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HollowPoint
01-19-2012, 11:08 AM
After a couple of years of procrastination I finally did my first re-barreling job on my old Lee Enfield No.4 Mk1.

I put it together as a dedicated cast bullet gun. Everything appears to have turned out according to plans. I just finished reassembling it yesterday.

After doing some research I decided to used the "Barrel Nut" method similar to what you find on Savage rifles.

Head Spacing was a breeze and metal around the chamber remained beefy enough to mitigate any concerns about weakening by using this method of re-barreling and chambering for the pressures of the 303 British cartridge.

It effectively qualifies this rifle as a "Switch-Barrel" if I ever get another Wild-Hair up my butt and feel like converting it to a 45-70 or a 7.62x39.

This is assuming that the Proof Testing of the new barrel works as I hope it will. Which leads me to my question.

How many rounds does one fire through a barrel in order to test its strength and/or functionality?

Although it will be a dedicated cast bullet gun, I want to Proof Test it with full power jacketed loads before I start shooting cast out of it. Would this be a correct way of going about it? If so, what test loads would be recommended?

One last thing that needs to be factored into any helpful replies; I re-barreled this 303 British rifle with a A&B 30 caliber barrel to replace the factory 303 barrel it came with. This means that I've gone from a .312" ID to a .308" ID according to dimensions I got when I slugged the new barrel.

Thanks for your help.

HollowPoint

Wayne Smith
01-19-2012, 03:07 PM
A true proof is only one shot - but an overload shot.

KCSO
01-19-2012, 03:33 PM
A proof load for the 303 would be one round in the 75,000 psi range and 2 in the 50,000 range. But as far as i am concerned if it handled one full proof load with no bulges or deformation I would figure you would be goo to go for cast loads.

I saw a neat Enfield the other day a customer brought in a #1 converted to 30-40 Krag. The gun had been rebarreled wit a springfield 2 groove barrel.

HollowPoint
01-19-2012, 07:49 PM
I have a box of 168 gain A-Max bullets I can try. I'll load three of them to full power and see if the old girl holds together.

I just have to find a long enough length of rope to act as my remote trigger.

Because it's an after market barrel I can't use the factory front sight any more. I've had to design and build a new windage-adjustable front sight with plenty of adjustment for it. It should be done and mounted tomorrow.

My metal lathe isn't as accurate as I'd like. Couple that with my inexperience with this type of project and you can see why I need a front sight with plenty of windage-adjustment. If I can hit anywhere on the paper target at a hundred yards I'll be happy for now.

With any luck I'll get a chance to load up those test rounds next week some time. I'm fairly confident that I'll experience no setbacks but, since I'm a newbie to re-barreling there's always that sense of apprehension.

KCSO: How did you arrive at the 75,000 psi and 50,000 psi numbers? Is there a formula for figuring the appropriate "Proof Load?"

Thanks for your input gentlemen.

HollowPoint

Skipper
01-19-2012, 08:08 PM
From http://kwk.us/pressures.html


"Proof Loads

For rifles, SAAMI recommends a proof load between 33 and 44 percent over the nominal rating, and the CIP today requires 25 percent over their rating (an older standard called for 30% over). While SAAMI requires only a single proof firing, the CIP wants two firings, except in long guns designed for low pressure cartridges (under 26 ksi), where only a single proof cartridge need be fired.

For handguns, the CIP uses 30 percent over, while SAAMI varies the proof load with the rated pressure. For cartridges rated over 20 ksi, SAAMI uses the same overloads as with rifles, but low pressure cartridges have a higher overload, with those rated under 15 ksi having a minimum of 44% over.

To conduct a proper proof, one would ideally need precise gauges to verify no stressed part has yielded (ie., taken a permanent deformation) in the slightest. If no yielding occurs at the proof pressure, then the gun should have an adequate fatigue life at normal operating pressures. I've read that in practice, visual inspections are permitted on production guns, so I suspect properly instrumented proofs are only conducted on prototypes.

Interestingly, the same percentage overload is used with both piezo and crusher ratings at SAAMI. Above, it was noted there is evidence that crusher's underestimation of pressure grows ever worse as the true pressure rises. One curious side effect is that rifles proofed with crushers may well be proofed to a higher standard than those proofed with piezo.

Under the British base crusher standards described below, proof loads ran 30 to 45% above normal. To maximize breech thrust, proof cartridges were oiled before firing."

HollowPoint
01-19-2012, 08:37 PM
Thanks Skipper:

That's the info I was looking for.

I recall reading somewhere that a British 303 rifle re-barreled with a thirty caliber barrel will exhibit a slight increase in pressure (7 to 10 percent) when the 303 brass is loaded with 30 caliber projectiles of equal weights. (I mean; 170 grain bullet with the dimensions of .312" compared to a 170 grain bullet with the dimensions of .308")

So I'm thinking that if I load and shoot one 168 grain bullet at full power -49000 psi- and two 110 grain bullets using the full power powder charges of 150 grain bullet, the first bullet should yield a little more than 60000-65000 psi and the second two rounds should come in at or near 49000 psi.

When you consider that the cast bullet loads I plan to shoot out of this rifle are generally about half those pressures, I think that should be enough Proof Testing.

HollowPoint

Casting Timmy
01-19-2012, 10:29 PM
I beleive that Ackley talked about using standard ammunition as proof loads, but slightly lubing the case so it gave the back pressure of an overload. He did that so he could use standard ammo but still get the same test. It also kept him from having seperate proof and test ammo for the guns to worry about keeping seperate.

I just read Dunlap's book on proofing and like his ideas the best. Ideally the gages woudl be used and tested again in the rifle after each firing. This is to ensure something isn't moving, and if it does move you find out before anything bad happens. If you no longer have gages but can find some fired cases in your caliber, barely resize it so you can feel the bolt closing on it and use that as your gage. Or you can shim the back of the case so that the bolt closes with a little resistance. Try this case out several times so you know how it feels closing the bolt on it.

If I remember right he said a new action could take avery small set, but an old action shouldn't move at all. Actually Dunlap's book Gunsmithing is an excellant book and still sold by Stackpole books.

At any rate congrates on your first rebarreling.

Mk42gunner
01-20-2012, 12:24 AM
To me, when you mention "proof testing" you are implying making up loads that are considerably over normal pressure, as KCSO and Skipper stated.

My problem with anyone, me included, making up their own "proof loads" is that you don't really have any idea as to what the pressure actually is. (There is quite a dearth of overpressure data available).

I would not just blindly add powder to a load, that sounds like a very good way to spontaneously disassemble your rifle.

In my opinion, the only way to safely develop proof loads is to have piezo pressure setup on hand and use it to make up loads.

Do you know anyone close that has an Ohler M43?

What I have done with my own rebarreling projects, is to fire several factory loads and use a micrometer and dial caliper on the cases. I verify the chamber is round and the cases don't grow too much. I also recheck the headspace with the guages that I used when reaming the chamber.

Hope this helps,

Robert

waksupi
01-20-2012, 12:27 AM
Since it is a proven action, I wouldn't get carried away with testing. The receiver is what would give up, not the barrel.

HollowPoint
01-20-2012, 11:03 AM
I can see the point of exact measurements but, all I was looking for was general numbers and procedures.

I don't own any of the equipment mentioned here. I don't ever intend to shoot anything "Full-Power" out of it other that the three "Proof Test Bullets." My main concern was that I could comfortably and safely shoot low power cast bullet loads out of it with out any mishaps caused by the new barrel itself.

My go-to low power load is the standard 16-18 grains of 2400 with cast bullets ranging from 130-200 grains.

By the way; do any of you guys know what pressures are generated using 16 grains of 2400 out of 303 British?

HollowPoint

Molly
01-20-2012, 05:59 PM
There's a little trick I read about from (IIRC) British proof practices. It simply wasn't practical to make up actual proof rounds for each and every oddball round ever designed, yet British law required that all foreign made guns be proofed before importation was permitted.

I'm not sure of the exact temperature, but the problem was solved by warming both the gun and a round of factory ammunition and firing them before they cooled off. I - THINK - the temperature was something like 120 or 130 degrees F. This (higher temperature) was deemed adequate to push pressures into the acceptable proof range. Gun Digest has published a ton of information on proofs and proof marks. If you want to take this approach, dig through the old Digests to be sure of what you are doing. Unlike crusty old codgers, the printed page simply doesn't forget.

HollowPoint
01-20-2012, 08:05 PM
There's a little trick I read about from (IIRC) British proof practices. It simply wasn't practical to make up actual proof rounds for each and every oddball round ever designed, yet British law required that all foreign made guns be proofed before importation was permitted.

I'm not sure of the exact temperature, but the problem was solved by warming both the gun and a round of factory ammunition and firing them before they cooled off. I - THINK - the temperature was something like 120 or 130 degrees F. This (higher temperature) was deemed adequate to push pressures into the acceptable proof range. Gun Digest has published a ton of information on proofs and proof marks. If you want to take this approach, dig through the old Digests to be sure of what you are doing. Unlike crusty old codgers, the printed page simply doesn't forget.


Hi Molly:

I may be completely misunderstanding your reply but is seems that if a person went to the range for an extended shooting session and left the last round in the chamber for a couple of minutes, the heat build up from the previously fired rounds would do exactly what you've described.

Have you ever felt the barrel of your gun after firing five or six rounds through it? I imagine that the inside of the chamber is even hotter than the outside.

This would mean that all of us goobers that frequent the shooting range for extended shooting sessions at some point are shooting "Over-Loaded" Proof Test cartridges without even realizing it.

I'm sure there's a little more to it than what I'm understanding here. My original plan was just to load up about 10 or so cartridges using the Jacketed bullets I had on hand. I intended to load them using load data from the Hodgdons loading manual.

Because I now have a slightly more constricted bore than the original 303 bore, I figured that the resulting increase in pressure caused by the smaller bore would bring up the pressures sufficiently to satisfy any safety concerns I may have.

I just didn't know exactly how many rounds to fire in order to call it "Proof Tested;" at least in my own mind. Now I know I only have to fire three "Over-Load" rounds.

I have no way of measuring pressures so I'm having to rely on the pressures listed in the load data and extrapolate from there.

I'd hate like heck to have done a good job of re-barreling my Enfield only to go out and blow it to smithereens needlessly out of shear ignorance.

Thanks for your input Molly.

HollowPoint

Casting Timmy
01-20-2012, 10:27 PM
You can increase pressure by leaving your gun and ammo inteh heat too long. I used to go to a range and talked to the range offer and they had problems at times with people and their guns and hot chambers. Actaully my friend found it out the hard way, by leaving the rifle and ammo in his trunk all day at work during the summer and then going to the range afterwards. It was factory ammo and the gun was sticking closed hard. A few minutes with the gun and ammo in the shade and he no longer had problems with extraction. Afterwards we starting talking to the range officer and they said it happened a lot and they tried watching for people acting strangly with their guns.

I also read an interesting comment on hot loads and overloading guns, one guy's thought was that people over loading guns usually get saved by no longer wanting to shoot the gun because it doesn't extract cases very well. The real reason is that the chamber is bulged from overpressure loads or a lot of hot loads. This locks the case in the chamber and the extractor can't pull it out, the gun gets set aside in favor of the gun that they can shoot. Unknowingly saving themselves from a blow up.

Another tip to keep from heating your gun up too much is to stick a fish tank thermometer on the side of your barrel. THey make them pretty small and you get to know the temperature at just a glance. They make some that are not to much bigger than your thumb. Another guy I've shoot with shoots a hot wildcat and the middle of the summer you can watch that little temp gage go up in just 4 or 5 slow paced shots.

Molly
01-20-2012, 11:16 PM
Hi Molly:

I may be completely misunderstanding your reply but is seems that if a person went to the range for an extended shooting session and left the last round in the chamber for a couple of minutes, the heat build up from the previously fired rounds would do exactly what you've described.

Have you ever felt the barrel of your gun after firing five or six rounds through it? I imagine that the inside of the chamber is even hotter than the outside.

This would mean that all of us goobers that frequent the shooting range for extended shooting sessions at some point are shooting "Over-Loaded" Proof Test cartridges without even realizing it.

I'm sure there's a little more to it than what I'm understanding here. . . .

No HP, believe it or not, you are absolutely correct. And it really doesn't take a whole lot of excess pressure to constitute a 'proof load':If I recall correctly (and I may be off), proofing of modern rounds that 'normally' operate at say 55,000 CUP is only something like 75,000 PSI. Don't take that as cast in concrete, as I'm going strictly by memory here. But in principle, if your primers flatten noticeably more than factory primers, or your case head expands measurably more than a factory round expands, take it from me, you ARE using proof loads.

Not only will leaving a round in a hot chamber raise pressures far above normal, there are innumerable stories from WWII (and other wars / police actions) of rounds 'cooking off' when the temperature of the barrel was high enough to ignite the powder charge.

Experienced reloaders have often observed signs of seriously elevated pressures from ammo stored in the back seat of a car, especially in the hot summer sun. And guns bulged or blown up from this cause are not exactly unknown either. The trick is to control the pressure elevation. The Brits (after considerable testing) established something in the order of 120 or 130 degrees as a practical equivalent of 'real' proof rounds. And the more I reflect on that, the more I think it was the lower temperature that they chose.

As for the temperature of the barrel being higher inside than outside (from firing rounds), this is also quite correct. In fact, the temperature of the skin of the bore is (very briefly) above the melting point of the steel itself. Burning gunpowder (nitrocellulose) is HOT stuff. My father was on the flight line crew crew of a bomber (B52?) , and he told me that even in the frigidity of high elevation, gunners would battle so fiercely that the guns would glow red and barrels would whip like a garden hose, and that it was not uncommon for his crew to replace barrels so badly distorted by the heat of the gunpowder that you could see that the bullets would come out of the side of the barrel, instead of the muzzle.

HollowPoint
01-21-2012, 12:20 PM
It sounds like we're all on the same page now.

On a simple subject like "Proof Testing" the different information one gets (even though it's valid documented information) tends to add a little confusion to the mix.

This is kind of Off-Base but I've often wondered why, with the Savage Barrel Nut system of changing out barrels, you hear virtually nothing about "Proof Testing" newly swapped barrels on any of their rifles.

I'm guessing that they've tested their prototype barrels so it's assumed that they'll all function safely without any further testing by their end-users. (us)

The action on a Savage short action can withstand the pressures of cartridges such as the 30 WSM and the metal thickness around the chamber is slightly less than the metal thickness of surrounding the chamber my newly barreled Enfield.

I wonder how vast the differences in metallurgy between the Savage action and the Enfield action? I guess as long as I stay within the established pressure limits of this particular action and cartridge it doesn't really matter.

HollowPoint

Molly
01-21-2012, 08:06 PM
Hi HP.

Interesting thread of discussion. Here's a little more for your consideration:


It sounds like we're all on the same page now.

On a simple subject like "Proof Testing" the different information one gets (even though it's valid documented information) tends to add a little confusion to the mix.

Well, mebby so, mebby no. You have to keep in mind the great variation in proof loads and practices between various nations. A gunn that passes proof in one country may fail in the next country. In fact, accidents with imported guns is what led the British to establish their own (and generally more rigorous) proofing procedures.

This is kind of Off-Base but I've often wondered why, with the Savage Barrel Nut system of changing out barrels, you hear virtually nothing about "Proof Testing" newly swapped barrels on any of their rifles. I'm guessing that they've tested their prototype barrels so it's assumed that they'll all function safely without any further testing by their end-users. (us)

["]That's for the simple reason that although proofing is a popular concept, and often employed, especially by the military in arms evaluations, there are NO US Proof Laws covering US manufactured or imported firearms. It seems that US liability laws are adequate to encourage US manufacturers (and importers) toward designs of considerable strength. I don't believe even England requires the proofing of US manufactured firearms any longer.

The action on a Savage short action can withstand the pressures of cartridges such as the 30 WSM and the metal thickness around the chamber is slightly less than the metal thickness of surrounding the chamber my newly barreled Enfield.


Actually, it requires astonishingly little to withstand ordinary proof pressures, and of course, less to stand factory ammo or equivalent reloads. Col Hatcher reported one set of tests to determine the safety margin of the standard issue 30-06 Springfield in his irreplaceable "Hatcher's Notebook" A standard rifle was fired with a proof load without damage. Then a lathe cut was made over the chamber and the rifle was re-tested without effect. A series of such lathe cuts and proof tests was conducted down to a chamber wall thickness (IIRC) of about 1/8 inch, where the forward portion of the chamber blew out.

I wonder how vast the differences in metallurgy between the Savage action and the Enfield action? I guess as long as I stay within the established pressure limits of this particular action and cartridge it doesn't really matter.

Actually, considering the huge safety margin of almost all US made firearms, my guess would be that as long as you stay anywhere NEAR handbook loads for your rifle and cartridge, you shouldn't do great harm to yourself, though the possibility of a bulged barrel from guns and ammo left in the sun can't be ignored entirely.

That's not to say that they can't happen. I once had a nearly new Rossi 22 semiauto pistol blow up in my hand, and I (for one) haven't reloaded the .22 LR in decades. There was no question but that factory ammo was being used, yet the grips blew off and the slide was partially detached.

In another case, one of my Mosin Nagant rifles disassembled itself once while being fired with surplus military ammo. Fortunately, I was just banging away some very inferior ammo from the hip, just to get rid of the junk. I was also wearing a very heavy winter coat. The bolt held, but the firing pin assembly blew out of the bolt, hitting my jacketed arm like a baseball bat, but first rearranging some of the tissue on my right thumb. Evidence suggested that a defective primer let gas back into the action, where it pressurized the much larger diameter of the firing pin and blew it out of the back of the gun. The angle in charge of fools and drunks was on double duty that day for sure, or I would have lost an eye.

cdet69
01-21-2012, 09:10 PM
Waksupi is correct. The action is realy the only thing that needs to get proof tested. No reason to subject your rifle to another uneeded test.

303Guy
01-25-2012, 02:03 PM
Waksupi is correct.This is my belief too. We've all heard of 308 ammo being fired in a 270. The one I know of, the receiver ring split, releasing the barrel to follow the swaged bullet downrange with no damage to the barrel! I've heard of a few shattered actions from serious overloads with intact barrels. FWIW.

By the way, oiling a cartridge does not make it a proof load. It merely puts more of the cartridge thrust onto the bolt face. According to Steves Pages, the extra thrust in a 308 is 10%. In a lower pressure cartridge that can hold all the thrust by case wall grip, things will be different but even then its only the full load thrust and not a proof load thrust. Again, FWIW.

However, on developing a proof load for a 303 Brit, one could use the loading charts and assemble a 308 load for it since the two cases have the same volumes (with lighter boolits).

HollowPoint
01-25-2012, 08:14 PM
I got my three loads all loaded up. Now I'm just waiting for some free time to come around so I can drive the fifty-miles out to where I can do the testing.

I'm really not expecting anything out of the ordinary to happen. In any event I have a pretty long length of cord to act as my remote triggering device.

All I've done is load three cartridges to maximum Load-Data-Book powder charges in two different bullet weights. The slightly tighter 30 caliber bore dimension should raise the pressure enough to tell me if it's a safe rifle to shoot or not.

If all goes as I anticipate, I'll have me a good plinking rifle. If not, I'll have a wall hanger and a good story to tell around the campfire; not to mention a little more gun-smithing experience.

HollowPoint

ipopum
01-25-2012, 09:28 PM
I do not think that necking the 303 to 308 will increase pressure. At least that is what was mentioned. You will have a 30Goverment or more commonly known as 30-40 Krag.

HollowPoint
01-26-2012, 11:00 AM
I do not think that necking the 303 to 308 will increase pressure. At least that is what was mentioned. You will have a 30Goverment or more commonly known as 30-40 Krag.

You could be right; and that would be absolutely OK with me. My main concern is that everything functions; and functions safely.

My reason for taking these precautions is that this is basically the Enfield that blew up in my face a couple of years back. I say "Basically" because the only thing that 's the same are the wood stocks. Everything else has been replaced but, still the stigma of that unfortunate event lingers.

It's taken a while to dust myself off and get back on this horse; so to speak.

The funny thing is, when I first started thinking about re-barreling I considered chambering it in 30-40 Krag. The only reason I didn't go that route was because this project had a limited budget that didn't include enough to buy a new set of loading dies and brass and such.

I've heard of the "30/Government" but other than just hearing about it I really didn't know anything about it.

Thanks for your input.

HollowPoint

HollowPoint
10-07-2012, 06:16 PM
It's been nearly a full 10 months since I re-barreled my Enfield and I just now got around to shooting it.

I've been dealing with severe allergy symptom for several months that just would not allow me to stay outdoors very long. (inner-ear problems due to allergies)

Well lately I've been feeling well enough to venture out to my old hunting and shooting grounds and this morning I took my Enfield, some bungi cords and a length of rope with me.

I'm happy to report that it fired safely and reliably. And once I got it generally sighted in, it seemed to shoot true as well.

I say, "generally sighted in" because the only draw back was that I had made up a new custom scope mount for it that was off at the back end just enough to have to max out my horizontal left to right scope adjustment. This was easily remedied by installing a home-made shim on the rear cross-pin. (the horizontal pin that holds the factory rear sight in place. I use the same pin to hold the scope mount in place.)

I was having to place my cross-hairs to the left of what I was aiming at in order to hit what I wanted to hit at a hundred yards.

In summary; my very first re-barreling job can now be considered a success. Hot Dang! Now I can start working up loads.

HollowPoint

ipopum
10-08-2012, 11:15 AM
I just reread my post about pressures on the re barrel with a 308 bore rather than 311. I assumed that you would be using 308 J bullets rather than 311. If you use 311 in a 308 bore you will increase pressures. If your brass when resized will not give good neck tension on 308 j bullets you may need a 308 neck sizer. I have found that my 308win neck sizer works for 30-06,30-30 & 300 sav. On cast bullets I run 309 up to 311 in my 308 barrels.

HollowPoint
10-08-2012, 09:31 PM
I just reread my post about pressures on the re barrel with a 308 bore rather than 311. I assumed that you would be using 308 J bullets rather than 311. If you use 311 in a 308 bore you will increase pressures. If your brass when resized will not give good neck tension on 308 j bullets you may need a 308 neck sizer. I have found that my 308win neck sizer works for 30-06,30-30 & 300 sav. On cast bullets I run 309 up to 311 in my 308 barrels.

I had to whittle down the chamber reamer I bought in order to ream a chamber with a neck to accommodate a true thirty calibers bullet (sized to 309") out of a true thirty caliber barrel.

As you've mentioned, I used my 308 Winchester neck sizer to size the neck to grip my cast bullets.

I fired three of what I would consider to be hot-jacketed-loads out of this Enfield. I then wiped the bore and proceeded to shoot several cast bullet loads. Which is what I planned to use this rifle for exclusively. (cast bullets)

I made the throat just long enough to be able to seat my longest cast bullet so that it doesn't go beyond the base of the neck. I don't believe I could even come close to chambering a factory 303 cartridge regardless if it had jacketed or cast bullets loaded up.

Next I'll have to do something about the less than optimum trigger on this old rifle. I've been looking into making up my own replacement trigger along the lines of the Huber Concepts aftermarket triggers but, that's a topic that belongs in another section of the gun smithing tips and tricks.

I've been looking for a close up picture of the correct trigger so I can see exactly how it's machined; then I can make my own.

It was good to hear from you.

HollowPoint