Moderator removal and Rezeroing

[gareth08 1]

Hi guys,

 

Recently removed the moderator off my .17HMR, as it was almost welded onto the barrel. So after much swearing and 'gentle persuation' - ahem - I took it apart and cleaned it out.

 

It was bought second hand, and I've put over 500 rounds through it myself since then, and it was absolutely minging!

 

Now I've screwed it back on, ive had to rezero the gun, as it was WELL off. Rounds were barely on the paper at 100yds. Just wondering why this would be. I'd assume as long as the sights weren't touched, the zero would be unaffected? Is this something I'll have to do every time I remove the moderator?

 

Also, any tips on stopping the moderator getting welded onto the screw cut on the barrel. Is copper ease something that can be used safely?

 

Cheers guys,

 

Gareth.

[paulus 26]

zero should not change, is the mod the type with washers and springs if you take the mod off before you put it back in the cabinet you will not have the same problem again.

[Moran 10]

From what I know which ain't a lot you should be taking the mod of every time you put the rifle away as it will weld its self to barrel and destroy the crown . I clean my rifle and mod after every outing

[gareth08 1]

No, there's no washers or springs in it. It's just a generic moderator. I think it's made by Edgar Brothers, as it's not got any manufacturer branding on it, and the scope that came with the gun (CZ452) was an edgar brothers brand.

 

Maybe the scope has taken a knock at some point when I had the gun on the bench and that's thrown the zero out. I was surprised by just how much it was off though!

[gareth08 1]

Moran, I think you're right! I always run the snake through the barrel at the end of a days shooting and I usually take the mod off too.

 

I stuck the gun in the cabinet with the mod still on only twice, and in that short space of time, it was stuck on, so I didn't bother trying to remove it. Started to get worried about the crap that was in there ruining the barrel, so eventually managed to get it off and it really was PROPERLY filthy - took me the best part of an hour to get all the layers of crap out! .17HMR is a pretty dirty round!

[JohnGalway 1,043]

What's the crown like?

 

Did you test it on paper before removing the mod, was it off beforehand as well?

 

How does the gun shoot without the mod on? The POI should be lower (I think) but how are the groups compared to the grouping with the moderator on?

 

Always ( x a billion times) remove the mod after a shooting session, clean the threads, use some copper grease to lubricate them, and always clean your crown.

[dogvixen01 34]

i have a cz hmr and removal of mod gives me a 1/2 inch different poi at 60 yds.

[gareth08 1]

Hey John. Yeah the more I read up on this the more it makes sense. Appears the only people having issues with zero, are guys with damage to the threads/crown.

 

I'm running a dose of copper solvent on the threads and crown at the minute, as there was a bit of a buildup on the surface of the crown. So when I've washed that off and given it a rub down with some oil, I'll take a picture of the crown and stick it up and see what you guys think.

 

Before the mod was off, I hadn't checked the groups on paper for a while, but the bunnies didn't like the groups!! Shot a few rounds through it with the mod off with no problems. Only since the mod is back on did I notice the issues with the groups on paper - not quite as good as they used to be - but I put it down to my crap shooting........ Maybe I've done a bit of damage to the threads/crown

[Moran 10]

It's worth checking it out mate doesn't sound good from what your saying

[gareth08 1]

Head on picture of crown

[gareth08 1]

Side picture of Crown

[gareth08 1]

Well I think these are pretty good exhibits of 'Why its bad to leave a mod attached for any length of time' - you live and learn!!!

 

The copper solvent took off a lot of the crap that had built up, and revealed a fair bit of pitting around the edge, and around the last few turns of the threading. Obviously this is why I had so much trouble getting the mod off!!!

 

Think this is going to need recrowned and possibly threaded. Any ideas how much that would cost guys?

 

Will have to visit the Gunsmiths on Monday.................................

[scoop8650 0]

as an airgunner who has had a moderator on a gun for 15 yrs with no problems and moving up to a .223 i was shocked to learn how moderators rot if not cared for correctly , reading more every day i am learning constantly and will do as long as i shoot . thanks

[Moran 10]

Oh dear I hope the gun smiths can sort it out mate let us know how you get on

[SNAP SHOT 194]

Another thing that will change the POI with refitting the mod is barrel harmonics, and how tight the mod is screwed on, compared to the last time

it was on,

 

If you simply have no adjustment to do then you are very lucky indeed, there are loads of factors to take into account,

And its way over my head, with tech stufff, and i've been shooting 20 odd years....

 

i only use mod in certain situations when needs must...

 

all the best.

 

 

Snap.