The case neck will never be jammed onto the lands, that's just not possible,sorry. You will never see rifling engraved on the case mouth...........JJEEEEZZZZEEE. There is a part to all chamber reamers ahead of the case mouth cut called a leade which, even with no freebore still cuts the rifling away at a taper so the bullet isn't jammed into the sharp rifling ends at the case mouth. Most chambers are also cut .010" over max case length listed in the books to prevent exactly this from happening and military chambers are even more generous, allowing for extra variances in ammo produced during wartime. I can tell you with 99% assurety that the case mouths are not being jammed into the leade. The reason the sooted cases are more difficult to extract is because of the soot and crap between the cases and the chamber walls. Excess pressure is not the culprit here, a lack of it for what ever reason that may be, is.
Never Assume
- Thread starter Airbob10
- Start date
It is possible, just incredibly unlikely unless something was terribly wrong. If the chamber was cut properly with a proper reamer on the proper equipment and within the proper tolerances and the shooter is using proper brass, it will never happen. I have however had some pretty terrible wartime rifles with terrible chambers that would allow the neck to be jammed into the throat or leade if it was long enough. Since we're talking about a wartime Arisaka that might or might not be a "last ditch" type rifle, I wouldn't assume much in terms of it's manufacture being "proper".
I do 100% agree that in this specific situation, that is not happening, but it is possible with some really bad rifles with terrible chambers. Again, these are not the symptoms of that.
http://i.imgur.com/q7mYCnK.jpg
Here are 3 cases with soot on them. The first 2 are where I felt blow back. There are no marks on the cases other than soot. I fired 15 rounds, and the other 12 cases have very little soot on them.
This is not a last ditch rifle. It is a Toyo Kogyo Series 32. It is all matching other than the firing pin and extractor. I did fire 5 Norma bullets 7.7 Jap 174gr that I bought from Ellwood Epp's, but I only had issues on the ones I had loaded.
I believe it is the lack of pressure causing the blow back. I was using new PRVI cases and .311 PRVI projectiles. I am going to try my new Norma cases (prep them first) with .312 Hornady projectiles. I am going to try different powders, H4895 or IMR3031 (I use this one for my .303 Lee Enfield). I will load closer to the max and let see what happens. I will also weigh each each powder charge to ensure that I have the right amount of powder.
I don't think it is a head space issue because the cases look good after firing. We had to go through quite a few #3 heads on my 303 before we found the right on to pass the no go gauge. The cases were bulged or had rings close to the bottom of the case. Even had a case separation with the 303. The Arisaka cases were fine.
I think it was really an issue with not taking my time prepping the cases, weighing the powder charge and doing it right. Operator error...
Here are 3 cases with soot on them. The first 2 are where I felt blow back. There are no marks on the cases other than soot. I fired 15 rounds, and the other 12 cases have very little soot on them.
This is not a last ditch rifle. It is a Toyo Kogyo Series 32. It is all matching other than the firing pin and extractor. I did fire 5 Norma bullets 7.7 Jap 174gr that I bought from Ellwood Epp's, but I only had issues on the ones I had loaded.
I believe it is the lack of pressure causing the blow back. I was using new PRVI cases and .311 PRVI projectiles. I am going to try my new Norma cases (prep them first) with .312 Hornady projectiles. I am going to try different powders, H4895 or IMR3031 (I use this one for my .303 Lee Enfield). I will load closer to the max and let see what happens. I will also weigh each each powder charge to ensure that I have the right amount of powder.
I don't think it is a head space issue because the cases look good after firing. We had to go through quite a few #3 heads on my 303 before we found the right on to pass the no go gauge. The cases were bulged or had rings close to the bottom of the case. Even had a case separation with the 303. The Arisaka cases were fine.
I think it was really an issue with not taking my time prepping the cases, weighing the powder charge and doing it right. Operator error...
The load you're using shouldn't be sooting up the cases that badly; it's a moderate-strong load. My guess would be overly hard Prvi cases. Have you ever annealed cases before? It isn't too difficult once you get the hang of it. Just remember to stop heating when they turn blue; if they glow cherry red they are overannealed and will be too soft. Cases that are too soft can stretch more than normal and can also collapse when seating the bullet.
No I haven't, and I will give it a shot. Do you think it might have been the fact of hard cases, as well I was using .311 boat tail projectiles that might of caused the soot? The min OAL is pretty long and bullet doesn't seat that deep.
Thoughts?
Thoughts?
It would have to be pretty hard to not seal with the load you mentioned so it could be multiple factors.
The bullets shouldn't have made that big of a difference unless you have a terribly oversized chamber. Have you ever slugged the bore or throat? (hammer a soft lead ball through it and mic it when it comes out)
I generally ignore published OAL's. If there's a cannalure, I seat to that if it's reasonable. If there isn't I seat as far as I can so it fits in the magazine and cycles but leaving at least a bullet diameter of shank in the neck.
The bullets shouldn't have made that big of a difference unless you have a terribly oversized chamber. Have you ever slugged the bore or throat? (hammer a soft lead ball through it and mic it when it comes out)
I generally ignore published OAL's. If there's a cannalure, I seat to that if it's reasonable. If there isn't I seat as far as I can so it fits in the magazine and cycles but leaving at least a bullet diameter of shank in the neck.
