Greek 303 Ammo

[Thunderbox]

Exactly my point - heresay easily becomes fact when the internet allows global interaction.

I can understand the theory that shorter (lighter) bullets will have less 'grip' or contact in the barrel and may have less accuracy but the 'escaping gas' and erosion theory eludes me - certainly when we look at the number of rounds we'll fire

Sure; one of the other throwaway line that supports a myth industry is "A few rounds of Mk7 destroys the accuracy of machine gun barrels." Without all of the supporting data, this is fairly meaningless.

What did they mean by "few": 3 or 4 rounds? 300 or 400, or 3,000 or 4,000? Viz, if a barrel has a normal service life of 10-15,000 rounds, then the proportional wear caused by a few tens of rounds is going to be of an order of magnitude so small that it'd be subsumed by other factors such as manufacturing tolerances and surface finishes in the new barrel, etc.

Without getting into the "accuracy" part - machine guns barrels aren't intended to be match barrels anyway, because they have to produce a "beaten zone" - there must be more to the MkVII/VIIz/VIIIz story than just the difference between cordite and nitro. E.g. I have a large quantity of MkVIIIz, and find that for some reason it shoots very well in P14s - whether they are very worn (presumably from a service life with cordite MkVII) or brand new bore condition. The performance in No4s varies from poor to exceptional with no obvious correlation to bore condition (again assuming that most bore wear in a well-used No4 has occurred with cordite ammo). Perhaps there are subtle variations in the form factor of the rifling itself that have an effect?

[Alan de Enfield]

Sure; one of the other throwaway line that supports a myth industry is "A few rounds of Mk7 destroys the accuracy of machine gun barrels." Without all of the supporting data, this is fairly meaningless.

?

What would be acceptable as supporting data ?
The following is word for word (I cannot cut and paste from a Pdf) extract from from "Regulations For Army Ordnance Services - Part 7 Small Arms Ammunition"

No 'spin', no hype, no rumours just the facts as they were seen in 1945.

Words in brackets are mine as way of an explanation, words in capitals / bold are as they appear in the in the regulations.

Mark 8Z 303-in SAA (Small Arms Ammunition) has a neonite load and a streamlined based bullet. Trial firings have proved that these (Mk7 and Mk8z) two types of ammunition do not wear the barrels in the same manner. Barrels which have been used for Mk7 or 303-in Tracer become inaccurate much sooner when Mk8Z is used in them, than barrels in which Mk8z only has been employed.
One advantage of Mk8z ammunition is that the barrel maintains accuracy and elevation until the actual moment of collapse. No indication of approaching barrel failure is given when Mk8z ammunition is used. Accuracy is liable to break down very suddenly and the barrel becomes dangerous for use for overhead fire in the latter stages of its life. To ensure the safety of our own troops during overhead fire by medium machine guns, the life of a Vickers gun barrel using Mk8z SAA ONLY has, therefore been fixed at 10,000 rounds (or 40 belts). This figure is well within the number of rounds successfully completed by the earliest failure of barrels firing and endurance accuracy test under conditions of excessively rapid rates of fire. If, however even a few rounds of cordite loaded SAA are fired, the Mk8z accuracy life drops considerable.

The following instructions regarding the use of these various types of 303-in SAA will be strictly enforced :-
a).303-in. Vickers machine gun battalions.
1) Mk8z ONLY to be used.
2) Mixed belts of Mk8z and tracer must NOT be used.
3) Any barrel that has fired Mk7 or .303-in tracer must NOT be used for firing Mk8Z
4) Barrel life for Mk8Z is 10,000 rounds.

Barrels of Vickers machine guns in machine gun battalions which have fired Mk7, .303-in tracer. Or .303-in AP SAA will be stamped with the figure 7 on the trunnion block and returned to ordnance through normal channels. New barrels for use with Mk8z will be demanded in exchange.


Light Machine Guns*
Mk8z being neonite loaded gives a small flash at night. When the Bren gun is being used for some special purpose at night, e.g. on a patrol, it may be desirable to make use of Mk8z in order to lessen the flash.

Rifles*
Mk8z SAA will not be used in rifles except as in the case of the Bren gun (see above), if necessity should arise.

*Although the use of Mk7 and kindred types of cordite loaded flat base, bulleted, ammunition reduces Mk8z barrel life, the reverse is not the case. No deleterious effects will therefore be produced by the occasional and restricted use of Mk8z ammunition in these weapons (Rifles) for the purposes indicated above.

[AKA Hugh Uno]

it just didn't happen when Sierra did testing (direct comparison in new barre;s BT vs. FB) a bout 15+ years ago (written up in Prec. Shooting at the time).

my only problem with 174 BTs in SMLEs is that they have never been any more accurate than a lot of FB bullets.

[rondog]

try IMR 4895 to start, TENDS to be the most accurate powder esp. with the lighter 54R bullets, but if I had only one powder for .303, it would be 4895.

Ah, music to my ears, since I just happen to have an 8# jug of IMR4895! Thank you!

[AKA Hugh Uno]

no less a personage than DICK Culver...
***********

The short answer (as you have apparently just found out from personal experience) is that your barrel should be good for another 5000 rds (at least according to a Frankfort Arsenal Report conducted in the 1945/1946 timeframe.
Old wives tails had long held that a maximum barrel life with service ammunition was approximately 5000 rds or less. Some said as few as 3500. And just EVERYONE knew that using AP would trash your barrel in a heartbeat. On the flip side of the coin, most experts considered that M1 (172-gr) Ball, (essentially a precursor of the 172-grain FA Match 30-'06) to be extremely accurate, however according to urban legend, it was BOUND to "eat" barrels at an accelerated rate due to the 9 degree boat-tail that would allow hot gasses forward of the bullet base while the projectile was still in the bore!
As it turns out, virtually every old wives tale was pure unadulterated "Moose Manure", however some very high priced help published them as gospel. Clark Campbell in his excellent book "The '03 Springfield" parroted the widely held belief concerning the 172-grain match ammo being hard on the bore, and Phil Sharpe, one of the developers of the .357 Magnum Cartridge an a WWII Army Ordnance Officer and regular contributor to the "Dope Bag" in the American Rifleman) put out the information in his "Complete Guide to Handloading" that while the mild steel jackets of the WWII .30-'06 Ball wouldn't harm the bore of your favorite target rifle, he would not shoot .30 caliber M2 AP in his rifle under ANY circumstances... Just goes to show you how wrong you can be.
Frankford Arsenal grew weary of the stories and decided to conduct a test to determine if they were correct. Without going into great detail, they found that when using either M1 Ball (almost identical to the later M72 Match Ball) or M2 Armor Piercing, the accuracy actually improved up through the first 1000 rounds or so (don't hold my feet to the fire on the exact numbers as I don't have my references in front of me and am too lazy to dig 'em out right this second). They continued to fire the test (using a test rack) and it seemed that the accuracy "improvement" seemed to taper off after 1000 rounds, but the accuracy itself did NOT decrease. The accuracy continued to be excellent to outstanding through at least 8000 rounds. They finally ceased the test, not because the accuracy was declining, but because they simply got tired of firing, since the accuracy showed no sign of decreasing. FA estimated that the excellent accuracy should continue through at least 10,000 rounds and probably beyond.
This was NOT the case with the 150 grain M2 Ball however, it seems that the accuracy began to drop off after about 3500 - 4000 rounds (again don't hold my feet to the fire, I plan to write an article on this and will include the actual figures when I do). The only common thread to the barrel longevity I can personally see, is that both the M1 Ball (172 gr. Match) and the 165-168 gr. AP have a boat-tailed configuration (9 degree for the 172 and a much less obvious 6 degree for the AP).
Throat erosion is another bugaboo that is usually blown out of proportion. We had a gent by the name of Eric England shooting for the Marine Corps for years. He had a favorite M70 that the Ordnance folks kept trying to get him to turn in since the throat was essentially non-existent... Eric steadfastly refused because he kept setting National Records with a shot-out throat... An old rule of thumb used to be that two things happened if your bore was shaped like a pyramid (i.e., bigger at one end than the other). If it was big at the muzzle and small in the throat, you had a boat anchor. If it was big at the throat and small at the muzzle, you had a (potential) shooter - please understand that I'm talking "relative measurements" here... In other words, if your muzzle was tight you were usually OK, but not the other way around.
At any rate, I've raved on much further than I had planned, but I think you can plan on an extremely long accuracy life out of your M1 or M1A barrel if you continue to use 168 -175 gr. boat-tailed bullets at normal velocities…
Best regards,
Dick

[jmoore]

Except that has nadda to do w/ Greek 303 which last I recall has a 174gr aluminum core tip w/ flat base using an IMR type powder. Are we done yet?

Sorry, its just that we've done all this before.

[FugWit2]

Interesting hash out of the information. Thanks.
It seems that, from the information posted here, I'm actually inadvertantly creating Mk VIIZ ronds when I reload, as I'm using 174Gr BT bullets, propelled by single base stick powder (3031) & have been doing so for years with no bad side effects.

One reason I was so interested in this thread was the fact that I may have access to a reasonable quantity of the Greek .303 ammo, & was unsure of the differences (if any) between the "Z" suffix ammo & "regular" Greek HXP headstamped .303.

[Badger]

Except that has nadda to do w/ Greek 303 which last I recall has a 174gr aluminum core tip w/ flat base using an IMR type powder. Are we done yet?

Sorry, its just that we've done all this before.

....

Can you imagine if we merged all the threads on this same subject into a single entity ...

Any volunteers out there who want to write up a single Knowledge Library article on this subject, so we can cut-n-paste the link instead of all the posts?

Regards,
Badger

[Edward Horton]

To: Jmoore, Thunderbox, et al.

From: Ed Horton

Subject: “Are we done yet?”

Answer: No friggin way (You expletive deleted commie pinko perverts and non-believers)

1. Sierra did a study and said boat tail bullets do not cause more barrel wear. Sierra sells boat tail bullets, WHAT the heck did you think Sierra was going to say.

2. Revolvers have top strap cutting from high temperature gas erosion and rifles can suffer from the same effects.

3. Worn automobile engines suffer from blow by from worn rings that no longer seal the bore of the cylinder.

4. Flat base bullets when fired or kicked in the a$$ will expand and fill the bore diameter and thus seal the bore. Boat tail bullets when fired do not expand and seal the bore.

5. In a perfect world where the bullet diameter matches the bore diameter boat tail bullets “may” not cause more barrel erosion vs. flat base bullets

6. Problem, we do not live in a perfect world and if the boat tail bullet is not the exact same size as the bore diameter you can get “blow by” and high temperature gas erosion.

The bullets below are a perfect example, steel core Russian pulls, .310 diameter boat tails, in a worn barrel they have “blow by” and want to go any direction but straight.



These same bullets shoot fine in a like new Enfield barrel but put them in a worn two groove barrel and they start shooting sideways.

Now read below and let this sink into your synaptic network.


Corbin Rebated Boattail Dies


In closing I want you people to think about the gun camera film you have seen from WWII fighters and the “odd” trajectories these boat tail bullets take when fired from a worn over heated barrel.

Yes I shoot boat tail bullets in my Enfield’s because I load them below 43,000 CUP which is the starting point where the peak flame temperature starts to melt barrel steel. I do this by using the slower burning powders that can take advantage of the Enfield’s longer 25 inch barrel.

To: Jmoore, Thunderbox, et al. “Bah Humbug”

[jmoore]

OK, then. When y'all figger it all out, let me know. Oh, whilst you're cipherin' see if rifling types and degrees of polish and cold worked versus cut rifling make any difference. First one to fire 10,000 rounds per variable wins!