LSW, LMG and 60mm to go

No not quite when you get home have a look, it will cheer you up, as for mods affecting MV yes it happens but oddly enough we found when testing 20 inch barrelled 6.5 Grendel and .280 British that MV can increase a(and as a rule did) when moderators extend barrel length slightly. We found anything from 20 to 50 feet per second increases.
Weight wise its about on par with a bayonet. I have found no impact to effective range.
Accuracy unaffected (assuming firer can group in the first place)?
 

ugly

LE
Moderator
Indeed as the moderators reduce jump, flash and felt recoil it certainly does help grouping
Edited to add most sporting or target rifles benefitting from moderators also have bipods fitted to eliminate error during testing. The chap firing the 100 plus year old 6.5 swede from the bench with no mod, scope or bipod was shooting without a rest other than his own elbows.
 
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Indeed as the moderators reduce jump, flash and felt recoil it certainly does help grouping
Edited to add most sporting or target rifles benefitting from moderators also have bipods fitted to eliminate error during testing. The chap firing the 100 plus year old 6.5 swede from the bench with no mod, scope or bipod was shooting without a rest other than his own elbows.
OK, next dumb question: how do these things work?
 

ugly

LE
Moderator
OK, next dumb question: how do these things work?
Gas expansion chambers that dont vent with the bullet or before it. Think about the old L1 flash eliminator, now imagine if it was contained in a tube, if it contained baffles that slowed the escape of the excess gasses arranged around the bore in a circular fashion!
how sound moderators work - Google Search
The simplest explanation is;
For those that struggle to see how a typical sound moderator works it is simply a case that all moderators reduce gas velocity to a level that causes less noise and recoil. This is exactly the same as the function of a car or motorcycle exhaust, in terms of noise attenuation and the effect that has in 'silencing' an engine. If you need further elaboration you can always ask me.
see; Sound Moderators - Ivythorn Sporting
 
Gas expansion chambers that dont vent with the bullet or before it. Think about the old L1 flash eliminator, now imagine if it was contained in a tube, if it contained baffles that slowed the escape of the excess gasses arranged around the bore in a circular fashion!
how sound moderators work - Google Search
The simplest explanation is;
For those that struggle to see how a typical sound moderator works it is simply a case that all moderators reduce gas velocity to a level that causes less noise and recoil. This is exactly the same as the function of a car or motorcycle exhaust, in terms of noise attenuation and the effect that has in 'silencing' an engine. If you need further elaboration you can always ask me.
see; Sound Moderators - Ivythorn Sporting
Henry Percy Maxin (son of Hiram) invented the first firearms silencer in 1902 using the techniques then currently in use for vehicle exhaust silencers. Slowing down the gas venting to atmosphere reduces the noise.
 
Henry Percy Maxin (son of Hiram) invented the first firearms silencer in 1902 using the techniques then currently in use for vehicle exhaust silencers. Slowing down the gas venting to atmosphere reduces the noise.
So the technical details are fundamentally the same, but the name has changed - is that right?

I ask because in my head is a persistent notion (from reading who knows what over 50 years) that silencers reduce MV and effective range.
 
So the technical details are fundamentally the same, but the name has changed - is that right?

I ask because in my head is a persistent notion (from reading who knows what over 50 years) that silencers reduce MV and effective range.
Muzzle velocity and effective range do reduce a bit, from the reading and watching YouTube videos I've done, but games companies that make Call of Duty and Battlefield games, in particular, over-emphasize the drop-off in those values in their first-person shooters out of "balance" reasons. Otherwise, nobody would use anything other than suppressed weapons in-game, and all the work done on the modelling for non-suppressed ones would be out of the window.
 

jrwlynch

LE
Book Reviewer
So the technical details are fundamentally the same, but the name has changed - is that right?

I ask because in my head is a persistent notion (from reading who knows what over 50 years) that silencers reduce MV and effective range.
Some do, because they're specifically designed to: suppressors for some permanently fitted 9mm weapons, like the MP5SD family, vent the barrel to reduce muzzle velocity. The aim is to get the round down to subsonic velocity; so as well as reducing the "thump" from the muzzle blast, you've got rid of the "crack" from the bullet's supersonic shockwave. From the Wikipedia page on the MP-5:- "The bullet leaves the muzzle at subsonic velocity, so it does not generate a sonic shock wave in flight. As a result of reducing the barrel's length and venting propellant gases into the suppressor, the bullet's muzzle velocity was lowered anywhere from 16% to 26% (depending on the ammunition used) while maintaining the weapon’s automation and reliability. The weapon was designed to be used with standard supersonic ammunition with the suppressor on at all times."

Others may have done because they impinged on the bullet, for instance using rubber 'wipes' to trap the gas.

However, it seems modern suppressors can reduce muzzle blast without significantly reducing muzzle velocity.
 
So the technical details are fundamentally the same, but the name has changed - is that right?

I ask because in my head is a persistent notion (from reading who knows what over 50 years) that silencers reduce MV and effective range.
'Silencers' might (as pointed out by @jrwlynch) because they vent gas from holes in the barrel in order to deliberately reduce MV below supersonic, to get rid of "crack"; and control the expansion of the gases, to reduce "thump".

However, if you think of the bullet being a plug in the barrel, then anything after the barrel shouldn't affect how fast the bullet comes out the end. Hanging a lump of metal on the end may affect the zero and barrel harmonics, but that's no different from having a bayonet fitted.

Where things get interesting is how the gases venting out of the now-unplugged barrel affect the bullet as it leaves. This is why the accuracy freaks get all excited about barrel crowning, and why it's a bad idea to gouge away at the muzzle of your SA80 with a combitool to get a nice shiny ring - any asymmetry hurts accuracy.

The best analogy was provided @Bollox, namely the muffling effect of an exhaust pipe on a car engine. Ripping the exhaust pipe off your 1.1 Clio doesn't make it go any faster... even if it does impress all the other teenagers...
 

ugly

LE
Moderator
So the technical details are fundamentally the same, but the name has changed - is that right?

I ask because in my head is a persistent notion (from reading who knows what over 50 years) that silencers reduce MV and effective range.
Well sometimes but only with subsonic ammo, which isn't used for military rifles normally
 

ugly

LE
Moderator
'Silencers' might (as pointed out by @jrwlynch) because they vent gas from holes in the barrel in order to deliberately reduce MV below supersonic, to get rid of "crack"; and control the expansion of the gases, to reduce "thump".
No legal UK definition apart from integrally moderated barrel, often used for special projects however the planned USMC issue is for ones that fit on the end of the rifle. These dont have the same effect as the ported barrel types like the welrod which used subsonic ammo but would still be effective with normal ammo

However, if you think of the bullet being a plug in the barrel, then anything after the barrel shouldn't affect how fast the bullet comes out the end. Hanging a lump of metal on the end may affect the zero and barrel harmonics, but that's no different from having a bayonet fitted.
Indeed if anyone recalls the Browning Boss system which allowed sweet spots to be tuned in on the muzzle for different loads

Where things get interesting is how the gases venting out of the now-unplugged barrel affect the bullet as it leaves. This is why the accuracy freaks get all excited about barrel crowning, and why it's a bad idea to gouge away at the muzzle of your SA80 with a combitool to get a nice shiny ring - any asymmetry hurts accuracy.
Any fule (apart from those trained by the SASC) know that

The best analogy was provided @Bollox, namely the muffling effect of an exhaust pipe on a car engine. Ripping the exhaust pipe off your 1.1 Clio doesn't make it go any faster... even if it does impress all the other teenagers...
 

ugly

LE
Moderator
Stonker, you will have to pop down to a range I am at or the farm and I can show the effects of the mod with a chronograph!
 

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