.303 chamber problem?
- Thread starter lledwod
- Start date
I enlarged your photo and it looks like brass that flowed forward into the throat from the mouth of the case.
Is what we see case brass or bullet jacket at the mouth of the case?
I'm wondering if you have a hard carbon ring that isn't allowing the mouth of the case to expand causing the brass to flow forward.
My second guess would be the same as Ganderite and the cases need trimed.
You could give the chamber a good scrubbing in the throat area and also try several applications of foam bore cleaner in the bore and chamber. The foam bore cleaner will remove any copper and carbon with little to no scrubbing.
Is what we see case brass or bullet jacket at the mouth of the case?
I'm wondering if you have a hard carbon ring that isn't allowing the mouth of the case to expand causing the brass to flow forward.
My second guess would be the same as Ganderite and the cases need trimed.
You could give the chamber a good scrubbing in the throat area and also try several applications of foam bore cleaner in the bore and chamber. The foam bore cleaner will remove any copper and carbon with little to no scrubbing.
The shoulder on the fired case looks odd as well, like it is shortened/compressed. To me it looks like the shoulder and neck are both flowing forward. As the others have asked, is that brass from the case or the bullet jacket? Looks like the neck case. Need more pics from different angles and some measurements as well; measurements of the neck before and after firing. It looks like the neck is larger on the fired case as well but that could just be an optical illusion. Does the ammo go into battery properly or does the bolt have to be forced? If it goes in easily then indications are that the throat and shoulder area of the chamber are quite possibly worn out from aggressive cleaning and/or use.
1873shootist
Regular
It looks possible that the case is expanding and stretching to fill the chamber shoulder area and that the neck is extruding into the chamber
An oversize chamber?
Just a guess. I've never seen anything like this before.
An oversize chamber?
Just a guess. I've never seen anything like this before.
To me it appears you may have an improved chamber of some kind, the shoulder angle is much steeper than a standard .303 British, in which case you will need a chamber cast to see what you actually have. How long have you had this rifle and do you get the same results with other ammo?
In 1914 the military Enfield chambers were reamed larger in diameter and longer to the shoulder location. The excuse given was the dirt and mud of trench WWI warfare but the real reason was poorly made .303 ammunition and the scandal of who was awarded the contracts to make it. The cordite powder was placed in the case "before" the case shoulder and neck were formed. And the location of the case shoulder was not critical because it was a rimmed cartridge. And the problem was some of the cases were so poorly made they did not chamber reliably.
Below in the top photo is South African .303 British case in a Wilson case gauge and the shoulder location meets SAAMI standards. In the bottom photo is a brand new unfired Remington .303 case and it would have dropped further into the gauge but was stopped by the rim.
Below the fired South African .303 British in the same Wilson case gauge. The amount the case is sticking above the gauge is how much longer the chamber was on the military Enfield chamber.
Below on the left a unfired Remington case and to the right of this case a once fired case. And on the far right a .303 case that was full length resized twice and started to separate.
The funny ring on the case mouth is
Case material, not from the bullet.
The neck on the unfired cartridge measures
.334" about 1/8" back from the mouth.
The fired cases measure about .343"
at about the same point. The rifle is new
to me. I fired 5 rounds and have no other
ammunition to try at this time. I will try
cleaning it!
Case material, not from the bullet.
The neck on the unfired cartridge measures
.334" about 1/8" back from the mouth.
The fired cases measure about .343"
at about the same point. The rifle is new
to me. I fired 5 rounds and have no other
ammunition to try at this time. I will try
cleaning it!
Rayleigh_Scattering
Regular
- Location
- Under the arch
The oxide band on new brass that I have bought is -exactly- in the same place on every unit.
Looking at that first photo, you would have to displace the right side case down about 1mm for the oxide bands to line up. That means that the top of the raggedy band is the top line of the original brass.
Rather than a bit having been extruded, I read this as the last part of the neck having been pushed in when chambering, and the friction of the passing pullet then tearing at it. The neck is soft, and the little-ridgy-ring-whose-name-I-forget gives it space to move into. The fatter bum of the bullet moving up then tears off the crimped in piece of the neck.
The root cause could be just a chamfer of hardened shmutz in the corner where the case neck usually sits.
Or I'm reading too much into the oxide band.
Looking at that first photo, you would have to displace the right side case down about 1mm for the oxide bands to line up. That means that the top of the raggedy band is the top line of the original brass.
Rather than a bit having been extruded, I read this as the last part of the neck having been pushed in when chambering, and the friction of the passing pullet then tearing at it. The neck is soft, and the little-ridgy-ring-whose-name-I-forget gives it space to move into. The fatter bum of the bullet moving up then tears off the crimped in piece of the neck.
The root cause could be just a chamfer of hardened shmutz in the corner where the case neck usually sits.
Or I'm reading too much into the oxide band.
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Rayleigh_Scattering
Regular
- Location
- Under the arch
>oxide band...transition between from the annealed portion
Yup.
>no resistance
With a dead soft neck and a gentle taper I'd still expect you'd notice some resistance, even with the ####-on-closing force to mask it. I may be completely off the mark.
It's easy to check for if you colour the neck of a new round with a sharpie, chamber it, eject it, and see if the ink is scraped off anywhere.
And the neck moved up a bunch, but who cares. Neck resize and keep brass with a single rifle, and your golden.
Yup.
>no resistance
With a dead soft neck and a gentle taper I'd still expect you'd notice some resistance, even with the ####-on-closing force to mask it. I may be completely off the mark.
It's easy to check for if you colour the neck of a new round with a sharpie, chamber it, eject it, and see if the ink is scraped off anywhere.
And the neck moved up a bunch, but who cares. Neck resize and keep brass with a single rifle, and your golden.
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What I pictured is from a military chamber and I do not know if the sporterized Enfield had the barrel set back and rechambered as part of being sporterized.
This is why my first guess is a carbon ring from firing in the end of the chambers neck that was never removed.
Think of firing .38 Specials in a .357 chamber and the carbon ring that forms and makes the .357 cases hard to chamber.
subliminal suggestion
"BUT" many things could be causing the problem, thin case rims, cases longer than specifications, or a carbon buildup. (read the links below)
Carbon Ring
http://benchrest.com/showthread.php?82146-Carbon-Ring
Barrel Cleaning Procedures
http://www.accurateshooter.com/technical-articles/barrel-cleaning-debate/
Break-Free Bore Cleaning Foam (subliminal suggestion)
Break-Free's Carbon Cutter was specially formulated to remove copper and carbon buildup from your firearm. (with no brushing)
NOTE: The British military after firing their Enfield rifles would pore at least 2 pints of boiling water down the bore. This removed all the corrosive salts from the primers "and" the carbon from the chamber, throat and bore.
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I cleaned the bore as thoroughly as I was able with the materials on hand. 2 kinds of copper remover and a powder solvent. The bore looked good before I started, and was not terribly dirty. The bore looks great to me, clean. I tried to take a photo of the chamber but I find this is never easy. I will try firing it again today. The patch in the photo in the body section of the chamber is a patch of corrosion that appears to my eyes to be fairly innocent?
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On your first picture, did the two case heads rest on the same surface? The fired one looks like it was too long.
Some .303 sporters had their barrels shortened in order to give the chamber more decent dimensions. Sometimes the "smith" forgot to check and fix OAL.
Did your gun come from France by any chance (Proof Marks...)? The .303 caliber was restricted there until recently and many shops would shorten barrels by one thread to convert them to .303 Sporting. Often regular ammo could still be chambered and your kind of problems wouldn't be surprising then.
Some .303 sporters had their barrels shortened in order to give the chamber more decent dimensions. Sometimes the "smith" forgot to check and fix OAL.
Did your gun come from France by any chance (Proof Marks...)? The .303 caliber was restricted there until recently and many shops would shorten barrels by one thread to convert them to .303 Sporting. Often regular ammo could still be chambered and your kind of problems wouldn't be surprising then.
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