Bayonet moves point of impact

[Charlie303]

I've found that firing a rifle with a bayonet hanging on the end of the barrel can have various affects on the POI, from none (as with my SMLE) to some (+ 2" with my No.4).

But yesterday, practicing for a comp coming up that requires a fixed bayonet on my M1 Garand, I was surprised that it raised the POI by a whopping 14" at 100 yards.

Just to say that the rifle is a fairly new build 'straight pull' action built to conform to UK 'Section 1' regulations. The bayonet is a 1943 M1 (M1905E1). I do recall firing the rifle with a standard WW2 M1 bayonet a couple of years ago and not seeing much difference with the POI, but only had the cut down M1905 with me yesterday. The rifle is generally very accurate and appears to function completely OK. The bedding of the furniture on the action appears to be fine, very tight as it's new wood. Taking the bayonet off, the rifle puts the bullets where I aim them.

Has anyone an explanation for the fairly excessive raise in POI, or experienced similar?

Thanks,

Charlie

Information

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[jond41403]

I have experienced similar but not on my M1 because I have never fired mine with the bayonet attached to be honest with you but I have a mosin nagant that does the exact opposite of your m1. My nagant shoots about three or four inches left without its bayonet and almost dead center with its bayonet attached. Different barrels have different barrel harmonics I have read

[Bob Womack]

In the TV version of Band of Brothers, as a new replacement is getting ready to parachute into Holland, the character of Bull Randleman says to him what I learned in the community: "Take that **** thing off, you won't shoot straight." I've never tried shooting with the bayonet on - it seems like just one more thing to clean.

Bob

[Charlie303]

Different barrels have different barrel harmonics I have read

Someone at the range suggested that it might be to do with the harmonics, of which I have only a vague understanding.

[Gil Boyd]

British and Commonwealth soldiers have always been told in training and therafter, that bayonets are for close quarters use, and if attached to a rifle at close quarters, it is then and only then, that the rifle should be fired to ensure short range accuracy "of sorts".

If you intend to shoot a military rifle with a bayonet fixed over distance, be prepared for very poor results.
Fixed bayonets were used successfully during the Afghanistan conflict Operation Herrick by British Troops to put the fear of God (Allah) into the opposition:

In May 2004, about 20 British troops were on the move 15 miles south of al-Amara, near the major city of Basra in Iraq. They were on the way to assist another unit that was under fire when their convoy was hit by a surprise ambush.

Troops from the 1st Battallion of the Princess of Wales’ Royal Regiment were on their way to aid Argyll and Sutherland Highlanders who were attacked by 100 militiamen from al-Sadr’s Mahdi Army when their vehicle struck an IED. The surprise attack actually hit two vehicles carrying 20 troops on a highway south of Amarah. Mortars, rockets, and machine guns peppered the unarmored vehicles.

The decision was made: the British troops fixed bayonets. They ran across 600 feet of open ground toward the entrenched enemy. Once on top of the Mahdi fighters, the British shot and bayoneted 28 of the militia. Fierce hand-to-hand combat followed for five hours. The Queen’s men suffered only three injuries.

So it has its uses..........................

[Bob Womack]

"Barrel harmonics" is a term used to describe the fact that waves are generated by the act of burning propellant at one end of the barrel to shove a bullet through the tube and out the muzzle. We tend to think of the barrel as a rigid tube but it actually vibrates exactly like a guitar neck vibrates when you pluck a string. If you hang a weight off the end of a guitar neck it alters the wave centers, or nodes, of the neck and it changes the sound. If you hang a weight off the end of the barrel is alters the location of the nodes along the barrel as well. Barrels are supported in places that constructively interfere with the vibration of the neck or don't interfere at all. If you alter the location of those nodes, the support locations may then fall at places that interfere DESTRUCTIVELY with the waves and harmonics (octave of the main or fundamental wave and octaves of that octave).


Three nodes:





An interesting example might be the Lee Enfield N.1 Mk.III.



This rifle has wood over its entire length and a couple of supports within that wood that are located so as to protect the vibrations of the barrel. When tinkerers modify these rifles to "sporterize" them by removing wood to drop their weight and relocating the supports, they can sometimes find that the point of aim has been drastically altered.

Bob

[jond41403]

Excellent description Bob!

[Charlie303]

If you intend to shoot a military rifle with a bayonet fixed over distance, be prepared for very poor results.

Cheers Gil - I'm prepared! As I mentioned, I was trying the bayonet out in preparation for a comp. It's the LERA 'Overlord' Comp, so we'll be using No.4s. 300 yds prone, 200 kneeling and the last detail is 100 yards standing (!) with bayonet fixed. As I have a M1 Garand I suggested we also include it as a class in the comp as it was a fairly important rifle on D-Day, hence my practicing yesterday. Actually, at my age with my eyes I don't need a bayonet to get poor results! I'll post when I get my results. Probably

"Barrel harmonics" is a term used to describe the fact that waves are generated by the act of burning propellant at one end of the barrel to shove a bullet through the tube and out the muzzle...

Brilliant! I now know considerably more about harmonics Bob. Thanks!

[Ovidio]

I noticed it myself with my Mosin M44.
If I extend the bayo, she starts shooting about 4” off at 100 metres (if I remember right, she prints right).
It was just a test for fun, but the result was pretty clear.

[browningautorifle]

Thing is...about thirty years back we did practices with FN C1 with bayonet, we thought we were training for war...and I honestly can't remember what the result was. At the time I don't remember any hoopla about strike being off POA. Our doctrine was blades on before crossing the start line. Too late for me to prove or disprove now...no FNs around here.