiwiGs getting at.. but making a blanket statement that 'it is so because so and so says its this way' is nothing more than plagiarising what they have published, not because it is right or of the extensive research you;ve done.
Stating god like 'be all and end all' facts based on what you're read on the internet is obviously going to draw controversy.
Not saying you havnt dicked around with stuff, but because 'this is how they do it' is a bollox reasoning to backup a point.
The yanks love carbs, V8s and the imperial system - it works - doesnt mean its the right way to do things.
Real numbers and real data back info up - and if they dont exist is it anymore than an opinion rather than the 'norm' or 'fact'???

Its quite possible that a 2" blank, that when fluted, shoots worse for whatever reason you want to dream up or so and so says.
However that X length barrel for Y weight when fluted, might shoot better than the unfluted barrel weight for weight, length for length, which in turn shoots worse that the original 2" blank.
Its not an even playing field - you've reduced the weight - it like comparing tomatoes and cherry tomatoes

There doesnt need to be a game of big dicks, because sooner or later someone is going to whip out a bigger one or chop it off.

Its a Hunting and Shooting forum, we're all just a number - noone is more more valuable that the next guy.

Simple physics would also dictate that the barrel is weakest at the thinnest point. So these fluted barrels don't go lighter than a light profiled sporting barrel or whatever the minimum wall thickness is for the rated pressure they are run at?

If you want stiffer for comp/precision shooting then logic would dictate getting whatever contour barrel (heavy as fuck) you want then welding fins onto it of a fairly serious nature. Or maybe getting it cast like that.

The point is since your talking engineering, if you want stiffer you go heavier OR you change the steel grade. Never ever seen an engineer try to make something stronger or stiffer by doing 'fins', whether you call it fluting or some other name.

Originally Posted by Wirehunt

Simple physics would also dictate that the barrel is weakest at the thinnest point. So these fluted barrels don't go lighter than a light profiled sporting barrel or whatever the minimum wall thickness is for the rated pressure they are run at?

If you want stiffer for comp/precision shooting then logic would dictate getting whatever contour barrel (heavy as fuck) you want then welding fins onto it of a fairly serious nature. Or maybe getting it cast like that.

I've make a cockup with my post last night - that data is for comparable minimum diameter between the 2, not weight - thats the other paperwork scribbles.
Will change it so it reflects, and sort the other version out.
The numbers dont change, given same minor diameter, fluted is ~27% stronger

The point is since your talking engineering, if you want stiffer you go heavier OR you change the steel grade. Never ever seen an engineer try to make something stronger or stiffer by doing 'fins', whether you call it fluting or some other name.

As far as engineering - strong backing something to make it stiffer is very common practice, the Ina is increased at a rate far surpassing an equivilent strength by increasing size.
Boats/Ships employ this extensively.

Originally Posted by Wirehunt

Simple physics would also dictate that the barrel is weakest at the thinnest point. So these fluted barrels don't go lighter than a light profiled sporting barrel or whatever the minimum wall thickness is for the rated pressure they are run at?

If you want stiffer for comp/precision shooting then logic would dictate getting whatever contour barrel (heavy as fuck) you want then welding fins onto it of a fairly serious nature. Or maybe getting it cast like that.

The point is since your talking engineering, if you want stiffer you go heavier OR you change the steel grade. Never ever seen an engineer try to make something stronger or stiffer by doing 'fins', whether you call it fluting or some other name.

Id have thought the fluting would have acted as strengening. More surface area too = harder to bend.. or not? Id have thought that weight for weight, a fluted barrel is stiffer than a straight barrel of equivalent weight.

I'm sure one of you metal experts will set me straight on this.

Originally Posted by headcase

Id have thought the fluting would have acted as strengening. More surface area too = harder to bend.. or not? Id have thought that weight for weight, a fluted barrel is stiffer than a straight barrel of equivalent weight.

I'm sure one of you metal experts will set me straight on this.

Size for size (OD) - no - weaker - negating the effects of the ridges - ie corrugated iron vs flat sheet as an example.
However weight for weight - yes - deff stronger

And what weight material is used for strong backing? Crazy big or it doesn't work. You wouldn't weld 5X5mm square bar onto 1/2 inch pipe and expect it to hold, in fact you would be pissing into the wind if you thought it would, and you know that already Spanners You'd go get heavier pipe. Just look at the weight on any strengthening done on steel work, always heavy as fuck compared to the base material.

Originally Posted by Wirehunt

And what weight material is used for strong backing? Crazy big or it doesn't work. You wouldn't weld 5X5mm square bar onto 1/2 inch pipe and expect it to hold, in fact you would be pissing into the wind if you thought it would, and you know that already Spanners You'd go get heavier pipe. Just look at the weight on any strengthening done on steel work, always heavy as fuck compared to the base material.

5x5 on 12.5mm is over 10% increase in strength.

I'll disagree with you an leave it at that as we're getting nowhere