Bayonet moves point of impact

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

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

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

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Originally Posted by jond41403

Different barrels have different barrel harmonics I have read

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

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..........................

"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:


https://www.milsurps.com/images/impo...06/65poM-1.jpg


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

https://www.by-the-sword.com/images/...rge/FD1090.jpg

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

Excellent description Bob!

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Originally Posted by Gil Boyd

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

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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 :D

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Originally Posted by 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...

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

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.

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.

Jim,
You'll remember it was always instilled in training to fix bayonets as a fear tactic, nothing more nothing less!
It is perhaps regarded as a safety blanket in CQB where you just physically don't have the time to change mags you are that close in.
It is then the SLR with its length gave you some degree of comfort, sadly the SA80 brings you right in close, as a much shorter rifle, so aggression is the key to success as shown in Afghanistan on a number of occasions.
I am sure the Armourers on here will tell you, it is what it is.............a sharp point and the extension to your arm. Never saw any soldiers in my Regiment ever sharpen the blades either, if thrust properly, it did its job first time, and exactly what it was designed for.

No need for sharpening, as Chefs have decent knives to cut up your chips when needed:thup:

Accounts I have read regarding the use of the bayonet in WWI our chaps in the AIF were very adept at using it in close quarters as the Turks and the Germans found to their peril some of the close stuff where the boys had to tear the roof off the trenches at Gallipoli then jumping in to get at the Turks in a dark and dusty trench beggars description.
The Germans in WWI hated being across from the Australians due to the fact of the dexterity our chaps had with the bayonet once in amongst them in their trench.

I remember a story I read on the Falklands conflict where the Ghurka's were to assault a known position up on a hill, the Argi's got wind of the impending attack and fled apparently not in the mood to face the men from Nepal armed with their Kukri's such was their reputation with that blade.

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Originally Posted by Gil Boyd

It is perhaps regarded as a safety blanket in CQB

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That was what I told the troops too, if you have a stoppage, it'll be when you're right on top of him.

............or out of ammo :sos:

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Originally Posted by Gil Boyd

out of ammo

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Remember...out of ammo is treated as a stoppage. Done as a drill.

:lol::surrender:

Have you checked your barrel dampening? On a mauser or 1903 you have a couple of pounds of up pressure at the forend tip.
On an m1 the front ferrule pulls the lower band *down* to dampen.

Here is a ferrule being glassed in place with a 40 pound oil bucket providing downforce.

Kuhnhausen specifies 30-50 pounds.

Many many stocks have zero dampening.

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Originally Posted by jesse_

Kuhnhausen specifies 30-50 pounds.

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I hadn't heard that one...

I should be home in a few days.

Will post the page from Kuhnhausens book as well as the Nat Match specs from that 1962 or 1963 manual.
The national match manual specs the ferrule datumed from the top of the stock.

Also there is a tool to check spec that i dont have. There is one critical dimension but no actual print for the tool.

Lets talk in a few days. If interested i can post my long journey on fixing this particular stock tenon from hell so i dont crap up the OPs thread

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Originally Posted by Gil Boyd

It is perhaps regarded as a safety blanket in CQB where you just physically don't have the time to change mags you are that close in.

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I was reading today of one such incident. A Marine veteran interviewed in a new book, The Rifle, gave an account of his personal experience during a very large Banzai charge on Saipan. A Japanese soldier attacked him before he had a chance to reload his M1. The soldier ran up to the Marine and impaled himself on the bayonet of the M1; probably didn't see the blade in the dark. The Marine was unable to pull the bayonet from the body and was then attacked by another Japanese who needed to be dispatched by the Marine's Ka-Bar.

https://www.milsurps.com/images/impo...s550x406-1.jpg

Thats close and personal, and as I said, and it often happens in built up areas and high grassed fields where "first come first serves" is the only motto for survival ;)

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Originally Posted by jesse_

Have you checked your barrel dampening?

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Thank you Jesse, but no not yet. I know that the Lee Enfield No.4 has defined movement / damping at the barrel tip, but no idea if the M1 should have. I'll look into it.

At the local range today, 100 yards with the M1. And another bayonet experiment. I remembered that when I got the M1 I’d tried it with a a standard WW2 M1 bayonet and it made no difference to the POI. So I tried it again today and same result, POA = POI. Put the M1905E1 on and POI up by 14”. Weird! Something about the harmonics of the M1905E1 blade, the metal and/or the shape, is having a hell of an effect on the barrel when fired. I have 2 more bayonets, another M1905E1 (Bowie tip to the blade) and a Korea era M5 which has a different mount which I will try to see what they do.
Attachment 118051

14” is a lot…

Sadly that sort of spread is not uncommon.
Bayonets are like bipods, any additional weight at the front end stops a "floating" barrel from doing its job, and one has to expect these types of performance.
Thats why it is a CQB (Close Quarter Battle) option to be fitted, when you are close in or low or out of ammo!

Charlie303, thanks very much for sharing that. I agree that is very odd that between two bayonets that look very similar and were issued interchangeably, one does not move the point of impact and the other moves it 14 minutes! You could have probably won a few bets on that.

I have never shot with a bayonet on or out and I am not 100% sure it would fly at my local range. I would also be interested to know: 1. Did your group size change with either bayonet vs. with none? 2. Did the group center only move up with the cut-down bayonet, or was there any side-to-side movement as well? 3. Did either bayonet feel looser in attachment than the other one?

Hi CalTex,

The POI movement was in the vertical plane, I didn't notice any lateral movement nor a change in the group size.

Yesterday out at the range again and more trials with different Garand bayonets.

The standard WW2 M1 by AF&H made no difference to the POI as before.

I then tried a different M1905E1 bayonet, this one with the 'Bowie' blade tip, a cut down 1942 OL (Oneida Limited) blade. This lifted the POI by about 8".

Then a post-WW2 M5 Bayonet. As you probaby all know, the M5 mounting was different on the rifle. It made no difference to the POI at all, but did fall off twice when firing :move eek:, a result of the bayonet's catches not engaging properly with the M1's lugs. Oiling the mechanism of the bayonet helped but didn't eradicate the problem entirely, the internal spring seems a bit weak.

Sorry CalTex, I didn't address your last question. The M1 and M1905E1 bayonets lock on the rifle using the same system and all appear to be exactly the same when mounted, a bit loose and wobbly.

As to why both the M1905E1 bayonets raise the POI, it may be the steel used. I'm no metal expert but both M1905E1 blades appear to be made of better quality steel and the finish is much better than the standard M1. The quality of the steel may be superior possibly due to them being cut down from a longer original bayonet which required a better steel. This may be having an affect on the harmonics of the barrel/bayonet when fired.

I’ve mounted bayonets on several rifles during my cas clubs BAM shoots. 1866 and 1873 Winchester muskets and my Krags. Of course we are shooting steel at close ranges. Never tried doing a comparison of with and without. Even fired my ‘97 and M12 trench guns with the looong bayonet. It’s a hoot.

Attachment 118334Attachment 118335

Thanks Charlie, very interesting tests, and no doubt fun to try. Re: looseness, I was thinking that one that was looser might dampen the harmonic effects, though it might also amplify them. Since no difference among them, no mileage on that theory.

Beyond any differences in steel density, the M1905E1s definitely have different sections along their length than the M1 and vs. each other, and so different density along their lengths that might explain the differences. It’s interesting that the M1 and the M5 showed the least difference. If this is consistent across different bayonets and different rifles, I wonder if this might have been due to any tweaking of their sections in final design to minimize the difference. Of course, not a lot could be done with the cut down versions if they were going to be the same length.