NO 4 headspace issues

icehunter121

icehunter121

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Picked up a sporter from a gun show a few weeks back and I think it has head space issues. 2 out of 3 cases split( x fired brass but it may be the brass) It has a #2 bolt head on it and I have different ones laying around I dug up. Which way does a fella go to tighten it up? I am trying to find a headspace gauge right now but may have to order one in. Or may have to order all 3 of them to have a set sitting here. Nearest gunsmith to me is 4 hours and he may not even have gauges for the ol 303. Advice is needed!!
 
Lee Enfield 303's are notoriously hard on brass. Without a "field" headspace gauge, it is difficult to say that "headspace" is actually the problem. They were never designed or intended for reloads. Typically, the chambers are much longer/larger than the original brass. You can probably see that the shoulder on the fired case is further forward than on an unfired case. If the reloader than "full sizes", which pushes the shoulder back to where it started, the next firing simply repeats. That process is stretching brass from the case head towards the neck, thinning the case walls. In as few as 1 or 2 re-loads, the case head breaks off, with the body stuck in the chamber. I assume, here, that when you say "split", you meant case head separated from the body of the case? The solution is to neck size; even better when combined with the "o-ring" trick on the very first firing of the new case.

If by "split", you are referring to a longitudinal crack in the neck, then the brass needs to be annealed - it is work hardened or age hardened, and needs to be softened. Nothing whatsoever to do with headspace.
 
Just to clarify - unlike the rimless cases that are way more common these days, the headspace set-up for the rimmed 303 British is about the clearance between the bolt face and the rear of the barrel face for appropriate clearance for the cartridge rim only. The gauge set for 303 British is essentially a set of "discs" with short body stubs on them - the set I have here are marked .064"; .069" and .074". So long as the bolt closes on GO (.064") and does not close on FIELD (.074"), the headspace is within spec. Unlike rimless cases, "adjusting" the headspace on a Lee Enfield does very little regarding the case fit in the usually oversize chamber. And, Britain, Canada, Australia and C.I.P. each had similar, but not identical, "standards" for headspacing dimensions for 303 British cartridge. The .074" as FIELD seems to be consistent (except for C.I.P. which does not have FIELD standards).
 
Over the years I've checked Headspace on a large number of LE's and found it out of spec on only one. Try a few rounds of some brand new PRVI in it and see if the brass shows problems. If you get gauges and find excess headspace you'll need to find a bolt head that is longer but also clocks correctly when screwed into the bolt body. Simply buying one (or two) that are a higher number than the current one doesn't guarantee you'll find one that works. There is considerable overlap in dimensions amongst the stamped "size". For example I have 3's that are shorter than 2's and 1's that are longer than 2's. You'll need to measure the length of your current head and advertise for longer examples and then hope one will give the correct overturn. Not impossible but ideally one has a big variety of heads to try.

milsurpo
 
A "cheap" way to get a dimension. Take a de-primed case and measure it's length from headstamp to mouth with a calliper. Partially insert a fired primer into the primer pocket - just use your fingers - you don't want to seat it all the way. Insert that case into the chamber and close the bolt - the bolt will push the primer in a bit more, and also make the leading edge of the rim contact its seat in the barrel. Carefully extract that case. The primer will probably be protruding a bit. Now measure the over-all length from the protruding primer to that case's mouth. The difference between the two measurements is the "air gap" that exists when the case is chambered. Add that "air gap" dimension to the thickness of that cartridge rim, and you will have your "headspace" dimension for that bolt and barrel. Repeat several times to be more certain. Not my original idea at all - have read it several times in books and on internet forums.
 
Wild West in West Edmonton Mall and Tier One Armoury in Edmonton have very good gunsmiths. They will be able to help you out.
 
Potashminer said:
A "cheap" way to get a dimension. Take a de-primed case and measure it's length from headstamp to mouth with a calliper. Partially insert a fired primer into the primer pocket - just use your fingers - you don't want to seat it all the way. Insert that case into the chamber and close the bolt - the bolt will push the primer in a bit more, and also make the leading edge of the rim contact its seat in the barrel. Carefully extract that case. The primer will probably be protruding a bit. Now measure the over-all length from the protruding primer to that case's mouth. The difference between the two measurements is the "air gap" that exists when the case is chambered. Add that "air gap" dimension to the thickness of that cartridge rim, and you will have your "headspace" dimension for that bolt and barrel. Repeat several times to be more certain. Not my original idea at all - have read it several times in books and on internet forums.
Click to expand...

I've done this before. It worked nicely, at least for me.
 
Potashminer said:
Lee Enfield 303's are notoriously hard on brass. Without a "field" headspace gauge, it is difficult to say that "headspace" is actually the problem. They were never designed or intended for reloads. Typically, the chambers are much longer/larger than the original brass. You can probably see that the shoulder on the fired case is further forward than on an unfired case. If the reloader than "full sizes", which pushes the shoulder back to where it started, the next firing simply repeats. That process is stretching brass from the case head towards the neck, thinning the case walls. In as few as 1 or 2 re-loads, the case head breaks off, with the body stuck in the chamber. I assume, here, that when you say "split", you meant case head separated from the body of the case? The solution is to neck size; even better when combined with the "o-ring" trick on the very first firing of the new case.

If by "split", you are referring to a longitudinal crack in the neck, then the brass needs to be annealed - it is work hardened or age hardened, and needs to be softened. Nothing whatsoever to do with headspace.
Click to expand...

Sorry I meant separation and not splitting. I was in a rush out the door for work this morning. I only have a couple of minutes to read the replies and then back to work.
 
Go here https://www.milsurps.com/showthread.php?t=16948 scroll down to the second frame and read the paper on cartridge headspace. That will help you understand what is going on and the proper way to fix a true headspace problem. As you will see, it very much is not just buying the next size bolt head and screwing it in. I agree with the posts above that you most likely don't have a headspace problem. In 45 years of collecting Lee Enfields and with about 60 sitting in the closet, I have yet to come across one with a headspace issue. Your problem is most likely the reloaded brass. Brass varies greatly by manufacturer. S&B has a bad reputation of being thin and only lasting a couple of reloads. HXP is the other end of the spectrum. If you are going to reload .303 it is crucial to segregate your brass by rifle and neck size only. Annealing the case mouth occasionally will extend the life of the brass. A separation just ahead of the rim is not necessarily an indication of excessive headspace. It is an indication of worn out brass. You can make a simple tool from a straightened paper clip with a short 90 degree bend at one end and use it to feel for a slight groove inside the case just forward of the rim. That lets you know that case is about finished. Or you can simply spend about $15 and buy a broken shell extractor and make sure it goes to the range with you. I've never had any undue excitement from a case separation. In fact you rarely know it has happened until you open the bolt and only find a rim where you were expecting a case.
 
Thanks for the replies guys..now a little addition to the story. I loaded up 10 rounds of a lighter load for testing purposes. I was testing for keyholing as I just picked up these 2 rifles. So with rifle number 1, I fired 5 rounds at 50 yards. no keyholeing and all brass came out easily with no sign of case head separation. Rifle number 2 was done the same for the same reason with the same brass out of the same bunch. Now 2 out of 3 came out with definite head separation immiment. I wouldn't be able to use them again. I have owned about 50 303"s in my life time and most were good with no problems,but this one just struck me as needing a head space check. Its one of those things that bother me and I want it checked out.

Yes I could buy some more new brass and fireform it and then neck size it only. I have been reloading for 35 years and know the routine. But it still will irk me!! I am doing this for my PH 303 that I picked up,hardly use it but it will still irk me!! Lotta irkin going on!! I have a NO1 mk111 on its way here and still want to pick up a jungle carbine. So for me to have a gauge or something sitting here is no biggie as it will get used again. When I bought the rifle in question I also got 7 boxes of ammo with it. Now there was about 20 rounds fired in total so I resized them. They were definitely tight to get resized. Headspace? Oversize chamber? Same rifle? Who knows??
 
Well - You were shooting resized brass. If you were a bit too zealous with the resizing, then you would promote case head separation. I think rimmed cases are vulnerable when combined with an oversize chamber. To this end, tightening up the rim headspace may not provide effective remedy against undersize brass "blowing out" in the chamber.
No need for fancy fireforming and neck sizing. Chances are, the brass fired in Number 1 rifle will chamber in Number 2 rifle. It has already been fireformed and can be pressed into service via neck sizing or partial resizing with your FL die. (A "loonie" gap between the bottom of the die and the shellholder usually does the job.)
Finally commercial brass generally has undersize rims to begin with. Meaning that some brass will be problematic in some rifles, and not in others....
 
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So what brass are you guys running in your rifles? Or are you just using new ammo? I live out in the middle of nowhere and shipping costs can be a killer and the next major center to me is a 4 hour drive.
 
The current fancy is to fire virgin brass with an O ring around the base of the case, essentially locking the rim in place. This reduces "blowout" to some degree, but also limits the amount of case expansion near the web. You can read up on this via the net. For me personally, the O ring trick is a relatively new fad, and I haven't had any opportunity to pursue this. I've been firing various commercial brass (Rem, Win) and partially resizing to my tightest chamber (P-14) such that the brass can be used in any of my 303's. Otherwise, one is reduced to segregating brass to a given rifle and neck sizing (PITA for someone like me).
I've had 3 firing/sizing cycles without issue.... As I have a fair amount of brass, I haven't had the need to push any further. I should point out that No4 rifles are the most prone to having the most oversize chambers - and I don't mean due to rim headspace.
 
Prvi partisan is pretty good brass, not to thin. The O ring will help hold the case against the bolt head so expansion occurs at the top of the body and neck saving the head from thinning out. A simple o-ring is a small hair elastic, double it around the case head and fire the round.

Some good posts Re: head separation in the reloading section:

https://www.canadiangunnutz.com/forum/showthread.php/1800063-303-brass-life

https://www.canadiangunnutz.com/forum/showthread.php/1780165-303-brit-case-head-separation-question
 
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