Boys Rifle Mk1 Muzzle Brake Help Needed!

[stencollector]

If you own a Universal (Bren gun) carrier, then you need to own a Boys rifle. But if you end up with a boys with the flat Mk2 muzzle brake , then you are frustrated in that it does not quite fit into the back of a mk1 universal carrier. One or two of my friends have been feeling this frustration (I am lucky, my Boys rifle is a proper mk1 with the round muzzle brake) so a machinist friend of mine decided to help them out. He had a CNC program made up for a portion of the brakes, and made a very small run of them. Below are some photos of the two. The new one is still in the white:






Now here is the problem. When my friend went to install his new muzzle brake to replace the mk2 muzzle brake, it did not snug up against the front sight by a fair bit of space. What we are wondering is if there is perhaps a crush washer on the mk1 Boys rifle muzzle brake to properly align the orientation of the brake. So the first question to the other owners of the Boys rifles, is what is between your muzzle brake and your front sight?






My second question pertains to the special wrench to remove the muzzle brake. I found the wrench to be too tight on my original, and so of course it is too tight on these exact copies. Has anyone else found they have to remove just a slight bit of material from the wrenches to make them work? I am talking about maybe .003".

Any help that other owners can offer would be appreciated. These repros are pretty meticulous, so these two problems are a bit of a puzzle. The barrel currently on my rifle is of no help, since it is a 50 cal replacement barrel. The gunsmith who did the initial work took a few liberties, so it is difficult to ascertain what is correct on it. For instance, he changed the left hand thread pitch on my muzzle brake to a difference of 2 TPI from the original to match the threads he put on the end of my new barrel. Why he did this I can't fathom. I have my demilled original 55 cal barrel which is what you see in the photos.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Peter Laidler]

I have a funny feeling that there were a set of different width spacers but my only experience with these is on the Mk2 'harmonica' type muzzle brake and these spacers were used to keep the brake hoprizontal (as the threads weren't indexed.....) So it stands to reason that there very probably were ring spacers on these Mk1 muzzle brakes.

The next question is why would there be on the radial Mk1 type. That COULD be so that the m/brake was positioned so that the two lower vents were directed at 120 degrees apart DOWN with the third blast being directed vertically. Muzzle blast was a BIG problem with these and some of the reports mention this unwelcome feature! This is the reason for the introduction of the horizontally vented Mk2 type.

As a bit of an anorack, the question I'd loke to know is how much more efficiant would one be over the other. Is this a case of Boyles Law of gas or am I mixing my physice lessons up here? In any case, these are true muzzle brakes/recoil reducers and not flash eliminators/hiders

[stencollector]

I posted this on gunnutz as well and had no confirmation of spacers on mk1 brakes. This lead me to head back out to the shop with the demilled barrel and the two brakes. I think I have discovered the problem......the threads on the repro muzzle brake need to be set back slightly, about .040", in order to go over a slight un-threaded portion of the barrel just before the fron tsight. So I believe the problem will be solved. A .035" thick spacer would likely work, but this would also increase the gap in between the barrel end and the internal face of the brake. Could that lead to a pressure problem within the brake? Or a problem down the road with the hot gasses wearing at that area? Not that anyone is gong to be firing hundreds of rounds out of a Boys rifle anyway, but we still want to be safe.

I can attest to the ferocity of the round muzzle brake. I was firing mine on a range in the spring time, and it was throwing chunks of ice back at me the size of my fist. I have owned both types of muzzle brakes on two different rifles, but several years apart. Both rifles would leave their mark on you if you feared them or did not respect their authority. You never felt it at first, but after the adrenaline wore off, you certainly did.

[Peter Laidler]

Personally, I suspect that the undercut you mention was to prevent the carbon laden gas from getting back into the threads and jambing them up solid and jambing the muzzle brake on - as happens with Bren gas cylinders.

I let my son fire the Barratt when he was quite little. One of our Sergeants was alongside him in the fire trench. He winced a bit but went on to shoot five or so rounds.

[Brit plumber]

If you own a Universal (Bren gun) carrier, then you need to own a Boys rifle. But if you end up with a boys with the flat Mk2 muzzle brake , then you are frustrated in that it does not quite fit into the back of a mk1 universal carrier. One or two of my friends have been feeling this frustration (I am lucky, my Boys rifle is a proper mk1 with the round muzzle brake) so a machinist friend of mine decided to help them out. He had a CNC program made up for a portion of the brakes, and made a very small run of them. Below are some photos of the two. The new one is still in the white:
https://www.milsurps.com/images/impo...2bb9b29a-1.jpg

https://www.milsurps.com/images/impo...d2c40116-1.jpg

https://www.milsurps.com/images/impo...5121f61d-1.jpg

Now here is the problem. When my friend went to install his new muzzle brake to replace the mk2 muzzle brake, it did not snug up against the front sight by a fair bit of space. What we are wondering is if there is perhaps a crush washer on the mk1 Boys rifle muzzle brake to properly align the orientation of the brake. So the first question to the other owners of the Boys rifles, is what is between your muzzle brake and your front sight?


https://www.milsurps.com/images/impo...44c2f025-1.jpg

https://www.milsurps.com/images/impo...869de6ee-1.jpg

My second question pertains to the special wrench to remove the muzzle brake. I found the wrench to be too tight on my original, and so of course it is too tight on these exact copies. Has anyone else found they have to remove just a slight bit of material from the wrenches to make them work? I am talking about maybe .003".

Any help that other owners can offer would be appreciated. These repros are pretty meticulous, so these two problems are a bit of a puzzle. The barrel currently on my rifle is of no help, since it is a 50 cal replacement barrel. The gunsmith who did the initial work took a few liberties, so it is difficult to ascertain what is correct on it. For instance, he changed the left hand thread pitch on my muzzle brake to a difference of 2 TPI from the original to match the threads he put on the end of my new barrel. Why he did this I can't fathom. I have my demilled original 55 cal barrel which is what you see in the photos.

Would there be any chance of another run? My Boys also has the Harmonica Mk2 brake and I've been after a Mk1 for about 8 years now with no look.

I've never seen a Boys with a washer or spacer between the sight and brake. I assume you've seen this sight but if you haven't, it may be of some use. One of the photos is a close up of the brake with no washer.

http://www.rifleman.org.uk/Enfield_B...Tank_Rifle.htm

[stencollector]

Interesting to note that on the shot of the "Tank's eye view" of the brake, that it is not positioned with the bottom openings at 4 and 8 o:clock. Perhaps it was not an issue, or perhaps the blast was so bad that it did not make a difference.

I have PM'd you with details of the availability. At this point I believe he has two still available. Not cheap, but a definite work of art.

[Peter Laidler]

I take the point about the gas venting SC (thread 6) but it ws just a thought...... The gas blast and the dust rasied was an issue in France/1940. Can you imagine what it must have been oike in the desert? Mind you, by the time of the desert war/1941 on, the Boys was probably only any good against soft skinned stuff.

I think I mentioned some years ago that we used one of ours against a Ferret hulk on Salisbury plain field firing area and it pinged right through!

[Brit plumber]

I'm not surprised Pete, I'd imagine the Armour on a ferret to be similar in standard to a pre-war tank. Can you tell us that little story about you ordering ammo and the dump finding a pallet of it in store after 70 years?

[stencollector]

My first Boys rifle, in it's original 55 cal configuration, would pass through two 3/4 in plates lined up at 100 yards. While the front armour on a Ferret is somewhat thick, the remainder barely even provides mine protection, besides protecting against the larger caliber steel penetrating round.

Peter, I was of the same frame of mind on the positioning of the muzzle brake......it should have a closed portion pointing straight down. One photo in a Disney movie does not make a consensus, so I think the jury does not have enough facts on this subject yet. If someone really wanted it to line up properly, it would be just a matter of running the face over a piece of emery until the orientation was correct.

The Canadians brought a fair number of Boys rifles onshore to the Dieppe raid. There are reports where the rifle did quite well against obstacles. While certainly marginal against any armour, as anti material, it was 60 years ahead of it's time.

My machinist friend came over yesterday, and it is obvious that the threads are set back. The batch of brakes are heading back to the machine shop to have an appropriate amount of material removed. We may be test firing with one today, depending on if it rains or not.

[Brit plumber]

With a big thanks to Rob (stencollector), my brake arrived last week and this week I've had chance to fit it and get some photos (I don't think I'd be any good as a photographer). I'm really pleased with it, I just needed to clean the threads on my barrel and it fitted perfectly.