Well, the board is either fixed, or it's going to run terribly. Cross your fingers and hope for the best. I'm at my technical limit right now.

Help with tightening a Jungle Carbine front sight

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Locofritz
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Help with tightening a Jungle Carbine front sight

#1 Post by Locofritz » Thu Sep 14, 2017 10:17 pm

I need some help securing a No5 Mk1 front sight. Took it to the range and could not hit the target. Sight slides in the dovetail slot.


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Re: Help with tightening a Jungle Carbine front sight

#2 Post by RWS » Fri Sep 15, 2017 7:06 am

How loose is it? Can you move the sight in the dovetail with finger pressure alone, or does it move only upon recoil? Is it so loose that if you turn the carbine sideways gravity will allow the sight to move on its own?

If the amount of looseness is minimal then using a broad flat-based brass punch & hammer to strike the top of the dovetail on the carbine (both front & rear) can tighten the dovetail slot enough to hold the front sight in place. Be very judicious with the amount of force and don't over-do it or you'll just make the dovetail too small.

If it's really, really loose then you can remove the front sight and cut a piece of .005" steel shim stock long enough so that when you set the front sight on the shim stock you can fold it up along the angled male dovetail sides. This will usually increase the girth of the dovetail enough to hold firm. In fact, if the looseness is really minimal then you might do better with .003" steel shim stock or running the .005" shim stock up only one side of the dovetail. Cold bluing the shim stock before installation will make the shim less noticeable.

If the problem is with the front sight rather than the dovetail mount on the barrel then buying a new sight might be preferable, although determining whether or not the current front sight dovetail is too small requires some dimensional specs that may not be easily found. Wouldn't be an expensive proposition to try a new front sight though.

Good luck. I hope it's an easy fix.

-Bob

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Re: Help with tightening a Jungle Carbine front sight

#3 Post by Tommy Atkins » Fri Sep 15, 2017 9:17 am

You can also prick punch the bottom of the blades dovetail.

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Re: Help with tightening a Jungle Carbine front sight

#4 Post by Locofritz » Fri Sep 15, 2017 2:07 pm

It's real loose, slides side to side. Wasn't like that when I acquired it loosened after 2 or 3 trips to the range. Are these the same site blades as the No 4? Have plenty of those


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Re: Help with tightening a Jungle Carbine front sight

#5 Post by INGarand » Fri Sep 15, 2017 3:39 pm

Sounds like the sight was possibly glued in place and shooting loosened it. All of the suggestions made could help. Adjusting the dovetail is often the most used fix. If you have some no 4 sights, try one of them. If it is tight then its the sight. You can then replace or stipple the original sight. Good luck with the repairs.

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Re: Help with tightening a Jungle Carbine front sight

#6 Post by Tommy Atkins » Fri Sep 15, 2017 5:15 pm

IIRC No4 & No5 are the same, for interchangeability, but No1 isn't.

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Re: Help with tightening a Jungle Carbine front sight

#7 Post by Alan De Enfield » Sat Sep 16, 2017 4:02 am

The No5 "Block Band" (the bit holding the blade) was not the same as the No4 - there were 6 different Block bands for the No4 as well to add to the 'mix'.

The 'mark' of sight blades varies :
Mk1 split block blade for the No5 equates to the Mk1* blade for a No4 rifle
and the
Mk 2 split block blade for the No5 equates to the Mk3 blade for a No4 rifle.
There were different part numbers for the blades indicating that there were subtle differences between the No4 and No5 types.

The blades were slightly different (eg split or non split, and 'size') for the various 'marks' of block bands so you need to ensure that you have the 'right blade for the right block band'
"When a well-packaged web of lies has been sold gradually to the masses over many years,

the truth will seem utterly preposterous and its speaker a raving lunatic". Dresden James

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Re: Help with tightening a Jungle Carbine front sight

#8 Post by RWS » Sat Sep 16, 2017 8:23 am

Well, LocoFritz, if you indeed have "plenty" of No.4 sight blades then trial & error fitment will cost you nothing. If the current blade is as loose as you say you should have no trouble pushing it out and trying your stash of No.4 sights to see if one is nice and tight. If a blade can be tapped into place with moderate force using a hammer and punch then you may have solved your problem. Do not continue if the force required to install the sight is excessive though. If the installation is successful, the blade height of the new sight may or may not be the same as what you removed. Shoot it and see where point of impact lies. I recommend 200-300 yards. If it shoots low then you can file some blade height down but if it shoots high only a new/different blade will work.

Alan:
I fear clarification will be necessary (for me at least) due to the uniqueness of British vs American technical jargon. Is the term "block band" the same as what we would call a dovetail, and does it refer to the fixed portion on the barrel or the removable portion that is currently loose & sliding? Also, does your definition of the term "bit" in the 1st parenthesis mean simply "a small amount" or is it a technical reference to the dovetailed portion of the removable part in which the actual blade is captured? The term "bit" in the U.S. has several technical definitions, i.e.: "drill bit".

Sorry to be so King's English challenged but just trying to get my head around the jargon.

-Bob

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Re: Help with tightening a Jungle Carbine front sight

#9 Post by Tommy Atkins » Sat Sep 16, 2017 12:05 pm

Its the machined part attached to the barrel with the sight dovetail in the top. You'd probably call it the "front sight base".

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Re: Help with tightening a Jungle Carbine front sight

#10 Post by RWS » Sun Sep 17, 2017 5:51 am

Thanks, Tommy. That's exactly what I was asking. Silly me, I didn't even think about using a Canadian interpreter. And yes, I would call it a front sight base although I recognize that the British nomenclature is equally correct, just different.

Thanks again for jumping in.

-Bob

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Re: Help with tightening a Jungle Carbine front sight

#11 Post by Alan De Enfield » Sun Sep 17, 2017 6:55 am

Tommy Atkins wrote:
Sat Sep 16, 2017 12:05 pm
Its the machined part attached to the barrel with the sight dovetail in the top. You'd probably call it the "front sight base".
RWS wrote:
Sat Sep 16, 2017 8:23 am
Well, LocoFritz, if you indeed have "plenty" of No.4 sight blades then trial & error fitment will cost you nothing. If the current blade is as loose as you say you should have no trouble pushing it out and trying your stash of No.4 sights to see if one is nice and tight. If a blade can be tapped into place with moderate force using a hammer and punch then you may have solved your problem. Do not continue if the force required to install the sight is excessive though. If the installation is successful, the blade height of the new sight may or may not be the same as what you removed. Shoot it and see where point of impact lies. I recommend 200-300 yards. If it shoots low then you can file some blade height down but if it shoots high only a new/different blade will work.

Alan:
I fear clarification will be necessary (for me at least) due to the uniqueness of British vs American technical jargon. Is the term "block band" the same as what we would call a dovetail, and does it refer to the fixed portion on the barrel or the removable portion that is currently loose & sliding? Also, does your definition of the term "bit" in the 1st parenthesis mean simply "a small amount" or is it a technical reference to the dovetailed portion of the removable part in which the actual blade is captured? The term "bit" in the U.S. has several technical definitions, i.e.: "drill bit".

Sorry to be so King's English challenged but just trying to get my head around the jargon.

-Bob
Thanks 'Tommy'.

Sorry - slang English - when I stated 'bit' I meant it as 'the piece', 'the item', 'the part'
The small 'part' (bit) that fits into the block-band via the dovetail is the 'sight blade'.
"When a well-packaged web of lies has been sold gradually to the masses over many years,

the truth will seem utterly preposterous and its speaker a raving lunatic". Dresden James

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