Runing in a barell with cast GC

[herbert buckland]

I have been trying to run in a 303 range rifle with cast and GC ,trouble is after 7 rounds acuracy disapears conpleatly ,i put this down to leading but when i clean the barell i can not see any lead,My load is 220gr CBE .314 boolit and 35gr AR 2208 pouder,CCI BR 2 primers ,Boolit is lubed with LLA ,am i doing somthing wrong or does it take time for the barell to be run in for cast

[JeffinNZ]

What is the alloy? 35gr of AR2208 (Varget to our US cousins) is likely to be exceeding the tensile strength of WW alloy (assuming it is WW alloy).
Tell us more about the rifle. 2 groove? Throat and groove measurement? Gas check?????

[Cbenc1]

If you are firing the 7 shots fairly close together you may be heating your barrel and changing the point of impact. Try shooting till accuracy fades, then let the barrel cool and shoot some more and see if your group doesn't return.

[herbert buckland]

What is the alloy? 35gr of AR2208 (Varget to our US cousins) is likely to be exceeding the tensile strength of WW alloy (assuming it is WW alloy).
Tell us more about the rifle. 2 groove? Throat and groove measurement? Gas check?????The rifle is a Lithgow No 111 fited with a H barell ,5 groove and very good bore very litle throat wear,I am hardening the WW boolits in the oven then droping them in the sink ,wating at least a week before i youse them ,the GC are Honady wich i have to flare a bit so they will fit the CBE shank then i fit them by a Lee .314 sizing die ,then put a bit more LLA on them,This rifle will shoot 30mm groups all day with 174gr jacketed BT ,i am just after a cheaper way to shoot that is still good to 600 meters,so far my PP trials have been a total disaster,so i thort i would try to get a good cast load that would work

[Buckshot]

I have been trying to run in a 303 range rifle with cast and GC ,trouble is after 7 rounds acuracy disapears conpleatly

What happens? The first few rounds group and then do what? If not that then is it wild from the git-go?

,i put this down to leading but when i clean the barell i can not see any lead,

You can't see any lead in the barrel, or you can't see any leading on the patch? Leading can be hard to see just by looking down the barrel. Run a solvent dipped bronze brush up and down the barrel once, then swap to a snug white patch. Run it down the barrel and out the muzzle. Inspect the patch under a bright light.

My load is 220gr CBE .314 boolit and 35gr AR 2208 pouder,CCI BR 2 primers ,Boolit is lubed with LLA ,am i doing somthing wrong or does it take time for the barell to be run in for cast

Ideally the barrel should be free of jacket fouling before shooting cast.

Your boolit is sized to .314", what does your barrel slug? What is the OD of the nose of the boolit design if a bore rider? What does the throat slug. ?

..............Buckshot

[303Guy]

... after 7 rounds acuracy disapears compleatly ...What is the accuracy before it disappears?

I'm thinking this rifle will have a reasonably close to spec bore. Do the CBE boolits fit into the muzzle freely or do they make rifling marks - just touching or well defined impressions?

I cannot remember off hand what AR2208 load I used under my 220gr boolits. The number '35.5gr' rings a bell. Pressure was mild but enough to burn the powder cleanly. Recoil was a comfortable 'push'. But most importantly, accuracy was good and the bore stayed clean and shiny. This was with my mint bore LE (1902 vintage with new barrel) which is also very accurate with j-words.

[herbert buckland]

Ideally the barrel should be free of jacket fouling before shooting cast.

Your boolit is sized to .314", what does your barrel slug? What is the OD of the nose of the boolit design if a bore rider? What does the throat slug. ?

..............BuckshotBefore i started with cast i thourly cleaned the bore with 7.62 Sweets solvent ,removed all traces of coper .OD of the bore riding nose is .304it just fits down the muzell ,throat is .312,The groups are fired one check fire another than check ,I get good grouping up till the 7th shot then the boolit fly anywere,i then clean the barell with Hoppys ,no sighn of lead ,youse a bronze brush and Hoppys again ,still no sighn of lead.I was wundering about the run in with cast as i had simular trouble with another 303 but in this one i was yousing Traill Boss pouder ,it would start to shoot high at fist after 5 or 6 shots i kept cleaning it till now i can shoot 40 shots and it will still hold a group,it is just that acuracy going off with the 35gr AR 2208 load is so suden and dramitic

[PAT303]

I went back through my notes and my Mk11 with H barrel started going off with 32grns of 2208 so maybe you want to drop the load back or better still switch to 2207 at around 20grns and go up to 25.All the 303's I've worked with have liked 2207. Pat

[herbert buckland]

I went back through my notes and my Mk11 with H barrel started going off with 32grns of 2208 so maybe you want to drop the load back or better still switch to 2207 at around 20grns and go up to 25.All the 303's I've worked with have liked 2207. PatWilltry that ,with 2207 do you youse a filler ,i am trying to aviod fillers if i can

[Bret4207]

If the boolit fits, and it sounds like it does, then it's possible the load is just a bit hot. Water quenched boolits still take time to reach full Bhn- up to 4 weeks. If you have access to a hardness testing method I'd check them over the course if a month and see what they do. Remember a harder boolit alters more than just Bhn- your burn rate/pressure curve changes too, among other things.

Lube is another issue you might look at. LLA is okay in light loads but past 1500fps or so it gets finicky.

[herbert buckland]

What would you segest for a higher velocity lube

[castshooter-too]

javelina

[StarMetal]

Although different lubes can effect accuracy if you're getting zero leading I doubt you have a lube problem. You can change it just for the heck of it, but a hassle to get the old stuff out of your luber/sizer if you use that type of equipment.

Sounds like you accuracy goes back and you brush and clean the bore and it's back. That means, depending on how fast you clean th bore, the barrel is still warm....so that tends to lead me to think of "some" kind of fouling. Since no lead..could it be the powder is fouling?

[218bee]

I would shoot 5 shots and let barrel cool for ten minutes without cleaning.....then shoot another 5. Sometimes the handguards and forend wood can play havoc on an Enfield also.

[303Guy]

Herbert's rifle shoots j-words accurately all day and with cast he is checking after each shot. The barrel should be farely cool. Unless the lube and/or alloy is failing as the barrel warms? The gun did the same thing with Trail Boss. That doesn't sound like too high a loading. But if it is that, AR2208 can be taken down to 30grs and still burn clean and not need filler (although I still prefer a little Dacron anyway although cotton wool is easier to work with - but it's a fire hazard).

It's interesting that herbert had the same experience with another rifle that sorted itself out after a fair bit of shooting and cleaning. This brings me back to his original question; How to 'run in' a barrel for cast? Perhaps a good few paper patched rounds? Patch with printer paper with the slightest amount of lube?

[MtGun44]

GC covering up poor lube performance? I am very suspicious of LLA in any but the
least demanding applications.

I would also lower the powder charge and see if that helps.

Try a real lube and see if that helps.

Bill

[herbert buckland]

I am biging to suspect lube,but one step at a time LLA is so easy,i will try the 2207 loading,my altomat goal is to get factory volocitys so i will have to go to PP ,just wating on a 308 mould to turn up so i can have another crack at it,has anyone else had problems lick i am having ,i have had the same problem with two other 303 at lower velocitys,I shoot in a military compition and you have no time to clean between stages 10 sots prone 10 shots nealing 10 shots ofhand,so i have to get at least 30 shots away without cleaning and keep the groups as close as posible

[herbert buckland]

Jus finished trying the AR 2207 22 1/2gr load ,acuracy was good for the fist 18 shots,then shots started to go higher a bit each shot,so i am again thinking that barells have to run in ,to check this after i can shoot 30 shots and keep a group i will go back and see what hapens with the 35gr AP2208 load,if it groups after more than 7 shots it must havr somthing to do with run in of barell

[Multigunner]

It occurred to me that with a .312 throat, which is the tightest I've heard of, you might be getting the same effect from simple fouling + residual bullet lube as the tests using greased bullets in the LE rifles.
In those tests excess mineral jelly perservative left in the chamber neck and on the bullet at case mouth were found to cause a slight increase in velocity over an ungreased cartridge.
They said it was due to a momentary seal effect preventing any gase blowby as the bullet left the expanded neck.

Ordinarily the compensation factor of the slim SMLE barrel would allow faster bullets to leave at a lower angle than slower bullets. The Heavy Target barrels such as yours and the relatively heavy No.4 barrels are known to show much less compensation than the standard weight SMLE barrel.

You might try swabbing the chamber out every five shots, a quick swabbing with mineral spirits as is suggested to remove residual oil before firing on the range, but repeated between five shot strings.

If not practical during a match it might at least reveal what the problem could be.

Perhaps a hair less lube and that of a different mixture could be the long term answer.

[303Guy]

Ordinarily the compensation factor of the slim SMLE barrel would allow faster bullets to leave at a lower angle than slower bullets. The Heavy Target barrels such as yours and the relatively heavy No.4 barrels are known to show much less compensation than the standard weight SMLE barrel. Ahhh....!:idea: So that's what whas meant by 'barrel compensation'. I couldn't figure it!

I want to learn more about 'running in' a barrel. This is a new concept to me.

In those tests excess mineral jelly perservative left in the chamber neck and on the bullet at case mouth were found to cause a slight increase in velocity over an ungreased cartridge.
They said it was due to a momentary seal effect preventing any gase blowby as the bullet left the expanded neck.Mmmmm..... that's very interesting info - thanks!

herbert, I'm sure glad you are doing this test. The AR2207 test is rather interesting! I might just get me some. (Ozzies make good powders! And other stuff too.:drinks:).

[herbert buckland]

I noticed i stated the lead was .312 my mistake (LEAD .314 ) Lands .312 sory for the confusion

[PAT303]

If your shooting 7 or 8 shots and then it's wondering it sounds like the barrel is just getting hot.With my Mk11* it's like I'm looking through a coke bottle as the heat rises out of the sight opening and blots out the front blade,I shot 22grns of 2207 as my standard 100m load and over the years have shot thousands of them but it doesn't matter how accurate the load is,you can't hit what you can't see. Pat

[herbert buckland]

If your shooting 7 or 8 shots and then it's wondering it sounds like the barrel is just getting hot.With my Mk11* it's like I'm looking through a coke bottle as the heat rises out of the sight opening and blots out the front blade,I shot 22grns of 2207 as my standard 100m load and over the years have shot thousands of them but it doesn't matter how accurate the load is,you can't hit what you can't see. PatI do not think heat is the problem as it is geting beter the more i shoot it ,I can now hold a 3 1/2 inch 30 shot group with 22 1/2 gr of AR 2207, nealy as good as my jacketed load ,this is of the bench and is nothing lick the groups in compitision ,for some reason having to run 303 barells in with cast is the way i had to go ,My 95 strait pull Styer had no such trouble and they have thin barells,i cant find any reason

[largom]

herbert,
I would shoot a few fire-lapping boolits thru your barrel. These can be made by hand lubing the boolits with a fine valve lapping compound [auto parts store].

I once built a custom 6.5-06 gun with a custom barrel that would shoot 3 shots touching, 4th shot out 1 in., 5th. shot out another 1 in. and so on. I was shooting jacketed bullets. I checked the bore with my bore scope and found copper fouling after 3 shots which progressively got worse. I fire-lapped the barrel and all flyers went away.

Larry

[Multigunner]

herbert,
I would shoot a few fire-lapping boolits thru your barrel. These can be made by hand lubing the boolits with a fine valve lapping compound [auto parts store].

I once built a custom 6.5-06 gun with a custom barrel that would shoot 3 shots touching, 4th shot out 1 in., 5th. shot out another 1 in. and so on. I was shooting jacketed bullets. I checked the bore with my bore scope and found copper fouling after 3 shots which progressively got worse. I fire-lapped the barrel and all flyers went away.

Larry

I don't think fire lapping would be a good idea in this case. The heavy barrel for the SMLE was a purpose made high accuracy barrel to begin with, and lead lapping of enfield bores was a common part of the manufacturing process when not subjected to wartime extingency.
Common wartime manufacture bores might benefit from fire lapping, but its likely that the already carefully lapped HT barrel would not benefit and might instead be degraded by fire lapping.

So long as modern propellants with low erosion properties are used a HT barrel in good condition will likely become more accurate after several thousand rounds have been fired than when new.
Fire lapping can in some cases excellerate this breakin period, but at the cost of reduced overall bore life.

In normal course of mechanical erosin due to friction, the bore becomes mildly tapered, larger at the leade and tighter at the muzzle, this greatly reduces blowby effects and reduces velocity variations.

[longbow]

Have you recovered any boolits? If so check the base bands for gas cutting.

My .30 cal. guns seem to like a large boolit at least a couple thou over groove diameter or I get gas cutting ~ moreso with plain base boolits but even with gas check boolits they seem to perform much better if a couple thou or more larger than groove diameter.

Doesn't really explain why the first few shoot well for you then accuracy drops off, but a larger boolit may be worth trying. You could Beagle the mould to try it so no permanent changes and no cost.

Longbow

[herbert buckland]

Have you recovered any boolits? If so check the base bands for gas cutting.

My .30 cal. guns seem to like a large boolit at least a couple thou over groove diameter or I get gas cutting ~ moreso with plain base boolits but even with gas check boolits they seem to perform much better if a couple thou or more larger than groove diameter.

Doesn't really explain why the first few shoot well for you then accuracy drops off, but a larger boolit may be worth trying. You could Beagle the mould to try it so no permanent changes and no cost.

LongbowMy groove diameter is .3127 ,I can not go use a larger boolit than .314 as the leed is .3144 ,very snug as i am using .314 sized boolits,I now think the barell just needed runing in as it is holding groups without cleaning for 3o shot now ,i will push it to 50 and then if it can stay in a 4 inch group i will be happy

[longbow]

Okay then, You have a tight one. But then you did say it was rebarrelled. Most milsurps have sloppy bores. Both mine run 0.314" and like a 0.316" boolit. In fact I can load and shoot 0.318" and it does quite well.

It was just a thought but you have covered this base already.

Longbow

[herbert buckland]

Okay then, You have a tight one. But then you did say it was rebarrelled. Most milsurps have sloppy bores. Both mine run 0.314" and like a 0.316" boolit. In fact I can load and shoot 0.318" and it does quite well.

It was just a thought but you have covered this base already.

LongbowIn Auatralia special target barells were made for rifle clubs ,these barells have a H on top the Knox form and are referd to as H barells ,Australia used these barell on its military sniper rifles also,a properly set up H rifle is much more acurate than a standard MK 111 and are also fited with target sights so they realy can not be conpared to standard mill sup MK111s

[303Guy]

I want to know more about this 'running in' thing. This is most interesting and I thank you, herbert buckland for your thread and keeping us informed.:drinks:

Multigunner, I have one or two such tapered bored Lee Enfields. One is so servere that the rifling is rounded at the chamber end. The other has fired about 450 rounds of MkVIII cordite machine gun ammo and has developed what I would consider a perfect taper bore. The last half of the bore is still a little rough and copper foul's and of course, also leads along one or two rifling lands if I'm not careful. I plan on 'paper patch lapping' this gun until it will shoot plain cast without leading. My current 'flavour of the day'.:roll:

[Multigunner]

I want to know more about this 'running in' thing. This is most interesting and I thank you, herbert buckland for your thread and keeping us informed.:drinks:

Multigunner, I have one or two such tapered bored Lee Enfields. One is so servere that the rifling is rounded at the chamber end. The other has fired about 450 rounds of MkVIII cordite machine gun ammo and has developed what I would consider a perfect taper bore. The last half of the bore is still a little rough and copper foul's and of course, also leads along one or two rifling lands if I'm not careful. I plan on 'paper patch lapping' this gun until it will shoot plain cast without leading. My current 'flavour of the day'.:roll:

MkVIIIz ammo with boat tail bullet is not cordite powered, it uses a single base powder originally IMR 3031 which was the first Dupount Improved Military Rifle powder, its numbers denoting its use in the .303 cartridge. the z is actually a sideways N for nitrocellulose.
The boat tail bullet does not do well in a bore previously eroded by Cordite.
US .30-06 ammo of WW1 used Pyro-Cellulose, an earlier more primitive single base powder.

A badly eroded throat and leade is usually due to Cordite erosion, the leade often becoming oversized and smooth for several inches by the time 5000-6000 rounds of MkVII have been fired.
Using MkVIIz (the MkVII bullet with IMR powder) the bore life can vary greatly, from 6000 to 12000+ depending on bore size when new. The looser bores erode more quickly with single base due to lack of initial bump up.
Bore life is not easily calculated due to changing accuracy standards. The SMLE was at best expected to deliver groups twice the size that the Springfield or M1917 rifles were expected to deliver. The US rifles had a optimum accuracy life of around 5000 rounds, and would normally be rebarreled at that point before accuracy dropped off noticably, but a usable accuracy life of 18000+ for the 1903 and possibly twice that for the M1917 due to its Enfield pattern rifling.

I've seen cordite eroded throats with lands rounded and grooves guttered till the lands looked like a sugar loaf in profile.
When gas erosion gutters the grooves that badly theres far too much blowby for accuracy unless the initial bump up is significant, and swells the bullet to fill the now far oversized throat.

I've heard of sherardizing a bore to handle cast zinc alloy bullets, if a zinc gas check is used there may be a similar process. I think that over the course of several hundred rounds the steel absorbs a bit of zinc at the surface to reduce friction and leading. Haven't really looked into it.

[herbert buckland]

I realy cant explain why some of my rifles have needed runing in ,a friend told me about this ,he belived not runing in a barell is why so many people give up on cast for target shooting ( harlf way through a match acuracy goes out the window) run your barell in till you can get the required number of shots away without cleaning and you wont run into any suprises,I do not know wheather any other method of laping will work ,i have fier laped a barell and it still needed runing in ,maybe PP will do the trick ,that is the way i want to go when my new mould turns up

[PAT303]

In Auatralia special target barells were made for rifle clubs ,these barells have a H on top the Knox form and are referd to as H barells ,Australia used these barell on its military sniper rifles also,a properly set up H rifle is much more acurate than a standard MK 111 and are also fited with target sights so they realy can not be conpared to standard mill sup MK111s

The H barrels that were fitted to range rifles weren't anything special,they were made to civy time tolerances that were tighter than war time spec's but overall the barrels were just Long Tom tubes cut to SMLE length.The barrels did shoot better being heavier but mostly it was due to the groove dia being around .312,which is still a thou over but not as bad as most stock barrels that are .314 and go up to .317,the reason was to lower the pressure when they switched to cordite as it ran excessive pressures in the desert. Pat

[PAT303]

I want to know more about this 'running in' thing. This is most interesting and I thank you, herbert buckland for your thread and keeping us informed.:drinks:

Multigunner, I have one or two such tapered bored Lee Enfields. One is so servere that the rifling is rounded at the chamber end. The other has fired about 450 rounds of MkVIII cordite machine gun ammo and has developed what I would consider a perfect taper bore. The last half of the bore is still a little rough and copper foul's and of course, also leads along one or two rifling lands if I'm not careful. I plan on 'paper patch lapping' this gun until it will shoot plain cast without leading. My current 'flavour of the day'.:roll:

450 rounds wouldn't errode the bore unless you fired all 450 in one string.I've heard countless stories about machine gun ammo burning out barrels,My No.4 shot box's of it and it's nun the worst for it. Pat

[Multigunner]

450 rounds wouldn't errode the bore unless you fired all 450 in one string.I've heard countless stories about machine gun ammo burning out barrels,My No.4 shot box's of it and it's nun the worst for it. Pat

The effects vary widely from one rifle to another.
A bore already eroded by cordite can become much more eroded very quickly by blowby when boat tail bullets are used. The boat tail bullet is more subject to keyholing when the barrel gets badly worn.
If MVIIIz only is used erosion is less than if Cordite MkVII is used.
The groove depth/major diameter is the most important deciding factor in how much useful life the bore will have with one type of ammo or the other.
If the bore is at the loose end of tolerance it may be accurate only with MkVII.

I don't think 303 guy meant 450 rounds of MkVIII wore the barrel out, but rather after firing that many the barrel was well broken in compared to what it had been.

To clarify the question of bore life, the figures given vary wildly, due to the standard of acuracy expected.
A barrel in excellent to new condition and on the tight side of acceptable specs (.313-314) was expected to maintain target grade accuracy for up to 6,000 rounds using the best available ammunition, but only so long as the bore was cleaned very carefully. Improper use of the pull through and wire gauze could destroy accuracy on the first few cleanings. Improper use of a cleaning rod could also damage accuracy very quickly, and use of cupro-nickel jacketed bullets often resulted in damage during cleaning due to the harsh chemicals and abrasive pastes used to remove it.

According to Sniper and instructor Major Hesketh-Pritchard the SMLE in the trenches could lose its long range accuracy in as little as 500 rounds with 1500 rnds being common. His standards for accuracy were very high of course. The sniper must be able to make headshots at long range and shoot through the loopholes of fortified positions.
Ammunition quality during WW1 was usually very poor compared to later years, bullet diameter especially varied greatly.
http://www.archive.org/details/snipinginfrancew00pricrich

Wartime pressure on manufacturing resulted in very loose tolerances, with bores of .319 major within acceptable limits. The looser the major dia the faster erosion set in.

Since individual accuracy was less emphasized than volley fire, so long as the rifle could place its bullets in a beaten zone with trajectory that matched its sight settings, and bullets didn't keyhole, it was still good to go.
A rifle can print respectable groups at shorter ranges yet still be burnt out by military standards if velocity varies from the norm enough due to blowby that the trajectory no longer matches the sight settings.

MkVIIIz ammunition seems prone to generate excessive pressures if degraded, and some was loaded to excessive pressures when new. The Maxim and Vickersguns handle these pressures with no problems but there are reports of worn No.4 rifles losing the bolthead and SMLE rifles with sprung action bodies after few rounds of suspect MkVIIIz ammunition.

All the surplus .303 ammo is getting long in the tooth. If the Indian Ordnance factory would sell its freshly manufactured MkVIIz ammunition I'd like to try it out, but otherwise I prefer to handload for my rifles.

Some milspec FMJ .303 of more recent manufacture should be safe enough, but accuracy is uninspiring. The bullets are not MkVII or MkVIII so long range characteristics are not the same and may not match the sight settings.

[smlekid]

[
MkVIIIz ammunition seems prone to generate excessive pressures if degraded, and some was loaded to excessive pressures when new. The Maxim and Vickersguns handle these pressures with no problems but there are reports of worn No.4 rifles losing the bolthead and SMLE rifles with sprung action bodies after few rounds of suspect MkVIIIz ammunition.

The only reference I have seen about MK8z ammunition setting back the lugs on a No1 Rilfe was the Khybar pass knock offs a clip of 5 was uasually used as a "proof Test" and the rifles suffered with headspace issues after
I do find it interesting that a powder can raise its pressure when it degrades as most times old powder looses its Zing
according to a reference book I have on hand the Mk8z was loaded with Neonite? if my memory is correct (and it is most likely not!) the Austrlain WW2 310 Cadet was loaded with Neonite and these days when you find it the loads will not fire and that is blamed on powder going off

[smlekid]

The H barrels that were fitted to range rifles weren't anything special,they were made to civy time tolerances that were tighter than war time spec's but overall the barrels were just Long Tom tubes cut to SMLE length.The barrels did shoot better being heavier but mostly it was due to the groove dia being around .312,which is still a thou over but not as bad as most stock barrels that are .314 and go up to .317,the reason was to lower the pressure when they switched to cordite as it ran excessive pressures in the desert. Pat

G'dat Pat303 if I may I will relate a story told to me by my local 303 amourer (sadly a dieing breed) this Gentleman has done military service and had a mate that worked at SAF Lithgow making 303's now this is just what he told me so take it with a grain of salt I was told the 303 H barrels were chambered with brand new reamers thay did 10 barrels and put the reamer back into store and used another new one for the next 10
like I said it is what I was told a story that came from someone who worked at SAF Lithgow in the glory years

[Multigunner]

[
MkVIIIz ammunition seems prone to generate excessive pressures if degraded, and some was loaded to excessive pressures when new. The Maxim and Vickersguns handle these pressures with no problems but there are reports of worn No.4 rifles losing the bolthead and SMLE rifles with sprung action bodies after few rounds of suspect MkVIIIz ammunition.

The only reference I have seen about MK8z ammunition setting back the lugs on a No1 Rilfe was the Khybar pass knock offs a clip of 5 was uasually used as a "proof Test" and the rifles suffered with headspace issues after
I do find it interesting that a powder can raise its pressure when it degrades as most times old powder looses its Zing
according to a reference book I have on hand the Mk8z was loaded with Neonite? if my memory is correct (and it is most likely not!) the Austrlain WW2 310 Cadet was loaded with Neonite and these days when you find it the loads will not fire and that is blamed on powder going off

Neonite is the British manufactured substitute for IMR 3031. There may also be a Double Base ball powder that also goes by the term Neonite.
Degraded powders can go either way when it comes to pressures, degraded primers are a major cause of failure to ignite.
Besides powder degradation cold soldering of jacket to case neck, and bullets frozen in place by degraded sealants or corrosion is another cause of excessive pressures.

A warning on a MkVIIIz eqivalent load damaging a No.4 rifle was posted to a Gunwriters website from Australia a few years back. The headstamp resembled that of Privi Partizan cases but may not have been manufactured by them. Privi cases are apparently sold in bulk to other European manufacturers.

There are reports of MkVIIIz used in Egypt that caused excessive pressures and unusually high velocities of over 2900 fps when fired in Vickersguns. Flattened primers that looked painted on was one comment. This was like as not due to heat affecting the ammo. Pressure was estimated to exceed 60,000 CUP.
Heres a quote from the book "Ordnance went up Front" by Roy Dunlap.

There appear to have been two distinct loadings of the Mark VIII cartridge: one small arms expert serving with the Royal Army Ordnance Corps at Dekheila noted that Mk VIIIz ammunition he examined had a claimed muzzle velocity of 2,900 fps, furthermore, primers on MK VIIIz fired cases he examined looked "painted on", normally indicating a pressure of around 60,000 lbs. per square inch.


Degraded cordite is better known for breakdown, with nitroglycerine begining to sweat out of strands at temperatures over 125 degrees. The ammunition pocket book warns that if the card wad is not seated glazed side to the cordite sweated out nitro can permeate the card causing a source of secondary detonation. If the nitro doesn't pool in the case it can be reabsorbed by the strands when the ammo cools.

PS
Another potential problem with old ammo, is physical breakdown of strands or extruded powder granules.
I first heard of this in the investigation of a blown up .44 magnum revolver.
Testing showed the pistol had no pre kaboom defects, there were no other complaints about the ammo of the lot used.
They then pulled bullets of remaing cartridges from the same box, and found the powder pulverised to dust.
The ammo had been kept in the glovebox of an oof road vehicle for many months. Bouncing over rough ground and severe engine vibration had disintegrated the powder granules.
Mk 1 Cordite had the same problem if the strands broke up due to rough handling or vibration in a vehicle, Mk 1 cordite strands were fairly brittle, a fault corrected in Cordite MD which has flexible strands.

Heres an excerpt from the Journal of Proceedings of the US Naval institute.

All nitro powders being highly exothermic chemical compounds, in place of a mere mixture of reagents, such as common black powder, are much more liable to deterioration when stored under high temperature. The disastrous explosion on board the Jena will be in the minds of all, and our own Navy and Army have also suffered from this unfortunate characteristic of the modern type of propellant. though fortunately, on a imich less serious scale.—Engineering, June 14, 1907, page 780. Editorial, " The Cordite Debate."

In December 1899 a six-inch cartridge on the Revenge ignited spontaneously, and two other cartridges in the same box were also found to have gone off. In the autumn of last year, moreover, there were two spontaneous explosions at Cordite Magazines in India. The spontaneously ignited ammunition cannot be represented as the natural outcome of a contractor's " greed for dividends." but was actually manufactured at Waltham Abbey under the supervision of officials as to whose complete honesty there is absolutely no question.—Engineering, June 14, 1907, page 780. Editorial. "The Cordite Debate."

All ships in the German Navy were fitted with apparatus to keep the magazine cool, but our Admiralty only seem to have appreciated the importance of this during the past year, when the matter was forced on the attention of the Government by the accident on H. M. S. Fox, though several years previously a similar accident had occurred on H. M. S. Ra-engc. In both cases by a simple chance, the loss of the ships and their crews, fortunately, did not occur.—Engineering, September 27, 1907, Editorial. " Back-flash from Modern Smokeless Powder."

.... it has long been recognized that some cordites decompose slowly, and might finally ignite and explode spontaneously. The change is due to the absorption of oxygen from the air, O combining with N of cordite. In order to watch this gas absorption, about 50 grams of cordite are placed in an inverted glass cylinder, which a long bent gas tube connects to a mercury column pressure gauge; the apparatus, without the gauge, is placed in a water bath kept at 70° C. After a while the gas absorption passes into a gas evolution and expansion. The new method is the only reliable one which gives a timely warning that the sample of cordite is not to be trusted; and it is to be hoped that it will prove a safeguard against spontaneous explosions in powder magazines, especially in the tropics.— Engineering, June 22, 191 r. "New Stability test of Cordite by Dr. Silberrad."

[303Guy]

Holy Cow! That's interesting stuff!:holysheep

OK, the ammo that 'ran in' my barrel was not MkVIIIz, it was R2M2 as opposed to R1M2 - the latter being MkVII and the former MkVIII. Both were cordite rounds with flat based bullets but the R2M2 had a 175gr bullet. I chronographed the stuff and it was pretty hot but nowhere near 2900fps! Still plenty above the normal 2440fps standard of MkVII ammo specs. It seemed to set my rifles bolt back a tad but not enough to worry about, specially since I do not full length size. This rifle's bore is is still very good and is probably in an ideal condition. I just had a look at it and the machining marks are still visible on the rifling leade. I'm planning on making this my 'paper patch varmint rifle'!

[Multigunner]

Holy Cow! That's interesting stuff!:holysheep

OK, the ammo that 'ran in' my barrel was not MkVIIIz, it was R2M2 as opposed to R1M2 - the latter being MkVII and the former MkVIII. Both were cordite rounds with flat based bullets but the R2M2 had a 175gr bullet. I chronographed the stuff and it was pretty hot but nowhere near 2900fps! Still plenty above the normal 2440fps standard of MkVII ammo specs. It seemed to set my rifles bolt back a tad but not enough to worry about, specially since I do not full length size. This rifle's bore is is still very good and is probably in an ideal condition. I just had a look at it and the machining marks are still visible on the rifling leade. I'm planning on making this my 'paper patch varmint rifle'!

They usually tested cordite by lots to determine the best charge weight for each lot according to its energy level. The ammunition pocket book gives charge weight for the MkVII ammo at between 35.5 gr to 37.5 gr. The exact number of strands can vary due to variations in the extrusion process and energy level of the cordite lot used.
Normally rifle cartridges give pretty decent std deviations, so a load that exceeds the 2440-2460 fps window was probably not intended for use in rifles.

Contrary to popular belief ammunition interchangability between rifle caliber LMG or MG and Infantry rifles was secondary to maximum performance of the MG when specialized ammunition was available.
It was expected that the LMG would often be used with Infantry ball ammo, and should operate efficienly when Infantry ball is used, but the limited issue of specialized MG ammo to riflemen, such as the German tungsten core heavy bullet AP rounds once issued five rounds per man, was for emergency use against light armorered vehicles or gun shields, not for regular use.

Some RAF MG ammo used cordite due to the difficulty in igniting the tracer compositions and incendiary component of specialized air combat ammunition used at the time. They'd found single based powders didn't generate enough heat to ignite the compounds when ammunition stores were chilled by the cold of high altitude flight.
The drawbacks were excessive muzzle flash , overheating of the breech (which lead to the RAF redesigning their wing guns to fire from an open bolt), and accumulation of carbon in the muzzle fittings of recoil operated guns (fixed by adding relief cuts and constant maintenance (if a gun jammed in less than 300 rounds the armourer was brought up on charges).

Its likely Air combat ammo would be loaded hot to offset reduced velocity of chilled ammunition.
I've seen tests run on a few types of ammo to determine loss of velocity when ammunition is subjected to sub zero cold, but no figures on the .303.
Some aircraft gun .303 has quite a bit of sealant that looks to be lacquer based.

Sometime back I ran across posts by military marksmen explaining how degraded sealants of the relatively fresh ammunition they'd been issued for a match had caused wide variations in velocity and pressures due to excessive pull resistence.
They'd solved the problem by seating the bullets a few thousandths deeper in the neck, breaking the hold of the sealant.

Deteriorated powder can cause a lot of problems inside the case and not visible to the naked eye.

I've examined an entire rack of late WW2 production Lithgow rifles that all showed clearly visible setback and upset of the metal of the lugs. I don't see that happening if only MkVII were used. The rifles had been restocked and refinished but bores were in very good to new condition. The boltheads were very loose.

[StarMetal]

They usually tested cordite by lots to determine the best charge weight for each lot according to its energy level. The ammunition pocket book gives charge weight for the MkVII ammo at between 35.5 gr to 37.5 gr. The exact number of strands can vary due to variations in the extrusion process and energy level of the cordite lot used.
Normally rifle cartridges give pretty decent std deviations, so a load that exceeds the 2440-2460 fps window was probably not intended for use in rifles.

Contrary to popular belief ammunition interchangability between rifle caliber LMG or MG and Infantry rifles was secondary to maximum performance of the MG when specialized ammunition was available.
It was expected that the LMG would often be used with Infantry ball ammo, and should operate efficienly when Infantry ball is used, but the limited issue of specialized MG ammo to riflemen, such as the German tungsten core heavy bullet AP rounds once issued five rounds per man, was for emergency use against light armorered vehicles or gun shields, not for regular use.

Some RAF MG ammo used cordite due to the difficulty in igniting the tracer compositions and incendiary component of specialized air combat ammunition used at the time. They'd found single based powders didn't generate enough heat to ignite the compounds when ammunition stores were chilled by the cold of high altitude flight.
The drawbacks were excessive muzzle flash , overheating of the breech (which lead to the RAF redesigning their wing guns to fire from an open bolt), and accumulation of carbon in the muzzle fittings of recoil operated guns (fixed by adding relief cuts and constant maintenance (if a gun jammed in less than 300 rounds the armourer was brought up on charges).

Its likely Air combat ammo would be loaded hot to offset reduced velocity of chilled ammunition.
I've seen tests run on a few types of ammo to determine loss of velocity when ammunition is subjected to sub zero cold, but no figures on the .303.
Some aircraft gun .303 has quite a bit of sealant that looks to be lacquer based.

Sometime back I ran across posts by military marksmen explaining how degraded sealants of the relatively fresh ammunition they'd been issued for a match had caused wide variations in velocity and pressures due to excessive pull resistence.
They'd solved the problem by seating the bullets a few thousandths deeper in the neck, breaking the hold of the sealant.

Deteriorated powder can cause a lot of problems inside the case and not visible to the naked eye.

I've examined an entire rack of late WW2 production Lithgow rifles that all showed clearly visible setback and upset of the metal of the lugs. I don't see that happening if only MkVII were used. The rifles had been restocked and refinished but bores were in very good to new condition. The boltheads were very loose.

You're dead on about that German tungsten ammo. My best friend got his hands on some of that and was demonstrating it to me in a 98 Mauser. The recoil was 1 1/2 times more (observing him by eye shooting the regular ball and the tungsten ammo) and the muzzle flash in daylight was 3-4 times more.

You have some interesting and good knowledge on the 303's and ammo.

[Multigunner]

You're dead on about that German tungsten ammo. My best friend got his hands on some of that and was demonstrating it to me in a 98 Mauser. The recoil was 1 1/2 times more (observing him by eye shooting the regular ball and the tungsten ammo) and the muzzle flash in daylight was 3-4 times more.

You have some interesting and good knowledge on the 303's and ammo.

Thank you, I just went back to the sources on most of it. I've done a fair amount of reloading and load development for my own Enfields and several belonging to friends. I was out of shooting all together for awhile due to injuries so it took awhile to get caught up on new powders.
I decided to learn as much as possible about the available milsurp ammo, poor quality milsurp .303 is the main reason I began handloading for these rifles, and investing in new bolt bodies and boltheads to tighten headspace for longer case life.

I'd also had a shock when i found the milsurp 8mm I'd obtained for my first Mauser, a Persian carbine with 18 inch barrel, was high powered antiaircraft or aircraft gun ammo. The rounds I got were tracers, with an extremely long burn time. Recoil was hard enough to set me back on one heel and spin me sideways, the muzzle blast from the short tube was so fierce I thought the gun had exploded. I threw the rest of those rounds in a pond.
The tracer continued to burn for a long time after it hit the backstop, shooting flame like a rocket motor, so bright I can't tell you what color it was because of purple and green after images that lasted awhile.

Improvements in ammunition and metalurgy helped increase useful bore life of the Enfield using Cordite ammo, but concessions to use of cordite made the bores less suited to more modern propellants, so it takes a taylored to the rifle handload
To get the best accuracy.
I was able to get consistent sub MOA groups with my No.4, though its not particularly accurate with most over the counter sporting ammo, and one brand keyholed at every shot, though the keyholed bullets still formed a fairly respectable group at point of aim. That brand shot very well in other rifles we tried it in.
Well I figure everyone here is going to be handloading so its a given that they'll work up the best loads for their individual rifles.

I would not be so concerned about milsurp ammo if I had not seen people on other sites describing ways of cleaning corroded cases with brillo pads so they'd fit in the chamber, and not taking into account the dangers of a hangfire self destructing in the air near the shooters head when ejected or letting loose when the action is opened.

I've heard that the NRA in Britian has issued old POF ammo at times, but I would expect they got theirs direct from Pakistan government storage facilities. The POF available here has a high incidence of misfires and hang fires.
One UK shooter did admit that he would hide misfired ammo in his shirt pocket when the range officer wasn't looking. I can imagine the result if the misfire had turned out to be a hangfire.

Some Milsurp .303 with an old headstamp is actually remanufactured ammo, the bullets pulled and old charge dumped the primer replaced and a fresh charge inserted along with the original bullets.
Unfired ammo long past its expiration date was occasionally reloaded this way as long as the cases were still sound, the case being the most valuable component.
Canada once had to remanufacture a huge lot of .303 ammunition they'd received from the British. I found a few of the records on that, with some remarks on the high cost of fixing someone else's mistakes.

Theres a market for recycled MkVI ammunition in Britian, for collectors of the Long Lee and SMLE MkI if not upgraded for MkVII at some point after 1917 and marked HV SC.
The SMLE MkI was intended for use with MkVI ammunition, and the original barrels were reverse taper lapped to relieve friction on the bullet so it would have the same muzzle velocity as the MkVI from a Long Lee barrel.
If you run across a SMLE MkI whose muzzle will swallow a plug gauge or bullet, it may simply be due to excessive taper lapping during manufacture. The rifle may still shoot well, but only with MkVI ammunition or a hadload taylored to MkVI specs with a propellant that provides some serious bump up.

[PAT303]

G'dat Pat303 if I may I will relate a story told to me by my local 303 amourer (sadly a dieing breed) this Gentleman has done military service and had a mate that worked at SAF Lithgow making 303's now this is just what he told me so take it with a grain of salt I was told the 303 H barrels were chambered with brand new reamers thay did 10 barrels and put the reamer back into store and used another new one for the next 10
like I said it is what I was told a story that came from someone who worked at SAF Lithgow in the glory years

Your right,the barrels were cut with new tooling but the tooling was military spec,they weren't tight chambered or anything.One day I'm going to get a MAB barrel that is the correct spec,.303 bore with .311 grooves and really see how much difference the correct spec makes. Pat

[StarMetal]

Thank you, I just went back to the sources on most of it. I've done a fair amount of reloading and load development for my own Enfields and several belonging to friends. I was out of shooting all together for awhile due to injuries so it took awhile to get caught up on new powders.
I decided to learn as much as possible about the available milsurp ammo, poor quality milsurp .303 is the main reason I began handloading for these rifles, and investing in new bolt bodies and boltheads to tighten headspace for longer case life.

I'd also had a shock when i found the milsurp 8mm I'd obtained for my first Mauser, a Persian carbine with 18 inch barrel, was high powered antiaircraft or aircraft gun ammo. The rounds I got were tracers, with an extremely long burn time. Recoil was hard enough to set me back on one heel and spin me sideways, the muzzle blast from the short tube was so fierce I thought the gun had exploded. I threw the rest of those rounds in a pond.
The tracer continued to burn for a long time after it hit the backstop, shooting flame like a rocket motor, so bright I can't tell you what color it was because of purple and green after images that lasted awhile.

Improvements in ammunition and metalurgy helped increase useful bore life of the Enfield using Cordite ammo, but concessions to use of cordite made the bores less suited to more modern propellants, so it takes a taylored to the rifle handload
To get the best accuracy.
I was able to get consistent sub MOA groups with my No.4, though its not particularly accurate with most over the counter sporting ammo, and one brand keyholed at every shot, though the keyholed bullets still formed a fairly respectable group at point of aim. That brand shot very well in other rifles we tried it in.
Well I figure everyone here is going to be handloading so its a given that they'll work up the best loads for their individual rifles.

I would not be so concerned about milsurp ammo if I had not seen people on other sites describing ways of cleaning corroded cases with brillo pads so they'd fit in the chamber, and not taking into account the dangers of a hangfire self destructing in the air near the shooters head when ejected or letting loose when the action is opened.

I've heard that the NRA in Britian has issued old POF ammo at times, but I would expect they got theirs direct from Pakistan government storage facilities. The POF available here has a high incidence of misfires and hang fires.
One UK shooter did admit that he would hide misfired ammo in his shirt pocket when the range officer wasn't looking. I can imagine the result if the misfire had turned out to be a hangfire.

Some Milsurp .303 with an old headstamp is actually remanufactured ammo, the bullets pulled and old charge dumped the primer replaced and a fresh charge inserted along with the original bullets.
Unfired ammo long past its expiration date was occasionally reloaded this way as long as the cases were still sound, the case being the most valuable component.
Canada once had to remanufacture a huge lot of .303 ammunition they'd received from the British. I found a few of the records on that, with some remarks on the high cost of fixing someone else's mistakes.

Theres a market for recycled MkVI ammunition in Britian, for collectors of the Long Lee and SMLE MkI if not upgraded for MkVII at some point after 1917 and marked HV SC.
The SMLE MkI was intended for use with MkVI ammunition, and the original barrels were reverse taper lapped to relieve friction on the bullet so it would have the same muzzle velocity as the MkVI from a Long Lee barrel.
If you run across a SMLE MkI whose muzzle will swallow a plug gauge or bullet, it may simply be due to excessive taper lapping during manufacture. The rifle may still shoot well, but only with MkVI ammunition or a hadload taylored to MkVI specs with a propellant that provides some serious bump up.

Now understand that old cordite loaded 303 were loaded with the cordite strands before the case was finished being formed, that is shoulder and neck portion. How in the devil did they reload these or didn't they refill them with cordite, but a tubular or ball powder?

[PAT303]

Factory loads were made in Oz after the war by pulling the FMJ and seating a 150grn SP straight over the cordite-4740-3031 military charge,there was a factory that manufactured 303 sporting ammo by simply filling the hoppers with SP's instead of FMJ's without any other changes and later still we had vast amounts of 9mm bullets that were swaged upside down so the solid nose became the base and the open base became a soft point nose,once again they were loaded into military cases straight over the standard military charge. Pat

[StarMetal]

Factory loads were made in Oz after the war by pulling the FMJ and seating a 150grn SP straight over the cordite-4740-3031 military charge,there was a factory that manufactured 303 sporting ammo by simply filling the hoppers with SP's instead of FMJ's without any other changes and later still we had vast amounts of 9mm bullets that were swaged upside down so the solid nose became the base and the open base became a soft point nose,once again they were loaded into military cases straight over the standard military charge. Pat

That's interesting stuff too. Might be worth it to live in AU a spell to learn things like that as we don't hear it all on this side of the pond. Thanks

[Multigunner]

Now understand that old cordite loaded 303 were loaded with the cordite strands before the case was finished being formed, that is shoulder and neck portion. How in the devil did they reload these or didn't they refill them with cordite, but a tubular or ball powder?

Not sure, but I once saw a wartime film clip of women loading .303 cartridges by hand counting out strands and inserting them one by one.
Loading with a measured charge by machine would be necessary for mass production, so I figure that film clip was of ammunition being reloaded. Its been suggested that this was a basement operation in Leningrad during the seige. The russians had a lot of WW1 surplus Maxim guns and vickersguns, as well as .303 MG on their borrowed British aircraft. Some Russian mounted troops carried Long Lee rifles that had been modified with the Mosin Nagant style sling slots, I've seen photos of those.
One poster on another forum reported finding some relic ammo found in Germany that was loaded with cordite but without a card wad. replies to that indicated these were probably German repacks of old ammo for use in captured British Bren guns and Vickers guns. They may have been reloads for that matter, possibly even captured Russian reloaded ammo or ammo left behind by them during their push to Berlin.

It would be possible to insert a card wad manually, but it would be time consuming, and the seal might not be as good.

Cordite MkVII when used without the Card Wad burned out bores within 1500 rnds.

I have seen images of broken down .303 that contained a wad made from three layers of a very thin flexible material. These might be flexible enough to insert into a case with shoulder already formed more easily than the original glazeboard wad.

I've removed the glaze board wad from a dud POF round without tearing it, I may still have it laying about somewhere. It was fairly flexible.

The ammunition plants were originally set up to load the BP era .303 so the process of forming the neck after the compressed pellet was inserted was already in place before cordite was ever used. Using that same process made insertion of a bundled charge of strands and the card wad easier and faster than trying to do it by hand.

The extra steps did restrict the ammo output, Britian was never able to supply her own ammunition needs in either world war, relying on US and Canadian factories to make up the short falls.

[PAT303]

Once again in Oz the cordite was pushed into the case and then cut off before the case moved to the next station that then necked the case down onto the bullet,the bullet itself was held in position so it acted like a mandrel as the neck was sized to it.It makes you wonder how it worked but worked it did very well.The case's were made that way as the BP pellet was 70grns and it needed hydraulic pressure to get that much in it,how it burnt through being that tight is anyones guess but when the ammo was superseeded they used the BP cartridges as proof rounds as they ran something like 2 tons chamber pressure higher than the cordite rounds,they are also very very sought after by collectors. Pat

[Multigunner]

Once again in Oz the cordite was pushed into the case and then cut off before the case moved to the next station that then necked the case down onto the bullet,the bullet itself was held in position so it acted like a mandrel as the neck was sized to it.It makes you wonder how it worked but worked it did very well.The case's were made that way as the BP pellet was 70grns and it needed hydraulic pressure to get that much in it,how it burnt through being that tight is anyones guess but when the ammo was superseeded they used the BP cartridges as proof rounds as they ran something like 2 tons chamber pressure higher than the cordite rounds,they are also very very sought after by collectors. Pat

An old British gun trade journal I found on line gave the chamber pressure of the MkI cordite cartridge tested by a radial method as 15 Tons (long tons I suppose)or 33,000 pounds per square inch. It didn't tell much about the pressure gun used, but the pressure guns used by US arsenals at that time used a blade that was pressed into a copper block, to determine pressure an identical block was cut using the same type blade pressed in by a hydraulic ram till it matched the block used with the pressure gun.

The BP pellet was a hollow tube, it burned from the inside out like a solid rocket motor.
If the BP pellet cracked it caused extreme high pressures.

[Brownie]

wheelweight alloy has a lot of antimony and it makes the bullets hard but but they will still lead the barrel because there is not enough tin. you need to add tin and pure lead to make Lyman #2 mix.