moderator
- Thread starter stoker150
- Start date
Yes, I remember 6 or 7 years ago practising with my T8 on my 243 and the shots got worse and worse. I decided to give up and call it a day. When I went to take the moderator off the rifle and put all my gear in the back of the car, I found the T8 was loose. I traded it in for an AU-S5 shortly afterwards. One recommendation made to me was to paint an index mark on the rear of the mod which is visible when shooting. If the mod becomes loose, the painted mark will show up the movement.
Regards JCS
Regards JCS
Thar
Well-Known Member
Most rifle barrels have a right hand twist so as the gases exit and hit the baffles they in fact try to un-screw a right hand threaded moderator from the barrel. Not a big problem on a stalking/foxing rifle. If you look at any of the USA moderators for use on military full auto firearms you will see that they are threaded left hand, so the gases screw the moderator tighter on as you fire more rounds, or are spigotted in place.
ATB
Tahr
ATB
Tahr
Big Stu
Well-Known Member
Will defiantly affect your rifles zero/accuracy i had this problem with a Predator 8 on my .270 ,No matter how tight i made it after 3 shots the end baffle kept on coming loose greatly affecting the rifles zero
This is the only make of mod i have do this never had this problem with the T8's , north star , a-tec mods
This is the only make of mod i have do this never had this problem with the T8's , north star , a-tec mods
Two thoughts:
1 Trade it in.
2 Find someone who can carefully open up the bush a fraction.
Rgds JCS
Last edited:
caorach
Well-Known Member
If you don't already do it then try a little grease on the threads when putting the mod on. Then tighten it up and see how that goes for you. My money says that it will at least give you some improvement. In saying that there is some potential for disaster if the mod were to work lose while shooting so it is worth checking that it is tight now and again as part of your normal shooting safety routine. It isn't a big job and is just a matter of getting into the habit.
Uncle Buck
Well-Known Member
SNUG, BUT NOT TOO SNUG
A thread should have a snug fit to the moderator, but not so tight you exert any real force. It should engage the first section and glide down the threads using a single hand. The contact with the muzzle shoulders, if cut square, is enough to keep it from unscrewing and ensures perfect alignment to the bore.
This factor is just as important for a muzzle-mounted moderator as it is for an over-the-barrel model. In fact, with moderators that sleeve down the barrel, the rear supporting bush can also be a contentious issue.
If you fit an over-the-barrel moderator to your rifle and look at the gap at the rear of the moderator with the bush removed, you should see a perfect concentric equal diameter between it and the outside diameter of the bore. If you do not, then the thread is on the skew, so when you fit the rear bush and tighten the moderator fully, the barrel will be tensioned between the muzzle and this point, as the moderator tries to straighten the misalignment.
This is not good for the rifle and certainly detrimental to accuracy. If there is proper alignment, then a tight rear bush is beneficial; if not, a couple of thou clearance would be better suited.
Rgds, Buck.
A thread should have a snug fit to the moderator, but not so tight you exert any real force. It should engage the first section and glide down the threads using a single hand. The contact with the muzzle shoulders, if cut square, is enough to keep it from unscrewing and ensures perfect alignment to the bore.
This factor is just as important for a muzzle-mounted moderator as it is for an over-the-barrel model. In fact, with moderators that sleeve down the barrel, the rear supporting bush can also be a contentious issue.
If you fit an over-the-barrel moderator to your rifle and look at the gap at the rear of the moderator with the bush removed, you should see a perfect concentric equal diameter between it and the outside diameter of the bore. If you do not, then the thread is on the skew, so when you fit the rear bush and tighten the moderator fully, the barrel will be tensioned between the muzzle and this point, as the moderator tries to straighten the misalignment.
This is not good for the rifle and certainly detrimental to accuracy. If there is proper alignment, then a tight rear bush is beneficial; if not, a couple of thou clearance would be better suited.
Rgds, Buck.
Not all rifles have a bore that is exactly centred in the barrel.When screw cutting, a barrel should always be centred in the lathe according to the bore, not the outside of the barrel.
As such is possible for the mod to look a bit off centre when compared to the outside of the barrel.
Both my Sako Finnfire and Tikka have bores that are slightly out of allignment with the centre of the barrel.
As such is possible for the mod to look a bit off centre when compared to the outside of the barrel.
Both my Sako Finnfire and Tikka have bores that are slightly out of allignment with the centre of the barrel.
This is not good for the rifle and certainly detrimental to accuracy. If there is proper alignment, then a tight rear bush is beneficial; if not, a couple of thou clearance would be better suited.
If there is clearance of even a few thou on the delrin bush then what is the point of it being there ???
If there is clearance of even a few thou on the delrin bush then what is the point of it being there ???
One reason is not to scratch the barrel when mounting the mod, other to keep out dirt a bit.
One cannot try to straighten the mod somehwere on the outside diameter of a barrel with the
outside not being center to the bore. Delrin is not a material that will stay put, it flows under pressure.
Remember the little waving hands that were stuck in car windows, Delrin, after a few weeks the hand sunk down
to one side further and further.
In the mods bush's case it would mean the pressure that the bush takes up will drop over time.
Unscrewing of a mod by itself: the lighter a mod the smaller the inertia and the less likely to unscrew.
edi
well chaps as usual with sd plenty of advice and tips and loads to think of.. i had allready toyed with the ptfe tape idea and the constantly checking the mod..so i think i will go with the ptfe tape and see how we go from there.. the rifle its self is a sako 85 sinth/stainless and was screw cut from the factory and mod was fitted by mcleods of tain.. so i think it would be sound given those facts ..ok well to the tgt and lets see how we get on then cheers
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