Military zeroing of the No. 4 - inconsistent data?

[Rick]

To shorten a bit of a long story, trying to help a friend who wants to do this with his rifle with its No. 2 300/600 aperture back site. And yes, he knows he isn't going to find any Mk VII ammunition, and his handloads will at the very best come close.

He asked and I dug up and sent him data from the forums here. I haven't paid much attention to it prior to this as I had a Parker-Hale PH4 vernier sight long before I ever owned a Lee-Enfield, and I've just zeroed as I wanted with that, whether HXP ball or cast bullet loads. (BTW, doesn't everybody first buy the ammunition or the sight for a rifle before they have the rifle, just so they have an excuse to buy the rifle?)

But he sent a return email, asking me if there isn't some inconsistency in what I sent. To wit:

If you aim precisely at the point of aim, the sights should cause the bullets to strike the 30 yard target 2.25 inches + or - .25” above the auxiliary aiming mark's base, and if it were to continue to the 100-yard target it would strike 8.5 inches above the auxiliary aiming mark's base.

- Shoot To Live, 1945

(I believe this is a to-scale target from Shoot To Live, thus the large image (P.S.: what does the .565" along the vertical bar refer to? I couldn't answer his question about that)



So the Canadians seem pretty clear: No matter which back sight is on the No 4 rifle, zero using a fixed bayonet and the 300 yard battle sight, MPI will be set to 2.25" (+/- .25") above POA at 30 yards; 8.5" (+/- 1") above POA at 100 yards. The sight will then be zeroed for all other sight settings on either folding leaf version of the back sight or either aperture of the Mk 2 sight.

But then there is this from the knowledgebase here:
REME Precis No. SA/Rifles/3 (Zeroing of No.1, No.3, No.4, No.5 Rifles)
Author: REME Techincal Training School RS/1802/1M/6-60
https://www.milsurps.com/content.php...4-No.5-Rifles)

With a Leaf Backsight fitted to a Rifle, the aperture or slide should be set to the lowest graduation, namely 200 yards. It it not however satisfactory to zero a Rifle at this range, as the ranges used are 100 yards or 25 yards. It will be seen therefore,that the resultant MPI to be correct. would have to be somewhere above the point of aim, so that when actually firing at 200 yards, or at other ranges with the correct reading on the Sight the shots will group at the point of aim.

In the case of Rifle No.4 fitted with a Mk2 Backsight, the apertures of which are sighted for 300 and 600 yards, the Rifle will be zeroed using the 300 yard aperture with a Bayonet fixed. Therefore the correct position of the MPI at at 100 yards or 25yards would be even higher than with a leaf sight. The following table shows the various parliculars applicable to each type of Rifle.

Reference the sighting data for the No. 4 with a Mk 1 or Mk 3 adjustable leaf sight set at 200 yards for zeroing at 100 yards, I don't have an opinion at the moment as to whether there's any inconsistency with the MPI figures provided in that table.

HOWEVER, The Canadian data says using the 300 yard battle sight, MPI is 8.5" (+/- 1") above POA at 100 yards; this presumably British zeroing table says MPI is 6.0 above POA at 100 yards using the same 300 yard battle sight. The same inconsistency exists when comparing 30 yards versus 25 yards between the two, even though the close zeroing distances are not exactly the same.

So there does appear to be an inconsistency with the Canadian Shoot To Live zeroing data, as both instruct that the back sight battle sight aperture is to be used, both with bayonet fixed.

To add to the confusion (I forwarded this to him as well), also from our forums here, which apparently agrees with the British REME chart - IF it is specifically addressing the No. 3 and not generically addressing both the No. 3 and No. 4 rifles as it seems to:

Sighting Instructions For The Enfield Rifle - Page 3
https://www.milsurps.com/enfield.php?pg=ti16.htm

This is an actual .303 Mark VII Ball Round zero target for use on a 25 yard range... When zeroing, the rounds should impact inline with the 200 yard mark if the sight is set to 200 and impact inline with the 300 when set to 300, etc.

So... same two rifles, same back sights, same Mk VII ammunition... two (or three) different sets of zeroing data. Unless I am missing something here, isn't at least one of these going to provide a zero that will not be correct for these same rifles/sights/ammunition as the zero is then used to shoot at 300 yards, 400 yards, 500 yards, etc.?

Or am I missing something here?

Information

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[M94/14]

The .565" grid dimension is there to help with the calculation for selecting the correct front sight blade, if the impact is out of the circular area shown (which is incidentally 2.26").

The Mk2 sight POI differences can be boiled down to two different countries, using two different sight in POI numbers. The Canadian POI numbers obviously print a bit higher on the target than the British sight in numbers, and may fit in with some desire on their part to have the POI hit around 2.5" above POA at all distances, or possibly a 6 o'clock hold. I can't see the ammo specs being that far different. Unless you're going to battle, I wouldn't worry about zeroing with a bayonet.

The other numbers, relative to zeroing with the slider sight apertures set at 200yds., are pretty close to what I've experienced when fired at those distances.

If you sight in with the sight slider aperture set at 200yds., using the British sight reference chart, you should find that the battle sight on the mk1 or mk3 sight to be on at 300yds using POA hold.

Biggest thing to decide on, is whether you favor POA hold or 6 o'clock hold on targets, and that alone could account for the discrepancy in the numbers. Once you get zeroed for either type of hold, you should find the sight graduations to work relatively well, as long as the projectile your shooting has a BC similar to that used with the Mk IIV round.

[Bindi2]

The bayonet on gives correct POI at 300yds off gives the correct POI at 400yds. With the long range sight up bayonet on POI is 500yds off is 600. A sneaky way to work simple made sights. Using a slider sight the bayonet still makes those differences. Using hand loads or commercial ammo you will have to make your own range/drop sheet.
Even using pulled Mk7 projectiles you cant match cordite with any other powder close but not matched.

[Rick]

The .565" grid dimension is there to help with the calculation for selecting the correct front sight blade, if the impact is out of the circular area shown (which is incidentally 2.26").

The answer to my question was right there in Shoot To Live: "The graduations on the vertical line represent one size each of foresight adjustment."

.565" at 30 yards subtends 1.88" at 100 yards. The variation in MPI for each step up or down in foresight height is 1.87"

The Mk2 sight POI differences can be boiled down to two different countries, using two different sight in POI numbers.

Perhaps. But both sets of sighting in procedures use the same rifles, the same back sights, and the same ammunition. And supposedly, when zeroed with the 300 yard back sight and bayonet fixed, both supposedly will be POA = MPI at 300 yards. Which can't be possible when the one zeros 8.5" above POA at 100 yards, while the other zeros 6" above POA at 100 yards, using the exact same rifle, sight, and ammunition.

The Canadian POI numbers obviously print a bit higher on the target than the British sight in numbers, and may fit in with some desire on their part to have the POI hit around 2.5" above POA at all distances, or possibly a 6 o'clock hold.

No sighting in procedure with a fixed sight can result in MPI being 2.5" above POA at all distances. One, or perhaps both, 100 yard sighting criteria are going to be either high or low at 300 yards relating to POA. Both criteria specify a specific distance above POA at 100 yards. That doesn't change whether using a 6 o'clock hold or a center of mass hold.

I can't see the ammo specs being that far different.

They wouldn't be - other than lot to lot variances. No Commonwealth soldier in WWI or WWII (or Canadians or Brits deploying these days for that matter) was guaranteed ammunition manufactured in their home country. Today 5.56 ball is manufactured to STANAG standards; back then the Commonwealth countries would have had a similar standard for Mark VII ball ammo.

Unless you're going to battle, I wouldn't worry about zeroing with a bayonet

I imagine he's more interested, as part of his personal version of the Lee-Enfield hobby, of replicating military zeroing as best he can. I have no idea if he's going to fix bayonets while attempting to zero, but I do know that so far he's rejected zeroing from the bench to instead shoot from the prone with his forearm cradled in a sand bag. I'm sure there's more than a few Lee-Enfield shooters that will never pull a trigger on their rifles unless they're seated at a bench - never once shoot while lying on the ground with their forearm resting on a sand bag as he is doing. Just different versions of the hobby, neither is wrong.

If you sight in with the sight slider aperture set at 200yds., using the British sight reference chart, you should find that the battle sight on the mk1 or mk3 sight to be on at 300yds using POA hold.

If so, then the 300 yard sight setting on the leaf sight should also be on at 300 yards, and conversely, the 300 yard battle sight as well as the 300 yard setting on the leaf sight should both be 1.5" above POA at 25 yards.

Biggest thing to decide on, is whether you favor POA hold or 6 o'clock hold on targets, and that alone could account for the discrepancy in the numbers.

Whether you prefer a 6 O'clock hold or a center hold, the resulting ballistics do not change. You may shoot more accurately with one over the other methods, but the MPI in relation to the POA does not change.

[Rick]

The bayonet on gives correct POI at 300yds off gives the correct POI at 400yds. With the long range sight up bayonet on POI is 500yds off is 600. A sneaky way to work simple made sights. Using a slider sight the bayonet still makes those differences.

That's an interesting piece of information. I received a bayonet in paper wrap with my Long Branch, but I've never taken it out of the wrap, much less fired the rifle with the bayonet fixed.

In fact, I can't remember a single time during my 30 years in the infantry where we fired on the range with bayonets fixed. Other than a few times when we still had the FN, when we did live fire assaults on ranges, the only time I've ever given the order to fix bayonets or been given the order to fix bayonets was for a parade march past/general salute/feu d'joie.

I guess zeroing with bayonets fixed died with the No.4 Mk1 in the Commonwealth. I think I may remember some old, old pams laying around regarding battle procedure at the section level where bayonets were to be fixed if the enemy was within 200 yards (but I also might be dreaming in my hazy old age). If so, zeroing rifles with bayonets fixed perhaps has some merit behind it.

I suppose more than a few Long Branch's had fixed bayonets at Kapyong...

Using hand loads or commercial ammo you will have to make your own range/drop sheet. Even using pulled Mk7 projectiles you cant match cordite with any other powder close but not matched.

My friend who has embarked on this project was also a Small Arms Instructor/Urban Ops Instructor prior to falling down the Lee-Enfield rabbit hole, so I'm pretty sure he's aware he will need to make up his own dope sheets with whatever he arrives at for a load. The last time I phoned him prior to Thanksgiving, he had purchased a bunch of Privi Partisan's 174 gr. bullets (from Graf's, I think).

It's actually a change from the Frankenguns he used to make out of badly Bubba'd Lee Enfields and other rifles that he would pick up for pocket change and drag into his basement lair. The last one I saw he had made kind of Mexican Mauser out of to serve as a camp Bear Wrench when out hunting and fishing on the coast. Ultimate result was something like a 40-65 Maynard, flinging a 400 grain or something like that lead bullet somewhere around 1800 fps.

Trying to emulate straight out of the book is quite a change of pace for him.

I don't even know if there's a G1/G7 ballistic coefficient for Mark VII ammunition - never thought to do a Web search to find out if one is available. Maybe I'll do that later tonight. G1 somewhere around .42?

[Bindi2]

Rick
It is not the BC it is the cordite burn rate pressure curve that is the issue. Also the open base changes things in cordite used barrels that flat based cant copy. Depending on how used the barrel is boat tails may not work at all. Forget trying to make it a vermin shooter or use 3031 to emulate cordite. .312 projectiles will be your friendly ones. I convert 174g OBBT to straight 174g BT to solve the cordite barrel issue but can not get a perfect match to Mk7 on the drop sheet. As said else where have fun.

[M94/14]

HOWEVER, The Canadianicon data says using the 300 yard battle sight, MPI is 8.5" (+/- 1") above POA at 100 yards; this presumably Britishicon zeroing table says MPI is 6.0 above POA at 100 yards using the same 300 yard battle sight. The same inconsistency exists when comparing 30 yards versus 25 yards between the two, even though the close zeroing distances are not exactly the same.

According to the numbers I just ran (using a BC of .467 which is probably close?), the MPI of 8.5" @ 100yds on a 300 yard zero would create a POI at 300 yards to be 6.5" higher than POA (or effectively a 355 yard zero).

The British charts MPI of 6.0" @ 100yds on a 300 yard zero would create a POI at 300 yards that matches POA nearly perfect.

So, the question is...were the Canadians looking to use a 355 yard zero with the 300 yard sight setting, or were they purposely setting the POI at 300 yards to be higher than POA during zeroing.

The British Chart info appears to check out (at least for me), so your friend could zero using those numbers.

[Bindi2]

Just doing away with the Bayonet trick.
I just noticed and I cant correct a mistake in post #6. It should read I convert 174g OBBT to straight 174g OB.

[CINDERS]

Bindi's correct with the burn rates between Cordite and modern powders they will never correlate. However on the BC's here is a difference the 2440FPS of the MkVII round is the accepted standard there has been a lot of conjecure but most agree that the MkVII projies BC is around the .467 with the 174SMK at 2200FPS BC being .499 a slight difference to be sure but it reflects on the sight settngs.
Bindi is also correct and I have stated many times get the load where you want it whether its 2440FPS or lower is your choice and do the range time to get the DOPE for your rifle as we have really beaten the skin off this horse time and again you can put into quick load what ever you please to try and figure out a decent load.
After trialing different powders I settled on 46ns AR 2209 (H4350) made the case the COAL the same as a POF MkVII live round and went from there gathering range data for the 5 rifles I shoot in comps but mainly my 2 No.4's time consuming yep but the load is the same for all just do different things to the cases for the rifles and thats that.

However I do feel this is not the last we will hear from this as it seems top resurface allot what needs to be done is for those wanting answers is to go to the search engine and go throuh the copious threads around this topic.
Use my load data at your own peril as I have no control how you may reload your rounds not saying youre not safe reloaders just its a sue your ar*se off world and I am not going to be held responsible for a load that is safe in my rifles but may not be in another shooters rifles. Cheers

[Rick]

Rick
It is not the BC it is the cordite burn rate pressure curve that is the issue. Also the open base changes things in cordite used barrels that flat based cant copy. Depending on how used the barrel is boat tails may not work at all. Forget trying to make it a vermin shooter or use 3031 to emulate cordite. .312 projectiles will be your friendly ones. I convert 174g OBBT to straight 174g BT to solve the cordite barrel issue but can not get a perfect match to Mk7 on the drop sheet. As said else where have fun.

Thank you and others for reminding me to pass on the cordite info.

I had already passed that on to him, along with the Canadian/British sighting data also found here during my searches. It would be hard to miss the various threads on how it is impossible to reproduce Mk VII ballistics - and part of the problem being cordite - during the website searches I did here for zeroing information to pass along to him. I never even tried to replicate MkVII ballistics with my handloads; having a PH4 vernier sight on top, seemed irrelevant to me. Now that 90% of my shooting is 200 yards with powder coated cast bullets, it means even less.

Anyways, he already knows he's embarked on an impossible task that more than a few here have already attempted before. Next time we talk, out of curiosity I'll ask him what his ultimate goal is, assuming he agrees it is impossible to match service ball ammo.

He was seconded to do some SAI work with the Canadian Rangers, and when the Rangers just converted to the new Tikka, one of the Rangers he had become acquainted with who kept their Long Branch despite having no interest in keeping it, gave it to him as a gift knowing of his interest in the rifles. According to him, the rifle is in fine shape - he gloated about that for a while when he told me about it.