Do You really need a bush on the end of the mod

gelert

Well-Known Member
I've owned both my tika t3, and t8 from new,and being the over barrel mod I've noticed it marks the last few inches where it's tight on the barrel.

This hasn't in all the years I've owned both affected accuracy in any way.
Is there any real need for a rear bush between the mod and barrel?
If there is,who can make them or take off a few thou.

Even without the bush it fits real snug,but I don't know what sort of movement there might be.
 

Gaothead

Well-Known Member
There has been previous discussion on this, some people use tape to protect the barrel, some discard the bush. I'm a little concerned that there doesn't seem to be much barrel left on a 308 if cut to 1/2x20 so a bit of support seems tempting but my one mod is used on different rifles and the bush is pretty loose on them all.
 

Ranger22

Well-Known Member
Anyone who supplies T8's can supply you with a bush, they cost pennies. Best to cut the hole on a lathe
 

Northwest

Well-Known Member
Problem is, most of these bushes are quite hard plastic. I was going to try flourosint (glass filled PTFE) as a bush because it is quite soft but durable, snag is the cost of the material. Or some soft Polyurethane, but I would have to grind the threads, which isn't straightforward.......

Bit more thinking about.......
 

AN DU RU FOX

Well-Known Member
what about delrin? polyexamethaline smooth as silk hard wearing ,?or acetal rod from plastocks uk heat/cold resistant
 
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NigelM

Well-Known Member
I'm running a Hardy mod without a rear bush on the 6.5. Can't say I have noticed any issues at all. Run a T8 on the 6mm with a bush and it has marked the barrel as you say. I don't think the bushes are there for structural integrity, just to stop any gasses blowing back at you, but have not has a problem with that on the Hardy.
 

Casual-T

Well-Known Member
I bought a Lawrence Precision mod in the recent clear-out / sale and hadn't considered the bush but Simon emailed after it had been sent and was adamant I had the bush cut to a fairly specific diameter around the barrel.
Not knowing much about it, I asked it was strictly necessary and he replied that I risked damaging both the mod and the barrel by not doing it.
I am not sure if this is unique to his moderators but I had it done anyway (at no cost, on a lathe, by a friendly gunsmith). Took a few minutes and feels / looks more 'snug'.
 

Casual-T

Well-Known Member
…sorry, I forgot to add that, as it's Friday night, I think Blaser do a 100% cardboard mod bush, lathe cut and laser honed for just £799.27… :eek:
 

Yorric

Well-Known Member
I seem to remember being told that some early moderators had "O" rings sealing the back end - I may be mistaken tho' . It may be worth a try - cut a groove in the bore of a bush & tuck an O ring in there so that it very lightly touches the barrelwhen the mod is in place. - It would give a bit & act as an extra centralizing thingy whilst screwing it on.

Ian
 
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Outback

Well-Known Member
It would give a bit & act as an extra centralizing thingy.
I would go for the above statement the bush would ensure the threads are squarely seated so the bush needs to be a correct fit, would the mod flex with the harmonics of the barrel and in the end if shooting a long string of shots come loose ?
 

ejg

Well-Known Member
The last thing you want is a tight fitting bush unless your smith has cut the mod thread aligned to the barrel outer diameter instead of the bore.
If your mod thread is cut properly centred to the bore you would not want to push it off line via a bushing centring on the outside. Bore of the barrel is mostly not 100% in the centre of the outside diameter. If I fit a bush then prefer to have a ~0.5mm gap to the barrel.
edi
 

Yorric

Well-Known Member
In my post #13 I did say "very lightly" LOL. - I should have added "whilst screwing it on" to the end of my post. -- I'll edit that in a mo.

Personally I have the bushes cut clear so that there is space for a wrap of tape on the barrel - I hate to see barrel surfaces damaged & prefer to use a disposable tape to avoid any marring of the surface & change it when it gets tatty or goooey.

Ian
 

bewsher500

Well-Known Member
the bush is there to stop any leverage that a large protruding mod will create on the thread, both internal to the mod and the rifle muzzle

you have a 6-10" lever attached to 14mm of thread on a thin tube

as above
get them cut oversize so they just clear.
 

Woodsmoke

Well-Known Member
My ASE doesn't have a bush at all. It just sits on the shoulder of the thread. It relies on the thread being cut true to the bore of course, but I've have no problems with it coming loose or being difficult to fit. I'd imagine most small-ish mods could do without the bush with no real ill effects
 

Farmerjoe

Well-Known Member
I use an Atec Maxim without the bush and its fine. bit wobbly when you first start threading it on mind.
Did use it with the bush to start with, then removed it as i thought it might improve heat dissipation by increasing airflow, if its done so i havent noticed!! also taking it out didnt effect poi.

Joe
 

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