Chamber Ringing 30-06 Alliant 2400

[paborn]

I remember reading of someone who wanted documented cases of chamber ringing, so here is my story.

I've shot about 7,000 rounds of Lyman 311284 GC at 210 grains out of a Winchester 70 XTR 30-06 over 20 grains of Alliant 2400 using WLR primers. This load shot under 2 inches at 100 yards without any filler, but got more consistent velocity and accuracy of close to an inch with a dacron filler. I'd always heard about chamber ringing, but never thought it would be a problem.

I started loading a Lee/Harris 155 grain in 7.62x39 and thought I'd try light loads in my 30-06. Loaded 20 each of 20 and 25 grains of Alliant 2400. Dacron was use to keep the powder down on the primer. Imagine my surprise when both loads printed 1.2 inches at 100 yards. The 20 grain load was at 1780 fps. Extraction was a little sticky, especially with the 25 grain loads. Both of these loads are well under max based on Lyman's Cast Bullet Handbook. I also loaded some of my standard 311284 loads.

Again imagine my surprise when close examination of the cases showed a 0.0015 expansion ring just where the base of the bullet would be, hence the cause of the sticky extraction. This was definitely from the Lee bullet loads, as the many prior Lyman loads were all seated to the juncture of the case neck. Case ringing occurred from firing 40 loads, and I believe the 25 grain load was the primary culprit.

I tried to think what I did different, if anything, with these loads. What I came up with is that for these loads I used a pencil to push the small tuft of dacron into the case, and reversed the pencil and used the eraser end to push the dacron down onto the powder. In the past I'd used a smaller diameter rod and I thought left the dacron looser.

Since I loaded the 311284 loads the same way, I took a second, closer look at a brass case after firing a Sierra 165 grain BT hunting load with 58 grains of IMR 4350. I figured the higher pressure would let the brass flow in any rings and show up better.

Lo and behold, as well as a 0.0015 ring where the base of the Lee bullet was, there was also a slight ring where the base of the Lyman bullet would be.

What I take from this is that as long as the dacron was loose and filled the airspace under the bullet, I was OK, but when I tamped the dacron down onto the powder and left an airspace between the tamped dacron and the bullet base I caused the ringing.

To repeat, it only took 40 rounds to ring the middle of the neck in the chamber with the Lee load, Personally, with the sticky extraction, I think it took less than that.

Well, as I like the rifle and the barrel as I've put good open sights on it to use with quick release scope mounts, I'm going to get it rebored to 35 Whelen.

Just talked to Jesse Occumpaugh at JES Rifle Reboring, and I can get the rifle rebored to 35 caliber and the neck and throat recut for the reasonable price of $225.

Guess I need a new 30-06.

Paborn

[49willys]

I did the very same thing to an all matching Winchester made 1917 American Enfield.Using unique powder.That hurt.

[Larry Gibson]

I tried to think what I did different, if anything, with these loads. What I came up with is that for these loads I used a pencil to push the small tuft of dacron into the case, and reversed the pencil and used the eraser end to push the dacron down onto the powder. In the past I'd used a smaller diameter rod and I thought left the dacron looser.

paborn

The mistake is bold high lighted. You in essence were not using the Dacron as a filler but as a wad. Many of us who espouse the use of the Dacron filler definitely caution against the use of Dacron as a wad. The faster burning powder under the Dacron as a wad left a lot of airspace between the Dacron and the base of the bullet. That is not then a filler (even though one particular member here will probably, once again, argue the semantics). Fact is, that was a wad and not a filler.

Thank you for posting and for your honesty with what you actually did in the post. It provides very useful information for use as a warning against the use of a wad, be it Dacron or any thing else. The fact that you fired so many rounds w/o problem using an even heavier cast bullet, the same powder and an actual Dacron filler w/o any problems and better accuracy also provides us with valuable insight. Sorry about the barrel though.

Larry Gibson

[Larry Gibson]

I did the very same thing to an all matching Winchester made 1917 American Enfield.Using unique powder.That hurt.

When using Unique powder and other such faster burning powders a filler is not needed nor recommended and a wad is certainly not recommended of Dacron or any other material.

Larry Gibson

[runfiverun]

I remember reading of someone who wanted documented cases of chamber ringing, so here is my story.


What I take from this is that as long as the dacron was loose and filled the airspace under the bullet, I was OK, but when I tamped the dacron down onto the powder and left an airspace between the tamped dacron and the bullet base I caused the ringing.

Paborn

one done this way is enough.

[Outpost75]

When I went through Ruger armorer's school in the 1980s, Joe Wallace in Customer Service had a huge pile sectioned, poulled off barrels with ringed chambers which would fill an outhouse. The majority were .45-70s, many of them having MULTIPLE chamber rings where people had tried various cast loads and you could tell where the bullet bases of 300, 330, 350, 405 and 500 grain bullets had been......

That was educational for me and I never used a filler in a cast bullet load again!

[waksupi]

I think when you do this, you are having a minor secondary explosive effect (SEE) situation. Enough to cause a bulge, just not enough to totally take the rifle apart. Thanks for sharing, sorry you learned it with a favorite rifle.

[tomme boy]

I did a 8x57 Mauser about 15 years ago. Using blue dot and jacketed bullets. 17 gr BD and a 154gr FMJ. It ringed the chamber about 1/4" in front of the base of the shell.

[Outpost75]

They actually had chamber ringing occur in .30-'06 Ball M2 ammo which was loaded with WC852 (AKA H380) powder.

No filler here, but the powder charge left alot of airspace in the case, and in Ball M2 the base of the bullet is well up in the neck, and chambered were ringed right where the bullet case was.

This didn't cause any functional problems in the M1 rifle or in Browning machineguns, but could be seen on fired brass. The Army never presumed it to be a safety problem but the DCM offered free arsenal replacement of barrels with ringed chambers, and I got an M1 rebarreled at Camp Perry in 1967 thanks to the whining technical experts at NRA who publicized this problem. Thank you Col. E.H. Harrison!

I still have a bunch of SL52 Ball of that lot.......

[Buzzard II]

This deserves to be a sticky! Great info, too bad it came at great expense!

[Wayne Smith]

I think when you do this, you are having a minor secondary explosive effect (SEE) situation. Enough to cause a bulge, just not enough to totally take the rifle apart. Thanks for sharing, sorry you learned it with a favorite rifle.

Not necessary, Ric. The compression of the air in the air space is adequate to do this. It works just like an obstructed barrel. It's not the impact with the obstruction that rings the barrel, or buldges it. It is the compression of the air between the two that does it.

[1Shirt]

Agree that this ought to be a sticky. Also as usual agree with Larry Gibson. I have used dac fill with 2400 and slower powders for years, and will continue to do so. A small amount goes a long way, and the factor of fill vs/wad as Larry points out is the issue. Found the post by Outpost quite interesting, as I had never run across that before.
1Shirt!

[waksupi]

Not necessary, Ric. The compression of the air in the air space is adequate to do this. It works just like an obstructed barrel. It's not the impact with the obstruction that rings the barrel, or buldges it. It is the compression of the air between the two that does it.

Yes, that's the way I see it, as the projectile acting as the obstruction due to the air space.

[john hayslip]

I have a relined 32-20 Remington Hepburn that I was breech seating and using cork over the load which I don't remember but it wasn't hot. It ringed the chamber.
Ross Seyfreid writing in Handloader years ago said never use less than about 10 grains of Dacron or you might regret it.

[dverna]

Very good thread. My preference is to avoid using a filler if at all possible. But if needed, this has been a good "wake up" call.

Thanks,

Don Verna

[303Guy]

Ross Seyfreid writing in Handloader years ago said never use less than about 10 grains of Dacron or you might regret it.That's interesting. It has stated many times and others have agreed that less then one grain is all that is required. In fact, ½ gr is what is recommended. I use a little more than that, about ¾ gr. But then the 303 Brit is a smaller case - the same volume as the 308.

Anyway, I've experienced pressure in the neck using Shotgun powder. No ringing but the neck was expanded into rust pits in the neck area of the chamber, jamming the case. Primer flattening was mild.

[LynC2]

I have a relined 32-20 Remington Hepburn that I was breech seating and using cork over the load which I don't remember but it wasn't hot. It ringed the chamber.
Ross Seyfreid writing in Handloader years ago said never use less than about 10 grains of Dacron or you might regret it.

Wow, is that # correct? That much would make a small throw pillow! ;-)

[shredder]

Wow, is that # correct? That much would make a small throw pillow! ;-)

I agree. I read that article as well so I went back to find it. Still looking through the pile..... 10 grains is enough to fill a couple of .470 cases. 1/2 to 1 grain pinch is more like it.