Nielsen .22 mod question

0yster

Hi,

I bought a Nielsen moderator for my .22LR a few weeks ago, and am shooting CCI subsonic HP. There seems to be a lot of variation in the amount of noise suppression. Sometimes it's almost just a click, sometimes it's like there's no mod on at all. Is it possible that variation in the CCI subs (rated 1070fps IIRC) is causing some of them to go super-sonic? Or is there another reason? There doesn't seem to be any rhyme or reason to which rounds are louder or quieter, though it _might_ be that it improves after firing 10 or 20 rounds. But I couldn't say for certain, just an impression.

Would another brand of mod work better? Does anyone have any recommendations?

rsole1

0yster wrote: »

Hi,

I bought a Nielsen moderator for my .22LR a few weeks ago, and am shooting CCI subsonic HP. There seems to be a lot of variation in the amount of noise suppression. Sometimes it's almost just a click, sometimes it's like there's no mod on at all. Is it possible that variation in the CCI subs (rated 1070fps IIRC) is causing some of them to go super-sonic? Or is there another reason? There doesn't seem to be any rhyme or reason to which rounds are louder or quieter, though it _might_ be that it improves after firing 10 or 20 rounds. But I couldn't say for certain, just an impression.

Would another brand of mod work better? Does anyone have any recommendations?

I am not familiar with the mod you are using but unless it is blocked up there should not be a diiference in the sound, unless you are using different velocity ammo through it. You should strip it down and give it a thorough clean, don't use it until you have it stripped down and checked.

sniperman

0yster wrote: »

Hi,

I bought a Nielsen moderator for my .22LR a few weeks ago, and am shooting CCI subsonic HP. There seems to be a lot of variation in the amount of noise suppression. Sometimes it's almost just a click, sometimes it's like there's no mod on at all. Is it possible that variation in the CCI subs (rated 1070fps IIRC) is causing some of them to go super-sonic? Or is there another reason? There doesn't seem to be any rhyme or reason to which rounds are louder or quieter, though it _might_ be that it improves after firing 10 or 20 rounds. But I couldn't say for certain, just an impression.

Would another brand of mod work better? Does anyone have any recommendations?

hi lad and welcome.i had the same experience with cci subsonic,tried a sak,parker hale,atec mod,made no difference,some were quite,alot were like using hv ammo.switched to winchester,and sk subs,have not heard a loud bang since,but like said above,clean it,and try it,but with cci subs i think you will still get alot that sound very loud,cant explain why

0yster

Thanks Sniperman, that's very interesting about the CCIs. I'll try a few other subs. Cheaper than trying a few other mods anyway! And I'll clean it and check it as rsole1 suggested (thanks too), though it's only a couple of weeks old and had the same odd variations from day 1.

Grizzly 45

Couple of things;
First[ and weird] What was the weather like when you were shooting and getting the different variations on sound?And where were you shooting?Same location on a range or out in the country side?
Athmospheric pressure and wind can have an effect on the precived sound of a silencer too. IOW rain approaching[low pressure] can make the sound differ than shooting on a clear cold dry day[high pressure]
Where you are shooting can also have an effect too as it could be if it is on a range,you are catching echos of the shot from the walls and back stop.While out in an open field ,this wont happen.

The speed of sound is generally accepted as being 1,100 feet per second at sea level in dry air,so the ammo you are using 1070 fps is getting close to speed of sound.However the only way to find out is it going over the speed of sound is a very tricky experiment to set up on a range or anywhere else.You would need to shoot past a line of poles or thru a few target frames set at equal distance in front of the target to see if there is a supersonic crack as the round passes them on its way to the target. Possibly you have got a bunch of hot loads in the CCI.Swop and change some sub sonic brands to see if this is the case.

Next the can itself.Does it start off loud and then start quieting out? Or vice versa? If it is the former,might be better just not to clean it too often and let it run dirty.No biggie,as I run one myself on a 308 and I let it get dirty..
If it is the latter,it is possibly because you are running it slightly "wet" with being cleaned and there is a film of gun oil,etc in there.As that burns off the noise increases. So try using it either wet or dry dirty and clean and see if there is any improvement or not.BTW on running a "wet" can,it 's not dangerous as all the liquid is doing is coating the internals,not physically blocking the bullet exit. Also are you tightning the baffles and can correctly?Everything should be hand tight.not torqued onto the barrel,it can apprently make a difference.

What .22 are you using with the suppressor?Some guns just dont mate well with certain brands or types of cans.Beg ,borrow or steal a different can and see if things improve or not.
Hope that helps.

cookimonster

Ref first part of Grizzly45 post- ....absolutely weather and location can have a big impact on perceived sound levels. Hills, vegetarian and density of the ground - dry , wet etc will soak up or reflect sound so giving various noise levels.
Often shots over farm land yields a very low report but may not be consistent due to the latter conditions.

I have found bulk buy HV ammo to have quite a few inconsistencies but not so much with Ely, Lupua and Winchester LV HP.

0yster

Hi Grizzly,

Thanks for the comprehensive answer. Lots of ideas to try. I have a strong impression that it is often the first few rounds that are louder, so I'll try running it dirty for a few weeks as you suggest. Then I'll thoroughly clean it and see if anything changes. And test different brands. And different cans. And different weather. I see a lot of testing in my future...

Today I was shooting in a valley and the variation was particularly noticeable: sometime almost just the click of the pin, then other times I'd hear the echo of shot coming back off the valley walls.

Thanks very much everyone.

Baker.22

The reason is as simple as the variation in the speed of your ammo. The listed speed on the box is an average speed. When using cheaper ammo like CCI the variation is greater than say competition grade ammo. Your ammo speed is close to the speed of sound so some will break the sound barrier. The speed of sound varies slightly with air pressure also.

I shoot large amounts of ammunition and when using cheaper ammo I will hear on occasion the 'crack' of a higher speed round going sonic.


Check the speed when buying and try to get a slower 'average' speed !!

0yster

Thanks for all the advice everyone. I tried a very non-rigorous, non-scientific test with a variety of ammunition. In order of perceived consistency, from worst (at the top) to best:

Remington subsonic (rated 1050ft/s)
CCI Sub HP (rated 1050ft/s)
Winchester T22 (rated 1085ft/s)
Selllier & Bellot - (rated 325m/s - 1070ft/s)
Eley Tenex Pistol (rated 326m/s 1070ft/s)

The CCIs and T22 were pretty much equal. The S&B I felt had fewer supersonic fliers. The Tenex (unsurprisingly) had none, though they did sound a little louder than the others (when the other weren't going super).

As I said, only a subjective impression and it wasn't like I tested 100s of rounds of each. But apart from the Tenex, I reckon most clips of 5 had at least one 'loud' round.

What was also of interest to me was that, because I was paying more attention to the sound than the shot, I suddenly realised that the I could correlate the louder reports to fliers on target. Some of the time at least. Not a bit surprising of course, but there you go. It was news to me. Haven't been shooting that long.

I also have an impression that the first few shots tend to be much louder. Is it possible the barrel changes very slightly as it warms and affects muzzle velocity? Could just be coincidence though.